AISG RET SupportGSM RBS 6000

DESCRIPTION

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Copyright

© Ericsson AB 2013–2014. All rights reserved. No part of this document may bereproduced in any form without the written permission of the copyright owner.

Disclaimer

The contents of this document are subject to revision without notice due tocontinued progress in methodology, design and manufacturing. Ericsson shallhave no liability for any error or damage of any kind resulting from the useof this document.

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Contents

Contents

1 Introduction 1

1.1 Benefits 1

1.2 Additional Information 2

2 Feature Overview 2

2.1 RET Hardware 42.1.1 Mechanical and Electrical Antenna Tilts 42.1.2 RET Types 5

2.2 Hardware Configurations 52.2.1 Configurations Supported in BTS G14A 62.2.2 Configurations Supported from BTS G14B and Higher 7

2.3 Parameters 9

3 Function 11

3.1 AISG RET Control Infrastructure 113.1.1 Macro RBS Infrastructure 123.1.2 Main-Remote RBS Infrastructure 14

3.2 AISG RET Feature Control 15

3.3 RET Unit Tilt Handling 16

3.4 RET Alarm Handling 16

3.5 Cascaded RET Support 17

3.6 RET Control in AIR 18

4 Operation and Maintenance Functions 19

4.1 Activating the Feature 19

4.2 Connecting RET Units 19

4.3 Configuring RET Units 20

4.4 Monitoring RET Units 21

4.5 Performing RET Unit Control and Operations 24

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AISG RET Support

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Introduction

1 Introduction

This document describes the Remote Electrical Tilt (RET) support function andconfiguration management of Antenna Line Devices (ALD) compatible withversion 2 of the Antenna Interface Standards Group (AISG) 3rd GenerationPartnership Project (3GPP) Iuant interface.

An ALD is a generic term referring to a physical tower-mounted device suchas a Tower-Mounted Amplifier (TMA) or RET unit that incorporates digitalremote control and monitoring facilities. AISG defines open specifications forthe interface of these devices to ensure basic interoperabillity of ALDs and tocontrol the communication infrastructure.

1.1 Benefits

RET functions are a proven asset for a network site and can offer dramaticreductions in operating costs. Remote antenna tilting means that fewer sitevisits and mast climbs are required. Remote control and supervision of antennasystems make optimization more effective.

RET units that are either factory installed on the antenna or integrated into theantenna are usually loaded with the relevant configuration data. However,third-party RET units supplied separately from the antenna can be suppliedwith no (or incorrect) configuration data because the translation instructionsmust be specific for the antenna to which it is attached. Configuration data issupplied by the antenna vendor, and is specific to the specified antenna type.The antenna vendor can provide the configuration data in the form of a filethat can be downloaded to the RET unit. The file format is vendor-specific.Some RET units are automatically configured for the antenna unit to which it isconnected, by means of identity recognition.

RET units installed in antenna systems and compatible with version 2 of the3GPP Iuant interface accept tilt commands only if they are configured. ALDconfiguration is a licensed feature that enables RBSs to send configurationdata to such RET units through their Iuant interfaces.

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AISG RET Support

1.2 Additional Information

For more information about this feature and related topics, see to the followingdocumentation:

• 3GPP TS 25.460 "UTRAN Iuant Interface: General Aspects and Principles"

• 3GPP TS 25.461 "UTRAN Iuant Interface: Layer 1"

• 3GPP TS 25.462 "UTRAN Iuant Interface: Signalling Transport" (L2)

• 3GPP TS 25.466 "UTRAN Iuant interface: Application Part" (L7)

• User’s Manual for OMT, Remote OMT and Remote OMT over IP,1/19817-CXC 112 516/1

• Setting IDB Parameters, 1/1543-LZA 701 6002

• Antenna Integrated Radio Unit Description, 101/1551-LZA 701 6001

The 3GPP documents above are written for UMTS Terrestrial RAN (UTRAN)but also apply to GSM.

