ED-2002-015 8 Ch Analog Input Module (4308).pdf

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Messung Systems NEXGEN PLC I/O Modules

8 Ch Analog Input Module (4308) Published Feb 2004Document No.: ED-2002-015/V1.01 Page 1 of 38

NEXGEN PLC

8 Channel Analog Input Module

(Ordering Code 4308)

Document No.:ED-2002-015

Version: 1.01

MESSUNG SYSTEMSEL-2, J- Block MIDC Bhosari,

Pune 411026.(INDIA)

Tel: (+91)-020-2712 0807, 2712 2807.Email : [email protected]

WEB:www.messung.com
mailto:[email protected]:[email protected]://www.messung.com/http://www.messung.com/http://www.messung.com/http://www.messung.com/mailto:[email protected]


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INDEX

1. Module Overview ............................................................................................................71.1 Analog Input Module Overview...................................................................................71.2 LED Indications...........................................................................................................91.3 General Specifications..............................................................................................10

2. Module Operation .........................................................................................................112.1 Block Diagram...........................................................................................................112.2 Analog Input types and range of binary values.........................................................122.3 On-Board Processor Operations...............................................................................12

2.3.1 Power On Operations..........................................................................................122.3.2 Analog to Digital Conversion...............................................................................132.3.3 Averaging ............................................................................................................14

2.4 Module Information ...................................................................................................152.4.1 Input Output Image Mapping...............................................................................152.4.2 Memory Mapping ................................................................................................162.4.3 Commands..........................................................................................................172.4.4 Module Status Bits ..............................................................................................17

3. Installations and Wiring ...............................................................................................183.1 Module Installation....................................................................................................183.2 Connection Details....................................................................................................183.3 Precautions to be taken ............................................................................................20

4. Configuration and Programming ................................................................................214.1 Slot Configuration .....................................................................................................214.2 Channel Configuration ..............................................................................................224.3 Programming with Nexgen 4000 CPU......................................................................264.4 Programming with Nexgen 5000 CPU......................................................................30

5. Troubleshooting ...........................................................................................................355.1 LED Indications for Diagnostics................................................................................36


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NEXGEN PLC I/O Modules Messung Systems

Published Feb 2004 8 Ch Analog Input Module (4308)Page 4 of 38 Document No.: ED-2002-015/V1.01

Index of Figures

Figure 1 : Front View.................................................................................................................8Figure 2 : Block diagram .........................................................................................................11Figure 3 : ADC Conversion Cycle ...........................................................................................13Figure 4 : Input Output Image Mapping...................................................................................15Figure 5 : Memory Mapping ....................................................................................................16Figure 6 : Connection diagram................................................................................................19


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Guidelines for the Safety of the user and protection of I/O Modules.

This manual provides information for the use of the I/O Modules. The manual hasbeen written to be used by trained and competent personnel. The definition of such aperson or persons is as follows:

a) Any engineer who is responsible for the planning, design and construction ofautomatic equipment using the product associated with this manual should be of acompetent nature, trained and qualified to the local and national standards required tofulfill that role. These engineers should be fully aware of all aspects of safety withregards to automated equipment.

b) Any commissioning or service engineer must be of a competent nature, trained andqualified to the local and national standards required to fulfill that job. These engineersshould also be trained in the use and maintenance of the completed product. ThisIncludes being completely familiar with all associated documentation for the saidproduct. All maintenance should be carried out in accordance with established safetypractices.

c) All operators of the completed equipment should be trained to use that product in asafe and coordinated manner in compliance to established safety practices. The

operators should also be familiar with documentation, which is connected with theactual operation of the completed equipment.

Note: The term-completed equipment refers to a third party constructed device, whichcontains or uses the product associated with this manual. Note on the Symbol used inthis ManualAt various times through out this manual certain symbols will be used to highlightpoints of Information, which are Intended to ensure the users personal safety andprotect the integrity of equipment. Whenever any of the following symbols areencountered its associated.

Note must be read and understood. Each of the symbols used is listed below; with abrief description of its meaning.

