ED-2002-017 8 Channel RTD Input Module(4311).pdf

8/12/2019 ED-2002-017 8 Channel RTD Input Module(4311).pdf

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NEXGEN PLC

8 Channels, RTD Input Module(Ordering Code 4311)

User Manual

Document No.:ED-2002-017

Version: 1.0

MESSUNG SYSTEMSEL-2, J- Block MIDC Bhosari,

Pune 411026.(INDIA)

Tel: (+91)-020-7120807, 7122807.Email : [email protected]

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


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8 Ch. RTD Input Module (4311) Messung Systems

Published July 2002 8 Ch. RTD Input Module User Manual/V1.0Page 2 of 47 Document No.: ED-2002-017

Revision

Version Date Description

1.0 16 July 2002 8 Channels, RTD Input Module(Ordering Code 4311)User Manual


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Messung Systems 8 Ch. RTD Input Module (4311)

8 Ch. RTD Input Module User Manual/V1.0 Published July 2002

Document No.: ED-2002-017 Page 3 of 47

INDEX

1. Module Overview........................................................................................................5

1.1 RTD Input Module Overview..............................................................................51.2 LED Indications..................................................................................................7

1.3 General Specifications.......................................................................................8

2. Module Operation .......................................................................................................9

2.1 Block Diagram....................................................................................................92.2 RTD types and range of temperatures.............................................................102.3 Lead Compensation.........................................................................................112.4 On-Board Processor Operations......................................................................13

2.4.1 Power On Operations ..................................................................................132.4.2 Analog to Digital Conversion .......................................................................132.4.3 Excitation Current Drift Compensation ........................................................142.4.4 Scaling.........................................................................................................152.4.5 Linearization ................................................................................................15

2.4.6 Averaging.....................................................................................................152.5 Module Information ..........................................................................................15

2.5.1 Input Output Image Mapping .......................................................................162.5.2 Memory Mapping.........................................................................................172.5.3 Commands ..................................................................................................182.5.4 Module Status Bits.......................................................................................19

3. Installations and Wiring.............................................................................................20

3.1 Module Installation ...........................................................................................203.2 Connection Details...........................................................................................213.3 Precautions to be taken ...................................................................................22

4. Configuration and Programming...............................................................................23

4.1 Slot Configuration.............................................................................................234.2 Channel Configuration .....................................................................................24

4.2.1 Static Configuration .....................................................................................244.2.2 Dynamic Configuration ................................................................................26

4.3 Channel Information.........................................................................................274.3.1 Channel Data...............................................................................................274.3.2 Channel Status ............................................................................................27

4.4 Programming with Nexgen 4000 CPU .............................................................294.5 Programming with Nexgen 5000 CPU

5. Troubleshooting........................................................................................................40

5.1 LED Indications for Diagnostics .......................................................................40

5.2 Fault Diagnostic ...............................................................................................40

6. Appendix 1................................................................................................................44

INDEX OF FIGURESFigure 1 :Front View of RTD Input Module..........................................................................6Figure 2 :Block diagram of RTD Input module....................................................................9Figure 3 :Schematic of input circuit ...................................................................................11Figure 4 :ADC Conversion Cycle ......................................................................................14Figure 5 :Input Output Image Mapping of RTD Input Module ...........................................16Figure 6 :Memory Mapping of RTD Input Module .............................................................17


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Figure 7 :Connection diagram of RTD input Module ........................................................ 21

Guidelines for the Safety of the user and protectionof the IO Module

This manual provides information for the use of the PLC Products. The manual has been written to

be used by trained and competent personnel. The definition of such a person or persons is asfollows:a) Any engineer who is responsible for the planning, design and construction of automatic equipmentusing the product associated with this manual should be of a competent nature, trained and qualified to thelocal and national standards required to fulfill that role. These engineers should be fully aware of allaspects of safety with regards to automated equipment.

b) Any commissioning or service engineer must be of a competent nature, trained and qualified to thelocal and national standards required to fulfill that job. These engineers should also be trained In the useand maintenance of the completed product. This Includes being completely familiar with all associateddocumentation for the said product. All maintenance should be carried out in accordance with establishedsafety practices.

c) All operators of the completed equipment should be trained to use that product in a safe andcoordinated manner in compliance to established safety practices. The operators should also befamiliar with documentation, which is connected with the actual operation of the completedequipment.

Note: The term-completed equipment refers to a third party constructed device, which contains oruses the product associated with this manual.

Note on the Symbol used in this Manual

At various times through out this manual certain symbols will be used to highlight points ofInformation, which are Intended to ensure the users personal safety and protect the integrity ofequipment. Whenever any of the following symbols are encountered its associated.

Note must be read and understood. Each of the symbols used is listed below; with a brief descriptionof its meaning.

Hardware Warnings

1) Indicates that the identified danger WILL cause Physical and Property damage.

2) Indicates that the identified danger could POSSIBLY cause physical and property

damage.

3) Indicates a point of further interest or further explanation.

Software Warning

4) Indicates special care must be taken when using this element of software.

5) Indicates a special point, which the user of the associate software element shouldbe aware of.

6) Indicates a point of interest of further explanation.

Warning

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


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1. Module Overview

This chapter describes the following

RTD Input Module Overview

LED Indications

General Specifications

1.1 RTD Input Module Overview

This RTD input module converts RTD input resistance values into theequivalent temperature values of 0.1C resolution with leadcompensation. This is sigma-delta type A/D conversion. It provides 8non-isolated channels and 16-bit resolution ADC. The individual channelcan be configured for specific type of RTD input. In current version, 3wires PT100 input is supported.

RTD Type C Temperature rangePT100 (385) -200.0 C to +850.0 C

The parameters and commands those are transferred to the module foradvanced processing are

RTD input type (in current version 3 wires PT100 (385) input issupported)

Return value in case of sensor fault Averaging Channel enable/disable Maximumminimum set points Static configuration write

The module provides diagnostic information for each channel. It includes

Maximum/minimum set points exceeded Invalid configuration Out of range Sensor fault detection

This is an intelligent module with on-board processor and memory. Thedata transfer between CPU module and RTD input module takes placeby 'READ_W' and 'WRITE_W' functions in the application program. Themodule status is available in input image and commands can be issuedthrough output image.

The figure 1 shows the front view of RTD input module


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Figure 1 : Front View of RTD Input Module

The module provides LED indications on the front. Brief information aboutchannel can be written on the front door. Behind front door, 38-pinremovable terminal block is provided for interfacing. The wiring detailsare shown on backside of front door.

The RTD input module can be configured in any IO slot of the PLC. Thenumber of RTD input modules is limited by back panel current capacity.

Front ShieldPlate

Terminal BlockFixingScrew

38 PinRemovableTerminal Block

ConnectionDetails Label

Front Door

IO Label

LEDIndications

ChannelStatusLEDs

ModuleStatusLEDs

Terminal BlockFixingScrew

NO 24 V SUPPLY

CPU FAULT

CH0

CH1

CH2

CH3

CH4

CH5

CH6

CH7

4311ANALOG INTPUT8 CH RTD

01

02

03

04

05

06

07

11

10

09

08

13

1415

16

17

18

19

22

21

12

20

23

24

25

26

27

28

29

33

32

31

30

35

36

37

38

34

RTD0 +

RTD1 +

RTD0 -

RTD1 -

RTD0 C

RTD1 C

RTD2 +

RTD3 +

RTD2 -

RTD3 -

RTD2 C

RTD3 C

RTD4 +

RTD5 +

RTD4 -

RTD5 -

RTD4 C

RTD5 C

RTD6 +

RTD7 +

RTD6 -RTD7 -

RTD6 C

RTD7 C

+ 24 V

GND

EARTH


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In general a channel has following information Dynamic configuration information Static configuration information Data and Status information

In all, 37 words information per module is available.

1.2 LED Indications

The following table explains significance of 10 numbers of LEDs provided

on the module.

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

24 VDC supply to module absent1 NO 24 V

SUPPLYOrange

ON24 VDC circuit on-board glass fuse blown

OFF Module hardware healthy and module is readyModule in self test

CPU watchdog faulty

2 CPU FAULT OrangeON

Module busyOFF Channel not enabledON Channel enabled and healthy

Parameter mismatchInvalid configurationOver rangeUnder rangeSensor open circuitSensor short circuit

3 Channel Status(Eight for eightchannels)

Green

Flashingwith 10 Hzfrequency

Lead compensation wire open circuit


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1.3 General Specifications

General specifications of 8 channels RTD input module are as givenbelow.