2 Feature Overview

AISG RET support is a licensed feature that provides 3GPP-compliant supportfor managing remotely controlled tilting of antennas in a Radio Access Network(RAN).

Antenna tilting is a key method to ensure high capacity by limiting interference.Changes to the antenna tilt are required during initial tuning. Recalculatingantenna tilt is also part of mature network management.

Configuration of the RET unit is usually a one-time event and typically takesplace during the commissioning of the cell site. Once the operator initiates theaction, the RBS configures (or reconfigures) installed RET units by uploadingthe configuration file to the units, using the interface procedures specified inthe AISG standard. The antenna configuration file is transparently uploaded tothe RET unit because the RBS does not validate the antenna configuration filein any way.

Antennas in operating networks need regular adjustment because of increasedtraffic loads, new fill-in sites that affect neighboring sectors, or unpredictableevents such as heavy storms.

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Feature Overview

The 3GPP adopted the AISG version 2 specifications to define an interface forcommunication between the RBS and ALD. For more information about theinterface, see the 3GPP documentation referred to in Section 1.2 on page 2.

The interface is used to communicate with the compatible RET unit to vary thetilt of the antenna remotely through the Operation and Maintenance Terminal(OMT). The interface is also used to monitor alarm status and upload theantenna configuration file to the RET unit.

The RET unit can adjust the electrical tilt angle of the variable-tilt antennathrough electromechanical actuators (such as a Direct Current (DC) motor).The RET unit can receive tilt commands through the interface and move the tiltactuator accordingly.

For correct operation the RET unit must have the ability to translate therequested tilt, specified in degrees, into the correct DC motor control signals forthe antenna to which it is connected. This translation of configuration data isstored in the RET unit.

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2.1 RET Hardware

This section describes the antenna tilt concept, the RET types, and thesupported hardware configurations.

2.1.1 Mechanical and Electrical Antenna Tilts

Antennas can have the following tilt mechanisms:

• Mechanical tilt – a fixed down-tilt angle can be set mechanically atinstallation

• Electrical tilt – the antenna lobe is electrically adjusted by remote control toa tilt angle relative to the plane at right angles to the antenna axis

The figure below illustrates mechanical and electrical tilt:

Ge2236A

Antenna Axis+

MechanicalTilt

MechanicalTilt

ElectricalTilt

Total Tilt

Figure 1 Mechanical and Electrical Tilts

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Feature Overview

2.1.2 RET Types

The following RET types are supported:

RET Type 1 Single-Antenna RET device (SRET)

External RET unit

Either stand-alone or cascade configuration is supported

2.2 Hardware Configurations

The hardware configurations supported in various versions of the BTS software,are described in Section 2.2.1 on page 6 and Section 2.2.2 on page 7.

RET units can also be configured in a cascade chain, which allows severalRET units to be controlled through one single ALD or RET port. For moreinformation, see Section 3.5 on page 17.

The RET unit field installation is performed without removing the antenna.Once the system is operational, the RET unit can be accessed through thefollowing systems:

• OMT – for on-site RET control

• Remote OMT (ROMT)

• Remote OMT over IP (ROMT/IP)

Using the remote versions of OMT, the tilt of an entire antenna cluster canbe changed centrally.

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2.2.1 Configurations Supported in BTS G14A

The following table specifies the RET configurations supported in BTS G14A.

Table 1 RET Configurations Supported in BTS G14A

Configuration Description

Main-Remote RBS: RET unitconnected to RRU(1)

RRU unit contains both power andsignalling interfaces

The RET unit is connected to theRRU ALD port

Air: The RET unit is an integratedpart of an AIR(2) unit

For more information on the AIRunit, see Section 3.6 on page 18 anddocument Antenna Integrated RadioUnit Description

(1) Remote Radio Unit (RRU)(2) Antenna-Integrated Radio (AIR)

The following figure shows the supported types of RET configurations.

