Servomex 1800-1900 Manual

Xendos 1800 SeriesSafe Area Oxygen Analyser

andXendos 1900 Series

Hazardous Area Oxygen Analyser

Service Manual

Reference: 01800/002B/1Order as Part No. 01800002B

Xendos 1800 and 1900 Series 1

WARNINGS, CAUTIONS AND NOTES

This publication includes WARNINGS, CAUTIONS AND NOTESwhich provide information relating to the following:

WARNINGS : Hazards which could result in personal injury ordeath.

CAUTIONS : Hazards which could result in equipment orproperty damage.

NOTES : Alert the user to pertinent facts and conditions.

WARNING

The electrical power used in this equipment is at a voltage highenough to endanger life. Servicing should only be performed bytrained personnel. Service training is available from Servomex.

Before carrying out servicing or repair the equipment should bedisconnected from the electrical power supply. Tests must be madeto ensure that disconnection is complete. Note that relay contacts maybe supplied from a separate source of electrical power.

It may be necessary to fault find with the electrical power connected.Where this is necessary extreme caution should be exercised.

The analyser may contain toxic, corrosive, flammable or asphyxiantgases. Vent the analyser to a safe area and flush with air beforecommencing work.

2 Xendos 1800 and 1900 Series

TABLE OF CONTENTS

1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.11.2 Service philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.11.3 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.21.4 Location of components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.31.5 Paramagnetic oxygen transducer . . . . . . . . . . . . . . . . . . . . . . . . . . 1.31.6 Analogue outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.31.7 Alarm relay outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.31.8 Switch mode power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.41.9 Sample gas requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.41.10 Overview of the service manual . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4

2 EQUIPMENT OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.12.1 Mechanical overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1

2.1.1 Xendos enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.22.1.2 Sample compartment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.22.1.3 Terminals compartment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.6

2.2 Electrical overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.122.2.1 Terminals PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.152.2.2 Protection Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.172.2.3 Housekeeping PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.17

2.3 Oxygen analyser overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.192.3.1 The Transducer module . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.192.3.2 Transducer control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.21

2.4 Electrical connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.222.5 Sample connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.23

2.5.1 1800 Series Sample conditions . . . . . . . . . . . . . . . . . . . . . 2.242.5.2 1900 Series Sample conditions . . . . . . . . . . . . . . . . . . . . . 2.25

2.6 Optional automatic flow control/filter assembly . . . . . . . . . . . . . . . 2.262.7 1800 Flow alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.282.8 1900 Flow Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.28

3 SPARES LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.13.1 Spares for the Xendos 1800 Series . . . . . . . . . . . . . . . . . . . . . . . . 3.13.2 Spares for the Xendos 1900 Series . . . . . . . . . . . . . . . . . . . . . . . . 3.3

4 FAULT FINDING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.14.2. Power Supply Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.14.3 Measurement faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3

4.3.1 Transducer faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.34.3.2 Noise faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.44.3.3 Stability faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.64.3.4 Flow faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8

4.4 Flow alarm faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.104.5 Relays malfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.11


4.6 Voltage output or current output malfunction . . . . . . . . . . . . . . . . 4.114.7 The range cannot be changed . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.114.8 The concentration set point alarm cannot be set . . . . . . . . . . . . . 4.124.9 Malfunction of the temperature controller . . . . . . . . . . . . . . . . . . . 4.12

5 PARTS REPLACEMENT PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . 5.15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.15.2 Terminals compartment cover (1800 Series) . . . . . . . . . . . . . . . . . 5.15.3 Flameproof terminals compartment cover (1900 Series) . . . . . . . . 5.45.4 Sample compartment hinged cover . . . . . . . . . . . . . . . . . . . . . . . . 5.75.5 Window replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.85.6 Replace optional AFCD filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.125.7 Display PCB removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 5.145.8 Housekeeping PCB removal and refitting . . . . . . . . . . . . . . . . . . . 5.165.9 Sampling options chassis removal and refitting . . . . . . . . . . . . . . 5.185.10 AFCD removal and replacement . . . . . . . . . . . . . . . . . . . . . . . . . . 5.265.11 Back pressure regulator removal and replacement . . . . . . . . . . . . 5.275.12 Flow alarm removal and replacement (1800) . . . . . . . . . . . . . . . . 5.285.13 Flow alarm pressure switch removal and replacement (1900) . . . 5.295.14 Sample pump removal and replacement . . . . . . . . . . . . . . . . . . . 5.305.15 Stainless steel pipework removal and replacement . . . . . . . . . . . 5.315.16 Transducer assembly removal and refitting . . . . . . . . . . . . . . . . . 5.315.17 Terminals PCB and power supply removal and refitting . . . . . . . . 5.335.18 Protection block module removal and refitting (1900 Series only) 5.355.19 1156A Paramagnetic transducer removal and replacement . . . . . 5.385.20 1158 Paramagnetic transducer removal and replacement . . . . . . 5.395.21 Replacement of measuring cell (1156A and 1158) . . . . . . . . . . . . 5.405.22 Housekeeping PCB link configuration . . . . . . . . . . . . . . . . . . . . . . 5.425.23 Operation of Output status (LK6) . . . . . . . . . . . . . . . . . . . . . . . . . 5.435.24 Transducer failure (1158) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.43

6 DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1


APPENDIX A DETAILED ANALYSER PERFORMANCE TESTING . . . . . A1A.1 Notes and conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A1A.2 Gas samples required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A1A.3 Sample system leak tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A2A.4 Preliminary adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A3A.5 Operating temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A3A.6 Range change indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A3A.7 Display calibration and coarse analyser calibration . . . . . . . . . . . . . A4A.8 Zero calibration and low alarm check . . . . . . . . . . . . . . . . . . . . . . . A4A.9 Span calibration and high alarm checks (earlier type) . . . . . . . . . . A5A.10 Span calibration and high alarm checks (later type) . . . . . . . . . . . . A6A.11 Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A7A.12 Flow alarm operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A7

APPENDIX B FULL ZERO AND SPAN ANALYSER SET UP . . . . . . . . . . B1B.1 ZERO SETUP PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . B1

B.1.1 Transducer 01156A with a 01800902A or a 018000912A displayPCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B1

B.1.2 Transducer 01156A with a 01800902 display PCB . . . . . . . B1B.1.3 Transducer 01158 with a 01800902A or a 018000912A display

PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B2B.1.4 Transducer 01158 with a 01800902 display PCB . . . . . . . . B2

B.2 SPAN SETUP PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . B2B.2.1 Transducer 01156A with a 01800902A or a 018000912A display

PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B2B.2.2 Transducer 01156A with a 01800902 display PCB . . . . . . . B3B.2.3 Transducer 01158 with a 01800902A or a 018000912A display

PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B4B.2.4 Transducer 01158 with a 01800902 display PCB . . . . . . . . B4

APPENDIX CPRODUCT ENHANCEMENT #1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C1

C.1 Summary of change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C1C.2 Details of change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C2

C.2.1 Terminals PCB update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C2C.2.2 Housekeeping PCB update . . . . . . . . . . . . . . . . . . . . . . . . . C3C.2.3 Xendos 1802 and 1902 transducer assembly modification . C3C.2.4 Corrosive sample pipework option . . . . . . . . . . . . . . . . . . . . C4C.2.5 Sample bypass option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C5

PRODUCT ENHANCEMENT #2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C7C.3 Summary of change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C7C.4 Details of change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C7

C.4.1 Terminals PCB update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C7C.4.2 Display PCB update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C7C.4.3 Transducer update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C7


LIST OF FIGURES

Figure 2.1 - The Xendos enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1Figure 2.2 - Sample compartment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3Figure 2.3 - Display panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5Figure 2.4 - Xendos 1800 Series mounting details . . . . . . . . . . . . . . . . . . . . . . . . 2.7Figure 2.5 - Xendos 1900 Series mounting details . . . . . . . . . . . . . . . . . . . . . . . . 2.9Figure 2.6 - Terminals compartment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.11Figure 2.7 - Xendos 1800 Series electrical block diagram (1156A Transducer) . 2.13Figure 2.8 - Xendos 1900 Series electrical block diagram (1156A Transducer) . 2.14Figure 2.9 - Terminals PCB (in situ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.16Figure 2.10 - Paramagnetic transducer - operating principle . . . . . . . . . . . . . . . 2.19Figure 2.11 - Automatic Flow Control Device . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.27Figure 5.1 - Terminals compartment cover removal (1800 Series) . . . . . . . . . . . . 5.3Figure 5.2 - Flameproof compartment cover removal (1900 Series) . . . . . . . . . . 5.5Figure 5.3 - Sample compartment hinged cover and display panel detail . . . . . . 5.9Figure 5.4 - Window replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.10Figure 5.5 - AFCD filter replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.13Figure 5.6 - Display PCB removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.15Figure 5.7 - Housekeeping PCB removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.17Figure 5.8 - Option assembly flow diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.19Figure 5.9 - Sampling options chassis removal (sheet 1 of 4) . . . . . . . . . . . . . . 5.21Figure 5.9 - Sampling options chassis removal (sheet 2 of 4) . . . . . . . . . . . . . . 5.22Figure 5.9 - Sampling options chassis removal (sheet 3 of 4) . . . . . . . . . . . . . . 5.23Figure 5.9 - Sampling options chassis removal (sheet 4 of 4) . . . . . . . . . . . . . . 5.24Figure 5.10 - Sampling options chassis detail . . . . . . . . . . . . . . . . . . . . . . . . . . 5.25Figure 5.11 - AFCD mounting detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.26Figure 5.12 - Back pressure regulator mounting detail . . . . . . . . . . . . . . . . . . . . 5.27Figure 5.13 - 1800 Flow alarm detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.28Figure 5.14 - 1900 Flow alarm pressure switch detail . . . . . . . . . . . . . . . . . . . . 5.29Figure 5.15 - Sample pump installation detail . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.30Figure 5.16 - Transducer assembly removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.32Figure 5.17 - Terminals PCB and switched mode power supply removal . . . . . 5.34Figure 5.18 - Protection assembly removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.36Figure 5.19 - 1156A Transducer assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.37Figure 5.20 - Cell replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.40Figure 5.21 - Mechanical zero (1156A only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.41Figure 5.22 - Link settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.44Figure A.1 Sample gas connection (sample pump option) . . . . . . . . . . . . . . . . . . A2Figure C.1 - Corrosive sample pipework option . . . . . . . . . . . . . . . . . . . . . . . . . . C4Figure C.2 - Corrosive sample bypass pipework option . . . . . . . . . . . . . . . . . . . . C5Figure C.3 - Stainless steel sample bypass pipework option . . . . . . . . . . . . . . . . C6


LIST OF TABLES

Table 2.1 Electrical connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.22Table 2.2 Xendos 1800 Series - Sample Condition Requirements . . . . . . . . . . 2.24Table 2.3 Xendos 1900 Series - Sample Gas Conditioning Requirement . . . . . 2.25Table 3.1 Xendos 1800 recommended spares list . . . . . . . . . . . . . . . . . . . . . . . . 3.1Table 3.2 Xendos 1800 comprehensive spares list . . . . . . . . . . . . . . . . . . . . . . . 3.3Table 4.1 Low voltage output at PL2 connector . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2Table 4.2 Power supply voltages on the Housekeeping PCB connector (TB1) . . 4.2Table 5.1 Housekeeping PCB link settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.42Table 6.1 Included drawings list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1

Xendos 1800 and1900 Series 1.1

1 INTRODUCTION

1.1 Introduction

NOTE

This manual refers to the following xendos 1800 and 1900 analysers;product numbers 1800A1, 1802A1, 1900A1, 1902A1, 1800A2, 1802A2,1900A2, 1902A2, 1800B1 and 1900B1. The general text in this manualrefers to all ten product numbers, except where specifically stated. Allanalysers with Serial Numbers less than 2500 are prior to analyserrelease 1800B1 and 1900B1 and use the transducers assemblies 01156A.Analysers with Serial Numbers greater than 2500 are analyser release1800B1 or 1900B1 and use transducers assemblies 01158. The analyserSerial Number is marked on the main identification label.

This manual contains essential information for the servicing of the ServomexXendos 1800 Series and 1900 Series Oxygen Analysers. Some componentsreferenced in this manual are specific to either the Xendos 1800 Series or theXendos 1900 Series. Where this is the case then this is highlighted in themanual text.

This service manual is intended for use by Servomex trained service personnel.The manual contains technical descriptions, fault diagnosis information, partsremoval, refitting and test instructions, tool and test equipment lists. Electricaldrawings are bound at the rear of this manual.

1.2 Service philosophy

WARNING

C All servicing should be referred to qualified personnel.

C Do not attempt to replace fuses or components on the protectionassembly or the intrinsic safety of the unit will be compromised(Xendos 1900 Series only).

Repairs to printed circuit boards are effected by module replacement.Component replacement is not recommended. The only exception to this is themains fuse on the Terminal PCB.

1.2 Xendos 1800 and 1900 Series

1.3 General description

The Xendos units are available in a number of versions based on the Servomexparamagnetic transducer. They are divided into two series of analysers as below.

C Xendos 1800 Series - safe area analyser

C Xendos 1900 Series - hazardous area analyser

The internal switched mode power supply on the ac inlet enables the unit to beinstalled anywhere in the world without modification to the internal wiring. (Note:sample pumps, where fitted, are voltage and frequency specific.)

CAUTION

On Xendos 1800 units fitted with the optional sample pump; the powersupply voltage and frequency is dictated by the sample pump type fitted.

Isolated (4 to 20 mA) and non-isolated (0 to 1 V dc) analogue output signalsallow the analyser to be connected to a chart recorder, data logger, PLC, PC,DCS or ESD system, as required.

The Xendos is designed for use in modern industrial environments withemphasis on durable, rugged construction, low cost of ownership, reliableperformance, simple operation and ease of service.

As standard the analysers are fitted with a stainless steel cell with viton pipework.

A number of optional features are available. These include the following:

C Back pressure regulator (1800 only)C Internal sample pump (1800 only)C Automatic flow control device (AFCD)C Flow alarmC Stainless steel pipe workC Solvent resistant cells and pipe workC 60l/hr cells, both solvent resistant and stainless steel C Enclosure purgeC Enclosure breather portC Flush panel mounting

Xendos 1800 and1900 Series 1.3

1.4 Location of components

The enclosure design provides ease of access to all internal components. Referto Section 5 for dismantling procedures.

1.5 Paramagnetic oxygen transducer

High purity oxygen measurements are made using a Servomex 1156A or 1158magneto-dynamic paramagnetic transducer. The measurement cell istemperature controlled at approximatly 40 C (50 C for 1156A transducers) too o

minimise the effects of ambient temperature variations on the accuracy ofmeasurement. The small internal volume and special gas flow characteristicsprovide fast response and minimal flow errors.

WARNING

The 1156A or 1158 paramagnetic transducer used in these analysers isdesigned for compatibility with intrinsically safe hazardous areaoperating requirements. Do not fit any alternative transducer variantwhen the analyser is intended for use in hazardous areas.