Number of Input channels 8 Non-isolatedConversion Method Sigma delta with digital filterRTD input types and output range PT100 (385) -2000 to +8500Temperature resolution 0.1 C

Accuracy 0.5 % of full scaleInput filter frequency 50 HzConversion time 60 ms per channelRTD linearization In steps of 10 CLead Compensation 50 ohms per lead wireExcitation current 1 mA

Channel to internal circuit 1.5 kV opticalIsolationChannel to channel Nil

External supply requirement 24 V DC, 100 mA(18 30 VDV including ripple)

External supply protection 315 mA miniature glass fuse on module Reverse polarity protection

Indications No 24 V Supply CPU fault Channel status (8)

Back-plane current (5 V consumption) 300 mAIO points consumed 8 input bits and 8 output bitsTermination / Connection Removable 38 pin terminal blockOrdering code 4311


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2. Module Operation

This chapter helps in getting started with the RTD input module. Itdescribes the basic operation of the module. This chapter explainsoperational details of

Block Diagram RTD Types and Range of Temperatures Lead Compensation On-Board Processor Operations Module Information

At the time of the application program development, the module can beconfigured using the programming software DOXMINI+so that thespecial features can be used. Refer chapter 4for configuration andprogramming details.

2.1 Block Diagram

Block diagram of RTD input module is shown below.

Figure 2 :Block diagram of RTD Input module

OPTI

CAL

ISOL

ATION

DC-to-DCConverter

+15 V

-15 V

+5 V

+ 24 VDC

24 V GND

Earth

MiniatureGlass Fuse

GND

No 24 V Supply Signal

Supply forADC Circuit

CPUModule

/

Analog toDigital

Converter

On boardProcessor

Memory forConfiguration,Data, StatusInformation

ModuleInterfaceCircuit

WatchDog+

InstrumentationAmplifier

ChannelMultiplexer

Channel 0Input

Circuit

Channel 7Input

Circuit

RTD0+RTD0-

RTD0C

+ 5 V

GND

Reference

Channel

ExcitationCurrent

Multiplexer

1 mAExcitationCurrentSource

RTD7+RTD7-

RTD7C


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The module provides eight analog to digital channels for RTD input. CPUbus is optically isolated from ADC circuit. The analog to digital converteroperates on serial data from the channels. RTD input sensor signalmeasurement is basically a resistance measurement which varies withtemperature. For the same, module provides 1 mA excitation current tosensor. The dual matched current source is multiplexed for eight channel

inputs.

The enabled channel input signals are multiplexed and theninstrumentation amplifier carries out amplification. Input electronic circuitprovides the lead compensation. For more details, refer chapter 2.3.Amplified lead compensated input signal is provided to ADC. Sigma-delta(/ ) ADC converts only enabled analog channels to digital value one byone. On-board processor manipulates the converted count for eachchannel. It has following functions. Scaling Linearization Averaging

Thus lead compensated, scaled and linearized temperature reading istransferred to module memory, which holds channel data information.

If averaging is required, depending on the averaging count, on-boardprocessor performs averaging of those many previous readings andupdates channel data information.

The channels can be independently enabled or disabled. On-boardprocessor detects signals, which are out of range of selected input type.It also detects sensor faults. All this information is available to main CPU.

The module provides auto-calibration facility to compensate for changesin excitation current due to ambient temperature.

The dynamic configuration, static configuration, data, status informationis available in dual port RAM on the module. The configuration of allchannels is transferred to the module memory using WRITE_W functionin the application program. Similarly data and status of all channels canbe read by READ_W function in the application program.

The module requires external 24 V for ADC circuit operation. InternallyDC-to-DC converter generates 15 VDC and + 5 VDC as required byeach channel. If 24 VDC is absent or on-board glass fuse is blown,module generates 'No 24 V Supply' signal for main CPU. The fuseprotection for external 24 VDC supply is provided on module.

2.2 RTD types and range of temperatures

This section describes the RTD types and data range of temperaturessupported by module. In current version, PT100 (385) is supported.

Type Resistance values C temperature range

PT 100 (385) 18.49 to 390.26 -200.0 C to +850.0 C


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2.3 Lead Compensation

RTD input measurement is basically sensor resistance measurementwhich changes with temperature. The sensor resistance is low and leadwires can add to the actual resistance of the sensor. This causes

noticeable offset in actual reading. This offset varies depending uponchange in lead wire resistance due to length, temperature, aging, etc. Soit is necessary to eliminate effect of lead wire resistance in measurement.

In RTD input module, lead compensation is provided by using 3 wire PT100 sensor input with proper electronic circuit. The bridge is formed bydual matched current source and 3 wires PT100 sensor. The schematicof input circuit is shown below.

Figure 3 :Schematic of input circuit

RL Lead resistanceR - Sensor resistance

As dual matched current sources are used, both follow each otherkeeping current equal.It is also assumed that lead wire resistance for three wires is equal.

V1 = I (2RL+R)

V2 = I (2RL)

V = (V1V2) =IR =R (as I =1 mA )

From above equations, it can be observed that effect of lead wireresistance (RL) is eliminated and the voltage V is direct indication ofsensor resistance (R).As explained in chapter 2.1, excitation currentsource is multiplexed for all the eight channels and eight sensor inputsignals are multiplexed to a ADC. The voltage V which is direct indicationof sensor resistance is amplified by instrumentation amplifier and inputedto ADC for conversion.

V1

V2

RL

RL

RL

R

I I

Excitation CurrentMultiplexer Channel

Multiplexer

InstrumentationAmplifier

PT100Sensor

ToADC


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2.4 On-Board Processor Operations

The RTD input module is an intelligent module with on-board processor.The functions of on-board processor are explained in below sections.

2.4.1 Power On Operations

After power ON, if 24 V supply to module is absent or on-board fuse isblown then on-board processor sets Ix.0 bit of input image. After powerON, this processor checks the hardware called as self test. During self-test and if hardware error is detected, Ix.0 bit of input image is set. AlsoCPU fault LED on front panel is put ON indicating that module is notaccessible. During module operation, if module hardware is found faultyor watchdog error is detected, Ix.0 bit is set.

If the module hardware is OK, Ix.0 bit is cleared. Module waits for staticand dynamic configuration from the CPU module. After reception of validconfiguration of RTD input channels, the module starts sampling and

digital conversion cycle of enabled channels. For more details of IOimage of module, refer chapter 2.9.

The module continues sampling, converting the channels and updatingmodule memory even after the PLC is put in STOP mode. But In thiscase, CPU module does not read the channel data and status.

2.4.2 Analog to Digital Conversion

The module samples a RTD input channel and converts leadcompensated input to its digital value one by one. After power ON, firstreference channel signal is sampled and conversion is started. Forreference channel, on-board highly precise and stable resistor of 100ohms is used as input. After that only enabled channels are converted asshown in the figure 4. If any error like invalid configuration is detected,channel is not converted. The disabled channels or channels with errordetected are bypassed retaining earlier values. After one channelconversion, module initiates next channel conversion. During thisconversion period, module processes converted data of previouschannel. This process includes scaling, linearization and averaging. Thusthe processed data for previous channel is made available during thisperiod. After converting all healthy channels, processed data and statusinformation of all the channels is transferred to respective memory areaon the module. This cycle continues. Thus when the processor module

performs READ_W operation, it reads either old or new information i.e.data and status of channels


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Figure 4 :ADC Conversion Cycle

The module takes certain time to sample all enabled channels andconvert into digital value. The required time is the module update time.The factors affecting module update time is number of channels enabled.The module update time is minimum when only one channel is enabled.Likewise the module update time is maximum when all channels areenabled. The module incorporates a digital low pass filter to reject noiseon the input signal. For RTD inputs, it is fixed to 50 Hz. It provides betternoise rejection for low filter frequencies.

2.4.3 Excitation Current Drift Compensation

As explained in chapter 2.3, excitation current has major effect onmeasurement. Drift in excitation current (1 mA) may occur due to changein ambient temperature, component aging, etc. This will create significantoffset in measurement. So it is necessary to compensate effect of drift inexcitation current.

In 8 channels RTD input module, excitation current drift compensation isachieved by flexible software method. As explained in chapter 2.4.2,module always samples a default reference channel. On-board highlyprecise and stable resistor (100 ohms) input is provided as a channel

input. In case of any drift in excitation current, proportional change ininput signal to ADC is observed for this channel. This change in inputsignal is direct indication of change in excitation current. This offset isnoted and then compensated for RTD input channels by software duringanalog to digital conversion cycle. This compensated count is thenscaled, linearized further.

Channel 0Conversion

Channel 1Conversion

Channel 2Conversion

Channel 3Conversion

Update allchannel dataand status

Channel 7Conversion

Channel 6Conversion

Channel 5Conversion

Channel 4Conversion

ReferenceChannel

Conversion

Channel 0disabled /

error detection

Channel 1disabled /

error detection

Channel 2disabled /

error detection

Channel 3disabled /

error detection

Channel 3disabled /

error detection

Channel 5disabled /

error detection

Channel 6disabled /

error detection

Channel 7disabled /

error detection


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2.4.4 Scaling

The resistance signal from RTD sensors is scaled for equivalenttemperature as per reference tables provided by standards. For thesame, refer appendix 1.