Figure 2 Supported RET Configurations

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Feature Overview

Key to Figure

AIR Antenna-Integrated Radio

ALD Antenna Line Device

DU Digital Unit

MU Main Unit

RET Remote Electrical Tilt

RRUS Remote RUS

2.2.2 Configurations Supported from BTS G14B and Higher

The following table specifies the RET configurations supported in BTS G14Band higher.

Table 2 RET Configurations Supported in BTS G14B and Higher

Configuration Description

Macro RBS: RET unit connected toRUS(1) and RIU(2)

RET power and AISG signalling overRF feeder

The RET unit is connected to the RIURET port

Main-Remote RBS: RET unitconnected to RRU(3)

RRU unit contains both power andsignalling interfaces

The RET unit is connected to theRRU ALD port

AIR: The RET unit is an integratedpart of an AIR(4) unit

For more information on the AIRunit, see Section 3.6 on page 18 anddocument Antenna Integrated RadioUnit Description

(1) Radio Unit Multistandard (RUS)(2) RET Interface Unit (RIU)(3) Remote Radio Unit (RRU)(4) Antenna-Integrated Radio (AIR)

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AISG RET Support

The following figure shows the supported types of RET configurations.

Figure 3 Supported RET Configurations

Key to Figure

AIR Antenna-Integrated Radio

ALD Antenna Line Device

DU Digital Unit

MU Main Unit

RET Remote Electrical Tilt

RIU RET Interface Unit

RRUS Remote RUS

RUS Radio Unit Multistandard

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Feature Overview

2.3 Parameters

The following table describes the special antenna and RET parameters handledby the AISG RET feature.

Table 3 AISG RET Parameters

Parameter OperationalParameter

ALD DeviceData

Optional

Description

Port Yes Specifies which port type the ALD isconnected to on the RE(1)

ALD Device Type Yes Needs to be defined at installationfor every ALD the operator wants tomanage, using the OMT

Unique ID(2) Yes Must be defined for cascaded ALDsat installation to make it possiblefor the RBS to correctly addressindividual ALDs

Optional for single ALD

Antenna Yes Specifies which antenna an ALDis mounted on and if the antennaresides in the RBS or resides inanother RBS

Mechanical Tilt Yes Must be defined at installation

The parameter defines the fixedantenna tilt angle of the installation

Max. Total Tilt Yes Must be defined at installation

The parameter defines the maximumantenna elevation includingmechanical tilt and electricaltilt

Positive value indicates down-tilt, andnegative value indicates up-tilt

Total Tilt = Mechanical Tilt + ElectricalTilt

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Table 3 AISG RET Parameters

Parameter OperationalParameter

ALD DeviceData

Optional

Description

Min. Total Tilt Yes Defines the minimum antennaelevation including mechanical tiltand electrical tilt

Positive value indicates down-tilt, andnegative value indicates up-tilt

Total Tilt = Mechanical Tilt + ElectricalTilt

Electrical Tilt Yes The electrically controlled tilt of theantenna main beam with respect tothe antenna element axis

The required value is set from theOMT and the current value is reportedfrom the RET unit

A change of the Electrical Tiltparameter automatically updates theTotal Tilt parameter

Total Tilt Yes The Total Tilt parameter automaticallyupdates the Electrical Tilt parameter,which changes the tilt of the antennamain beam with respect to theantenna element axis

Total Tilt = Mechanical Tilt + ElectricalTilt

Base Station ID Yes ID of the base station where the ALDis installed

Sector ID Yes Sector ID of the antenna where theALD is installed

Installation Date Yes Date of installation of the ALD

Installer's ID Yes ID of the installer of the ALD

Antenna ModelNumber

Yes Vendor-specific model number of theantenna connected to the ALD

Antenna SerialNumber

Yes Serial number of the antennaconnected to the ALD

Antenna Bearing Yes Bearing of the antenna connected tothe ALD

Antenna OperatingBands (1–3)

Yes Operating bands of the antennaconnected to this ALD

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Function

Table 3 AISG RET Parameters

Parameter OperationalParameter

ALD DeviceData

Optional

Description

Beam Width Yes Beam width for each operating band

Antenna Gain Yes Antenna gain for each of the operatingbands

Installed Mechanical Tilt

Yes Installed mechanical tilt value of theantenna connected to the ALD

Note: This is not the same parameteras Mechanical Tilt used in the ALDSystem Setup.