1.6 Analogue outputs

The analogue output signals measurement range can be configured, in earlieranalysers, to be one of two pre-selected values from 0 to 5, 10, 25, 50 and 100%oxygen. In later analysers an alternative set of pre-selected range values hasbeen supplied, where a 2.5% oxygen range has replaced the 50% range. Thepre-selected ranges are indicated by a label which is inserted in a window on thedisplay panel. It is Indicated that a particular range has been selected or hasbeen changed by means of a panel mounted LED and a volt-free relay output.

WARNING

The Xendos 1900 Series hazardous area analysers are not suitable foruse with oxygen enriched samples and should not be used for oxygenconcentrations exceeding 22%.

1.7 Alarm relay outputs

Oxygen concentration alarms are by means of two volt-free relay outputs and aLED on the control panel. The alarm outputs can be configured to be high or lowalarms by the user. The set point is adjustable over the range 0 to 100% oxygen.


WARNING

When used in hazardous atmospheres, at least one of the alarms mustbe configured as a HIGH alarm and be set at not more than 22% Oxygen.

1.8 Switch mode power supply

The internal switch mode power supply is designed to accept universal mainsvoltages from 100 to 240 V ± 10% ac, 50 to 60 Hz and is not affected by mainsvoltage selection. (see Caution on next page)

CAUTION

Note that if the optional internal sample pump is fitted (1800 only) theelectrical supply must be of the correct voltage and frequency for thesample pump fitted.

1.9 Sample gas requirements

The sample gas requirements will differ according to the options fitted. Refer toSection 2 for details.

1.10 Overview of the service manual

The various Sections of this service manual cover the following topics:

SECTION 2 Provides a mechanical and electrical overview. This shouldbe read to provide an overall understanding of theequipment before carrying out servicing operations.

SECTION 3 Lists the available spares.

SECTION 4 Describes fault finding procedures.

SECTION 5 Describes procedures to remove and replace parts.

SECTION 6 Electronic circuit diagrams.

APPENDIX A Provides a detailed performance test specification for theXendos 1800 and 1900 Series analysers based on thestandard factory test specification.

APPENDIX B Product enhancements and design changes.

1

2

Xendos 1800 and 1900 Series 2.1

1. Sample compartment (intrinsically safe for 1900 Series)2. Terminals compartment (flameproof for 1900 Series)

Figure 2.1 - The Xendos enclosure

2 EQUIPMENT OVERVIEW

2.1 Mechanical overview


2.1.1 Xendos enclosure

Refer to Figure 2.1.

The Xendos unit is housed in a epoxy painted one piece aluminiumcasting with two compartments. Sealed covers and appropriate cableglands (not supplied) make the compartments weatherproof (IP66 andNEMA 4X) and, in the case of the Xendos 1900 Series, the right handcompartment is flameproof and explosion proof.

The left hand compartment (1) houses the sample pipework, transducerassembly, control assembly, display panel and any factory fitted options.The right hand compartment (2) houses the electrical terminals PCB andswitched mode power supply. In the case of the Xendos 1900 Series theright hand compartment also houses the protection assembly.

2.1.2 Sample compartment

Refer to Figure 2.2

The left hand sample compartment has a hinged cover (9) secured by 4screws (6) and sealed by a Viton 'O' ring (7). A glass window (8) in thecover provides visual access to the display panel LCD, power LED, flowand oxygen alarm LEDs, sensitivity range LEDs and the range label.


1. IP65 gland 7. Viton ‘O’ ring2. Transducer assembly 8. Glass window3. Housekeeping PCB 9. Hinged access cover4. Display PCB 10. Interconnection cable5. Display panel 11. Transducer PCB6. Captive screws (4 off) used with 1156A

Figure 2.2 - Sample compartment


Refer to Figure 2.3

With the hinged cover open, access is given to the display panel includingSpan and Zero calibration presets (3, 2), the Alarm Set button (4) andAlarm set point potentiometers (5). Access is also given to the Rangeselect button (12). If the optional Automatic Flow Control Device (AFCD)is fitted, it will be necessary to check the sample filter (14) periodically toprevent it from becoming blocked (refer to Section 5.6).

The display panel is hinged on its left hand edge and secured by a pawllatch (9). With the display panel hinged open, access is given to thetransducer assembly and housekeeping PCB and any sample optionsfitted.

WARNING

To maintain the ingress protection (IP20) required by hazardousarea approval requirements the user must isolate the analyserfrom the electrical supply before opening the hinged display panelfor any reason.


1. Power On LED 8. Flow failure LED2. Set ZERO preset control 9. Pawl latch3. Set SPAN preset control 10. Alarm LED4. ALARM set button 11. Range label5. Alarm set point controls 12. Range selection button6. Alarm LEDs 13. Range LEDs7. Digital display 14. Sample filter

Figure 2.3 - Display panel


2.1.3 Terminals compartment

2.1.3.1 Xendos 1800 Series Version


The right hand terminals compartment has a lift off cover (4)secured by four screws (5)and sealed with a Viton 'O' ring. TheXendos 1800 is only suitable for installation in a safe, non-hazardous area and is not suitable for use with flammable samplegases.

The terminals compartment houses the terminals PCB and switchmode power supply.

Removal of the 4 screws and cover gives access to the terminalsPCB. Electrical cables fitted with suitable glands are fed throughthe appropriate entry holes (10) and wired to the terminals asshown in Figure 2.9. Any unused cable entries should be fittedwith appropriate blanking plugs.

Access to the switch mode power supply can be achieved afterdisconnecting and withdrawing the electrical connection cablesand removing the terminals PCB.


1. Captive M6 screw (4 off) 8. Sample outlet ¼" NPT2. LH hinged cover 9. Sample inlet ¼" NPT3. Display window 10. Cable entries ¾" NPT (3 off)4. RH cover 11. M6 earth terminal5. Captive M6 screw (4 off) 12. Breather ¼" NPT6. M8 mounting slot (4 off) 13. Purge inlet ¼" NPT (if used)7. Purge outlet ¼" NPT (if used)

Figure 2.4 - Xendos 1800 Series mounting details


2.1.3.2 Xendos 1900 Series version


The right hand flame proof/explosion proof terminals compartmenthas a threaded access cover (4) sealed with a Viton 'O' ring. Theenclosure is provided with three 3/4 inch NPT cable entryholes(10). These must be fitted with suitable certifiedflameproof/explosion proof cable entry devices. Unused cableentries must be closed by means of a suitable certifiedflameproof/explosion proof stopping plug.

When the threaded access cover (4) is fully engaged, the coverposition is locked via a M4 grub screw (5).


1. Captive M6 screw (4 off) 8. Sample outlet ¼" NPT2. LH hinged cover 9. Sample inlet ¼" NPT3. Display window 10. Cable entries ¾" NPT (3 off)4. RH threaded cover 11. M6 earth terminal5. M4 grub screw 12. Breather ¼" NPT6. M8 mounting slot (4 off) 13. Purge inlet ¼" NPT (if used)7. Purge outlet ¼" NPT (if used)

Figure 2.5 - Xendos 1900 Series mounting details



The interconnecting cable between the two compartments is fittedwith a flameproof/explosion proof gland (1). This cable is factoryfitted and is not user serviceable to ensure the integrity of theflameproof/explosion proof hazardous area approvals.

The terminals compartment houses the terminals PCB (8), switchmode power supply (3) and protection assembly (2).

Unscrewing the threaded cover (6) gives access to the terminalsPCB (8). Electrical cables fitted with suitable glands are fedthrough the appropriate entry holes and wired to the terminalsshown in Figure 2.9.

Access to the switch mode power supply (3) and protectionassembly (2) can be achieved after disconnecting and withdrawingthe electrical connection cables and removing the terminalsPCB(8).

WARNING

There are no serviceable items on the protection assembly.In the event of a fault condition, the entire assembly mustbe replaced. Do not attempt to replace fuses on theprotection assembly. Failure to follow this restriction mayinvalidate the intrinsically safe hazardous area approval.


1. Flame proof cable gland 6. Threaded access cover2. Protection assembly 7. User connections3. Power supply assembly 8. Terminals PCB4. Insulating cover 9. Interconnection cable5. ‘O’ ring

Figure 2.6 - Terminals compartment


2.2 Electrical overview

Refer to the electrical block diagrams Figures 2.7 and 2.8.

All the electrical components are mounted on printed circuit boardsinterconnected by ribbon cables. A 15-way screened cable communicatesbetween the sample and terminals compartments of the Xendos unit. Thecircuits are distributed between the two compartments as follows:

Terminals compartment

C Terminals PCBC Power supplyC Protection assembly (Xendos 1900 Series only). See Figure 2.8.

Sample compartment

C Housekeeping PCBC Display PCBC Paramagnetic transducer assembly including heater and transducer

control PCB.C Factory fitted sample options


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1. Range terminals 6. Output terminals (isolated)2. Flow alarm terminals 7. Electrical supply terminals3. Alarm 2 terminals 8. Output cable gland entry4. Alarm 1 terminals 9. Supply cable gland entry5. Output terminals (non-isolated) 10. Alarm cable gland entry

2.2.1 Terminals PCB


The Terminals PCB carries the following terminal blocks:

C TB-3 electrical supply mains inlet terminalsC TB-4 user analogue output terminalsC TB-2 user alarm relay terminals

Refer to the appropriate Circuit Diagram of the Terminals PCB. The a.c.mains supply at terminal block TB3 is applied to the switched modepower supply connector PL3 via the line fuse F1 and the EMC filter X1.The d.c. power rails from the power supply return on connector PL2. Thepower supply features overvoltage and short circuit protection withautomatic restart.

The auxiliary fused and filtered mains outlet at connector PL4 is used toprovide power to the optional sample pump on the Xendos 1800.Connector PL4 is not used on the Xendos 1900.

The voltage-free alarm relay changeover contacts are available at TB2 viaEMC filters: Alarm 1 at pins 1,2 and 3; Alarm 2 at pins 4, 5 and 6; optionalflow failure alarm at pins 7, 8 and 9; and range indication at pins 10, 11and 12.

The customer analogue outputs are available at TB4 via EMC filters. Allother input/outputs are via connector PL1.

The analogue signals are derived from the transducer signal at PL1 1,3.On the Xendos 1900 Series these signals are routed via the protectionassembly to maintain intrinsically safe conditions within the samplecompartment. The signal is filtered, buffered and output on TB4 (1, 2) asthe non-isolated analogue voltage output. The signal also goes via thethe isolated analogue output circuit, which includes zero and span setpotentiometers, to TB4 (3, 4).

The analyser heater control signal arriving at PL1 8 is fed to the powerswitching transistor to control the heater power.


Figure 2.9 - Terminals PCB (in situ)


The power rails used by other PCBs are given additional filtering on theTerminals PCB. The -5V rail is derived from the -12V rail. On the Xendos1900 Series these power rails are transmitted via the protection assemblyto limit the possible power dissipation within the intrinsically safe samplecompartment.

2.2.2 Protection Assembly

NOTE

The protection assembly is only used on the Xendos 1900 Series and isnot provided with the Xendos 1800 Series.

WARNING

There are no serviceable items on the protection assembly. In the eventof a fault condition, the entire assembly must be replaced. Do notattempt to replace fuses on the protection assembly. The protectionassembly is a pre-tested item which effects the safety approval status ofthe analyser. If necessary the complete assembly is available as areplacement.

The protection assembly ensures the intrinsic safety of the samplecompartment. The protection assembly contains twelve Zener shuntseach consisting of three Zener diodes, a current limiting resistor and aseries protection fuse.

Two Zener shunts are necessary to transmit the power required to heatthe transducer. Each shunt includes three Zener diodes and two powerresistors connected in series.

The remaining ten Zener shunts transmit the + 5 V and - 5 V power railsto the sample compartment and transmit the analogue and digital signalfrom the sample compartment to the terminals compartment.

2.2.3 Housekeeping PCB

The output signal from the paramagnetic transducer at PL2 (9,10) is fedthrough the filter network and the differential amplifier to the display toshow the Oxygen concentration. Links are provided to preset the twoanalogue output ranges. The analogue output range is selected by thepush-button Range switch on the Display PCB.

The two concentration alarms can be configured by the user to be highor low alarms by means of links LK1 and LK2. The momentary action


push-button Alarm Set on the Display PCB enables the alarm levels to bedisplayed. These are set using the multi-turn preset potentiometers onthe Display PCB. When Alarm Set button is pressed, the alarmconcentration is displayed and an LED indicates which alarm is to be set(1 or 2) and the configuration of the alarm (high or low).

The temperature control circuit is preset at approximately 40 C (50 C foro o

1156A transducers) so that the effect of ambient temperature changes onthe measurement cell is minimised.


1. Mirror 4. Amplifier2. Sample cell 5. Optical carrier3. Dumb-bell 6. Photocell assembly

Figure 2.10 - Paramagnetic transducer - operating principle

2.3 Oxygen analyser overview

2.3.1 The Transducer module


A physical property of Oxygen is that it is paramagnetic, which can beused to discriminate between it and most other common gases. That is,molecules of oxygen (unlike most other gasses) are weakly attracted intoa magnetic field. This characteristic is used in the Paramagnetictransducer to measure the concentration of oxygen in the sample gasmixture.


Two glass spheres, filled with an inert gas are fixed to the ends of a barto form a dumb-bell which is sealed (3). The sample gas surrounds thedumb-bell in the sample cell (2). The dumb-bell is suspended in asymmetrical but non-uniform magnetic field. The dumb-bell is slightlydiamagnetic so that it rotates by a few degrees to take up a position awayfrom the most intense part of the magnetic field.

If the sample gas contains oxygen, then the oxygen molecules will beattracted into the strongest part of the magnetic field increasing the gaspressure at this point. This pushes the dumb-bell further out of themagnetic field due to the relatively stronger force on the paramagneticoxygen. The magnitude of the torque acting on the dumb-bell will beproportional to the magnetic susceptibility of the surrounding gases andhence proportional to the oxygen concentration.

The paramagnetic transducer incorporates a strong rare metal, taut-bandsuspension mechanism which supports the dumb-bell (3). The 'zero'position of the dumb-bell is sensed by a photocell assembly (6) whichreceives light from a mirror (1) attached to the bar of the dumb-bell. Theoutput from the photocell is amplified (4) and fed back to a coil woundaround the dumb-bell so that the torque acting upon it due to thepresence of oxygen in the sample is balanced by an opposing torque dueto the feedback current in the coil.

This feedback current is directly proportional to the volume magneticsusceptibility of the sample gas and hence, after calibration, to the partialpressure of oxygen in the sample. A voltage output is derived which isproportional to the current. Linearity of scale is such that it is possible tocalibrate the instrument for all ranges by checking at two points only.

All materials in contact with the sample are highly resistant to aggressivesubstances. The internal design of the cell body has a special flowchannel to optimise the flow characteristics, while the internal volume iskept to a minimum to provide an excellent response time. The opticalcarrier (5) has provisions for adjustment of the photocell mount for settingthe initial zero and also incorporates the LED light source andtemperature sensing devices.