Warning !

This product can only function correctly and safely if it is transported,stored, setup, and installed correctly, and operated and maintained asrecommended.

Warning !

The specifications of product and contents of manual are subject tochange without notice.


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1. Module Overview

This chapter describes the followingAnalog Input Module Overview

LED IndicationsGeneral Specifications

1.1 Analog Input Module Overview

This analog input module converts input voltage or current values into equivalentbinary values. This is sigma - delta type A/D conversion. It provides 8 non-isolated channels. The individual channel can be configured for specific typeof voltage or current input. The voltage and current ranges are

-10 to 10V0 to 10 V0 to 5 V

1 to 5 V0 to 20 mA4 20 mA

The resolution of ADC is 305.176 V / 1.221 A for voltage / current input irrespectiveof range. The parameters that are passed to the module for advancedprocessing are

input filter frequency (50 / 60 / 250 / 500 Hz)open circuit valuenumber of averaging samples

The module provides diagnostic information for each channel. It includes open circuit

invalid configuration

This is an intelligent module with on-board processor and memory. The data transferbetween CPU module and analog input module takes place by 'READ_W' /IM_Read and 'WRITE_W' / IM_Write functions in the application program.The module status is available in input image and commands can be issuedthrough output image.

The figure on next page shows front view of analog input module


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01

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COM 0

V IN0

V IN1

I IN0

I IN1

COM 1

+ 24 V

GND

EARTH

COM 2

V IN2

V IN3

I IN2

I IN3

COM 3

COM 4

V IN4

V IN5

I IN4

I IN5

COM 5

COM 6

V IN6

V IN7I IN6

I IN7

COM 7

NO 24 V SUPPLY

CPU ERROR

CONF. ERROR

CH0

CH1

CH2

CH3

CH4

CH5

CH6

CH7

4308ANALOG INTPUT

8 CH V/I

Figure 1 : Front ViewThe module provides LED indications on the front. Brief information about channel can

be written on the front door. Below the front door, 38-pin removable terminalblock is provided for interfacing analog signals. The connection details areshown on backside of the front door.

Front ShieldPlate

Terminal BlockFixing Screw

ConnectionDetails

Front Door

IO Label

LEDIndications

Channe

StatusLEDs

ModuleStatusLEDs

Terminal BlockFixing Screw

38 PinTerminalBlock


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The analog module can be configured in any IO slot of the PLC. The number of analoginput modules is limited by back panel current capacity. In general a channelrequires following information

registers to hold configuration information (2 words)register to hold data (1 word) andregisters to hold status information (1 word)

1.2 LED Indications

The following table explains significance of 11 numbers of LEDs provided on themodule.

No. LED Color Status DescriptionOFF 24 VDC supply to module healthy.

24 VDC supply to module absent.1 NO 24 V SUPPLY OrangeON

24 VDC circuit on-board glass fuse blown.OFF Module hardware healthy and module is ready.

Module in self test.

CPU watchdog faulty.2 CPU ERROR Orange

ONModule busy.

OFF Channel configuration valid.3 CONF. ERROR Orange

ON Channel configuration invalid.OFF Channel not enabledON Channel enabled and healthy

Open circuit for input type 1- 5 VDC and 4 -20 mA.Over range

4Channel Status(Eight for eightchannels)

GreenFlashing

Under range


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1.3 General Specifications

General specifications of 8 channel analog input module are as given below.

Number of Input channels 8 Non isolated.