MaximumSupportedElectrical Tilt

Yes Maximum electrical tilt supported bythe RET subunit

Note: This is not the same parameteras Max Total Tilt used in the ALDSystem Setup.

Minimum Supported Electrical Tilt

Yes Minimum electrical tilt supported bythe RET subunit

Note: This is not the same parameteras Min Total Tilt used in the ALDSystem Setup.

(1) Radio Equipment (RE).(2) Identity (ID).

3 Function

3.1 AISG RET Control Infrastructure

This section describes the infrastructure used to control an AISG RET unit.

The feature is controlled from the Base Station Controller (BSC) administeringthe feature licence. The RET feature cannot be activated in the RBS without anactivation signal from the BSC.

The functions of the AISG RET feature are handled in the OMT, where ALDsetup data and other device data are registered in the Installation Data Base(IDB) file. Also RET unit control is handled from OMT.

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For RET control infrastructure details in different RBS types, see the followingsections:

• Macro RBS control infrastructure is described in Section 3.1.1 on page 12

• Main-Remote RBS control infrastructure is described in Section 3.1.2 onpage 13

• Control infrastructure for Main-Remote RBS with AIR is described inSection 3.6 on page 18

3.1.1 Macro RBS Infrastructure

Note: RET control over RF feeder and a RIU is only available in BTS softwareversion G14B and higher.

This section describes the RBS RET control infrastructure in a Macro RBS.

Communication between Digital Unit GSM (DUG) and the RUS is maintainedthrough the optical cable interface.

Communication between RUS and RET is maintained over the RF feeder andthrough a RIU.

The RET unit is connected to the RIU through the RET port (RS-485).

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Function

The following figure shows the AISG RET control infrastructure for a MacroRBS.

Figure 4 Macro RBS AISG RET Control Infrastructure

Key to Figure

BSC Base Station Controller

CPRI Common Public Radio Interface

DUG Digital Unit GSM

IDB Installation Database

MU Main Unit

OMT Operation and Maintenance Terminal

RF Radio Frequency

RRUS Remote RUS

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3.1.2 Main-Remote RBS Infrastructure

Note: RET control in Main-Remote RBSs is only available in BTS softwareversion G14A and higher.

This section describes the RBS RET control infrastructure in a Main-RemoteRBS.

Communication between Digital Unit GSM (DUG) and the RRU is maintainedthrough the optical cable interface.

The RET unit is connected to the RRU through the ALD port (RS-485).

The following figure shows the AISG RET control infrastructure for aMain-Remote RBS.

Figure 5 Main-Remote RBS AISG RET Control Infrastructure

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Function

Key to Figure

BSC Base Station Controller

CPRI Common Public Radio Interface

DUG Digital Unit GSM

IDB Installation Database

MU Main Unit

OMT Operation and Maintenance Terminal

RF Radio Frequency

RRUS Remote RUS

3.2 AISG RET Feature Control

This section describes AISG RET feature control, when the RBS operatesin remote mode and in local mode.

ALD Setup and Start

Operators use the OMT to define RET units in the IDB. The setup parametersdefines the connection of individual RET units to the corresponding RE andRE port.

After installation of the IDB in the RBS and startup of the RBS, the RET unit ispowered-up and connected.

Feature Control in Local Mode

If the Base Transceiver Station (BTS) runs in local mode (for example, when noconnection to the BSC is established) and before a feature control command isknown, then the BTS can enable all defined control and configuration functionsof the AISG RET ALDs.