2.3.2 Transducer control

The control electronics on the transducer control PCB provide all of thefunctions necessary to provide operation of the transducer and to producean electrical output proportional to the partial pressure of oxygen. ThisPCB is mounted either externally to the transducer or on later versionsinternally.

The Transducer control PCB includes the following circuit functions:

C constant current sourceC signal amplification/conditioning C thermometer/signal circuitsC span temperature compensationC output signal conditioningC voltage referenceC zero temperature compensationC 'kick' circuitC negative supply

NOTE

The transducer module and its control PCB are supplied together.During factory test the control PCB is adjusted to compensate forthe zero temperature coefficient of the measuring cell. It is notpractical to perform this procedure in the field. The transducermodule and control PCB must therefore be replaced together atthe same time.


2.4 Electrical connections

All electrical connections are made to the terminals PCB inside the right handenclosure of the analyser (see figure 2.9). Full specifications are given in Table2.1. To gain access refer to Figure 5.2, slacken off the M4 grub screw whichlocks the cover and unscrew the cover with the aid of a bar if needed. The coverthread is pre-greased and no additional non-setting sealant is required. Afterelectrical connections are complete, ensure the threads are correctly aligned,screw the cover fully down and re-tighten the grub screw to lock the cover.

Table 2.1 Electrical connections

Power Connection Terminal

Electrical Power, Protective Earth TB-3 (1)100V to 240Vac ± 10%, Neutral TB-3 (2)50/60 Hz, 50VA maximum Live TB-3 (3)(Check sample pump voltage if fitted)

Alarm Connection Terminal

Alarm 1 Closes on Alarm 1 or Power Fail TB-2 (1)250Vac, 3A Opens on Alarm 1 or Power Fail TB-2 (2) 28Vdc, 1A Common TB-2 (3)

Alarm 2 Closes on Alarm 2 or Power Fail TB-2 (4)250Vac, 3A Opens on Alarm 2 or Power Fail TB-2 (5) 28Vdc, 1A Common TB-2 (6)

Flow Fail Alarm Closes on Flow Fail Alarm or Power Fail TB-2 (7)250Vac, 3A Opens on Flow Fail Alarm or Power Fail TB-2 (8) 28Vdc, 1A Common TB-2 (9)

Range Selected Output Connection Terminal

Range 2 selected Closes on Range 2 or Power Fail TB-2 (10)250Vac, 3A Opens on Range 2 or Power Fail TB-2 (11) 28Vdc, 1A Common TB-2 (12)

Analogue Output Signal Connection Terminal

0 to 1Vdc Oxygen output signal, + ve TB-4 (1)(non-isolated), output impedance 470 Ohms typical - ve TB-4 (2)

4 to 20 mA Oxygen output signal, + ve TB-4 (3)(isolated), maximum load impedance 600 Ohms - ve TB-4 (4)


2.5 Sample connections

WARNING

The sample and calibration gases may be toxic or asphyxiant. Verify thatconnections are leak free at full operating pressure before applyingsample and calibration gases.

Instrument vent gases may also be toxic. They should be vented into asuitable area.

Before performing any service operations, ensure that the samplesystem has been flushed with inert gas before opening sampleconnections. This is to prevent accidental exposure to toxic gases.

The Xendos 1800 Series are not suitable for operation with flammablegases.

CAUTION

Allow the analyser to warm up before admitting sample gas to preventcondensation of the sample in the measuring cell.

The sample gas must not exceed the specified pressure or flow rate ordamage can occur to the measuring cell.

When leak testing the system ensure that the pressure is increased anddecreased slowly. High internal flow rates when pressure is changedrapidly will damage the measuring cell.

The sample port locations and sizes are given in Figures 2.4 and 2.5. Thesample conditioning requirements are given in Tables 2.2 and 2.3.


2.5.1 1800 Series Sample conditions

Table 2.2 Xendos 1800 Series - Sample Condition Requirements

Sample Analyser Sample + BPRBase High-flow AFCD AFCD + AFCD

Pump

Inlet / OutletConnections

¼” NPT female

InletPressure

Adjust Adjust 1 to 5 -0.03 to 1 17 to 22pressure / pressure / psig psig psia

flow flow 7 to 35 -0.2 to 7 119 to 154externally externally KPag KPag KPaa

Flow Rate 50 to 250 50 to 70l/hr 1.2 to 3.5 1.6 to 1.8 1 to 2 ml/min (601/hr nom.) l / min l / min l / min

Dew point Non-condensing at ambient temperature

Temperature -10°C to +50°C (+14°F to +122°F)

Particulates < 3Fm (micro metres)

Condition Clean, non-flammable *, non-corrosive ** and free from oil

* If the sample gas is flammable then use a Xendos 1900 Series

** Check compatibility of sample options if fitted before use with corrosive samples

AFCD - Automatic Flow Control Device BPR - Back Pressure Regulator

The optional sample pump, back pressure regulator and automatic flowcontrol device are not available for use with solvent resistant cells.

If the automatic flow control device option is fitted no external flow control isnecessary, the sample pressure must be between the limits specified in theabove table. If the automatic flow control device option is not fitted it will benecessary to regulate the sample pressure / flow within the limits specified in theabove table to ensure stable operation and to prevent damage to the measuringcell.

If an external sample pump is used it may be necessary to reduce pressurepulsing with a reservoir. The sample exhaust from the analyser should be ventedfreely to atmosphere. The sample inlet and outlet connection sizes and locationare shown in Figure 2.4.

If the optional flow alarm is fitted then the red flow alarm indicator will flash if thesample flow falls below a satisfactory level.


2.5.2 1900 Series Sample conditions

Table 2.3 Xendos 1900 Series - Sample Gas Conditioning Requirement

SampleBase Analyser High-flow Xendos 1900

Xendos 1900 Series with AFCD

Inlet / OutletConnections

¼” NPT female

Inlet Pressure Adjust pressure / flow Adjust pressure 1 to 5 psigexternally / flow externally 7 to 35 KPag

Flow Rate 50 to 250 ml/min 50 to 70l/hr 1.2 to 3.5 l / min(601/hr nom.)

Dew point Non-condensing at ambient temperature

Temperature -10EC to +50EC (+14EF to +122EF)

Particulates < 3Fm (micro metres)

Condition Clean, non-corrosive * and free from oil

* Check the compatibility of sample options if fitted before using with corrosivesamples or use the Xendos 1900 solvent resistant version.

AFCD - Automatic Flow Control Device

If the automatic flow control device option is fitted no external flow control isnecessary, the sample pressure must be between the limits specified in theabove table and/or Technical Data Sheet.

If the optional automatic flow control device option is not fitted, it will benecessary to regulate the sample pressure / flow within the limits specified in theabove table to ensure stable operation and to prevent damage to the measuringcell.

If an external sample pump is used it may be necessary to reduce pressurepulsing with a reservoir. The sample exhaust from the analyser should be ventedfreely to atmosphere. See Warning above for safety details.

If the optional flow alarm is fitted then the red flow alarm indicator will flash if thesample flow falls below a satisfactory level.

The sample inlet and outlet connection sizes and locations are shown in Figure2.5.


2.6 Optional automatic flow control/filter assembly


The optional AFCD is a combination filter/flow control device designed toprovide an approximately constant sample flow rate to the transducer for a widerange of inlet sample pressures.

The sample gas enters the AFCD through the gas inlet port (1). This port isfitted with an orifice restriction to limit the total sample flow. A 0.6Fm cylindricalfilter element (8) prevents particulate contamination of the transducer. A balland spring valve (4 and 5) generates a constant pressure difference between thesample outlet port (2) and the sample bypass port (3). The bypass port is fittedwith an orifice restriction to control the sample flow rate to the transducer.Excess sample gas is exhausted through the bypass port (3). If the optional flowalarm is fitted then the orifice restriction in the sample outlet port is omitted andthe separate orifice restriction included within the flow alarm hardware controlsthe sample flow to the transducer.

The spring tension is adjusted via the screw control (6). This is factory set andsealed. The transducer flow rate is adjusted by changing the diameter of theorifice restriction in the sample outlet port. The spring tension should only beadjusted in cases where the pressure pulsing on the outlet port results inexcessive noise on the measured concentration reported.

If the automatic flow control device is fitted, no external flow control is necessary.The sample pressure must be within the limits specified in Tables 2.2 and 2.3.The filter is not intended to provide primary sample conditioning but only toprovide backup protection for the transducer. It is recommended that the filter bereplaced at 3 monthly intervals. This period may be extended for clean samples.Refer to section 5.6 for removal and replacement instructions.

1

2

3

4

56

9

7

8

1. Sample inlet port 2. Sample outlet port3. Sample bypass port4. Ball valve5. Spring

6. Flow adjustment control7. Knurled sample filter cover8. Filter element9. AFCD body


Figure 2.11 - Automatic Flow Control Device


2.7 1800 Flow alarm

The optional low flow alarm for the Xendos 1800 (see Figure 5.8 E) is an integralunit which is inserted in the sample line to the transducer inlet. The flow alarmproduces an output if the sample flow falls below the preset value. The sampleflow is detected by measuring the pressure drop across an orifice restriction. Inthe Xendos 1800 flow alarm this pressure drop is measured using a differentialpressure switch. The orifice restriction and differential pressure switch areintegral to the flow alarm unit and are not user serviceable.

The flow alarm option is also available in conjunction with the AFCD, samplepump and back pressure regulator options (Figure 5.8 B, C and D).

2.8 1900 Flow Alarm

The optional flow alarm for the Xendos 1900 (see Figure 5.8 F) operates bymeasuring the pressure drop across an orifice restrictor in the sample line to thetransducer. In the Xendos 1900 this pressure drop is detected by two gaugepressure switches P1 and P2.

The Xendos 1900 flow alarm option is not available with the stainless steelpipework option and is not tolerant to solvent loaded samples.


3 SPARES LIST

The following spare patrs apply to the 1800B1 and 1900B1 analysers only (analyserwith serial numbers 2500 and above). For spare parts prior to these releases, see theoriginal Quickstart manuals supplied with the analyser.

3.1 Spares for the Xendos 1800 Series

WARNING

Xendos 1800 spares must be supplied by Servomex to comply with personnelsafety requirements and to maintain performance specification.

The following spares are required to maintain normal operation of the Xendos 1800analyser.

Part Description - xendos 1800 Series Recommended qty.Number

No. of analysers

1-2 3-5 6+

S1800986 Enclosure seals kit 1 1 1

S1800987 Fuse kit (F3.15A HBC) (10 off) 1 1 1

with AFCD fitted

S1800985 AFCD filter element kit (10 off) 1 2 2

The following spares are also available for the analyser.

Part Number Description - xendos 1800 Recommended qty.common parts No. of analysers

1-2 3-5 6+

S1800911 Housekeeping pcb complete 0 1 1

S1800902A 3.5 digit display pcb complete 0 1 1


S1800913C Terminals pcb complete 0 1 1

2822-2028 Switch mode power supply module 0 1 1

3950-6087 Anti-static glass window 0 0 1


Part Number Description - xendos 1800 Recommended qty.sample option - standard No. of analysers

1-2 3-5 6+

S1800966 Sample Inlet & Outlet Tubes (SS316) 0 0 1Kit

S1800981 Sample Flow Alarm (xendos 1800) 1 1 1

S1800989B Standard O Transducer Assy. 0 0 12

S1800967 Standard O Paramagnetic Cell 0 1 12

S1800982 Sample pump 240V 50Hz 0 1 1

S1800983 Sample pump 110V 50Hz 0 1 1

S1800984 Sample pump 110V 60Hz 0 1 1

S1800988 Back Pressure Regulator 0 1 1

00570915 AFCD for analysers without optional 0 1 1flow alarm

S1420935 AFCD for analysers fitted with optional 0 1 1flow alarm

Part Number Description - xendos 1800 Recommended qty.sample option - solvent resistant/high-

flow cellNo. of analysers

1-2 3-5 6+

S1802966 Sample Inlet & Outlet Tubes (Hastelloy C- 0 1 1276) Kit

S1802967 Solvent resistant O Paramagnetic Cell 0 1 12

S1804967 High-flow O Paramagnetic Cell 0 1 12

S1806967 Solvent resistant high-flow O 0 1 12

Paramagnetic Cell

S1802989B Solvent resistant O Transducer Assy. 0 0 12

S1804989B High-flow O Transducer Assy. 0 0 12

S1806989B Solvent resistant high-flow O Transducer 0 0 12

Assy.


3.2 Spares for the Xendos 1900 Series

WARNING

Xendos 1900 spares must be supplied by Servomex to comply with hazardousarea approvals, personnel safety requirements and to maintain performancespecification.

The following spares are required to maintain normal operation of the Xendos 1900analysers.

Part Description - xendos 1900 Series Recommended qty.Number

No. of analysers

1-2 3-5 6+

S1800986 Enclosure seals kit 1 1 1

S1800987 Fuse kit (F3.15A HBC) (10 off) 1 1 1

with AFCD fitted

S1800985 AFCD filter element kit (10 off) 1 2 2

The following spare items are also available for the analyser.

Part Number Description - xendos 1900 Recommended qty.common parts No. of analysers

1-2 3-5 6+

S1800911 Housekeeping pcb complete 0 1 1



S1800913C Terminals pcb complete 0 1 1

S1900995 IS Protection Block Module 0 1 1

2822-2028 Switch mode power supply module 0 1 1

3950-6087 Anti-static glass window 0 0 1


Part Number Description - xendos 1900 Recommended qty.sample option - standard No. of analysers

1-2 3-5 6+

S1800966 Sample Inlet & Outlet Tubes (SS316) Kit 0 0 1

S1800980 Sample Flow Alarm (xendos 1900) 1 1 1

S1800967 Standard O Paramagnetic Cell 0 1 12

S1800989B Standard O Transducer Assy. 0 0 12

00570915 AFCD for analysers without optional flow 0 1 1alarm

S1420935 AFCD for analysers fitted with optional flow 0 1 1alarm

Part Number Description - xendos 1900 Recommended qty.sample option - solvent resistant/high-

flow cellNo. of analysers

1-2 3-5 6+

S1802966 Sample Inlet & Outlet Tubes (Hastelloy C- 0 1 1276) Kit

S1802967 Solvent resistant O Paramagnetic Cell 0 1 12

S1804967 High-flow O Paramagnetic Cell 0 1 12

S1806967 Solvent resistant high-flow O 0 1 12

Paramagnetic Cell

S1802989B solvent resistant O Transducer Assy. 0 0 12

S1804989B high-flow O Transducer Assy. 0 0 12

S1806989B solvent resistant high-flow O Transducer 0 0 12

Assy.


4 FAULT FINDING

4.1 Introduction

This section is included as a guide to possible fault symptoms and theirdiagnosis and is not intended as a complete list of potential fault conditions.Because there are basically only four PCBs with active circuitry, the servicephilosophy is to diagnose any fault which is not immediately apparent bysubstituting PCBs until the fault is cleared.