2.4.5 Linearization

RTD signals are not linear e.g. 10 percent change in a RTD voltage doesnot correspond to a 10 percent change in its temperature. Thereforelinearization of RTD signal is necessary to get equivalent temperature.Also, each RTD input type requires different linearization.

In RTD input module linearization is performed by flexible softwaremethods. This is done with look up table in steps of 10 C for each RTDinput type. ADC count is mapped within its 10 C temperature range andequivalent temperature is calculated using linear interpolation method.

2.4.6 Averaging

The module provides user selectable averaging facility so that stablevalue is available for processing and necessary control action. Themodule samples and converts enabled channels one by one. The modulekeeps digital value into different memory locations. Depending on theaveraging count, the module performs averaging of those many previousreadings and updates channel data information.

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

4 and 8 conversion cycles respectively. After that, it gets updated inevery cycle. One conversion cycle means sampling and converting allenabled channels as explained in chapter 2.3.2.Thus combination offilter frequency and averaging count can be selected to get optimumchannel update time and stable temperature reading.

2.5 Module Information

This section explains the entire information required and available withRTD input module. The following points are discussed

Input Output Image MappingMemory Mapping

Commands Module Status Bits


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2.5.1 Input Output Image Mapping

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

Figure 5 :Input Output Image Mapping of RTD Input Module

The module consumes 8 input bits (1 byte) of input image and 8output bits (1 byte) of output image in the CPU module. CPUreads the status of module in input scan. CPU writes usercommands to module in output scan. For immediate updation ofinput and output image, IMM_IN and IMM_OUT functions can beused in application program whenever required. For the detailsrefer chapter 2.4.3and 2.4.4.

CPU module

1.1.1.1.1Input ImageModule Not OK Ix.0Invalid Configuration Ix.1Set Points Exceeded Ix.2Out of Range Ix.3Sensor Fault Ix.4

RTD Input module

ModuleInterface

circuitChannel 4

Output ImageStatic ConfigurationWrite

Qx.0

Input Scan

Logic Scan

SLOT

ENO

IMM_IN

EN

Output Scan

Logic Scan

SLOT

ENOIMM_OUT

EN Channel 5

Channel 6

Channel 7

Channel 0

Channel 1

Channel 2

Channel 3


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2.5.2 Memory Mapping

The memory mapping related to RTD input module is shown in figurebelow.

Figure 6 :Memory Mapping of RTD Input Module

The configuration (grouped as static and dynamic) from PLC variablearea e.g. memory or page is transferred to module memory whenWRITE_W function gets executed in application program i.e. in logicscan. The module takes action on static configuration information onlywhen static configuration write command is issued. This can be issued bysetting Qx.0 bit of output image. In case of dynamic configurationinformation, the module detects any change in configuration and if anyvalid change is detected, it takes appropriate action. After power ON,module starts its channel conversion operation only after receiving validconfiguration. If channel configuration is modified or channel is enabled /disabled, it takes effect only in the subsequent conversion cycle. Thechannel configuration can be modified using WRITE_W function.Similarly channel can be enabled or disabled during normal operation foroptimum results.

The channel temperature readings and status information can be readfrom the module using READ_W function.

Logic Scan

CPU module17 words hold channel dynamicInformation of 8 channelsChannel Enable Word MW66Channel 0 High Set Point MW68Channel 0 Low Set Point MW70

Channel 7 High Set Point MW96Channel 7 Low Set Point MW98

8 words hold channel static information of8 channelsChannel 0 Static Configuration MW50

Channel 7 Static Configuration MW64

8 words hold data for 8 channelsChannel 0 Data MW100

Channel 7 Data MW114

4 words hold status of 8 channelsChannel Set Point Status MW120Channel Configuration Status MW122Channel Input Range Status MW124Channel Sensor Fault Status MW126

SLOT

DATA

LEN

ADDR

ENO

WRITE_W

EN

Logic Scan

SLOT

DATA

LENADDR

ENO

READ_W

EN

RTD Input module17 words hold channel dynamic informationof 8 channelsChannel Enable Word MMW00Channel 0 High Set Point MMW02Channel 0 Low Set Point MMW04

Channel 7 High Set Point MMW30Channel 7 Low Set Point MMW32

8 words hold channel static information of 8channelsChannel 0 Static Configuration MMW96

Channel 7 Static Configuration MMW110

8 words hold data for 8 channelsChannel 0 Data MMW128

Channel 7 Data MMW142

4 words hold status of 8 channelsChannel Set Point Status MMW146Channel Configuration Status MMW148Channel Input Range Status MMW150Channel Sensor Fault Status MMW152


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2.5.3 Commands

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

through application program. CPU writes commands in output imagearea of module in output scan. The module reads output image areacyclically and takes appropriate action. If 'IMM_OUT' function is executedin logic scan for a particular slot, it stops current logic scan, executesoutput scan for defined slot and resumes logic scan again. This is usefulwhen ever immediate updation of output image is needed. The functionsof output image bits are given below

No Bit Address Command Status Description

ONIt gives command to the module to acceptstatic configuration or change staticconfiguration as per contents of modulememory words MMW #96 to MMW#110.1 Qxx.0

Write staticconfiguration

OFF Write static command is OFF.

Notexxis slot number in which module is fixed.Qxx.1 to Qxx.7 are reserved and should not be used.


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2.5.4 Module Status Bits

As discussed in chapter 2.4.1,input image bits are used as modulestatus indications. User can check the module status through applicationprogram. The module writes status in its input image area cyclically. TheCPU reads this input image area in input scan. If 'IMM_IN' function is

executed in logic scan for a particular slot, it stops current logic scan,executes input scan for defined slot and resumes logic scan again. Thisis useful when ever immediate updation of input image is needed. Thefunctions of input image bits are given below

NoBit

AddressModuleStatus

Status DescriptionMMW for

storing thedetails

24 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 NotReady

OFFModule healthy and ready

NotApplicable

Invalid static configurationONParameter mismatchValid static configuration

2 Ixx.1 InvalidConfiguration

OFFValid parameters

#148

Any channel temperature readingabove high set point

ON

Any channel temperature readingbelow low set point

3 Ixx.2 Set pointexceeded

OFF All channel temperature readingswithin high and low set points

#146

Over range for any enabledchannels/s.

ON

Under range for any enabledchannels/s.

4 Ixx.3 Out of Range

OFF All enabled channel inputs arewithin specified range

#150

Sensor open circuit for any enabledchannels/s.Sensor short circuit for any enabledchannels/s.

ON

Lead compensation wire opencircuit for any enabled channels/s.

5 Ixx.4 Sensor Fault

OFF All enabled channel inputs areconnected properly.

#152

Notexxis slot number in which module is fixed.Ixx.5 to Ixx.7 are reserved and should not be used.

Whenever accessing the module, user must check the module status bitIx.0. If any error condition is detected in input image, checkcorresponding module memory word to get more details to locate exactproblem.


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3. Installations and Wiring

This chapter provides the following information Module Installation Connection Details

Precautions to be taken

3.1 Module Installation

The installation procedure for RTD input module is same as any otherdiscrete I/O module.

Put the module in to the desired slot of the PLC.1. Tighten the screw provided at the top of the module.2. Connect the terminal block at the front of the module and tighten

it.


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3.2 Connection Details

The figure shows the connection diagram of RTD input module

Figure 7 :Connection diagram of RTD input Module

In figure, RTDs are connected to channel 0 and 7. For interfacing RTDs,38-pin terminal block is provided. RTD input is connected to RTDn+,RTDn-and RTDnC terminals, where nis a channel number. For healthyworking, ensure correct polarity of RTD element. It is ensured that all thethree connections of a RTD element come in line on terminal block foreasy connectivity. RTD 0 is connected to terminal cumbers 10, 12 and14. RTD 1 is to be connected to terminal numbers 11, 13 and 15. RTD 7is to be connected to terminal numbers 29, 31, and 33.

RTD 1

RTD 8

+ 24 VDC

GND

EARTH

01

02

03

04

05

06

07

11

10

09

08

13

14

15

16

17

18

19

22

21

12

20

23

24

25

26

27

28

29

33

32

31

30

35

36

37

38

34

RTD0+RTD1+

RTD0-

RTD1-

RTD0C

RTD1C

RTD2+

RTD3+

RTD2-

RTD3-

RTD2C

RTD3C

RTD4+

RTD5+

RTD4-

RTD5-

RTD4C

RTD5C

RTD6+

RTD7+

RTD6-

RTD7-

RTD6C

RTD7C

+ 24 V

0 V

EARTH


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For functioning of RTD input module, external 24 VDC supply is required.Connect 24 VDC supply between terminals 36 (+ 24 V) and 37 (0 V).Connect terminal 38 to earth busbar in control panel.