Conversion Method Sigma Delta-10 to 10 V DC0 to 10 V DC0 to 5 V DC

Voltage

1 to 5 V DC0 to 20 mA

Analog Inputtypes

Current4 to 20 mAFilterfrequency

Channel Updatetime

Significant bits

50 Hz 60 ms 16 bits60 Hz 50 ms 16 bits250 Hz 12 ms 13 bits

Analog to Digital conversion time

500 Hz 6 ms 10 bitsDigital output -32768 to 32767

Voltage / Current range Significant bits Resolution per LSB-10 to 10 V DC 16 bits 305.176 V0 to 10 V DC 15 bits 305.176 V0 to 5 V DC 14 bits 305.176 V1 to 5 V DC 13.67 bits 305.176 V0 to 20 mA 14 bits 1.2207 A

Number ofsignificant bits( With 50 Hzfilter )

4 to 20 mA 13.67 bits 1.2207 AAmbient at 25C, 5C Ambient at 58C, 5CAccuracy at filter frequency 50 HzLarger value 20 counts or0.1 % of FSD

Larger value 60 counts or0.3 % of FSD

Channel to channel NoIsolation

Channel to internal circuit 1.5 KV opticalVoltage 15 VDCAbsolute maximum

input Current 30 mAVoltage 1 M Ohms

Input ImpedanceCurrent 250 Ohms

External voltage requirement 24 V DC, 200 mA (18 to 30 VDC including ripple)External supply protection 315 mA miniature glass fuse on module

Reverse polarity protection

Indications

No 24 V Supply CPU error Configuration error Channel status (8 nos.)

Back-plane current consumption 210 mAIO points consumed 8 input bits and 8 output bitsTermination Removable 38 pin terminal blockOrdering code 4308


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2. Module Operation

This chapter helps in getting started with the analog input module. It describes thebasic operation of the module. This chapter explains operational details of:

Block Diagram

Analog input Types and Range. On-Board Processor Operations Module Information

At the time of application program development, the module can be configured usingthe programming software so that above special features can be used..

2.1 Block Diagram

Block diagram of analog input module is shown below.

Figure 2 : Block diagram

CPUModule

+ 5 V

GND

/ Analog to

DigitalConverter

OPTICAL

ISOL

ATION

On boardProcessor

Memory forConfiguration,Data, StatusInformation

ModuleInterfaceCircuit

WatchDog

Amplifier

Multiplexer

DC-to-DCConverter

+15 V

-15 V

+5 V

-5 V

+ 24 VDC

GND

EarthGND

No 24 V Supply

Supply forADC Circuit

V IN0

I IN0

COM0250

22 K

4K7PF

Tranzorb

Analog Ground

V IN7

I IN7

COM7250

22 K

4K7PF

Tranzorb

Analog Ground


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The module provides eight analog to digital channels for voltage/ current input. CPUbus is optically isolated from ADC circuit. ADC operates on the data from thechannels. The enabled channel input signals are multiplexed and thenamplified for ADC input. Thus sigma-delta (/ ) ADC converts only enabledanalog channels to digital value one by one. The converted count for eachchannel is manipulated by on-board processor and binary data is transferred

to module memory, which holds channel data information.

If averaging is required, depending on the averaging count, on-board processorperforms averaging of those many previous readings and updates channeldata information.

The configuration, data, status information is available in dual port RAM on themodule. The configuration of all channels is transferred to the module memoryusing WRITE_W / IM_Write function in the application program. Similarly dataand status of all channels can be read by READ_W / IM_Read function in theapplication program.

The module requires external 24 VDC supply for ADC circuit operation. Internally DC-to-DC converter generates 15 VDC and 5 VDC as required by each

channel. If 24 VDC is absent or on-board glass fuse is blown, modulegenerates 'No 24 V Supply' signal for main CPU. The fuse protection forexternal 24 VDC supply is provided on module.

2.2 Analog Input types and range of binary values

This section describes the analog input types and data range of binary values.

Input Type Binary Value Range

-10 to 10 VDC -32000 to 320000 to 10 VDC 0 to 320000 to 5 VDC 0 to 160001 to 5 VDC 3200 to 16000

0 to 20 mA 0 to 160004 to 20 mA 3200 to 16000

2.3 On-Board Processor Operations

The analog input module is intelligent module with on-board processor. The functionsof on-board processor are explained in the sections below.