WARNING

The electrical power used in this equipment is at a voltage high enoughto endanger life. Servicing should only be performed by trainedpersonnel.

It may be necessary to fault find with the electrical power connected.Where this is necessary extreme caution should be exercised.

The Xendos 1900 Series are designed for installation in potentiallyhazardous environments. Servicing of these analysers should bereferred to personnel trained in hazardous area operation. All serviceoperations should comply with local codes of practice.

4.2. Power Supply Failure

Symptoms:

Display panel without power (no LEDs or LCD illuminated).

Measurements and diagnosis

1. Check that the supply voltage is present on the TB3 terminals; TB3 pin 1is the live connection, TB3 pin 2 is the neutral connection and TB3 pin 3is the earth connection. If the supply voltage does not reach TB3, checkthe installation wiring, connections and any associated fuses. If the supplyvoltage at TB3 is satisfactory, proceed to the next point.

2. Check the mains fuse (F1) on the Terminals PCB and replace it ifnecessary. If the front panel display is still without power, proceed to thenext point.

3. Check the low voltage outputs from the power supply in accordance withthe Table 4.1.


Table 4.1 Low voltage output at PL2 connector

Pins of PL 2 connector Lower limit voltage Upper limit voltage

between pins 1 and 4 11.5 Volts 12.5 Volts

between pins 6 and 4 -11.5 Volts -12.5 Volts


These voltages can be measured on the Terminal board behind the label.

WARNING

Parts of the power supply are connected to the mains and mainssupply is also present on the Terminals board. It is necessary tofault find with the electrical power connected. Therefore extremecaution should be exercised.

PL2 is the row of pads at the top of the board and pin 1 is on the right. Ifany voltage is outside the limits stated in Table 4.1 replace the powersupply. If the voltages are still outside the limits the fault must beassumed to be on one of the four PCBs. Replace the PCBs in turn inorder to identify the faulty PCB. If the voltages are within the limits andthe display panel is still without power, proceed to the next point.

4. Check the power supply voltages on the Housekeeping PC in accordancewith Table 4.2:

Table 4.2 Power supply voltages on the Housekeeping PCBconnector (TB1)

Pins of TB 1 connector Lower limit voltage Upper limit voltage



between pins 10 and 9 -3.5 Volts -5.1 Volts

If any voltage is outside the limits stated in Table 4.2, disconnect the PL1connector and check the voltages again. If the voltages are still outsidethe limits, check that the that the ribbon cable between the Protectionblock module and the Terminals PCB is not damaged (Xendos 1900Series only). If the ribbon cable is not damaged, replace the Protectionblock module. If the voltages are within the limits proceed to the nextstep.


5. Replace the Display PCB. If the fault is not cured, replace theHousekeeping PCB.

4.3 Measurement faults

4.3.1 Transducer faults

Symptoms:

C No response to changing gas composition.C Transducer producing invalid results.C Instrument fails to meet performance specification.

Check:

1. Determine the general nature of the fault and the conditions underwhich it occurs.

2. Faults will usually fall into one of three categories:C Sample system.C Transducer.C Electrical or interconnection.

3. For diagnostic purposes, the transducer may be temporarilydisconnected by unplugging the ribbon cable connector at PL2 onthe Housekeeping PCB. While the transducer is disconnected, theinstrument should give a reading of ‘zero’ % oxygen and theanalogue current output should be stable (at 4mA) and essentiallyfree from noise.

4. If the condition in point ‘3' above cannot be achieved, the fault isassociated with either the Housekeeping PCB, the TerminalsPCB, or the Protection block module (Xendos 1900 Series only).These should be replaced in turn until the fault is located.

5. If the condition in point ‘3' above can be achieved the fault is withthe transducer or gas sampling system.

6. Ensure that the connector at PL2 on the Housekeeping PCB iscorrectly and securely refitted.

7. According to the fault symptoms observed, perform theappropriate measurement and diagnostic checks described insections 4.3.2 to 4.3.4.


4.3.2 Noise faults

Symptoms:

C Unstable readingC Noisy reading.C Reading drifts.C Instrument requires frequent re-calibration.

Measurements and Diagnosis:

1. Check which sampling options are fitted and refer to theappropriate sample flow diagram (see Figure 5.8).

2. If a sample conditioning system is fitted external to the analyser,verify that it is free from leaks and that the sample gas is beingsupplied at a stable pressure and flow and in a condition which isappropriate to the sample options fitted. Carry out correctiveactions as necessary and re-verify the instrument performance.

NOTE

Any excessive output noise or short term instability thatcan be corrected by temporarily reducing the sample flowto zero is usually due to sample system faults.

3. Verify that the sample flow rate through the transducer is in therange 50 to 250 ml/min (50 to 70 l/hr, for analysers fitted with highflow cells) and is stable. Check that any flow restrictors within theinstrument are not blocked. Correct or replace where necessaryand re-verify the instrument performance.

4. Perform a leak test to verify that the internal pipework is free fromleaks. Tighten fittings and replace seals or tubing wherenecessary and re-verify the instrument performance.

CAUTION

Ensure that the test pressure is applied and released slowlyto avoid damage to the measuring cell.


5. Verify that the instrument is free from liquid condensate. Smallamounts of water droplets which have accidentally entered thesample system may sometimes be removed by passing a dry gassample through the sample system for several hours. Correct orreplace where necessary and re-verify the instrumentperformance.

6. AFCD option ( if fitted)

Verify that the sample filter is not blocked or wet and that therestrictors in each of the ‘inlet’ and ‘sample’ hose fittings of theAFCD are not blocked. Ensure that there are no obstructions in theAFCD or instrument vent line and that the instrument vents freelyto atmosphere. Note that dirt or liquid deposits within the AFCDcan produce excessive noise or unstable readings. Replace thefilter or AFCD as necessary and re-verify the performance.

7. 1800 Pump option (if fitted)

Verify that the pump is operating satisfactorily and that anadequate pressure and flow is being generated.

If the pump is not operating satisfactorily then check the following:

C The pump is operating with the correct voltage andfrequency.

C The pump is free from leaks.

C The pump armature moves freely.

C There is no blockage or restriction in the pump inletpipework.

C There is an adequate supply of sample gas available.

C The sample source pressure is not too high or too low,relative to atmosphere.

Correct the problem or replace the pump as necessary and re-verify the instrument performance.


8. 1800 Flow Alarm option (if fitted)

Verify that the restrictor within the flow alarm assembly is notblocked. If necessary, replace the flow alarm assembly and re-verify the instrument performance.


Verify that the restrictor located between the two pressureswitches is not blocked. Replace if necessary and re-verify theinstrument performance.

10. 1800 Back pressure regulator option (if fitted)

Verify that the vent flow from the back pressure regulator is withinthe range 1 to 2 litres / min and is stable.

NOTE

Dirt or liquid deposits within the back pressure regulatormay cause excessive noise or unstable readings.

11. Verify that the transducer operating temperature is correct andstable. The temperature output voltage measured at TP3 withrespect to TP2 on the Housekeeping PCB is 620mV±2mV(635mV±2mV for 1156A transducers). If the temperature isincorrect, refer to Section 4.9.

12. Check instrument sensitivity by performing a zero and spancalibration. If the instrument sensitivity is low then perform theinstrument stability fault checks in Section 4.3.3.

13. If none of these checks cure the problem then replace thetransducer and verify the instrument performance.

4.3.3 Stability faults

Symptoms:

C Unable to perform a satisfactory zero calibration.C Unable to perform a satisfactory span calibration.C Low instrument sensitivity.C Poor instrument accuracy.C Instrument requires frequent re-calibration.


Measurements and Diagnosis:

1. Check which sampling options are fitted and refer to theappropriate sample flow diagram (see Figure 5.8).

2. If a sample conditioning system is fitted external to the analyser,verify that it is free from leaks and that the sample gas is beingsupplied at a stable pressure and flow and in a condition which isappropriate to the sample options fitted. Carry out correctiveactions as necessary and re-verify the instrument performance.

3. Verify the contents of the calibration gas samples and check thatthe calibration gases are correctly connected. Check that thecalibration gas container is not empty and ensure that the gas isreaching the instrument. Correct or replace where necessary andperform instrument calibration to verify performance.

4. If any calibration valves are fitted external to the analyser, verifythat they are free from leaks and operate correctly. Correct orreplace where necessary and perform instrument calibration toverify performance.

5. Perform a leak test to verify that the internal piping of theinstrument is free from leaks. Correct or replace where necessaryand re-verify the instrument performance.

CAUTION


6. Verify that the sample flow rate through the transducer is in therange 50 to 250 ml/min (50 to 70 l/hr, for analysers fitted with highflow cells) and is stable. Check that any flow restrictors within theinstrument are not blocked. Correct or replace where necessaryand re-verify the instrument performance.

7. AFCD option (if fitted)

Verify that the sample filter is not blocked or wet and that therestrictors in each of the ‘inlet’ and ‘sample’ hose fittings of theAFCD are not blocked. Ensure that there are no obstructions in theAFCD or instrument vent line and that the instrument vents freelyto atmosphere.


NOTE

Dirt or liquid deposits within the AFCD may causeexcessive noise or unstable readings.

Replace the filter or AFCD as necessary and re-verify theinstrument performance.


Verify that the restrictor within the flow alarm assembly is notblocked. If necessary, replace the flow alarm assembly and re-verify the instrument performance.


Verify that the restrictor located between the two pressureswitches is not blocked. Replace if necessary and re-verify theinstrument performance.

10. Verify that the instrument exhaust port is not restricted and that theinstrument is not being pressurised above ambient pressure.Correct or replace where necessary and perform instrumentcalibration to verify performance.

11. If none of these checks cure the problem then replace thetransducer and verify the instrument performance.

4.3.4 Flow faults

Symptoms:

C Slow instrument response.C Drift.C Noise.C Flow sensitive results.


Measurement and Diagnosis:

1. Check which options are fitted and refer to the appropriate sampleflow diagram (see Figure 5.8).

2. Verify that the sample flow rate through the transducer is in therange 50-250 ml/min (50 to 70 l/hr, for analysers fitted with highflow cells) and is stable. If any flow stability problems areencountered, verify that they are not produced by any sampleconditioning system used prior to sample entry into the instrument.Particular attention should be made to knock out pots, samplepumps, chillers and filters. Correct or replace where necessaryand re-verify instrument performance.

3. By performing a leak test verify that the external pipework of thesample system is leak tight. Pay particular attention to leaks fromneedle valves and flow meters, if these are fitted. Correct orreplace where necessary and re-verify instrument performance.

4. Perform a leak test to verify that the internal pipework is free fromleaks. Correct or replace where necessary and re-verify theinstrument performance.

CAUTION


5. Verify that the optional sample filter (if fitted) is clean and notblocked. Correct or replace where necessary and re-verifyinstrument performance.

6. Verify that the sample flow through the transducer is in the range50 to 250 ml/min (50 to 70 l/hr, for analysers fitted with high flowcells) and is stable. Check that the orifice flow restrictors within theinstrument are not blocked. Correct or replace where necessaryand re-verify instrument performance.

7. Verify that the pipework attached to the instrument vent is notrestrictive and resulting in pressurization of the sample cell.Correct or replace where necessary and re-verify instrumentperformance.

8. Verify that the transducer is not contaminated (particularly withcondensed water). Correct or replace the transducer if necessaryand re-verify instrument performance.


4.4 Flow alarm faults

Symptoms:

C The flow alarm is permanently on.C The flow alarm is permanently off.C The analogue outputs are ‘off scale’.


1. When the flow failure alarm operates, the analogue outputs will optionallybe driven ‘off scale’ in either a positive or negative polarity according tothe position of link LK6 on the Housekeeping PCB.

2. Verify that the sample flow through the transducer is within the range 100to 250 ml/min. Refer also to Section 4.3.4. For 1900 analysers, verify thatthe sample gas vents freely to atmosphere.

3. Temporarily move the link LK5 on the Housekeeping PCB into the upperposition. In this position, the link disables the flow alarm. The flow alarmLED on the display panel should be off; the flow alarm relay energised(terminals 8 and 9 on terminal block TB2 on the Terminals PCB shouldbe short circuit); and the analogue output voltage and current shouldreflect the oxygen concentration. If any of these conditions are notcorrect, the Housekeeping PCB, Display PCB, or the Terminals PCBshould be substituted until the fault is located and rectified. Ensure thatlink LK5 on the Housekeeping PCB is replaced into the lower position(FLAL).

4. 1800 Flow alarm option.

Verify that with a flow of nominally 100 ml/min the switch contacts areclosed and with a flow below 50 ml/min the contacts are open. Ifnecessary replace the flow sensor assembly and revalidate theinstrument performance.

5. 1900 Flow alarm option.

Each switch is set to nominally 12 cm water gauge (relative toatmospheric pressure). The switch at the vent side of the analyser usesthe normally closed contacts which will open (and indicate an alarm) if thevent pressure exceeds the pressure setting. The switch at the‘pressurised’ side of the restrictor uses the normally open contacts whichclose when the pressure reaches the set point. Verify that the restrictoris not blocked and replace as necessary. Check that the micro switchesoperate at the appropriate pressure setting and replace as necessary.


4.5 Relays malfunction

Symptoms:

The relays on the Terminals PCB do not operate correctly.


Check that the respective LED is working on the front panel (alarm LED for thealarm relay, range LED for the range relay or flow LED for the flow alarm relay).If the LED is working on the front panel, change the Terminals PCB. Check theconnection cable and that the connectors are fully inserted before changing theTerminals PCB. If the front panel LED is not working, replace in turn the DisplayPCB or Housekeeping PCB.

4.6 Voltage output or current output malfunction

Symptoms:

The voltage output or current output does not correspond to the Oxygenconcentration on the display.


1. If a flow alarm is fitted then refer to Section 4.4.

2. Carry out a zero and span calibration and check that the digital displaycorresponds to the concentration of the calibration gases used. Changethe transducer if you cannot set either the zero or span concentration onthe display.

3. If the calibration is completed successfully, replace in turn the Protectionblock module or the Terminals PCB. Check that the connection cable isundamaged and that the connectors are fully inserted before changingthe PCBs.

4.7 The range cannot be changed

Symptoms:

The range LEDs do not change when the range switch is pressed.


Replace in turn the Display PCB or the Housekeeping PCB.


4.8 The concentration set point alarm cannot be set

Symptoms:�� The set point alarm is unstable.� The alarm can not be set at the desired level.� The alarm does not activate for the specified concentration.


Change the Housekeeping PCB.

4.9 Malfunction of the temperature controller

Symptoms: The transducer temperature is not maintained at 40°C (50oC for1156A transducers).


1. Check that the voltage at test point TP3 with respect to TP2 on theHousekeeping PCB is 620mV±2mV (635mV±2mV for 1156Atransducers). If the voltage is outside the limits, set the voltage using theRV1 potentiometer on the Housekeeping PCB.