3.3 Precautions to be taken

All the normal precautions concerning the wiring and protection of anelectronic equipment in an industrial environment should be observed. Toguard against coupling noise from one conductor to another, follow theguidelines given below.

Inside control panel

Following guidelines to be observed inside control panel. All power circuit wiring e.g. connected to Power Supply Module,

power contactors, etc i.e. high voltage wiring should be keptseparate and apart from RTD signals.

Digital Input wiring and Digital Output wiring (especially, relay

output and AC output) should be separately bundled and kept asapart as possible from RTD signals.

RTD 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 shouldbe provided for

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

thermocouple/ RTD input modules and for communication.

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 closevicinity of power cables.

Run cables on metallic surfaces

Avoid number of joints Keep cable lengths as short as possible.


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4. Configuration and Programming

This chapter explains configuration of RTD input module and transferringinformation with RTD input module. This information is useful forapplication program development. The module configuration consists of

Slot configurationand

Channel configuration

4.1 Slot Configuration

The RTD input module provides eight RTD input channels, which can beindependently operated. Configuring the slot for RTD input module is justlike any other discrete IO module only. The programming anddocumentation software DOXMINI+ is used for configuration andprogramming. The module consumes 1 byte of input image and 1 byte ofoutput image. The input image is used for reading status of module. Theoutput image is used for writing user commands to module. For moredetails, refer chapter 2.4.3and 2.4.4.

The IO byte consumption along with configuration of Nexgen PLC isshown below.

Power SupplyModule

Nexgen 4000CPU Module

Slot 0 Slot 1 Slot 2 Slot 3

32 DC InputModule

32 DC OutputModule

RTD InputModule

16 DC OutputModule

I0.0 to I0.7I1.0 to I1.7I2.0 to I2.7I3.0 to I3.7

Q4.0 toQI4.7Q5.0 to Q5.7Q6.0 to Q6.7Q7.0 to Q7.7

I8.0 to I8.7Q8.0 to Q8.7

Q9.0 to Q9.7Q10.0 to Q10.7

Input module in first slot 0 consumes IB0 to IB3 of input image. Outputmodule in slot 1 consumes QB4 to QB7 of output image. RTD inputmodule consumes IB8 of input image and QB8 of output image.16 DCOutput module in slot 3 consumes QB9 and QB10 of output image.

The IO byte consumption along with configuration of Nexgen5000 PLC is shownbelow.

Power SupplyModule

Nexgen5000CPU Module

Slot 032 DC Input

Module (4632)

%IX0.0 - %IX0.7%IX1.0 - %IX1.7%IX2.0 - %IX2.7%IX3.0 - %IX3.7

Slot 132 DC OutputModule (4732)

%QX0.0 - %QX0.7%QX1.0 - %QX1.7%QX2.0 - %QX2.7%QX3.0 - %QX3.7

Slot 2RTD Input

Module (4311)

%IX4.0 - %IX4.7%QX4.0 - %QX4.7

Slot 316 DC OutputModule (4716)

%QX5.0 - %QX5.7%QX6.0 - %QX6.7

Input module in first slot 0 consumes IB0 to IB3 of input image. Output module inslot 1 consumes QB0 to QB3 of output image. The analog input module consumesIB4 of input image and QB4 of output image.16 DC Output module in slot 3consumes QB5 and QB6 of output image.


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4.2 Channel Configuration

The RTD input module can be configured in any slot of PLC. It provideseight non-isolated channels. These channels can be independently

configured for different types of RTD inputs.

The channel configuration is grouped in two types

Static configuration This information decides basic functioning of achannel. Normally, this information is not altered in run time e.g. type ofRTD.

Dynamic configuration This information does not affect basicfunctioning of channel. This information is changed during run time e.g.high and low set points for temperature reading.

4.2.1 Static Configuration

After power ON, the configuration of one or more channels can betransferred to the module using WRITE_W function. The global variables,memory or page can be used to hold channel configuration. The channelstatic configuration information includes

RTD input type Filter frequency (fixed to 50 Hz for RTD inputs) Return value on sensor fault and Averaging

This information is transferred to module memory by using 'WRITE_Wfunction. The module takes action on this information when static

configuration write command is issued (on rising edge of Qx

.0 bit). Afterthat only static configuration or change in static configuration is effective.

This static configuration information is to be stored in bit form in one wordfor each channel. The following table gives information to be stored. Thevalid combination of bits must be set.

Module memory words MMW #96 to MMW #110 are module memorywords for static configuration.

MMW #96 - Channel 0 Static Configuration Word

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

PT100 (385) 0 0 0 0 0

Invalid 0 0 0 0 1Input type

Invalid 1 1 1 1 150 Hz 0 0 0Invalid 0 0 1

Filter

Invalid 1 1 1Zero 0 0Upper Scale 0 1Lower Scale 1 0

Returnvalue onsensorfault Invalid 1 1

16 0 08 0 1

Avg.Samples

4 1 0


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1 1 1Res. -- 0 0 0 0

MMW #98 to MMW #110 Channel 1 to 7 static configuration words.

MMW #98 Channel 1 static configuration wordMMW #110 Channel 7 static configuration word

Input type

The RTD input module supports different types of inputs. The inputsinclude

3 wires PT100 (385)

Bit 0 to bit 4 hold input type information.

Filter frequency

Next three Bits, Bit 5 to bit 7 defines the low-pass filter frequency. ForRTD input module, 50 Hz filter is fixed by default. User has no selectionchoice.

Bit 7 Bit 6 Bit 5 Filter Frequency Update time for a Channel0 0 0 50 Hz 60 ms

This is in built function of ADC. The filter frequency affects noise rejectionon incoming RTD signal. Also it affects channel update time.

Return value on sensor fault circuit

Next two bits, bit 8 and bit 9 define the value of the channel temperaturereading when sensor fault is detected for that channel. Here sensor faultmeans sensor open circuit, sensor short circuit and lead compensationwires open circuit.

Bit9 Bit8 Sensor Fault value0 0 Zero0 1 Upper scale1 0 Lower scale1 1 Invalid

In such sensor fault condition, the channel value can be set to any one ofabove options considering safety in control action.

Averaging

Next two Bits, Bit10 and Bit 10 define the selection of sampling value foraveraging.

Bit10 Bit11 Averaging Samples0 0 160 1 81 0 41 1 1


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If the averaging counts of channel 0, 1 and 2 are 1, 4 and 8 respectively,then initially data of channel 0, 1 and 2 are updated after 1, 4 and 8conversion cycles respectively. After that, it gets updated in every cycle.One conversion cycle means sampling and converting all enabledchannels as explained in chapter 2.3.2.

Module memory words MMW #0 to MMW #32 are module memory wordsfor dynamic configuration. MMW #0 is a channel enable / disable word.MMW #2 to MMW #32 provides high and low set points for individualchannels.

4.2.2 Dynamic Configuration

The channel dynamic configuration information includes - Channel enable/ disable Channel high and low set points

This information is transferred to module memory by using 'WRITE_W

function. The module detects change in dynamic configurationinformation in its own scan. If valid change is detected, appropriate actionis initiated and dynamic configuration or change in dynamic configurationis effective in consecutive scan.

Channel Enable

The eight bits in module memory word MMW #0 defines the enablestatus of the all the channels. If it is 0 channel is disabled and if it is 1channel is enable. The module samples only enabled channels andconverts into digital value. The channel data for disabled channels isforced to zero. Thus enabling only used channels can minimize themodule update time. If a particular channel is important at particularinstance, all other channels can be disabled temporarily and only onechannel conversion can be carried out to get fast response.

MMW #0 Channel enable / disable word


Disable 0Ch 1Enable 1

Disable 0Ch 8

Enable 1Res - 0 0 0 0 0 0 0 0

Bit 0 of MMW #0 is enable / disable bit for channel 0.Bit 7 of MMW #0 isenable / disable bit for channel 7.

Bits 8 to 15 are reserved and should not be used.

Channel High and Low set points

User can define high and low set points for individual channeltemperature readings available in 0.1 C resolution. If channeltemperature is above high set point, corresponding high bit in MMW #146


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is set. If channel temperature is below low set point, corresponding bit inMMW # 146 is set.

MMW #2 to MMW #32 - Channel High and Low set points

MMW #2 Channel 0 high set point (in 0.1 C resolution)

MMW #4 Channel 0 low set point (in 0.1 C resolution)

MMW #30 Channel 7 high set point (in 0.1 C resolution)MMW #32 Channel 7 low set point (in 0.1 C resolution)

Valid range for high and low set points is 200.0 C to 800.0 C for PT100 input type. If settings are not within range of that input type, Ixx.1 bitis set indicating invalid configuration. Refer MMW #148 to point out faultychannel configuration. If high set point for a channel is less than that oflow set point and vice versa, Ixx.1 bit is made ON indicating parametermismatch. Refer MMW #148 to point out faulty channel configuration.