2.3.1 Power On Operations

After power ON, if 24 V supply to module is absent or on-board fuse is blown then on-board processor sets Ix.0 bit of input image. After power ON, this processorcarries out self test. During self-test and if hardware error is detected, Ix.0 bitis set. Also CPU fault LED on front panel is put ON indicating that module isnot accessible. During module operation, if module hardware is found faulty orwatchdog error is detected, Ix.0 bit is set.


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If the module hardware is OK, Ix.0 bit is cleared. The module waits for configurationfrom the CPU module. After reception of valid configuration of input channels,the module starts sampling and digital conversion cycle of enabled channels.

The module continues sampling, converting the channels and updating modulememory even after the PLC is put in STOP mode. But In this case, CPUmodule does not read the channel data and status.

2.3.2 Analog to Digital Conversion

The module samples the input channel and converts voltage or current input to itsdigital value one by one. After power on, as shown in the figure below, onlyenabled channels are converted. If any error like invalid configuration isdetected, channel is not converted. The disabled channels are bypassedretaining earlier values. After one channel conversion, module initiates nextchannel conversion. During this conversion period, module processesconverted data of previous channel. This process includes averaging as perconfiguration. Thus the processed data for previous channel is made availableduring this period. After converting all healthy channels, processed data andstatus information of all the channels is transferred to respective memory areaon the module. This cycle continues. Thus when the processor moduleperforms READ_W operation, it reads either old or new information i.e. dataand status of channels.

Figure 3 : ADC Conversion Cycle

The module takes certain time to sample all enabled channels and convert into digitalvalue. The required time is the module update time. The factors affectingmodule update time is filter frequency selected and number of channelsenabled. The module update time is minimum when only one channel is

enabled. Likewise the module update time is maximum when all channels areenabled.

Channel 0disabled

Channel 1disabled

Channel 2disabled

Channel 3disabled

Channel 7disabled

Channel 6disabled

Channel 5disabled

Channel 4disabled

Channel 0Conversion

Channel 1Conversion

Channel 2Conversion

Channel 3Conversion

Update allchannel dataand status

Channel 7Conversion

Channel 6Conversion

Channel 5Conversion

Channel 4Conversion


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The module incorporates a digital low pass filter to reject noise on the input signal. Thedigital filter is programmable. It provides better noise rejection for low filterfrequencies. Its noise rejection decreases as filter frequency is increased. Alsofilter frequency affects channel update time. The channel update time reducesas filter frequency is increased. The following shows update times required fordifferent filter frequencies.

Filter Frequency Channel Update time50 Hz 60 ms60 Hz 50 ms250 Hz 12 ms500 Hz 6 ms

2.3.3 Averaging

The module provides user selectable averaging facility so that stable value is availablefor processing and necessary control action. The module samples andconverts enabled channels one by one. The module keeps digital value into

different memory locations. Depending on the averaging count, the moduleperforms averaging of those many previous readings and updates channeldata information.

Thus if the averaging counts of channel 0, 1 and 2 are 0, 4 and 8 respectively, theninitially data of channel 0, 1 and 2 are updated after 1, 4 and 8 conversioncycles respectively. After that, it gets updated in every cycle. One conversioncycle means sampling and converting all enabled channels as explained inchapter 2.3.2.Thus combination of filter frequency and averaging count canbe selected to get optimum channel update time and stable temperaturereading.


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2.4 Module Information

This section explains the entire information required and available with analog inputmodule. The following points are discussed.

Input Output Image Mapping Memory Mapping Commands Module Status Bits

2.4.1 Input Output Image Mapping

Input output image mapping related to analog input module is shown below.

Figure 4 : Input Output Image Mapping

The module consumes 8 input bits (1 byte) of input image and 8 output bits (1 byte)of output image. CPU reads the status of module in input scan. CPU writesuser commands to module in output scan. For immediate updation of inputand output image in application program, IMM_IN / Refresh_In and IMM_OUT

/ Refresh_Out functions can be used in application program wheneverrequired. For the details refer chapter 2.4.3and 2.4.4.