2. If the voltage at TP3 is correct, check that the voltage on TP4 is620mV±2mV (635mV±2mV for 1156A transducers). If this voltage isoutside these limits, check that the heaters are working by measuring thevoltage between TB3 pins 1 and 2 on the Housekeeping PCB. Thisvoltage should be higher than 5 Volts when the heaters are on. Changethe transducer if the heating voltage is higher than 5 Volts but thetransducer does not warm up.

3. If the heating voltages on TB3 pins 1 and 2 are lower than 5 Volts and thevoltage on TP3 is lower than 618mV (633mV for 1156A transducers),change the Housekeeping PCB.

NOTE

The transducer requires up to two hours to reach a stable temperature. If theanalyser was switched off before starting the investigation, allow at least twohours for the transducer to warm up. The heating circuit will keep thetransducer above 40°C if the ambient temperature is higher than 10°C. If theambient temperature is lower than 10°C, the heaters should be fully on (thevoltage between pins 1 and 2 of TB3 higher than 5 Volts). The voltage on TP4may be less than 620mV (635mV for 1156A transducers) for ambienttemperatures below 10°C.


5 PARTS REPLACEMENT PROCEDURES

5.1 Introduction

The Xendos instrument is designed for ease of access for maintenance. Coversare easily removed and refitted and internal PCBs and components are easilyreplaceable. Before opening the compartments, brush off any dust and wipeaway any oil or liquid which could contaminate or damage the seals. Take carewhen removing or refitting PCBs and components to avoid sharp edges.

WARNING

The Xendos Unit weighs approximately 26kg (57lbs) and care must betaken when handling. It is recommended that it is lifted with the fingerspositioned underneath the rear casting.

On the Xendos 1900 Series the Terminals compartment on the right handside of the analyser must not be opened while energised or within 3minutes following removal of power to allow time for capacitors todischarge.

The Xendos 1900 Series is designed for operation in a potentiallyhazardous area. Refer servicing to personnel experienced in working inpotentially flammable atmospheres.

5.2 Terminals compartment cover (1800 Series)


The non-hazardous terminals compartment of the Xendos 1800 Series are fittedwith a Viton ‘O’ ring sealed cover secured by four screws.

Removal

1. Undo the 4 captive M6 screws (5) and lift off the cover (4).

2. To gain access to the electrical terminals and the mains fuse, remove theretaining screw (1) and lift out the clear plastic cover (3) which insulatesthe terminals. Be sure to refit the plastic cover (3) when you reassemblethe analyser as it is a safety item.


WARNING

Removal of the plastic insulating cover exposes the user to potentiallylethal voltages. It is essential that only suitably trained and competentpersonnel are allowed access to hazardous live parts.

Refitting

1. Check that all the electrical connections are secure, check the insulatinglabel (2) position and refit the clear plastic cover (3) and secure it with thescrew (1).

2. Check that the 'O' ring seal (6) in the cover is correctly located andundamaged. Wipe the 'O' ring and mating surfaces to remove any dustor grease.

3. Refit the cover (4) and secure it with the 4 captive screws (5).


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5.3 Flameproof terminals compartment cover (1900 Series)Refer to Figure 5.2.

NOTE

The threaded right hand cover on the Xendos 1900 Series has an anti-scuffing paste lubricant applied to the thread. Avoid touching the threadwhen you remove the cover as the lubricant is difficult to remove fromclothes and surfaces.

Removal

1. Loosen the M4 grubscrew (6) which locks the screw cover (4).

2. Apply a suitable lever or large screwdriver across the slots (7) in thecover (4) and exert sufficient anti-clockwise force to release the ‘O’ ringseal (5). It should then be possible to unscrew the cover by hand. Placethe cover aside on a clean disposable material.

CAUTION

The use of a soft surface material on the cover will prevent damage topaint work.

3. To gain access to the electrical terminals and the mains fuse, remove theretaining screw (1) and lift out the clear plastic cover (3) which insulatesthe terminals. Be sure to refit the plastic cover (3) when you reassemblethe analyser as it is a safety item.

WARNING

Removal of the plastic insulating cover exposes the user to potentiallylethal voltages. It is essential that only suitably trained and competentpersonnel are allowed access to hazardous live parts.

Refitting

1. Check that all the electrical connections are secure, check the insulatinglabel (2) position and refit the clear plastic cover (3) and secure it with thescrew (1).


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2. Check that the 'O' ring seal (5) in the cover (4) is correctly located andundamaged. Wipe the 'O' ring and mating faces with a clean lint-free clothto remove any dust or grease.

3. Offer up the cover (4) and engage the thread in the compartment. Rotatethe cover clockwise until hand tight.

CAUTION

Check that no dust or dirt has collected onto the enclosure thread, brushoff if necessary. If necessary, renew the anti-scuffing grease beforerefitting the cover. Failure to do this may make the cover difficult toremove.

4. Apply a suitable lever or large screwdriver across the slots (7) in thecover (4) and turn clockwise to compress the seal (approximately 1/16turn).

CAUTION

The use of a soft surface material on the cover will prevent damage topaint work.

5. Tighten the M4 grubscrew (6) to lock the thread.

WARNING

Tightening the M4 grub screw is a requirement of the hazardous areasafety standard. Failure to do this may invalidate the hazardous areaclassification.


5.4 Sample compartment hinged cover


The sample compartment has a hinged cover (1) fitted with a Viton ‘O’ ring andsecured with 4 captive M6 screws (2).

To open the hinged cover

1. Undo the 4 captive M6 screws (2) and open the cover (1).

2. Access is obtained to the controls on the display panel (3). If furtherdismantling is required the display panel (3) can also be hinged open byreleasing the pawl latch (4).

WARNING

For the Xendos 1900 Series. To maintain the ingress protection (IP20)required by hazardous area approval requirements the user must notopen the internal hinged display panel to make adjustments andchanges. Appropriate alternative protection methods should beobserved should the hinged display panel be opened while the analyseris under power.

To close and seal the hinged cover

1. Check that the Viton ‘O’ ring in the cover is correctly located andundamaged. Wipe the seal and mating surface with a clean lint-free clothto remove any dust or grease.

2. Close the cover (1) and secure it with the 4 captive M6 screws (2).


5.5 Window replacement


The sample compartment hinged cover is fitted with a glass window. The insidesurface has a conductive metallised coating for the purpose of EMC screening.One corner of the window is radiused so that it can only be fitted in the correctorientation.

CAUTION

Handle the glass window by the edges and place it on a soft cleansurface to avoid damage to the inner conductive coating.

Removal

1. Open the sample compartment cover (see Section 5.4) and remove theM3 socket head screws (1) which retain the window (2).

2. Lift off the bracket frame (3) and remove the window (2).

Refitting

1. Check that the 'O' ring (4) is undamaged and correctly located in thegroove. If necessary, fit a new 'O' ring.

CAUTION

Ensure that all mating surfaces are cleaned and free from dirt and dust.If necessary remove the ‘O’ ring to clean out the ‘O’ ring groove.

2. If a new glass is to be fitted, peel off the protective film from both facesof the glass. Take care not to touch or damage the back face of the glass.

NOTE

If necessary the inside of the glass window may be cleaned using a lintfree cloth and clean water.

3. Fit the glass window (2) into position observing correct orientation (notethe position of the radiused corner ( A)).


1. Hinged cover 3. Display panel2. Captive M6 screws (4 off) 4. Pawl latch

Figure 5.3 - Sample compartment hinged cover and display panel detail


A Radiused corner of window

1. M3 screws (8 off) 3. Frame2. Window 4. ‘O’ ring

Figure 5.4 - Window replacement


4. Refit the retaining frame (3) and secure with the M3 screws (1). Fit all 8screws and then tighten the screws evenly.

5. Close the sample compartment hinged cover (see Section 5.4).


5.6 Replace optional AFCD filter


The AFCD filter should be checked and replaced if necessary at approximately3 monthly intervals. (Less frequently if sample gases are clean).

Removal and replacement

1. Open the sample compartment (see Section 5.4) and undo the knurledscrew cover (2) to remove the filter element.

NOTE

If the knurled screw cover (2) is tight then it may be necessary to openthe display panel (1) to gain better access to it.

2. Inspect the filter element and replace it if necessary.

3. Refit the knurled filter cover (2) and close the compartment (seeSection 5.4).


1. Display panel2. Knurled filter cover3. AFCD filter assembly

Figure 5.5 - AFCD filter replacement


5.7 Display PCB removal and refitting


The Display PCB is mounted on the rear of the hinged display panel.

Removal and refitting

1. Open the sample compartment hinged cover and open the hinged displaypanel (see Section 5.4).

2. Remove the 6 screws (3) retaining the Display PCB (2) to the displaypanel (1).

3. Carefully ease off the 34 way ribbon cable (4) using the ejector latchesfrom the edge of the Display PCB.

4. Reassemble using the reverse procedure.

CAUTION

When attaching the Display PCB to the display panel, ensure that theLEDs, LCD display and switches are aligned with the holes in the displaypanel before tightening the 6 retaining screws. Ensure that the switchoperation is not hindered.


1. Display panel 4. Ribbon cable2. Display PCB 5. Spacers (6 off)3. Screws and washers (6 off) at locations ‘X’

Figure 5.6 - Display PCB removal


5.8 Housekeeping PCB removal and refitting


The Housekeeping PCB is mounted on top of the transducer assembly.


1. Open the sample compartment hinged cover and the hinged displaypanel (see Section 5.4).

2. Disconnect the two ribbon cables from connections PL1 (9) and PL2 (8)on the right hand side of the Housekeeping PCB (3).

3. Disconnect the 4 off heater wires from terminal block TB3 (6) on the lefthand side of the Housekeeping PCB noting the wire colours andcorresponding terminal numbers.

4. If the optional flow alarm is fitted then disconnect the two wires fromterminal block TB2 (5) on the left hand side of the Housekeeping PCB.

5. Unplug the 15 way interconnecting cable from the connector TB1 (7) atthe top of the Housekeeping PCB.

6. Remove the three screws (10) retaining the Housekeeping PCB to thetransducer assembly (4).

7. Carefully remove the Housekeeping PCB from the sample enclosure.

8. Replace using the reverse procedure.

WARNINGWhen refitting the Housekeeping PCB into the sample enclosure ensurethat the plastic insulation shield is correctly located over the PCBmounting pillars.

NOTEC When reconnecting the 4 heater wires to terminal block TB3 on

the Housekeeping PCB, the two orange wires are connected toterminals 1 and 2 and the two grey wires are connected toterminals 3 and 4.

C For instructions on setting links refer to the setup instructions inSection 5.20.


Figure 5.7 - Housekeeping PCB removal

1. Display panel 6. Terminal block TB32. Display PCB 7. 15-way cable connector TB13. Housekeeping PCB 8. 16-way ribbon connector PL24. Transducer assembly 9. 34-way ribbon connector PL15. Terminal block TB2 10. Screws (3 off)


5.9 Sampling options chassis removal and refitting

Refer to Figure 5.8 for example option assembly flow diagrams.

The optional sample features are mounted on a separate metal chassis that maybe removed from the sample compartment. The sample options may include thefollowing:-

Xendos 1800 options:

C AFCD option - see Figure 5.8 (A)C AFCD and flow alarm options - see Figure 5.8 (B)C Sample pump, AFCD and flow alarm options - see Figure 5.8 (C)C AFCD, flow alarm and back pressure regulator (BPR) - see Figure 5.8 (D)C Flow alarm option only - see Figure 5.8 (E)C Stainless steel sample pipework - see Figure 5.9 (G)

Xendos 1900 options:

C Flow alarm option - see Figure 5.8 (F)

Access for servicing of any of these options is obtained by removal of the entireoptions chassis from the analyser compartment. Attempting to service theseoptions in situ is not recommended.


A = assembly with AFCD option (Xendos 1800)B = assembly with AFCD and flow alarm options (Xendos 1800)C = assembly with sample pump AFCD and flow alarm options (Xendos 1800)D = assembly with AFCD, flow alarm and back pressure regulator (BPR) (Xendos1800)E = Flow alarm option (Xendos 1800)F = Flow alarm option (Xendos 1900)

Figure 5.8 - Option assembly flow diagrams




1. Open the sample compartment hinged cover and open the hinged displaypanel (see Section 5.4).

2. If the optional flow alarm is fitted then disconnect the flow alarm wiresfrom the terminal block TB2 (7) on the Housekeeping PCB.

3. If the sample pump option is fitted then unplug the sample pump at thein line connector inside of the sample compartment.

4. Detach the flexible inlet and outlet pipes (1, 6) from the transducerassembly inlet and outlet pipes (it is advisable to label the pipes beforeremoval to highlight inlet and outlet). Slide the pipe retaining clips backfrom the connection points and ease off the tubing by applying gentleleverage with a screwdriver. Do not apply excessive force when removingthe pipework.

5. Detach the flexible inlet and outlet pipes from the analyser inlet and outletports (3, 4). Slide the pipe retaining clips back from the connection pointsand ease off the tubing by applying gentle leverage with a screwdriver.Do not apply excessive force when removing the pipework.

NOTE

It may be necessary to cut the pipework from tubes to prevent excessiveforce.

Note that the analyser inlet bore is smaller than the outlet bore. The inletis the right hand pipe when viewed from the front of the analyser.

6. Loosen the 3 screws (2) which secure the sample options chassis to thebase of the casting. Slide the assembly upwards to clear the screwheads from the keyhole slots and then carefully lift out the sample optionschassis.

7. Refit using reverse procedure.


A = assembly with AFCD optionB = assembly with AFCD and flow alarm option

Figure 5.9 - Sampling options chassis removal (sheet 1 of 4)


C = assembly with sample pump (3), AFCD (1) and flow alarm (2) optionsD = assembly with AFCD (1), flow alarm (2) and back pressure regulator (BPR) (4)



E = assembly with flow alarm option (5) (Xendos 1800)F = assembly with flow alarm option (6) (Xendos 1900)



G = assembly with stainless steel pipework (1) (Xendos 1800)


7

6


Figure 5.10 - Sampling options chassis detail

1. Transducer inlet pipe2. Screws (3 off)3. Analyser inlet port4. Analyser outlet port5. Options chassis6. Transducer outlet pipe7. Terminal block TB2

2 1

3

4

56

7

1. Knurled filter cover 5. Sample outlet port2. Knurled locking ring 6. Sample inlet port3. Spring tension adjustment 7. Bracket mounting screws4. Sample bypass port 8. AFCD mounting bracket

8


Figure 5.11 - AFCD mounting detail

5.10 AFCD removal and replacement

Refer to figure 5.11

1. Refer to Section 5.9 to remove the Sampling options chassis.

2. Remove the pipework from the back of the AFCD(4,5,6), taking note ofits position for reassembly.

3. Remove the knurled cover(1) and then the knurled locking ring (2) andwithdraw the AFCD from the bracket (8). Note how the bracket is keyedfor correct orientation when reassembling.

4. Inspect the AFCD and clean it if necessary. If the AFCD is corroded orseverely contaminated, we recommend that you replace the unit.

5. Refit using the reverse procedure.

NOTE

If a flow alarm is fitted then replace the outlet restrictor (5) when fittinga new AFCD.