Feature Control in Remote Mode

If the BTS runs in remote mode (a connection is established to the BSC) and afeature control command is received from the BSC that deactivates the AISGRET, then the BTS disconnects all defined and connected ALDs and disablesany control and configuration of the AISG RET ALDs.

If a feature control command is received from the BSC that activates the AISGRET, the BTS enables all defined control and configuration functions of theAISG RET ALDs.

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3.3 RET Unit Tilt Handling

This section describes how to send Calibrate, Get Tilt, and Set Tilt commandsfrom the OMT to a single AISG RET unit.

The function includes three subfunctions:

• Calibrate

On command from the OMT the radio unit can send out an AISG calibratecommand to the RET unit. The OMT operator can activate this function byclicking Calibrate in dialog box Define ALD Data.

The RET unit then runs through a calibration procedure that includes thewhole range (minimum to maximum) of the electrical tilt. In response theRET unit sends back a message OK or Failed.

• Get Tilt

On command from the OMT the radio unit can send out an AISG Get Tiltcommand to the RET unit that replies with the currently set tilt value.

The OMT operator can activate this function by clicking Refresh in dialogbox Define ALD Data. The tilt value is also updated when this dialogbox is opened.

• Set Tilt

On command from the OMT the radio unit can send out an AISG Set Tiltcommand to the RET unit. The RET unit then sets the electrical tilt to therequired value and replies with the set tilt value.

The OMT operator can activate this function by entering a tilt value andclicking Apply in dialog box Define ALD Data.

3.4 RET Alarm Handling

This section describes AISG RET alarm handling.

AISG RET applicable alarm indications, AISG-related alarms and AISG Layer 7(L7) return codes according to 3GPP TS 25.466 are handled as follows:

1. Get Alarm Status

Momentary display of alarm status when selecting Display ALD Data inOMT, using AISG Layer 7 (L7) procedure Get Alarm Status.

Autonomous activation of AISG Layer 7 (L7) procedure Get Alarm Statuswhen selecting Display ALD Data in OMT; return codes are reported andshown in the OMT window ALD Status.

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Function

2. Clear Active Alarms

OMT button Clear Active Alarms activates AISG Layer 7 (L7) procedureClear Active Alarms.

3. Reset Software

OMT button SW Reset activates AISG Layer 2 (L2) Reset procedure.

4. Self-test

OMT button Self Test activates AISG Layer 7 (L7) procedure Self-test;return codes are reported and shown in the OMT window ALD Status.

3.5 Cascaded RET Support

This section describes the handling of cascaded AISG RET units.

By cascading, that is, connecting several RET units to the same multidrop bus,several antennas can be controlled through the ALD interface of one radio unit.

Handling is controlled through OMT, as follows:

• Up to six RET units, connected in a chain to one ALD or RET port, can bedefined using the OMT. A Unique ID must be set for each individual RETunit when cascaded.

After installation of the IDB in the RBS and startup of the RBS, the RETunits are powered and connected.

• RET configuration data can be downloaded to each of the cascaded RETunits, using the OMT.

• Device data (such as product number and serial number) can be sent toand fetched from each of the cascaded RET units, using the OMT.

• Calibrate commands can be sent to each of the cascaded RET units, usingthe OMT, to ensure fault-free operation and synchronize the measuredand actual beam tilt of the antenna.

The cascaded RET units are calibrated one by one while uncalibrated unitsare queued waiting for calibration. The result of the calibration is shown inthe OMT window ALD Status.

• The operator can also get and set the electrical tilt for each of the cascadedRET units, using the OMT.

Modifying the electrical tilt will trigger an antenna beam tilt in the physicalantenna that the RET unit belongs to.

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3.6 RET Control in AIR

This section describes the handling of AISG RET units connected to AIR.

Note: For detailed information on RET functions in variants of AIR, seedocument Antenna Integrated Radio Unit Description.