MMW #34 to MMW #94 are reserved and should not be used.

4.3 Channel Information

For the configured channels, necessary information is available aschannel data and status bits. This is explained in details below.

4.3.1 Channel Data

Module memory words MMW #128 to MMW #142 are module memorywords for channel temperature readings. This is nothing but ambienttemperature. The temperature reading resolution is 0.1 C. For enabled

channels, this information is updated cyclically in module. The data isread and stored using READ_W function in application program.

RTD Type C Temperature rangePT 100 (385) -200.0 C to 850.0 C

4.3.2 Channel Status

Channel status information is available in MMW #146 to MMW #152 in bitform as follows.

Channel high and low set point status

MMW #146 stores high and low limit status of individual channels.

Item Description 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0< Max. limit 0> Max. limit 1> Min. limit 0

Ch 1

< Min. limit 1

< Max. limit 0Ch 8> Max. limit 1


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Item Description 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0> Min. limit 0< Min. limit 1

First two bits bit 0 and bit 1 holds high and low point status of channel 0comparing high and low set points in MMW #2 and MMW #4 respectively.

Channel 0 high bit, bit 0 becomes ON when temerature reading is abovehigh set point. It becomes OFF when temprature reading is below highset point. Low bit becomes ON when temerature reading is below low setpoint. It becomes OFF when temprature reading is above low set point.

Similarly next two bits gives high and low point status of cahnnel 2 and soon.

Channel configuration status

Module memory word MMW #148 holds status of validity of configurationand parameters for all the channels.

MMW #148 Channel configuration and parameter mismatch status


Config. valid 0Ch 1

Config. Invalid 1

Config. valid 0Ch 8

Config. Invalid 1Res - 0 0 0 0 0 0 0 0

Bit 0 of MMW #148 gives channel 0 configuration status and bit 7 ofMMW #148 gives channel 7 configuration status. Configuration bit is ONwhen

In dynamic configuration if high set point is not within specified input range if low set point is not within specified input range if high set point < low set point

In all these cases, Ixx.1 bit becomes ON. Corresponding green channelLED starts flashing.

Channel out of range status

MMW #150 stores over range and under range status of individual

channels.

Item Description 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0< Over range 0Over range 1> Under range 0

Ch 1

Under range 1

< Over range 0Over range 1> Under range 0

Ch 8

Under range 1


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First two bits bit 0 and bit 1 gives over range and under range status ofchannel 0 depending on input type selected. Next two bits give overrange and under range status of channel 1 and so on.

Over range bit becomes ON when RTD input is above specified inputsignal. Under range bit becomes ON when RTD input is below specified

input signal. In all these cases, corresponding green channel LED startsflashing.

Sensor Fault Error

MMW #152 stores sensor fault status of individual channels.

Item Description 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0Input connected 0

Ch 1Sensor fault 1

Input connected 0Ch 8 Sensor fault 1Res - 0 0 0 0 0 0 0 0

Bit 0 of MMW #152 holds status of channel 0. It becomes ON if channel 0is configured and input signal is not connected. Bit 1 of MMW #154 holdsstatus of channel 1. In ADC conversion cycle, first sensor fault status forconfigured channel is checked. If sensor fault is detected, channel isbypassed and returns value in case of open circuit is stored as channeltemperature reading. Bit 9 and bit 8 of static configuration word of achannel decides return value as zero, upper scale or lower scaleconsidering safety in control action.

If open circuit error bit is set for a channel, corresponding channel LED

(green color) on module starts flashing.

4.4 Programming with Nexgen 4000 CPU

The data in PLC variables is transferred to the RTD input module when'WRITE_W' function is executed. The data in the PLC variables can beupdated using functions like 'MOV_W', arithmetic or any other functions.The data from RTD input module memory can be transferred to PLCvariables when 'READ_W' function is executed.

The WRITE_W function below shows data transfer from the CPUmodule's memory to RTD input module memory. The details of transferare -

RTD 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 8 words Address on the RTD input module in slot 2 is #96


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M0.0 ----- WRITE_W ---- M0.1+---| |---+--------- |EN ENO|-+---------+---( )---

| |#2 -|SLOT |

| |MW50 -|DATA || |

#8 -|LEN || |

#96 -|ADDR || |-------------------

'WRITE_W' function gets executed when condition for enable 'EN' is ON.'ENO' output becomes ON, when EN is ON and function is executedsuccessfully.ENO is OFF if

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

So 8 words (MW50 to MW64) information from CPU memory istransferred to the memory at address #96 onwards of RTD input modulefitted in slot 2.

The 'READ_W' function below shows data transfer from the RTD inputmodule memory to CPU memory. The details of transfer are -

RTD input module is configured in slot 2 of PLC Address on the RTD input module in slot 2 is #128 Start address of memory on the CPU module is MW100 Length of data area to be transferred is 8 words

M0.2 ------ READ_W ----- M0.3+---| |---+--------- |EN ENO|-+---------+---( )---

| |#2 -|SLOT |

| |#128 -|ADDR |

| |#8 -|LEN |

| |MW100-|DATA |

| |

---------------READ_W' function gets executed when condition for enable 'EN' is ON.'ENO' output becomes ON, when EN is ON and function is executedsuccessfully. ENO is OFF if parameters of function are invalid or notwithin specified range. RTD input module is not accessible to CPUmodule. So 8 words (MMW128 to MMW142) information on RTD inputmodule fitted in slot #2 are transferred to the CPU memory words(MW100 to MW114).

Example of basic application program is given below. For the same, refer

Nexgen PLC configuration shown inchapter 4.1. In the configuration,following points are to be noted.


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I 8.0 is a module status bit as 'Module Not OK' bit. I8.0 is set if 24 VDCsupply to module is not healthy and / or hardware fault, watchdog fault isobserved on module.

I 8.1 is a configuration status bit as 'Invalid Configuration' bit. I 8.1 is set iffor one or more channels, configuration is invalid.

I 8.2 is a maximum minimum set point status bit as 'Set pointExceeded' bit. I 8.2 is set if for one or more configured channels, inputsignal is below or above limits set.

I 8.3 is a RTD input range status bit as 'Out of Range' bit. I 8.3 is set if forone or more configured channels, input signal is below or above specifiedrange.

I 8.4 is a open circuit status bit as 'Sensor Fault ' bit. I 8.4 is set if for oneor more configured channels, input is not connected.Q 8.0 is a command for 'Static Configuration Write'. When this bit is setby user, RTD input module accepts static configuration available in

module memory words MMW#96 to MMW#110 and configures themodule accordingly.

S 4.2 is a 'Module Error' bit for the module fitted in slot 2.

While developing the application program, first check whether the moduleis healthy. For the same, check 'Module Error' bit S 4.2 and 'Module NotOk' bit I8.0. If any bit is set, declare respective fault. In this case, moduleis not accessible. If both are OFF, then only enable 'WRITE_W' and'READ_W' functions for RTD input module.

The static configuration information consists of basic attributes like returnvalue in case of sensor fault of input signal (zero, upper scale, lower

scale) and no. of averaging samples ( 0, 4, 8, 16 ). This configuration isto be transferred to module memory MMW#96 to MMW#110, if all the 8channels are used. In this example, channels are configured for

PT 100 50 Hz filter Return value is of upper scale in case of sensor fault No. of averaging samples is 4

For this configuration, the value $0900 should be written to respectivemodule memory word.

Static ConfigurationWord 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

$0902 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0

So MW50 to MW 64 should contain $0900, for the configuration required.This information is transferred to RTD module memory MMW#96 toMMW#110, when 'WRITE_W' function is executed.

Reserved Returnvalue ofupperscale

Avg. of4Samples

50 HzFilter

RTD input


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When 'WRITE_W' function is executed successfully, ENO outputbecomes ON, When ENO is ON, set 'Static Configuration Write'command bit informing the module to accept the static configuration orchange in configuration. Once this information is transferred to module, itis valid as long as PLC power is present.

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 and Any other condition as per requirement of application program e.g.

memory bit M2.0 is ON.S0.6 ------ WRITE_W ---- Q8.0

+---| |---+---------+---------|EN ENO|-+---( )---| | |

S0.7 | | |+---| |---+---------| #2 -|SLOT |

| | |S4.2 M0.4 | | |

+---| |---+---|N|---| MW50 -|DATA || | |

I8.0 M0.5 | | |+---| |---+---|N|---+ #8 -|LEN |

| | |M2.0 M2.1 | | |

+---| |---+---|P|---+ #96 -|ADDR || |-------------------

If 'WRITE_W' function is executed successfully, Q8.0 bit becomes ON for

one scan duration. If this bit is not ON even if function enable conditionsare ON, declare fault and take appropriate action.