1

4

2

3

5

1. Options chassis 4. Back pressure regulator2. BPR mounting bracket 5. Sample ports3. Bracket mounting screws


Figure 5.12 - Back pressure regulator mounting detail

5.11 Back pressure regulator removal and replacement

Refer to figure 5.12.


2. Disconnect the pipework (5) from the back pressure regulator (BPR) (4),taking note of its position for reassembly.

3. Loosen the 2 M4 retaining screws (3) holding the bracket (2) to theoptions chassis (1) and slide the BPR (5) from the bracket.

4. Inspect the BPR and clean it if necessary. If the BPR is corroded orseverely contaminated, we recommend that you replace the unit.


2

3

6

5

4

1

1. Bracket mounting screws 4. Flow alarm unit2. Mounting bracket 5. Flow alarm mounting screws3. Sample connection ports 6. Options mounting chassis


Figure 5.13 - 1800 Flow alarm detail

5.12 Flow alarm removal and replacement (1800)



2. Disconnect the pipework from the flow alarm, taking note of its positionfor reassembly.

3. Loosen the two screws (1) and remove the alarm with the bracketattached.

4. Remove the two screws (5) that hold the flow alarm to the bracket.

5. Inspect the flow alarm and clean it if necessary. If the flow alarm iscorroded or severely contaminated, we recommend replacing the unit.


NOTE

If installing a new flow alarm in an analyser not previously fitted with aflow alarm then it is necessary to replace the AFCD outlet restrictor (ifan AFCD is fitted).

2

1

3

4

5

1. Sample connection ports 4. Pressure switch P12. Electrical connections 5. Pressure set point adjustment3. Pressure switch P2 6. Options chassis

6


Figure 5.14 - 1900 Flow alarm pressure switch detail

5.13 Flow alarm pressure switch removal and replacement (1900)

Refer to figure 5.14


2. Disconnect the pipes (1) and electrical connections (2) from the pressureswitches (3,4) noting the positions of the pipes and wires for reassembly.

3. Remove the flow alarm pressure switch retaining screws from theunderside of the Options chassis(6).

4. Inspect, test and replace the switch if necessary.


NOTE

If installing a new flow alarm in an analyser not previously fitted with aflow alarm then it is necessary to replace the AFCD outlet restrictor (ifan AFCD is fitted).

1

2

3

4

5

1. Options chassis 4. Mounting screws2. Pump mounting plate 5. Sample ports3. Sample pump


Figure 5.15 - Sample pump installation detail

5.14 Sample pump removal and replacement


1. Refer to Section 5.9 to remove the sampling option chassis.

2. Disconnect the pipework (5) from the sample pump (3) and take note ofits position for reassembly.

3. Remove the 4 off M4 retaining screws(4) to release the pump from thechassis (1).

4. Inspect and test the pump and replace it if necessary.



5.15 Stainless steel pipework removal and replacement

CAUTION

Take care when removing and refitting connections to avoiddamaging the transducer inlet/outlet pipes.

1. Use a suitable spanner to hold the couplings before loosening thecompression nut. Undo the fittings from both ends of the pipes.

2. Compress the tubing slightly to release it from the fittings.

3. Inspect and clean the pipework and replace it if necessary.

4. When fitting new pipes, adjust the pipe alignment by hand before makingthe final connections to reduce the strain on the transducer connections.

5.16 Transducer assembly removal and refitting


The paramagnetic transducer assembly has the Housekeeping PCB attachedto the front of the assembly.


1. Remove the sample options chassis as described in Section 5.9. If nosample options are fitted then detach the inlet and outlet pipes from thetransducer assembly, taking note of the positions for reassembly.

2. Unplug the 15-way interconnection cable from connector TB1 (1) on thetop of the Housekeeping PCB (2). Disconnect the 34 way ribbon cablefrom the edge of the Display PCB using the ejector latches.

3. Loosen the 3 screws (3) which secure the transducer bracket (4) to thebase of the analyser casting.

4. Slide the transducer assembly sideways to the left (A) to clear the screwheads (3) from the keyhole slots. Withdraw the transducer assembly clearof the screw heads (B) then rotate the assembly 90 clockwise (C) ando

remove from the enclosure. Be careful not to damage the PCBs on thetop and side (where fitted) of the assembly as you withdraw the assembly.



1. 15-way cable connector TB12. Housekeeping PCB3. Screws (3 off)4. Transducer bracket

Figure 5.16 - Transducer assembly removal


5.17 Terminals PCB and power supply removal and refitting



1. Refer to Section 5.2 for Xendos 1800 Series or Section 5.3 for Xendos1900. Remove the terminals compartment cover and the clear plasticinsulation cover.

2. Disconnect all the wires from the terminals and withdraw the cables toallow clearance for PCB removal. Undo the earth retaining screw anddisconnect the earth wire (ring terminal).

3. Remove the plastic insulating label to uncover the Terminals PCB.

4. Undo the 3 screws (4) and lift out the Terminals PCB (3). As you lift thePCB, take note of the way the ribbon cable is folded to assist inreassembly later. Carefully remove the ribbon cable connector PL1 fromthe edge of the PCB.

5. The Switched Mode PSU (2) is fixed to the PCB with 4 screws (7). Toremove the PSU from the PCB, undo the 4 screws and pull out the ribboncable connectors PL2, PL3 and PL4.


7


1. Terminals PCB insulating cover2. Switched mode PSU3. Terminals PCB4. Terminals PCB retaining screw (3 off)5. Terminals PCB cover screw6. Lid7. PSU retaining screws (4 off)

Figure 5.17 - Terminals PCB and switched mode power supply removal


5.18 Protection block module removal and refitting (1900 Series only)

NOTE

The protection assembly is only used on the Xendos 1900 Series and isnot provided with the Xendos 1800 Series

WARNING

The Protection block module is not a serviceable item. Do not attempt toreplace fuses or any other components mounted on the assembly or youwill invalidate the safety approval status of the equipment.


Removal

1. Refer to Section 5.2 (Xendos 1800) or Section 5.3 (Xendos 1900/1902).Remove the terminals compartment cover and the clear plastic insulationcover.

2. Remove the Terminals PCB and switched mode power supply (seeSection 5.17).

3. Remove 2 off M4 screws (2) and washers and lift out the clear plasticinsulating panel (3). Remove the 2 off M5 screws (4) which secure theProtection block module (5) to the casting (do not remove any of theremaining screws).

4. Withdraw the protection block module (5) carefully to avoid damage tocomponents. Note the correct route of the 15-way cable around the fixingposts to assist reassembly later. Disconnect the ribbon cable and the 15-way cable from the Protection block module and remove the module .



1. Terminals PCB insulating cover 7. Switched mode PSU2. Protection block cover screw 8. Terminals PCB3. Protection block insulating cover 9. Terminals PCB retaining4. Protection block retaining screw (2 off) screw (3 off)5. Protection block module 10. Terminals PCB cover screw6. Ribbon connector 11. Compartment cover

Figure 5.18 - Protection assembly removal


1. Thermal insulation boot 11. 16-way ribbon connector to2. Transducer (1156A) Transducer Control PCB (PL7)3. Foam pad 12. Screw (3 off)4. Isolation mounts (3 off) 13. Transducer Control PCB5. Clinch stand off (3 off) 14. Clinch stand off (3 off)6. Insulation sheet 15. Earth tag, stud, washers, nut7. Housekeeping PCB8. Screw and washer (3 off) 16. Bracket9. 34-way ribbon connection to 17. 10-way ribbon connector to

Display PCB (PL1) Control PCB10. Nut and washer (3 off) 18. Heat exchanger coil and plate

Figure 5.19 - 1156A Transducer assembly (see text for 1158 transducer)


5.19 1156A Paramagnetic transducer removal and replacement

NOTE

The spare transducer assembly provided for the Xendos 1800 and 1900Series analysers is supplied complete with Control PCB, heaters andconnection wires.


Removal

1. Remove the transducer assembly from the sample compartment (seeSection 5.16).

2. Disconnect the ribbon cable (17) to the 1156A transducer from theTransducer Control PCB (13) mounted on the side of the transducerbracket (16). Disconnect the 16-way ribbon cable (11) to the analyserhousekeeping PCB (7) from the Transducer Control PCB (13).

3. Remove the 3 mounting screws (12) retaining the transducer controlPCB (13) to the transducer bracket and remove the transducer controlPCB.

4. Remove the black high density foam thermal insulation boot (1) from thetransducer assembly (2). Ease it off progressively as it is a tight fit andwires are fed through slots in the boot. At the same time thread theribbon cable (17) through the hole in the thermal insulation boot until theboot is free from the transducer assembly.

5. Disconnect the transducer earth tag (15) from the transducer mountingbracket (16).

6. Undo the 3 nuts (10) on the underside of the transducer assembly torelease the transducer from the mounting bracket (16).

7. Undo the heater coil inlet pipe and sample exit pipe from the transducermeasurement cell.

8. Gently work off the thermal base (3) from the isolation mounts (4) andundo the 3 isolation mounts (4) to release the heater coil plate (18).



NOTES

C Use thread lock on the isolation mounting points.

C Check that the heater wires are carefully routed around thetransducer body to the exit point on the black thermal boot andnot snagged. Ensure the heater wire sleeving is pushed farenough through the boot to be encased by the thermal boot.

C Note that the black thermal boot is a tight fit onto the transducerand care is needed on insertion to avoid dislodging the heaterwires and ribbon cable.

5.20 1158 Paramagnetic Transducer Removal and Replacement

The later type 1158 transducer has a built-in control board. Refer to section 5.19 and Figure 5.19Follow the procedure for the 1156A transducer but note that the Transducercontrol PCB (item 13) is not used for the 1158 transducer. Also note the ribboncable (item 11) is longer for the 1158 and connects the Housekeeping PCB(item 7) to the 1158 transducer directly, and that the earth lead and thermal bootare changed.


Figure 5.20 - Cell Replacement

5.21 Replacement of Measuring Cell (1156A and 1158).

This procedure is only applicable to 1156A transducers serial numbers 1250 and above,and to all 1158 transducers. It should only be attempted with the instrument in a serviceworkshop on a suitable bench. Clean and dry Nitrogen and Air supplies are required,controlled either by a needle-valve and flowmeter or AFCD to provide a flow rate of100mL/min maximum.

1. Refer to section 5.9 to remove Sampling options chassis.

2. Refer to section 5.16 to remove Transducer assembly.

Refer to Figures 5.19 and 5.20

3. Pull off the thermal boot (1) and disconnect ribbon cable (17) from thetransducer (2).

4. Disconnect the sample pipe connections and remove the three nuts and washers(10) from under the transducer assembly. (note that the wires to the heatingresistors can remain connected)

5. Unsolder the yellow and black wires from the measuring cell and with an Allenkey loosen the cell locking clamp screw. Grip the cell by the sides and pull thecell out of the magnet frame. (note that the magnet will exert a very strongholding force on the cell)

6. The replacement cell must be fitted the correct way up with the yellow spotconnection at the top. With the cell fully home tighten the cell locking clampscrew and resolder the wires to the cell with the yellow wire to the connectionmarked with the yellow spot.

7. Refit the transducer to the bracket and reconnect the sample pipes using new‘O’ rings and only tighten the connector nuts one half turn beyond finger tight.


Figure 5.21 - Mechanical zero (1156A only)

8. Reconnect the ribbon cable (17) to the transducer but do not fit thermal boot atthis stage

9. Set the Zero on the front panel to mid point (5 turns from either end).

10. Connect the Nitrogen supply (flow of 100mL/min) to the transducer assemblyinput pipe (the right-hand pipe when viewed from the housekeeping board side).Support the transducer assembly using the upturned thermal boot in front of theanalyser with the housekeeping board towards the analyser. Connect the displayribbon cable (9) and the 15 way cable from the analyser to the houskeepingboard.

11. Ensure the electrical safety of all parts and power-up the analyser.

SETTING MECHANICAL ZERO (1156A ONLY) (follows on from cell changeprocedure)

12. Set RV1 on the transducer control PCB (13) to mid position (12 turns from eitherend).

Refer to Figure 5.21

13. Loosen photo cell clamping screw and slide photo cell assembly a small amountleft or right as required to obtain a display reading of zero within 2%. Tighten thescrew and ensure the display reading is still within limits.


SETTING ELECTRICAL ZERO (1158 ONLY) (follows on from cell change procedure)

14. Adjust the ZERO pot on the top of the 1158 transducer for a display reading ofzero within 2%

SETTING SPAN (1156A and 1158) (follows on from cell change procedure)

15. Set the Span control on the front panel fully clockwise (maximum). Connect theAir supply (100ml/min) to the transducer input pipe. Adjust the coarse span potfor the transducer as defined below:For 1156A the coarse span pot is RV3 on the transducer control board (13).For 1158 the coarse span pot is marked Coarse Span on the top of thetransducer.

16. Remove power from the analyser and re-assemble with reference to sections 5.9and 5.16.

17. Calibrate analyser for fine setting of front panel Zero and Span controls.

5.22 Housekeeping PCB link configuration


Check that the link setting on the Housekeeping PCB match the usersrequirements. Table 5.1 details the functions of the different links and the normalfactory configuration.

Table 5.1 Housekeeping PCB link settings

Link Parameter Factory setting

LK1 Alarm 1 Low = 0.0% Oxygen

LK2 Alarm 2 High= 21.0% Oxygen

LK3 Range 1 0-10% Oxygen

LK4 Range 2 0-25% Oxygen

LK5 Flow alarm “Fitted” if option included

LK6 Output status Low on fault


5.23 Operation of Output status (LK6)

Where the sample flow failure alarm option is fitted and a low sample flow condition isdetected then, depending on the link setting selected, the voltage output and theisolated 4-20mA output will go to the fault indicating states as below.

Voltage output fault states (flow fail) - High on Fault = +1.2V. Low on Fault = -1.2V.

mA output fault states (flow fail) - High on Fault = >20mA. Low on Fault = 0mA.

5.24 Transducer failure (1158)

The 1158 transducer has in-built failure monitoring circuits that cause the signal outputof the transducer to go to the -5V supply on failure. The failures detected within thetransducer are - no LED output - photocell open or short circuit - cell suspension brokenor jammed - wire broken.

Failure of the 1158 transducer will produce a ‘Low on Fault’ condition on both thevoltage and mA outputs. Transducer failure will also cause the front panel display toshow a reading of -1.


Figure 5.22 - Link settings

1. Flow alarm (LK5)2. Range 1 (LK3) (later ranges - 2.5%, 5%, 10%, 25%, 100%)3. Range 2 (LK4) (later ranges - 2.5%, 5%, 10%, 25%, 100%)4. Failure mode (LK6)5. Alarm 2 (LK2)6. Alarm 1 (LK1)


6 DIAGRAMS

The following electronic circuit diagrams are included as part of this servicemanual.