AIR units contain both an active and a passive antenna part that can be usedtogether for various radio network access standards. Each part also has its ownindependently operated RET unit, and the two RET units can be cascaded ornot (see document Antenna Integrated Radio Unit Description), as follows:

In AIR units without RET unit cascading, the RET unit in the active part of theAIR unit is controlled by the RBS connected to the active part, whereas the RETunit in the passive part is controlled by the RBS connected to the passive part.

In AIR units with RET unit cascading, both RET units in the AIR unit must becontrolled from either the active- or passive-connected RBS, which must beconfigured accordingly.

Using the OMT the operator can handle the AISG RET units in an AIR in asimilar way as a RET unit connected to an RRUS.

The following special RET functions apply to the AIR:

• Two separate RET functions can be integrated in the AIR unit:

� RET function for active part of AIR unit

� RET function for passive part of AIR unit

For AIR units with RET unit cascading, A1 (active) or P1 (passive) mustbe specified during setup.

• Not all ALD Device Data parameters can be specified for AIR units

• Configuration files for RET units in AIR are factory configured and cannotbe altered on-site

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Operation and Maintenance Functions

4 Operation and Maintenance Functions

4.1 Activating the Feature

This section describes the activation and deactivation of the AISG RET supportfeature from BSC.

The AISG RET support feature is activated and deactivated by BTS oncommand from BSC.

When activation is ordered from BSC, BTS software checks in BTS capabilitiesif the BTS supports this feature. Activation or deactivation is sent further toRBS software that controls AISG. The feature is activated per TransceiverGroup (TG).

4.2 Connecting RET Units

This section describes the entering of setup parameters for a RET unit.

When installing an RET unit it must be defined regarding connection to aspecific RE and the corresponding RE port.

In addition, the properties of the RET unit must be defined.

These definitions are performed in the OMT dialog box ALD System Setup.

Definitions are entered in the dialog box in OMT mode Disconnected and storedin the IDB file. When OMT is connected the definitions are transferred to theRBS (= Install IDB) and the RET unit is connected.

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The following figure shows an example of the parameters to be defined. Forparameter specifications, see Section 2.3 on page 8.

Figure 6 ALD System Setup

4.3 Configuring RET Units

This section describes how to apply a predefined configuration file to an RETunit.

Vendor-specific configuration data for an RET unit can be stored in aconfiguration file.

OMT dialog box Define ALD Data includes functions for the selection of such aconfiguration file and sending it to an individual RET unit.

The configuration file is selected by clicking Browse... in dialog field RETConfiguration Data and selecting the file name in the file system.

The file is then sent to the RET unit (selected in the field ALD:) by clickingthe Send button.

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Operation and Maintenance Functions

Figure 7 Define ALD Data

4.4 Monitoring RET Units

This section describes how the RET unit operation is monitored in OMT.

The following OMT dialog boxes are used for monitoring installed RET units:

• Display ALD Data

• ALD Status

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Display ALD Data

In the OMT dialog box Display ALD Data the following parameters and data foran individual RET unit are monitored:

• RET unit properties and connection (OMT: dependency way)

• Active alarms

• Current tilt values

• Tilt values set in IDB

• ALD Device Data

Figure 8 Display ALD Data

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Operation and Maintenance Functions

ALD Status

Return codes are reported and shown in the OMT dialog box ALD Status.

ALD Status is a log dialog box presenting all actions (connections,disconnections, and so on) for all RET units connected to the RBS.

Figure 9 ALD Status

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4.5 Performing RET Unit Control and Operations

Remote RET unit control and operation is performed from the OMT dialogbox Define ALD Data.

Figure 10 Define ALD Data

Operations

The Operations field includes buttons for the following:

• Reset of the RET unit

• RET unit Self Test

• Clear Active Alarms

• RET unit Calibration

The operations are ordered by selecting the individual RET unit in the ALD:field and then selecting the required Operation button.

Tilt

Using the functions in the Tilt field, required tilt values can be ordered forindividual RET units.

The tilt values are ordered by selecting the individual RET unit in the ALD:field and then entering the required tilt value, Electrical or Total Tilt. Valuesare sent by clicking Apply.

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