Once, static configuration is written, channels are enabled as perrequirement. To enable all the channels, memory word MW166 shouldcontain $00FF value. Enable 'WRITE_W' function with any conditionM0.6 with interlocks of Module Error bit S4.2 and 'Module Not Ok' bit I8.0.


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When 'WRITE_W' function is executed, the data $00FF is transferred tomodule memory MMW#00. The maximum and minimum set points foreach channel is transferred to module memory words MMW#02 toMMW#32 if 'WRITE_W' function is executed successfully, M0.7 bitbecomes ON. If this bit is not ON even if function enable conditions areON, declare fault and take appropriate action.

M0.6 S4.2 I8.0 ------ WRITE_W ---- M0.7+---| |---+---|/|---+---|/|---|EN ENO|-+---( )---

| || |

#2 -|SLOT || || |

MW166 -|DATA || || |

#17 -|LEN || |

| |#0 -|ADDR || |-------------------

After transferring static and dynamic configuration information to RTDmodule memory, module starts functioning. Enable 'READ_W' functionwith any condition M1.0 with interlocks of Module Error bit S4.2 and'Module Not Ok' bit I8.0. When 'READ_W' function is executed, thetemperature readings (0.1 C resolution) stored in module memoryMMW#128 to MMW#142 are transferred to CPU memory MW100 toMW#114 respectivelIf 'READ_W' function is executed successfully, M1.1bit becomes ON. If this bit is not ON even if function enable conditionsare ON, declare fault and take appropriate action.

M1.0 S4.2 I8.0 ------ READ_W ----- M1.1+---| |---+---|/|---+---|/|---|EN ENO|-+---( )---

| || |

#2 -|SLOT || || |

#128 -|ADDR || || |

#8 -|LEN || |

| |MW100 -|DATA || |-------------------


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To read the status of temperature readings for maximum and minimumset points, it is necessary to read MMW#146 when I8.2 bit 'Set pointExceeded' in ON.

I8.2 S4.2 I8.0 ------ READ_W ----- M1.5+---| |---+---|/|---+---|/|---|EN ENO|-+---( )---

| || |

#2 -|SLOT || || |

#146 -|ADDR || || |

#1 -|LEN || |

| |MW126 -|DATA || |-------------------

Here M126.0 is over range bit for channel 0 and M126.1 is for underrange for channel 0. Similarly, M127.6 is over range bit for channel 7 andM127.7 is for under range for channel 7.With this status, appropriate action can be taken for temperature control.

To read the status of each channel, read the status information whenever corresponding input image bit is ON. This is depicted below.

'Invalid Configuration bit I8.1 becomes ON, if one or more channelconfiguration data is invalid. To find out exact faulty channel/s, readMMW#148 from module.

I8.1 S4.2 I8.0 ------ READ_W ----- M1.2+---| |---+---|/|---+---|/|---|EN ENO|-+---( )---

| || |

#2 -|SLOT || || |

#148 -|ADDR || |

| |#1 -|LEN || || |

MW118 -|DATA || |-------------------

When this 'READ_W' function is executed successfully, check CPUmemory bits M118.0 to M118.7. M118.0 bit is ON if channel 0configuration is invalid, M118.1 bit is ON if channel 1 configuration isinvalid and so on. In this correct the configuration of faulty channel. Incase of invalid configuration for particular channel, channel temperature

reading becomes #0.


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'Out of Range' bit I8.3 becomes ON, if one or more channel input signal/sis/are below or above specified range for selected input type. To find outexact faulty channel/s, read MMW#150 from module.

I8.3 S4.2 I8.0 ------ READ_W ----- M1.3

+---| |---+---|/|---+---|/|---|EN ENO|-+---( )---| || |

#2 -|SLOT || || |

#150 -|ADDR || || |

#1 -|LEN || || |

MW120 -|DATA |

| |----------------When this 'READ_W' function is executed successfully, check CPUmemory bits M120.0 to M121.7 for over range and over range status.M120.0 bit is ON if channel 0 input signal is above specified range,M120.1 bit is ON if channel 0 input signal is below specified range and soon. In this case, take proper action. For a particular channel, if inputsignal is above specified range, channel temperature reading remains atmaximum value. For PT100 input, this is 850.0 C. For a particularchannel, if input signal is below specified range, channel temperaturereading remains at minimum value. For PT100 input, this is -250.0 C

'Sensor Fault' bit I8.4 becomes ON, if one or more channel input is

disconnected. To find out exact faulty channel/s, read MMW#152 frommodule.

I8.4 S4.2 I8.0 ------ READ_W ----- M1.4+---| |---+---|/|---+---|/|---|EN ENO|-+---( )---

| || |

#2 -|SLOT || || |

#152 -|ADDR || || |

#1 -|LEN || || |

MW122 -|DATA || |

----------------When this 'READ_W' function is executed successfully, check CPUmemory bits M122.0 to M122.7 for sensor fault status. M122.0 bit is ON ifchannel 0 sensor is faulty, M122.1 bit is ON if channel 1 sensor is faultyand so on. In this case, take proper action. For a particular channel, incase of sensor fault, channel temperature reading is forced to value


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selected by user. In this case, it is upper scale value, which is 850.0 Cfor PT100 input type.

4.5 Programming with Nexgen 5000 CPU The configuration data in PLC variables is transferred to the RTD input modulewhen 'IM_Write function is executed. The data in the PLC variables can be updated

using operators like 'MOVE', arithmetic or any other functions. The data from analoginput module memory can be transferred to PLC variables when 'IM_Read' function isexecuted.

The IM_Write function below shows data transfer from the CPU module'smemory to Thermocouple input module memory. The details of transfer are

The RTD input module is configured in slot 2 of PLC

The configuration information is stored in an 8 word array Static_Config

& in 17 word array Dynamic_Config.

Length of data area to be transferred is 16 bytes at MMW96 for

Static_Config & 34 bytes at MMW0 for Dynamic_Config.

'IM_Write' function gets executed when BOOLean input 'Config_Dn' &Wr_Delay.Q is TRUE. BOOLean output 'Config_Dn' becomes TRUE, when functionis executed successfully. It is FALSE if

Parameters of function are invalid or not within specified range.

RTD input module is not accessible to CPU module .


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So 8 words configuration information ( Static ) from CPU memory is transferredto the memory at address 96 onwards & 17 words configuration information (Dynamic) from CPU memory is transferred to memory 0 onwars of Thermocoupleinput module fitted in slot 2.

The 'IM_Read function shows data transfer from the Theromocouple inputmodule memory to CPU memory. The details of transfer are -

The Thermocouple input module is configured in slot 2 of PLC

Address on the Thermocouple input module in slot 2 is 128

The data to be stored in PLC variable array Thermocouple_Data &

AIStatus array.

Length of data area to be transferred is 16 bytes for Thermocouple_data

& 8 bytes for AIstatus .

'IM_Read' function gets executed when ' Rd_Delay.Q ' is ON. 'Rd_Dn' & Stat_Rdyoutput becomes ON, when EN is ON and function is executed successfully. ENO isOFF if

Parameters of function are invalid or not within specified range

The module is not accessible to CPU module


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Example of basic application program is given below. For the same, refer NexgenPLC configuration shown in chapter 4.1. In the configuration, following points are tobe noted.

%IX4.0 is a module status bit as 'Module Not OK' bit. %IX4.0 is set if 24 VDCsupply to module is not healthy and / or hardware fault, watchdog fault is observed onmodule.

%IX4.1 is a channel status bit as. %IX4.1 is set if for one or more channels,configuration is invalid and / or any channel error like open circuit is observed.

_BRACK_0_IOERR.2 is a 'Module Error' bit for the module fitted in slot 2.

While developing application program, first check whether the module is healthy.For the same, check 'Module Error' bit _BRACK_0_IOERR.2 and 'Module Not Ok' bit%IX4.0. If any bit is set, declare respective fault. In this case, module is notaccessible. If both are OFF, then only enable 'IM_Write' and 'IM_Read functions forRTD module.

Once Thermocouple input data is read successfully, the data can be processedas the application requirement. If RTD input data read is to be displayed on HMI orSCADA, the varaible AIData should be mapped to any memory varaible whiledeclaration like

RTD_Data AT%MW100: ARRAY [0..7] OF INT;


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Here the RTD data for the channels is stored in memory variable %MW100 to%MW116 in integer format. Channel 0 data is stored in %MW100 while channel 7data is stored in %MW16.

If input image bit %IX4.0 or %IX4.1 is TRUE, the appropriate error should bedeclared and further processing of analog 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 thermocouple input module arediscussed.

LED Indications for diagnostics

Fault Diagnostic

5.1 LED Indications for Diagnostics

The following table explains significance of LED provided for modulestatus and diagnostic purpose on the module.