Table 6.1 Included drawings list

Drawing No. Description

01800/101 Housekeeping PCB

01800/111 Housekeeping PCB

01800/102 Display PCB

01800/102A Display PCB

01800/112A Display PCB

01800/103 Terminals PCB

01800/113 Terminals PCB

01800/113A Terminals PCB

01800/113C Terminals PCB

01900/101 Protection PCB

01156/103 Transducer Terminal PCB

01156/104 Transducer Control PCB


Xendos 1800 and 1900 Series A.1

APPENDIX A DETAILED ANALYSER PERFORMANCE TESTING

A.1 Notes and conditions

The performance tests detailed in this section are based on the factory testspecification for the Xendos 1800 and 1900 Series analysers. As standard, theanalysers are tested at 240V unless the sample pump options are fitted. If thesample pump options are fitted then the analysers are tested at the specifiedvoltage and frequency for the sample pump.

WARNING

The procedure detailed within this section involves the use of pureoxygen for span calibration, display calibration and analogue outputadjustment. These tests must not be performed upon an analyserinstalled within a hazardous area. If necessary the tests should beperformed using clean dry air as an alternative to oxygen and thespecified output values listed in this section scaled accordingly.

A.2 Gas samples required

The gas samples required to adjust and test the analyser are as follows:

C Zero gas Plant nitrogen.C Span gas Commercially pure oxygen.C Test gas Plant air.

When the optional automatic flow control device (AFCD ) is fitted then thesample gases should be applied at pressures between 1 and 5 psig. When theoptional back pressure regulator is fitted then the sample gases should beapplied at pressures between 3 and 8 psig. When the optional sample pump isfitted then the sample gases should be applied in the manner shown in FigureA.1. When the optional sample bypass option is fitted then the sample flow rateshould be externally regulated to provide a sample flow to the analyser of 750ml/min. If no sampling options are fitted then the sample flow rate should beexternally regulated to provide a sample flow to the analyser of 150 ml/min.

A.2 Xendos 1800 and 1900 Series

Figure A.1 Sample gas connection (sample pump option)

A.3 Sample system leak tests

CAUTION

The analyser sample system should be pressurised and depressurisedslowly. Failure to do this may result in damage to the transducer cell.

a) No sampling options fitted.

Connect the sample inlet pipe to a vacuum leak tester. Seal the sampleoutlet pipe. The test is passed if the measured leak rate is less than 10-6

mbar litres/second.

Alternatively connect a manometer to the sample outlet and pressurisethe sample system to 500mm WG via the inlet pipe. The test is passedif the observed leak rate is less than 1mm WG/2 minutes.


b) Sampling options fitted.

Connect a manometer to the sample outlet pipe and pressurise thesample system to 500mm WG via the inlet pipe. The test is passed if theobserved leak rate is less than 2mm WG/minute. Alternatively anequivalent test may be performed with leak test apparatus.

A.4 Preliminary adjustments

Before powering up the analyser, set up the options on the Housekeeping PCBas follows:

1. Set the default ranges of the analyser to be 0-25% (range 1) and 0-100%(range 2) using links LK4 and LK3.

2. Set alarm 1 to “Low” and alarm 2 to “High” using links LK1 and LK2.

3. If the flow alarm option is fitted then select position “FLAL” on link LK5.If no flow alarm is fitted then select position opposite to “FLAL” on linkLK5.

4. Set the analogue output to read high on flow failure by setting link LK6 toits lower position.

A.5 Operating temperature

With the instrument powered up at 240 V nominal supply, set the transduceroperating temperature by adjusting potentiometer RV1 until the voltage betweentest point TP3 and TP2 on the House keeping PCB is 620mV ± 2mV (635mV ±2mV for 1156A transducers).

Monitor the temperature output voltage (TP4 and TP2 on the House keepingPCB) on a chart recorder until the output voltage has been stable to ±1mV fora period of at least one hour. When stabilised, check the transducer operatingtemperature. The temperature output voltage should be 620mV ± 2mV (635mV± 2mV for 1156A transducers). The display should be stable with no more than0.1% O change. The peak to peak variation on the chart over a one hour2

period should be less than 2mV.

A.6 Range change indication

Select range 1 on the front panel of the instrument. Check that pins 11 and 12of terminal block TB2 of the Terminals PCB are short circuit and that pins 10 and12 are open circuit.

Select range 2 on the front panel of the instrument. Check that pins 10 and 12of terminal block TB2 of the Terminals PCB are short circuit and that pins 11 and12 are open circuit.


A.7 Display calibration and coarse analyser calibration

The analogue output voltage is monitored on pins 1 and 2 on terminal block TB4on the Terminals PCB. The analogue current output is monitored between pins3 and 4 on terminal block TB4. Set the range switch to range 2 (0-100%).

Connect a clean, dry nitrogen sample in accordance with Section A.2. Wait untilthe analogue output voltage has been stable (±1 mV) for at least 1 minute.

Adjust the instrument zero calibration control to give an analogue voltage outputof 0 mV ±1 mV.

Connect a clean, dry oxygen sample in accordance with Section A.2. Wait untilthe analogue output voltage has been stable (±1 mV) for at least 1 minute.

Adjust the instrument span calibration control to give an analogue voltage outputof 1000mV ±1 mV.

Adjust the potentiometer RV2 on the Housekeeping PCB until the LCD displayreads 100.0 ±0.1 % O .2

A.8 Zero calibration and low alarm check

Ensure that the transducer temperature has stabilised prior to calibrating theinstrument. The analogue output voltage is monitored on pins 1 and 2 onterminal block TB4 on the Terminals PCB. The analogue current output ismonitored between pins 3 and 4 on terminal block TB4. Set the range switch torange 2 ( 0-100% ).

Press the alarm switch ( SW1 ) on the display panel until the LO LED for alarm1 is lit and then hold the switch in. Adjust the alarm 1 set potentiometer ( RV1) on the display panel while holding SW1 in until the LCD display reads 0.0% O .2

Release switch SW1.

Connect a clean, dry nitrogen sample in accordance with Section A.2. Wait untilthe analogue output voltage has been stable (±1 mV) for at least 2 minutes.

Adjust the calibration zero control on the front panel so that alarm 1 is off. Verifythat pins 2 and 3 on terminal block TB2 on the Terminals PCB are short circuitand pins 1 and 3 are open circuit.

Adjust the calibration zero control counter clockwise until alarm 1 just triggers.Verify that pins 1 and 3 on terminal block TB2 on the Terminals PCB are shortcircuit and pins 2 and 3 are open circuit. Verify that the LCD display reads 0.0±0.3 % O .2

Adjust the calibration zero control clockwise until alarm 1 just turns off. Verifythat the display reading is in the range 0.0 to 0.5% O . 2


Adjust the zero calibration potentiometer on the front panel until the analogueoutput is 0mV ±1mV.

Check that the analogue current output is 4.00 mA ±0.05 mA. If necessary adjustRV1 on the Terminals PCB to obtain a stable analogue current output readingof 4.00mA±0.05mA

Verify that the display reads 0.0 ± 0.1 % O .2

A.9 Span calibration and high alarm checks (earlier type)with 01800902 display board and 1156A transducer.


Connect a clean, dry oxygen sample in accordance with Section A.2. Wait untilthe analogue output voltage has been stable ( ±1 mV ) for at least 2 minutes.


Check that the analogue current output reads 20.00mA ±0.05 mA. If necessaryadjust RV2 on the Terminals PCB to obtain a stable analogue current output of20.00mA±0.05mA.

Press the alarm switch ( SW1 ) on the display panel until the HI LED for alarm2 is lit and hold the switch in. Adjust the alarm 2 set potentiometer ( RV2 ) onthe display panel while holding SW1 in until the LCD display reads 105.0% O .2

Release switch SW1. Verify that pins 5 and 6 on terminal block TB2 on theTerminals PCB are short circuit and that pins 4 and 6 are open circuit.

Adjust the calibration span control clockwise until alarm 2 just triggers. Verifythat pins 4 and 6 on terminal block TB2 on the Terminals PCB are short circuitand that pins 5 and 6 are open circuit. Verify that the LCD display reads105.0±0.3 % O . 2

Adjust the calibration span control fully clockwise. Adjust potentiometer RV2 onthe Transducer PCB until the LCD display reads 116 % O . RV2 is the upper of2

the two potentiometers visible on the edge of the PCB as viewed from the frontof the instrument.

Adjust the calibration span control slowly counter clockwise until alarm 2 justturns off. The LCD display at this point should be in the range 104.5 to 105.0%O . Continue to adjust the calibration span control fully counter clockwise.2

Verify that the LCD display reading is less than 95 % O .2


Adjust the calibration span control until the LCD display reads 99.7 ±0.1 % O .2

A.10 Span calibration and high alarm checks (later type)with coarse span potentiometer RV3 on display board (any transducer).


Connect a clean, dry oxygen sample in accordance with Section A.2. Wait untilthe analogue output voltage has been stable ( ±1 mV ) for at least 2 minutes.


Check that the analogue current output reads 20.00mA ±0.05 mA. If necessaryadjust RV2 on the Terminals PCB to obtain a stable analogue current output of20.00mA±0.05mA.

Press the alarm switch ( SW1 ) on the display panel until the HI LED for alarm2 is lit and hold the switch in. Adjust the alarm 2 set potentiometer ( RV2 ) onthe display panel while holding SW1 in until the LCD display reads 105.0% O .2

Release switch SW1. Verify that pins 5 and 6 on terminal block TB2 on theTerminals PCB are short circuit and that pins 4 and 6 are open circuit.

Adjust the calibration span control clockwise until alarm 2 just triggers. Verifythat pins 4 and 6 on terminal block TB2 on the Terminals PCB are short circuitand that pins 5 and 6 are open circuit. Verify that the LCD display reads105.0±0.3 % O . Adjust the calibration span control fully clockwise. Adjust the2

coarse span potentiometer RV3, accessible from the edge of the display board,until the LCD display reads 116 % O .2

Adjust the calibration span control slowly counter clockwise until alarm 2 justturns off. The LCD display at this point should be in the range 104.5 to 105.0%O . Continue to adjust the calibration span control fully counter clockwise.2

Verify that the LCD display reading is less than 95 % O .2

Adjust the calibration span control until the LCD display reads 99.7 ±0.1 % O .2


A.11 Noise

Connect a clean, dry nitrogen sample in accordance with Section A.2. Set theoutput to 0-5% O ( range 1 ) using link LK4 on the Housekeeping PCB. Set2

the output range to range 1 on the display panel. Monitor the analogue outputvoltage on pins 1 and 2 at terminal block TB4 on the Terminals PCB on a chartrecorder. Wait until the analogue output voltage has been stable (±1 mV) for atleast 5 minutes.

Measure the peak to peak noise on the analogue output voltage for a five minuteperiod. Verify that the peak to peak noise value measured on the analoguevoltage is less than the values given in the following table.

The noise on the analogue current output is determined by measuring thevoltage across a 100 Ohm resistor. The voltage across this resistor should bemeasured using a chart recorder. Verify that the peak to peak noise valuemeasured on the analogue current is less than the values given in the followingtable.

Sample option Fitted Analogue voltage Analogue currentnoise level noise level

No sample options fitted 1 mV 0.016 mA

AFCD only 1.5mV 0.024 mA

AFCD plus sample pump 3 mV 0.048 mA

AFCD plus back pressure 2 mV 0.032 mAregulator

A.12 Flow alarm operation

If the optional flow alarm hardware is fitted then perform the following tests asappropriate.

a) AFCD only or AFCD and back pressure regulator fitted.

Connect a clean, dry air or nitrogen supply in accordance with sectionA.2, then reduce the sample pressure to zero. Check that the flow alarmindicator is flashing. On terminal block TB2 on the Terminals PCB checkthat pins 7 and 9 are short circuit and pins 8 and 9 are open circuit.

Increase the supply pressure to approximately 1.5 psig and then slowlyreduce to 1 psig. Check that the flow alarm indicator is off. On terminal


block TB2 on the terminals PCB check that pins 8 and 9 are short circuitand pins 7 and 9 are open circuit.

Temporarily block the outlet pipe and ensure that the flow alarm LED isflashing. Remove the blockage.

Slowly reduce the supply pressure until the flow alarm indicator beginsflashing. The sample pressure for the AFCD only should be in the range0.3 to 1.0 psig. With the back pressure regulator fitted the pressure maybe 0.5 psig higher.

b) AFCD and pump fitted.

With the pump operating normally, sampling ambient air, check that theflow alarm indicator is off. On the terminal block TB2 on the TerminalsPCB check that pins 8 and 9 are short circuit and pins 7 and 9 are opencircuit.

Block the inlet and outlet in turn and check that the flow alarm indicatoris flashing in each case. Check on the Terminals PCB that TB2 pins 7and 9 are short circuit and pins 8 and 9 are open circuit.

c) No AFCD fitted.

Connect a clean dry air or nitrogen supply, externally flow regulated, inaccordance with Section A.2.

Reduce the flow alarm to 80 ml/min and ensure that the flow alarm LEDis ON, and TB2 pins 7 and 9 are connected and pins 8 and 9 are opencircuit.

Increase the flow to 120 ml/min and ensure that the flow alarm LED isOFF, and TB2 pins 8 and 9 are connected and pins 7 and 9 are opencircuit.

Xendos 1800 and 1900 Series B.1

APPENDIX B FULL ZERO AND SPAN ANALYSER SET UP

The following procedures are to be used if difficulties are experienced in the setup ofthe analyser. They are intended as a comprehensive guide to the setup and calibrationof the analyser.

B.1 ZERO SETUP PROCEDURES

B.1.1 Transducer 01156A with a 01800902A or a 01800912A display PCB

a. Supply the analyser with zero gas (usually clean, dry nitrogen).b. Set the links on the display PCB (LK1 and LK2) to position B (see figure

5.7, item 2).c. Check that the display of the analyser can be adjusted to <-2% O and2

>2% O , using the front panel zero. If this cannot be achieved, proceed2

to ‘d’. If this can be achieved, proceed to ‘f’.d. Only perform procedure ‘d’, if procedure ‘c’ cannot be achieved.

Set the front panel zero to its mid point (5 turns from either end). AdjustRV1, bottom of the two visible potentiometers on the transducer controlPCB, on the side of the transducer thermal assembly (see figure 5.19,item 13), so as obtain a zero reading on the display PCB of 0±2%O . If2

this cannot be achieved, proceed to ‘e’. If this can be achieved, repeatprocedure ‘c’.

e. Only perform procedure ‘e’, if procedures ‘c’ and ‘d’ cannot be achieved.Carry out the procedures detailed in section 5.9 to remove the Samplingoptions chassis, section 5.16 to remove the transducer assembly andsection 5.21, procedures 8 to 13, so as to setup the mechanical zero ofthe 01156A. Refit transducer assembly and repeat procedure ‘c’.

f. Using the front panel zero, set the display to 0.0% O (0.00% O ).2 2

B.1.2 Transducer 01156A with a 01800902 display PCB

a. Supply the analyser with zero gas (usually clean, dry nitrogen).b. Check that the display of the analyser can be adjusted to <-2% O and2


to ‘c’. If this can be achieved, proceed to ‘e’.c. Only perform procedure ‘c’, if procedure ‘b’ cannot be achieved.