CPU Module

Input ImageNo 24 V Supply or

CPU fault. Ix.0Invalid configuration

or out of range.Ix.1

ModuleInterface

circuit

Output ImageAuto calibration Qx.0

Input Scan

Logic Scan

SLOT

ENO

IMM_IN

EN

Output Scan

Logic Scan

SLOT

ENO

IMM_OUT

EN

Channel 0

Channel 1

Channel 2

Channel 3

Channel 4

Channel 5

Channel 6

Channel 7

Analog Input Module


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2.4.3 Commands

As discussed in chapter 2.4.1,output image bits are used as user commands tomodule. User can issue various commands to module through application

program. CPU writes commands in output image area of module in outputscan. The module reads output image area cyclically and takes appropriateaction. If 'IMM_OUT' / Refresh_Out function is executed in logic scan for aparticular slot, it stops current logic scan, executes output scan for defined slotand resumes logic scan again. This is useful when ever immediate updation ofoutput image is needed. The functions of output image bits are given below.

No.Bit

AddressCommand Status Description

ON It gives command to ADC to calibrate itself.1 Qxx.0

AutoCalibration

OFF Auto calibration command is OFF.

Note Qxx.1 to Qxx.7 are reserved and should not be used.

Normally, ADC is calibrated during self test after power ON and when ever 24 VDCpower to the module is switched ON. Also, it is calibrated at regular intervalduring operation. The output image bit Qxx.0 is additional facility to the user tocalibrate ADC when ever required.

2.4.4 Module Status Bits

As discussed in chapter 2.4.1,input image bits are used as module status indications.User can check the module status through application program. The modulewrites status in its input image area cyclically. The CPU reads this input imagearea in input scan. If 'IMM_IN' / Refresh_In function is executed in logic scanfor a particular slot, it stops current logic scan, executes input scan for defined

slot and resumes logic scan again. This is useful when ever immediateupdation of input image is needed. The functions of input image bits are givenbelow

No. Bit Address Module Status Status Description24 VDC supply to module absent24 VDC circuit fuse blown.Module CPU watch dog fault.

ON

Module not ready.24 VDC Supply to module healthy

1 Ixx.0 Module Not Read

OFFModule healthy and readyInvalid static configuration

ONParameter mismatchValid static configuration

2 Ixx.1InvalidConfiguration or

Open circuit OFF Valid parameters

Note Ixx.2 to Ixx.7 are reserved and should not be used.

Whenever accessing the module, user must check the module status bit Ixx.0.


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Figure 6 : Connection diagram

In figure, first channel is configured for voltage input where as fourth channel isconfigured for current input.

For interfacing analog signals, 38 pin removable terminal block is provided. Thevoltage input is connected to terminals V INnand COMn. Here n is channelnumber from 0 to 7. Current Input is connected to terminals I INnand COMn.To connect current input, short terminals V INnand I INnfor respectivechannel. This is shown for the channel 3 in figure.

Voltage Input connectedto channel 0

+ 24 VDCGND

EARTH

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V IN0

V IN1

I IN0

I IN1

COM 1

+ 24 V

GND

EARTH

COM 2

V IN2

V IN3

I IN2

I IN3

COM 3

COM 4

V IN4

V IN5

I IN4

I IN5

COM 5

COM 6

V IN6

V IN7

I IN6

I IN7

COM 7

+

-

Current Input connected tochannel 3


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Being susceptible to industrial noise, analog signal is to be carried out on the fieldthrough shielded twisted cable. Connect both ends of shield to Earth busbarin control panel.

For functioning of analog input module, external 24 VDC supply is required. Connect24 VDC supply between terminals 36 (+ 24 V) and 37 (GND). Connect terminal38 to earth busbar in the control panel.

3.3 Precautions to be taken

All the normal precautions concerning the wiring and protection of an electronicequipment in an industrial environment should be observed. To guard againstcoupling noise from one conductor to another, follow the guidelines givenbelow.

Inside control panel

Following guidelines to be observed inside control panel.

All power circuit wiring e.g. connected to Power Supply Module, powercontactors, etc i.e. high voltage wiring should be kept separate andapart from analog signals.