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

24 VDC supply to module absent1 No 24 V Supply OrangeON

24 VDC circuit on-board glass fuse blownOFF Module hardware healthy and module is ready

Module in self test

CPU watchdog faulty

2 CPU fault Orange

ONModule busy

OFF CJC sensor OK.CJC sensor short3 CJC Fault Orange

ONCJC sensor open

OFF Channel not enabledON Channel enabled and healthy

Parameter mismatchInvalid configurationOver rangeUnder rangeOpen circuit

4Channel Status(Eight for eightchannels)

Green Flashingwith 10 Hzfrequency

CJC fault

5.2 Fault Diagnostic

This section explains various possibilities of faults related tothermocouple Input Module and external interface and corrective actionto be taken. Faults may occur in

Modules as a whole Specific channel only Application Program.

In first two cases, replacement of module is required where as third casecan be sorted out by on line monitoring of application program.

Equipments required

The following equipments are required for fault diagnosis ofthermocouple input module.

Screw driver Digital Multi meter with measuring facility for

o mV DC voltage.o Continuity and resistance.

Set up for on line monitoring of application program as follows.o PC with DOXMINI+ softwareo PC to Nexgen PLC Cable


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The following diagnostic flow chart shows various possibilities of faults ifthermocouple module is not in operation as per requirement andcorrective action to be taken.

Module not working

Confirm 24 VDC supply at terminals 36 &37.Take proper action.

Check on-board glass fuse.*If blown, replace it by same type.

No 24V Supply LED status?

Replace Module

No 24V SupplyLED status?

No 24V SupplyLED status?

Module

working OK?

Diagnosis Over

ON

ON

ON

OFF

OFF

OFF

YES NO

CPU Fault LEDStatus? OFFON

Replace Module

CJC FaultLED Status? OFFON

Replace Module

Module Hardware faulty

CJC sensor short or open.All enabled channel LEDswill start flashing

A


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Diagnostic flow chart continues.

IO ERR LEDStatus?

Module ErrorSystem bit Status ?

Fix module properly. Check expansioncable if it is in expansion rack. Checkconfiguration of PLC. Take proper action.

Module ErrorSystem bit Status?

Replace ModuleModuleworking OK?

Diagnosis Over

Channel LED Status?

Check application program.Enable channel.

Channel LEDStatus?

Replace Module

C

OFFON

ON OFF

YES NO

ON OFF

OFF

ON

OFF ON

A

Flashing

Check module input imagebits Ix.1 to Ix.4

Ix.1 is setInvalid configuration or parameterMismatch. Take proper action.

Ix.2 is setTemperature reading beyondMaximum - minimum set points. Takeproper action.

Ix.3 is setTemperature reading out of range ofinput type configured. Take properaction.

Ix.4 is setThermocouple element connectionsopen circuit. Take proper action.


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Diagnostic flow chart continues.

* The fuse should be replaced by same type strictlyRating - 315 mA, 250 VSub- miniature fuse link no. 372Make WICKMANN

Note For healthy operation of module always ensure that supply to module is withinspecifiedrange i.e. 18 VDC to 30 VDC including ripple.

Always ensure that thermocouple elements are of isolated tip type.

Remove thermocouple element and shortthe terminals. Now module should showambient temperature.

C

Temperature readingOk?

Monitor binary data value

for channel with PC basedProgramming Software

Check application program.

Check for JMP, MCR-MEinterlocks if any.

Temperature readingOk?

Probably problem is onthermocouple element side.Take proper action.Connect wires to terminal block.

Temperature reading

Ok?

Diagnosis Over Contact MESSUNGSYSTEMS

YESNO

YESNO

YESNO

Temperature readingOk? YESNO

Diagnosis Over


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6. Appendix 1

This section shows the reference tables for PT100 (385). The table givesresistance value of PT100 sensor and equivalent temperature.

C Ohms C Ohms C Ohms C Ohms C Ohms C Ohms-200 18.52 -140 43.88 -80 68.33 -20 92.16 0 100.00 +60 123.24-199 18.96 -139 44.29 -79 68.73 -19 92.55 1 100.39 61 123.62-198 19.39 -138 44.71 -78 69.13 -18 92.95 2 100.78 62 124.01-197 19.82 -137 45.12 -77 69.53 -17 93.34 3 101.17 63 124.39-196 20.25 -136 45.53 -76 69.93 -16 93.73 4 101.56 64 124.77-195 20.68 -135 45.95 -75 70.33 -15 94.12 5 101.95 65 125.17-194 21.11 -134 46.35 -74 70.73 -14 94.52 6 102.34 66 125.55-193 21.54 -133 46.76 -73 71.13 -13 94.91 7 102.73 67 125.93-192 21.97 -132 47.18 -72 71.53 -12 95.30 8 103.12 68 126.32-191 22.40 -131 47.59 -71 71.93 -11 95.69 9 103.51 69 126.70-190 22.83 -130 48.00 -70 72.33 -10 96.09 10 103.90 70 127.08-189 23.26 -129 48.41 -69 72.73 -9 96.48 11 104.29 71 127.46-188 23.69 -128 48.82 -68 73.13 -8 96.87 12 104.68 72 127.85-187 24.12 -127 49.23 -67 73.53 -7 97.26 13 105.07 73 128.23-186 24.55 -126 49.64 -66 73.93 -6 97.65 14 105.46 74 128.61

-185 24.97 -125 50.06 -65 74.33 -5 98.04 15 105.85 75 128.99-184 25.39 -124 50.47 -64 74.73 -4 98.44 16 106.24 76 129.38-183 25.82 -123 50.88 -63 75.13 -3 98.83 17 106.63 77 129.76-182 26.25 -122 51.29 -62 75.53 -2 99.22 18 107.02 78 130.14-181 26.67 -121 51.70 -61 75.93 -1 99.61 19 107.40 79 130.52-180 27.10 -120 52.11 -60 76.33 20 107.79 80 130.90-179 27.52 -119 52.52 -59 76.73 21 108.18 81 131.28-178 27.95 -118 52.92 -58 77.13 22 108.57 82 131.67-177 28.37 -117 53.33 -57 77.52 23 108.96 83 132.05-176 28.80 -116 53.74 -56 77.92 24 109.35 84 132.43-175 29.22 -115 54.15 -55 78.32 25 109.73 85 132.81-174 29.65 -114 54.56 -54 78.72 26 110.12 86 133.19-173 30.07 -113 54.97 -53 79.11 27 110.51 87 133.57-172 30.49 -112 55.38 -52 79.51 28 110.90 88 133.95-171 30.92 -111 55.78 -51 79.91 29 111.28 89 134.33-170 31.34 -110 56.19 -50 80.31 30 111.67 90 134.71

-169 31.76 -109 56.60 -49 80.70 31 112.06 91 135.09-168 32.18 -108 57.00 -48 81.10 32 112.45 92 135.47-167 32.61 -107 57.41 -47 81.50 33 112.83 93 135.85-166 33.03 -106 57.82 -46 81.89 34 113.22 94 136.23-165 33.45 -105 58.22 -45 82.29 35 113.61 95 136.61-164 33.86 -104 58.63 -44 82.69 36 113.99 96 136.99-163 34.28 -103 59.04 -43 83.08 37 114.38 97 137.37-162 34.70 -102 59.44 -42 83.48 38 114.77 98 137.75-161 35.12 -101 59.85 -41 83.88 39 115.15 99 138.13-160 35.54 -100 60.26 -40 84.27 40 115.54 100 138.51-159 35.96 -99 60.67 -39 84.67 41 115.93 101 138.89-158 36.38 -98 61.07 -38 85.06 42 116.31 102 139.27-157 36.80 -97 61.48 -37 85.46 43 116.70 103 139.65-156 37.22 -96 61.87 -36 85.85 44 117.08 104 140.03-155 37.63 -95 62.29 -35 86.25 45 117.47 105 140.39-154 38.05 -94 62.69 -34 86.64 46 117.85 106 140.77-153 38.47 -93 63.10 -33 87.04 47 118.24 107 141.15-152 38.89 -92 63.50 -32 87.43 48 118.62 108 141.53-151 39.31 -91 63.91 -31 87.83 49 119.01 109 141.91-150 39.72 -90 64.30 -30 88.22 50 119.40 110 142.29-149 40.14 -89 64.70 -29 88.62 51 119.78 111 142.66-148 40.56 -88 65.11 -28 89.01 52 120.16 112 143.04-147 40.97 -87 65.51 -27 89.40 53 120.55 113 143.42-146 41.39 -86 65.91 -26 89.80 54 120.93 114 143.80-145 41.80 -85 66.31 -25 90.19 55 121.32 115 144.18-144 42.22 -84 66.72 -24 90.59 56 121.70 116 144.56-143 42.64 -83 67.12 -23 90.98 57 122.09 117 144.94-142 43.05 -82 67.52 -22 91.37 58 122.47 118 145.32-141 43.46 --81 67.92 --21 91.77 59 122.86 119 145.69