Set the front panel zero to its mid point (5 turns from either end). AdjustRV1, bottom of the two visible potentiometers on the transducer controlPCB, on the side of the transducer thermal assembly (see figure 5.19,item 13), so as obtain a zero reading on the display PCB of 0±2%O . If2

this cannot be achieved, proceed to ‘d’. If this can be achieved, repeatprocedure ‘b’.

B.2 Xendos 1800 and 1900 Series

d. Only perform procedure ‘d’, if procedures ‘b’ and ‘c’ cannot be achieved.Carry out the procedures detailed in section 5.9 to remove the Samplingoptions chassis, section 5.16 to remove the transducer assembly andsection 5.21, procedures 8 to 13, so as to setup the mechanical zero ofthe 01156A. Refit transducer assembly and repeat procedure ‘b’.

e. Using the front panel zero, set the display to 0.0% O (0.00% O ).2 2

B.1.3 Transducer 01158 with a 01800902A or a 01800912A display PCB

a. Supply the analyser with zero gas (usually clean, dry nitrogen).b. Set the links on the display PCB (LK1 and LK2) to position A (see figure

5.7, item 2).c. Check that the display of the analyser can be adjusted to <-2% O and2


to ‘d’. If this can be achieved, proceed to ‘e’.d. Only perform procedure ‘d’, if procedure ‘c’ cannot be achieved.

Carry out the procedures detailed in section 5.9 to remove the Samplingoptions chassis, section 5.16 to remove the transducer assembly andsection 5.21, procedures 8, 9, 10, 11 and 13 so as to setup the zero ofthe 01158. Refit transducer assembly and repeat procedure ‘c’.

e. Using the front panel zero, set the display to 0.0% O (0.00% O ).2 2

B.1.4 Transducer 01158 with a 01800902 display PCB

a. Supply the analyser with zero gas (usually clean, dry nitrogen).b. Check that the display of the analyser can be adjusted to <-2% O and2


to ‘c’. If this can be achieved, proceed to ‘d’.c. Only perform procedure ‘c’, if procedure ‘b’ cannot be achieved.

Carry out the procedures detailed in section 5.9 to remove the Samplingoptions chassis, section 5.16 to remove the transducer assembly andsection 5.21, procedures 8, 9, 10, 11 and 14 so as to setup the zero ofthe 01158. Refit transducer assembly and repeat procedure ‘b’.

d. Using the front panel zero, set the display to 0.0% O (0.00% O ).2 2

B.2 SPAN SETUP PROCEDURES

B.2.1 Transducer 01156A with a 01800902A or a 01800912A display PCB

a. Fit the transducer to the thermal assembly, but do not fit the thermalassembly to the analyser. Connect to the analyser via the ribbon cableof the thermal assembly. Adjust RV2, top of the two potentiometers onthe transducer control PCB, on the side of the transducer thermalassembly (see figure 5.19, item 13), fully clockwise.

Xendos 1800 and 1900 Series B.3

b. Set potentiometer RV3 (coarse span adjustment) on the display PCB(accessible at the side of the display PCB with the front panel open), fullycounter clockwise. Set the front panel span fully clockwise.

c. Supply the thermal assembly with span gas and adjust RV3 on thetransducer control PCB, on the side of the transducer thermal assembly(see figure 5.19, item 13), so that the 0-1V output reads 106±4% of thespan gas concentration. Fit the thermal assembly into the analyser.

d. Set potentiometer RV3 (coarse span adjustment) on the display PCB(accessible at the side of the display PCB with the front panel open), sothat the 0-1V output reads 116±1% of the span gas concentration.

e. Set the front panel span so that the 0-1V output reads 100±0.1% of thespan gas concentration.

f. Adjust RV2 on the terminals PCB (see figure 5.17, item 3), so that the mAoutput reads 100±0.1% of the span gas concentration.

g. Adjust RV2 on the housekeeping PCB (see figure 5.7, item 3), so that thedisplay reads 100±0.1% of the span gas concentration.

B.2.2 Transducer 01156A with a 01800902 display PCB

a. Fit the transducer to the thermal assembly, but do not fit the thermalassembly to the analyser. Connect to the analyser via the ribbon cableof the thermal assembly. Adjust RV2, top of the two potentiometers onthe transducer control PCB, on the side of the transducer thermalassembly (see figure 5.19, item 13), fully clockwise.

b. Set the front panel span fully counter clockwise.c. Supply the thermal assembly with span gas and adjust RV3 on the

transducer control PCB, on the side of the transducer thermal assembly(see figure 5.19, item 13), so that the 0-1V output reads 108±4% of thespan gas concentration. Fit the thermal assembly into the analyser.

d. Set the front panel span fully clockwise and adjust RV2, top of the twovisible potentiometer on the transducer control PCB, on the side of thetransducer thermal assembly (see figure 5.19, item 13), so that the 0-1Voutput reads 116±1% of the span gas concentration.

e. Set the front panel span so that the 0-1V output reads 100±0.1% of thespan gas concentration.

f. Adjust RV2 on the terminals PCB (see figure 5.17, item 3), so that the mAoutput reads 100±0.1% of the span gas concentration.

g. Adjust RV2 on the housekeeping PCB (see figure 5.7, item 3), so that thedisplay reads 100±0.1% of the span gas concentration.

B.4 Xendos 1800 and 1900 Series

B.2.3 Transducer 01158 with a 01800902A or a 01800912A display PCB

a. For new transducers, make sure that the Fine Span on the transducerbody is fully clockwise.

b. Fit the transducer to the thermal assembly, but do not fit the thermalassembly to the analyser, nor fit the thermal boot. Connect to theanalyser via the ribbon cable of the thermal assembly.

c. Set potentiometer RV3 (coarse span adjustment) on the display PCB(accessible at the side of the display PCB with the front panel open), fullycounter clockwise. Set the front panel span fully clockwise.

d. Supply the thermal assembly with span gas and adjust the coarse spanon the transducer so that the 0-1V output reads 108±4% of the span gasconcentration. Fit the thermal assembly into the analyser.

e. Set potentiometer RV3 (coarse span adjustment) on the display PCB(accessible at the side of the display PCB with the front panel open), sothat the 0-1V output reads 116±1% of the span gas concentration.

f. Set the front panel span so that the 0-1V output reads 100±0.1% of thespan gas concentration.

g. Adjust RV2 on the terminals PCB (see figure 5.17, item 3), so that the mAoutput reads 100±0.1% of the span gas concentration.

h. Adjust RV2 on the housekeeping PCB (see figure 5.7, item 3), so that thedisplay reads 100±0.1% of the span gas concentration.

B.2.4 Transducer 01158 with a 01800902 display PCB

a. For new transducers, make sure that the Fine Span on the transducerbody is fully clockwise.

b. Fit the transducer to the thermal assembly, but do not fit the thermalassembly to the analyser, nor fit the thermal boot. Connect to theanalyser via the ribbon cable of the thermal assembly.

c. Set the front panel span fully counter clockwise.d. Supply the thermal assembly with span gas and adjust the coarse span

on the transducer so that the 0-1V output reads 111±4% of the span gasconcentration.

e. Adjust the front panel span fully clockwise and adjust the fine span on thetransducer so that the 0-1V output reads 116±1% of the span gasconcentration. Fit the thermal assembly into the analyser.

f. Set the front panel span so that the 0-1V output reads 100±0.1% of thespan gas concentration.

g. Adjust RV2 on the terminals PCB (see figure 5.17, item 3), so that the mAoutput reads 100±0.1% of the span gas concentration.

h. Adjust RV2 on the housekeeping PCB (see figure 5.7, item 3), so that thedisplay reads 100±0.1% of the span gas concentration.

Xendos 1800 and 1900 Series C.1

APPENDIX C

PRODUCT ENHANCEMENT #1 (Nov 1996)

C.1 Summary of change

This appendix covers the first product changes and enhancements to theXendos 1800, 1900 and 1902 product range implemented in November 1996.The product enhancement covers 5 additions and changes to the originalproduct range.

A brief description of the product enhancements is as follows:

1. The addition of a corrosive resistant sample pipework option.

2. The addition of a sample bypass option extending the sample flow raterange for those analysers configured with metallic internal pipework.

3. The addition of PG13.5 to the list of supplied cable gland adaptors.

4. The replacement of the 0-50% measuring range for the analogue outputswith a 0-2.5% range.

5. Modification of the analogue current output circuitry to limit the maximumanalogue output current to a maximum of 22mA.

The changes resulted in minor modifications to the 01900A1 and 01902A1products, an updated issue number for the Xendos 1800 product plus theaddition of three new product variants to the analyser range. A summarydescription of the changes to the existing products and the new products are asfollows:

Xendos 01800A2

The existing Xendos 1800 analyser (part number 01800A1) has beenreplaced by a later issue (part number 01800A2) and includes all of theproposed product enhancements excepting the corrosive sample option.

Xendos 01802A2

This is a new safe area oxygen analyser for use with solvent containingor corrosive gas samples. It includes all of the proposed productenhancements.

C.2 Xendos 1800 and 1900 Series

Xendos 01900A1

Minor enhancement to include the new PG13.5 cable gland option only.All modifications to the 1900A1 are backwards compatible to all earlieranalyser versions.

Xendos 01902A1

Modified to use a nickel plated paramagnetic measuring cell and hastelloy‘C’ transducer inlet and outlet tubes as standard and to include thePG13.5 cable gland option. All modifications are backwards compatibleto all earlier analyser versions.

Xendos 01900A1EUR

A new version of the Xendos 1900 hazardous area analyser certified byATEX only. This includes all of the proposed product enhancementsexcepting the corrosive sample option.

Xendos 01902A1EUR

A new version of the Xendos 1902 hazardous area analyser certified byATEX only. This includes all of the proposed productenhancements.

C.2 Details of change

C.2.1 Terminals PCB update

A new version of the Terminals PCB has been produced for use in theXendos 1800, 1802, 1900EUR and 1902EUR analysers. The newTerminals PCB has part number 01800913. The new Terminals PCBimplements the analogue output current limit and includes the followingchanges (see drawing number 01800/113).

C Resistor R11 changed to a value of 100kS to modify the gain ofthe operational amplifier IC2.

C Diode D7 is changed to a 6.2V Zener diode type BZX79B6V2 inorder to clamp the maximum voltage applied to the isolationamplifier.

C The voltage applied to the isolation amplifier is divided by usingresistors R12, R20 and R21.


C.2.2 Housekeeping PCB update

A new version of the Housekeeping PCB has been produced for use inthe Xendos 1800, 1802, 1900EUR and 1902EUR analysers. The newHousekeeping PCB has part number 01800911. The new HousekeepingPCB implements the output gain range modifications and includes thefollowing changes (see drawing number 01800/111).

C Resistor R47 is changed to a value of 51kS.C Resistor R46 is changed to a value of 4.7kS.C Resistor R50 is changed to a value of 40kS.C Resistor R71 is changed to a value of 10kS.C Resistor R52 is changed to a value of 5kS.

The new resistors change the ratios of the IC12 operational amplifier inorder to implement the following analogue output ranges: 0-2.5%, 0-5%,0-10%, 0-25% and 0-100%.

C.2.3 Xendos 1802 and 1902 transducer assembly modification

The transducer assembly used in the existing Xendos 1902 and the newXendos 1802 and 1902EUR analysers has been modified to becompatible with corrosive as well as solvent containing sample gases.The changes are as follows:

C The paramagnetic measuring cell in the 1156A701 transducer hasbeen modified to use a nickel plated version of the existing 364cell.

C The material used for the transducer inlet and outlet sample tubeshas been modified from stainless steel to Hastelloy ‘C’.

The modification is backwards compatible to all earlier 1902 analyserswithout effecting hazardous area certification. This enhancement isprovided as standard on all Xendos 1802, 1902 and 1902EUR analysers.

1

2

3

8

9

7

6

5

4

1. Hastelloy Bulkhead connector. 6. Anti rotation plate.2. PTFE ferrule set. 7. Plate mounting screws.3. Bulkhead holding nut. 8. PFA 1/8" equal union.4. Swagelock nut. 9. Hastelloy sample tubes.5. Washer.


Figure C.1 - Corrosive sample pipework option

C.2.4 Corrosive sample pipework option

Refer to Figure B.1.

A new option has been provided for use with corrosive samples. The newoption is available on the new Xendos 1802 and 1902EUR analysers.The new option is similar to the existing stainless steel pipework optionbut with the following changes:

C A Hastelloy C, 1/4" NPT threaded, bulkhead for user sampleconnections.

C Hastelloy C internal sample tubes.C A PFA 1/8" equal union connecting the internal sample tubes and

the transducer inlet and outlet tubes .

1

8

9

10

2

4

5

36

7

1. Hastelloy Bulkhead connector. 6. Anti rotation plate.2. PTFE ferrule set. 7. Plate mounting screws.3. Washer.. 8. PFA 1/8" equal tee.4. Bulkhead holding nut.. 9. Hastelloy sample bypass tube.5. Swagelock nut. 10. Hastelloy sample tubes.


Figure C.2 - Corrosive sample bypass pipework option

C.2.5 Sample bypass option

Refer to Figure B.2.

A new option has been introduced to implement a sample bypass for usewith higher sample flow rates. The new option is available on the newXendos 1802 and 1902EUR analysers. Two versions of the bypassoption are provided for use with the stainless steel and hastelloy Cpipework options. The design of the bypass option is to use twoproprietary tee fittings with the 1156 transducer fitted across the branchport of the tee. The sample bypass consists of a stainless steel orHastelloy C pipe 1/8" outside diameter and 120 mm long.


Figure C.3 - Stainless steel sample bypass pipework option


PRODUCT ENHANCEMENT #2 (July 2000)

C.3 Summary of change

This appendix covers the enhancements to the Xendos 1800 and 1900 Seriesimplemented in May 2000.

A brief description of the product enhancements is as follows.

The xendos 1800 and 1900 Series has been raised to revision B1. This includesnew features and options codings and improvements to the Terminals board, theDisplay board and a new Transducer.

C.4 Details of change

C.4.1 Terminals board update

The Terminals board (01800913B) now has an improved current output circuitmore compatible with data-logging systems and shows improved temperaturestability. It is fully retro-fitable in all xendos 1800 and 1900 Series analysers.

C.4.2 Display board update

The 3.5 digit Display board (01800902A) update was required to provide theoption of reversing the operating direction of the front panel Zero control for thenew 1158 Transducer. In addition a course span control is now provided on thedisplay board to increase the range of operation of the front panel Span control.A new version of the optional 4.5 digit Display board (01800912A) is alsoavailable with the same improvements as the 3.5 digit Display board. Bothboards are fully retro-fitable in all xendos 1800 and 1900 Series analysers.

C.4.3 Transducer update

The Transducer used in the xendos 1800 and 1900 Series analysers is now the1158 paramagnetic oxygen transducer. A complete transducer assembly isavailable enabling it to be used for spares requirements.A new High-Flow cell is also available which removes the requirement for apiped bypass in the high flow analyser option.


Documents

Servomex 1800-1900 Manual