Digital Input wiring and Digital Output wiring (especially, relay outputand AC output) should be separately bundled and kept as apart aspossible from analog signals.

Analog signals should be carried through shielded cables.

Outside control panel

Following guidelines to be observed outside control panel.

Depending upon the type of modules used in PLC, separate ducts should be providedfor

Power circuit wiring and power cables. Input cables. Output cables. All cables carrying low level signals for analog IO modules,

thermocouple/ RTD input modules, for communication, high frequencypulse input and output.

Wherever possible, it is recommended to Avoid parallel routing of cables carrying analog signals and power

cables, etc over long distances Ensure that cables carrying analog signals cross at right angles to

power cables so that minimum length of cable will be in close vicinityof power cables.

Run cables on metallic surfaces Avoid number of joints Keep cable lengths as short as possible.


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4.2 Channel Configuration

The analog input module can be configured in any slot of the PLC. The 8 channelscan be independently configured for different types of analog inputs.

After power on the configuration of one or more channels can be transferred to themodule using WRITE_W / IM_Write function. The PLC variables hold channel

configuration. The channel configuration information includes Input typeFilter frequencyOpen circuit valueChannel Enable

Averaging

The configuration of channels is to be written at module memory adress starting from256. This information is stored in bit form in 2 consecutive words for eachchannel. The tables below give information required to configure any channel.The valid combination of bits must be set. Any invalid combination of bits mayresult in unpredictable module operation.

Configuration word 1 for a channel -

Item Description 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0-10 to +10V 0 0 0 0 00 to 10V 0 0 0 0 10 to 5V 0 0 0 1 01 to 5V 0 0 0 1 10 to 20mA 0 0 1 0 0

InputType

4 to 20mA 0 0 1 0 150 Hz 0 0 060 Hz 0 0 1250 Hz 0 1 0

Filterfrequency

500 Hz 0 1 1Zero 0 0Upper scale 0 1

Lower scale 1 0

Open

CircuitValueInvalid 1 1

Reserved -- 0Disabled 0Channel

Status Enabled 1Reserved 0 0 0 0

Configuration Word 2 for a channel -

Item Description 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 00 0 04 0 18 1 0

Averaging

16 1 1


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The module detects open circuit of a channel for 4-20 mA and 1 to 5 V input types. Insuch open circuit condition, the channel value can be set to any one of aboveoptions considering safety in control action. If such open circuit is detected fora channel, corresponding channel LED starts flashing.

Channel Enable

Bit11 defines the enable status of the channel. If it is 0 Channel is disable and if it is1 Channel is enable. The module samples only enabled channels andconverts into digital value. Thus enabling only used channels can minimize thechannel update time.

Bit12 to Bit15 are reserved and these must be 0

Averaging

Next two Bits, Bit16 and Bit 17 define the selection of sampling value for averaging.

Bit16 Bit17 Averaging Sample0 0 No0 1 41 0 81 1 16

The module provides averaging facility so that stable value is available for processingand necessary control action. The module samples and converts enabledchannels one by one. The module keeps digital value into different words.Depending on the averaging count, the module performs averaging of thosemany words and updates channel data information.

Thus if the averaging counts of channel 0, 1 and 2 are 0, 4 and 8 respectively, then

data of channel 0, 1 and 2 are updated every 1, 4 and 8 conversion cyclesrespectively. One conversion cycle means sampling and converting allenabled channels. Thus combination of filter frequency and averaging countcan be selected to get optimum channel update time.

Channel Data

The module memory words MMW #0 to MMW #14 are module memory words forchannel data. For enabled channels, this information is updated cyclically inmodule. The data is read and stored in PLC variables using READ_W /IM_Read function in application program.

MMW#0 Channel 0 dataMMW#2 Channel 1 data

MMW#12 Channel 6 dataMMW#14 Channel 7 data


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Channel Status

The module continuously updates status of all channels into its memory. Theprocessor module can read the status information as required using READ_Wfunction. This information is also useful to check validity of configuration data.