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C Ohms C Ohms C Ohms C Ohms C Ohms C Ohms120 146.07 180 168.48 240 190.47 300 212.05 360 233.21 420 253.96121 146.45 181 168.85 241 190.83 301 212.40 361 233.56 421 254.30122 146.82 182 169.22 242 191.20 302 212.76 362 233.91 422 254.65123 147.20 183 169.59 243 191.56 303 213.12 363 234.26 423 254.99124 147.58 184 169.96 244 191.92 304 213.47 364 234.60 424 255.33

125 147.95 185 170.33 245 192.28 305 213.83 365 234.95 425 255.67126 148.33 186 170.69 246 192.66 306 214.19 366 235.30 426 256.01127 148.71 187 171.06 247 193.02 307 214.55 367 235.65 427 256.35128 149.08 188 171.43 248 193.38 308 214.90 368 236.00 428 256.70129 149.46 189 171.80 249 193.74 309 215.26 369 236.35 429 257.04130 149.83 190 172.17 250 194.10 310 215.61 370 236.70 430 257.38131 150.21 191 172.54 251 194.47 311 215.97 371 237.05 431 257.72132 150.58 192 172.91 252 194.83 312 216.32 372 237.40 432 258.06133 150.96 193 173.27 253 195.19 313 216.68 373 237.75 433 258.40134 151.34 194 173.64 254 195.55 314 217.03 374 238.09 434 258.74135 151.71 195 174.01 255 195.90 315 217.39 375 238.44 435 259.08136 152.09 196 174.39 256 196.26 316 217.73 376 238.79 436 259.42137 152.46 197 174.75 257 196.62 317 218.08 377 239.14 437 259.76138 152.84 198 175.12 258 196.98 318 218.44 378 239.48 438 260.10139 153.21 199 175.49 259 197.35 319 218.79 379 239.83 439 260.44140 153.58 200 175.86 260 197.71 320 219.15 380 240.18 440 260.78141 153.95 201 176.23 261 198.07 321 219.50 381 240.52 441 261.12

142 154.32 202 176.59 262 198.43 322 219.85 382 240.87 442 261.46143 154.71 203 176.96 263 198.79 323 220.21 383 241.22 443 261.80144 155.08 204 177.33 264 199.15 324 220.56 384 241.56 444 262.14145 155.46 205 177.70 265 199.51 325 220.91 385 241.91 445 262.48146 155.83 206 178.06 266 199.87 326 221.27 386 242.25 446 262.83147 156.21 207 178.43 267 200.23 327 221.62 387 242.60 447 263.17148 156.58 208 178.80 268 200.59 328 221.97 388 242.95 448 263.50149 156.96 209 179.16 269 200.95 329 222.32 389 243.29 449 263.84150 157.33 210 179.53 270 201.31 330 222.68 390 243.64 450 264.18151 157.71 211 179.90 271 201.67 331 223.03 391 243.98 451 264.52152 158.08 212 180.26 272 202.03 332 223.38 392 244.33 452 264.86153 158.45 213 180.63 273 202.38 333 223.73 393 244.67 453 265.20154 158.83 214 180.99 274 202.74 334 224.09 394 245.02 454 265.54155 159.20 215 181.36 275 203.10 335 224.45 395 245.36 455 265.87156 159.56 216 181.73 276 203.46 336 224.80 396 245.71 456 266.21157 159.94 217 182.09 277 203.82 337 225.15 397 246.05 457 266.55

158 160.31 218 182.46 278 204.18 338 225.50 398 246.40 458 266.89159 160.68 219 182.82 279 204.54 339 225.85 399 246.74 459 267.22160 161.05 220 183.19 280 204.90 340 226.21 400 247.09 460 267.56161 161.43 221 183.55 281 205.25 341 226.56 401 247.43 461 267.90162 161.80 222 183.92 282 205.61 342 226.91 402 247.78 462 268.24163 162.17 223 184.28 283 205.97 343 227.26 403 248.12 463 268.57164 162.54 224 184.65 284 206.33 344 227.61 404 248.46 464 268.91165 162.91 225 185.01 285 206.70 345 227.96 405 248.81 465 269.25166 163.28 226 185.38 286 207.05 346 228.31 406 249.15 466 269.58167 163.66 227 185.74 287 207.41 347 228.66 407 249.50 467 269.92168 164.03 228 186.11 288 207.77 348 229.01 408 249.84 468 270.26169 164.40 229 186.47 289 208.13 349 229.36 409 250.18 469 270.59170 164.77 230 186.84 290 208.48 350 229.72 410 250.53 470 270.93171 165.14 231 187.20 291 208.84 351 230.07 411 250.89 471 271.27172 165.51 232 187.56 292 209.20 352 230.42 412 251.21 472 271.60173 165.88 233 187.93 293 209.55 353 230.77 413 251.55 473 271.94

174 166.25 234 188.29 294 209.91 354 231.12 414 251.90 474 272.27175 166.62 235 188.65 295 210.27 355 231.47 415 252.24 475 272.61176 167.00 236 189.02 296 210.62 356 231.81 416 252.59 476 272.95177 167.37 237 189.38 297 210.98 357 232.16 417 252.94 477 273.28178 167.74 238 189.74 298 211.34 358 232.51 418 253.28 478 273.62179 168.11 239 190.11 299 211.69 359 232.86 419 253.62 479 273.95

Z


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C Ohms C Ohms C Ohms C Ohms C Ohms C Ohms480 274.29 542 294.87 604 315.00 666 334.68 728 353.91 790 372.71481 274.62 543 295.20 605 315.32 667 334.99 729 354.22 791 373.01482 274.96 544 295.53 606 315.64 668 335.31 730 354.53 792 373.31483 275.29 545 295.85 607 315.96 669 335.62 731 354.83 793 373.61484 275.63 546 296.18 608 316.28 670 335.93 732 355.14 794 373.91

485 275.96 547 296.51 609 316.60 671 336.25 733 355.44 795 374.21486 276.31 548 296.84 610 316.92 672 336.56 734 355.75 796 374.51487 276.64 549 297.16 611 317.24 673 336.87 735 356.06 797 374.80488 276.97 550 297.49 612 317.56 674 337.18 736 356.37 798 374.10489 277.31 551 297.82 613 317.88 675 337.50 737 356.68 799 375.40490 277.64 552 298.14 614 318.20 676 337.81 738 356.98 800 375.70491 277.98 553 298.47 615 318.52 677 338.12 739 357.29 801 376.00492 278.31 554 298.80 616 318.85 678 338.43 740 357.59 802 376.29493 278.64 555 299.12 617 319.17 679 338.75 741 357.90 803 376.59494 278.98 556 299.45 618 319.49 680 339.06 742 358.20 804 376.89495 279.31 557 299.78 619 319.81 681 339.37 743 358.51 805 377.19496 279.64 558 300.10 620 320.12 682 339.68 744 358.81 806 377.49497 279.98 559 300.43 621 320.44 683 339.99 745 359.12 807 377.79498 280.31 560 300.75 622 320.76 684 340.30 746 359.42 808 378.09499 280.64 561 301.08 623 321.08 685 340.62 747 359.72 809 378.39500 280.98 562 301.41 624 321.40 686 340.94 748 360.03 810 378.68501 281.31 563 301.73 625 321.72 687 341.25 749 360.33 811 378.98

502 281.64 564 302.06 626 322.03 688 341.55 750 360.64 812 379.28503 281.97 565 302.38 627 322.34 689 341.87 751 360.94 813 379.57504 282.31 566 302.71 628 322.66 690 342.18 752 361.24 814 379.87505 282.64 567 303.03 629 322.98 691 342.49 753 361.55 815 380.17506 282.97 568 303.36 630 323.30 692 342.80 754 361.85 816 380.46507 283.30 569 303.68 631 323.61 693 343.11 755 362.15 817 380.76508 283.63 570 304.01 632 323.93 694 343.42 756 362.46 818 381.05509 283.97 571 304.33 633 324.25 695 343.73 757 362.76 819 381.35510 284.30 572 304.66 634 324.57 696 344.04 758 363.06 820 381.65511 284.63 573 304.98 635 324.88 697 344.35 759 363.36 821 381.94512 284.96 574 305.30 636 325.21 698 344.66 760 363.67 822 382.24513 285.29 575 305.63 637 325.53 699 344.97 761 363.97 823 382.53514 285.62 576 305.95 638 325.85 700 345.28 762 364.27 824 382.83515 285.95 577 306.28 639 326.16 701 345.59 763 364.57 825 383.12516 286.

ED-2002-017 8 Channel RTD Input Module(4311).pdf

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