This status information is stored in bit form in one word for each channel starting frommodule memory address 16. The following table gives status bit informationavailable.

Item Description 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0-10 to +10V 0 0 0 0 00 to 10V 0 0 0 0 10 to 5V 0 0 0 1 01 to 5V 0 0 0 1 10 to 20mA 0 0 1 0 0

InputType

4 to 20mA 0 0 1 0 150 Hz 0 0 0

60 Hz 0 0 1250 Hz 0 1 0Filterfrequency

500 Hz 0 1 1Zero 0 0Upper scale 0 1Lower scale 1 0

OpenCircuitValue

Invalid 1 1Reserved -- 0

Disabled 0ChannelStatus Enabled 1

Valid 0ConfigInvalid 1No open circuit 0Open

Ckt. Open circuit 1No under range 0Under-

range Under range 1No over range 0Over

range Over range 1

The copy of Bit 0 to Bit 11 from configuration word is available in status word as it is.This information is useful to check validity of configuration as written byWRITE_W function when ever configuration is set or modified. The applicationprogram should confirm validity of configuration before reading channel data.

MMW#16 Channel 0 statusMMW#18 Channel 1 status

MMW#28 Channel 6 statusMMW#30 Channel 7 status

The copy of Bit 0 to Bit 11from configuration word.


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Configuration Error

Bit 12 of status word is set ifInvalid configuration is writtenBit 12 to 15 in configuration word are non zero

If configuration error bit is set, configuration Error LED ( yellow colour )on moduleglows.

Open Circuit Error

Open circuit detection is applicable forInput type 1 to 5 VInput type 4 to 20 mA

Bit 13 of status word is set ifInput voltage is less than 0.75 V for input type 1 to 5 VInput current is less than 3 mA for input type 4 to 20 mA

If open circuit error bit is set for a channel , corresponding input indication LED (green

colour) on module starts flashing. The channel data holds the data as perconfiguration. It can be zero or upper scale reading or lower scale reading.

4.3 Programming with Nexgen 4000 CPU

The configuration data in PLC variables is transferred to the analog input modulewhen 'WRITE_W' function is executed. The data in the PLC variables can beupdated using functions like 'MOV_W', arithmetic or any other functions. Thedata from analog input module memory can be transferred to PLC variableswhen 'READ_W' function is executed.

The WRITE_W function below shows data transfer from the CPU module's memory toanalog input module memory. The details of transfer are - The analog input module is configured in slot 2 of PLC Start address of memory on the CPU module is MW50 Length of data area to be transferred is 16 words Address on the analog input module in slot 2 is #256


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When 'WRITE_W' function is executed successfully, ENO output becomes ON, WhenENO is ON, set 'Static Configuration Write' command bit informing the moduleto accept the static configuration or change in configuration. Once thisinformation is transferred to module, it is valid as long as PLC power ispresent. It is recommended to enable 'WRITE_W function when

Warm start is observed i.e. System bit S0.6 is ON

Cold start is observed i.e. System bit S0.7 is ON Module Error bit becomes OFF i.e. System bit S4.2 is ON Module Not OK bit becomes OFF i.e. Input bit I8.0 is ON.

S0.6 ------ WRITE_W ---- M3.0+---| |---+---------+---------|EN ENO|-+---(S )---

| | |S0.7 | | |

+---| |---+---------| #2 -|SLOT || | |

S4.2 M0.4 | | |+---| |---+---|N|---| MW66 -|DATA |

| | |I8.0 M0.5 | | |

+---| |---+---|N|---+ #16 -|LEN |

| || |

#256 -|ADDR || |-------------------

S4.2 M3.4 M3.0+---| |---+---|P|---+---------|--------|---------|---(R )---|

||

I8.0 M3.5 |+---| |---+---|P|---

If 'WRITE_W' function is executed, M3.0 bit is set. If this bit is not ON even if function

enable conditions are ON, declare fault and take appropriate action. The bitM3.0 is reset. If any error is detected.

After transferring configuration data to analog module memory, module configures thechannels and starts functioning accordingly. It takes about 500 ms time formodule to take necessary action if configuration is changed. So after a properdelay (say 1 sec), enable 'READ_W' function. When 'READ_W' function isexecuted, the binary values of channels stored in module memory MMW#0 toMMW#14 are transferred to CPU memory MW#100 to MW#114 respectively.

M3.0 S4.2 I8.0 ---- TON100MS ----- M3.1+---| |---+---|/|---+---|/|---|EN ENO|-+---( )---

| || |

#10 -|PT ET || || |

T#10 -|TNO || |

---------- -------------------


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The IM_Write function below shows data transfer from the CPU module's memory toanalog input module memory. The details of transfer are -

The analog input module is configured in slot 2 of PLC The configuration information is stored in an 16 word array Config Length of data area to be transferred is 32 bytes Address on the analog input module in slot 2 is 256

'IM_Write' function gets executed when BOOLean input 'Config_Wr' is TRUE.BOOLean output 'Config_Dn' becomes TRUE, when function is executedsuccessfully. It is is FALSE if

Parameters of function are invalid or not within specified range. analog input module is not accessible to CPU module

So 16 words configuration information from CPU memory is transferred to the memoryat address 256 onwards of analog input module fitted in slot 2.

The 'IM_Read function shows data transfer from the analog input module memory toCPU memory. The details of transfer are -

The analog input module is configured in slot 2 of PLC Address on the analog input module in slot 2 is 0

The data to be stored in PLC variable array AIData Length of data area to be transferred is 8 words


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Configuration Word 1 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 016#801 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 1

Configuration Word 2 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 016#3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1

So configuration words should contain 2049(16#801) and 3, for the configurationrequired. This information is transferred to analog module memory MMW256to MMW286, when 'IM_Write' function is executed. The application programrequired to handle analog input module is shown below along with commentsand PLC variable declaration.

Reserved Returnvalue ofupper

scaleChannelEnable

50 HzFilter

010 VDC type oinput

16averaginsamples

Reserved


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Once analog input data is read successfully, the data can be processed as theapplication requirement. If anaolg input data read is to be displayed on HMI orSCADA, the varaible AIData should be mapped to any memory varaible whiledeclaration like


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Here the analog input data for the channels is stored in memory variable %MW100 to%MW114 in integer format. Channel 0 data is stored in %MW100 whilechannel 7 data is stored in %MW14.

If input image bit %IX4.0 or %IX4.1 is TRUE, the appropriate error should be declaredand further processing of anaolg input data read should be hold.

If input image bit %IX4.1 is TRUE, the status of all the channels can be read andindividual channel error and exact cause can be located with the help of anapplication program as shown below.


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5. Troubleshooting

In this chapter, following points related to analog input module are discussed.

LED Indications for diagnostics

5.1 LED Indications for Diagnostics

The following table explains significance of LED provided for module status anddiagnostic purpose on the module.

No. LED Color Status DescriptionOFF 24 VDC supply to module healthy.

24 VDC supply to module absent.1 NO 24 V SUPPLY OrangeON

24 VDC circuit on-board glass fuse blown.OFF Module hardware healthy and module is ready.

Module in self test.CPU watchdog faulty.2 CPU ERROR Orange ONModule busy.

OFF Channel configuration valid.3 CONF. ERROR Orange

ON Channel configuration invalid.OFF Channel not enabledON Channel enabled and healthy

Open Circuit for input type 1- 5 VDC and 4 -20 mA.Over range

4Channel Status(Eight for eightchannels)

GreenFlashing

Under range


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Published Feb 2004 8 Ch Analog Input Module (4308)Page 38 of 38 Document No : ED-2002-015/V1 01

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NEXGEN PLC I/O Modules8 Channels, Analog Input Module (Ordering Code 4308)

Document No.: ED-2002-015

Documents

ED-2002-015 8 Ch Analog Input Module (4308).pdf