ed-2002-016 8 channel thermocouple input module(4310).pdf

8/12/2019 ED-2002-016 8 Channel Thermocouple Input Module(4310).pdf

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NEXGEN PLC I/O Modules Messung Systems

Published July 2002 SD-2002-016 8 Channel Thermocouple Input Module(4310)mod.docPage 2 of 53 Document No.: ED-2002-006/V1.0

Revision

Version Date Description

1.0 22 May 20048 Channel, Thermocouple Input Module(Ordering Code 4310)NEXGEN Series of PLCs.


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Messung Systems NEXGEN PLC I/O Modules

SD-2002-016 8 Channel Thermocouple Input Module(4310)mod.doc Published July 2002Document No.: ED-2002-006/V1.0 Page 3 of 53

INDEX1. MODULE OVERVIEW........................................................................................................................................ 6

1.1 THERMOCOUPLE INPUT MODULE OVERVIEW ...................................................................................................... 61.2 LED INDICATIONS............................................................................................................................................. 81.3 GENERAL SPECIFICATIONS................................................................................................................................9

2. MODULE OPERATION....................................................................................................................................10

2.1 BLOCK DIAGRAM............................................................................................................................................. 102.2 THERMOCOUPLE TYPES AND RANGE OF TEMPERATURES................................................................................... 122.3 ON-BOARD PROCESSOR OPERATIONS.............................................................................................................12

2.3.1 Power On Operations ............................................................................................................................ 122.3.2 Analog to Digital Conversion ............ .............. ............. .............. ............. .............. ................. .............. .. 132.3.3 Cold Junction Compensation...... .............. .............. ............. .............. .............. .............. ............... ......... 142.3.4 Scaling................................................................................................................................................... 142.3.5 Linearization ..........................................................................................................................................142.3.6 Averaging .............................................................................................................................................. 15

2.4 MODULE INFORMATION ................................................................................................................................... 152.4.1 Input Output Image Mapping ................................................................................................................. 152.4.2 Memory Mapping............ ............. .............. ............. .............. .............. ............. ............... .............. ......... 162.4.3 Commands ............................................................................................................................................ 172.4.4 Module Status Bits..... ............. .............. .............. ............. .............. ............. .............. ............... .............. 18

3. INSTALLATIONS AND WIRING...................................................................................................................... 19

3.1 MODULE INSTALLATION ................................................................................................................................... 193.2 CONNECTION DETAILS .................................................................................................................................... 193.3 PRECAUTIONS TO BE TAKEN ............................................................................................................................ 21

4. CONFIGURATION AND PROGRAMMING..................................................................................................... 22

4.1 SLOT CONFIGURATION.................................................................................................................................... 224.2 CHANNEL CONFIGURATION.............................................................................................................................. 23

4.2.1 Static Configuration ...............................................................................................................................234.2.2 Dynamic Configuration .......................................................................................................................... 25

4.3 CHANNEL INFORMATION..................................................................................................................................274.3.1 Channel Data....... ............. .............. ............. .............. ............. .............. ............. ............... .............. ....... 274.3.2 Channel Status...................................................................................................................................... 27

4.4 PROGRAMMING WITH NEXGEN 4000 CPU ....................................................................................................... 304.5 PROGRAMMING WITH NEXGEN 5000 CPU ....................................................................................................... 37

5. TROUBLESHOOTING.....................................................................................................................................42

5.1 LED INDICATIONS FOR DIAGNOSTICS............................................................................................................... 425.2 FAULT DIAGNOSTIC......................................................................................................................................... 42

6. APPENDIX 1 ....................................................................................................................................................46

6.1 REFERENCE TABLE - T TYPE THERMOCOUPLE (COPPER VS. COPPER-NICKEL) ................................................. 476.2 REFERENCE TABLE - E TYPE THERMOCOUPLE (NICKEL-CHROMIUM VS. COPPER-NICKEL)................................. 486.3 REFERENCE TABLE - R TYPE THERMOCOUPLE (PLATINUM-13% RHODIUM VS. PLATINUM) ................................ 486.4 REFERENCE TABLE - S TYPE THERMOCOUPLE (PLATINUM-10% RHODIUM VS. PLATINUM).................................496.5 REFERENCE TABLE - B TYPE THERMOCOUPLE (PLATINUM-30% RHODIUM VS. PLATINUM-6% RHODIUM)...........506.6 REFERENCE TABLE - N TYPE THERMOCOUPLE (NICKEL-14.2% CHROMIUM-1.4% SILICON VS. NICKEL-4.4%SILICON- 0.1% MAGNESIUM)................................................................................................................................... 51


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INDEX OF FIGURES

FIGURE 1 : FRONT VIEW OF THERMOCOUPLE INPUT MODULE.........................................................7

FIGURE 2 : BLOCK DIAGRAM OF THERMOCOUPLE INPUT MODULE..................................................11

FIGURE 3 : ADC CONVERSION CYCLE ........................................................................................13

FIGURE 4 : INPUT OUTPUT IMAGE MAPPING OF THERMOCOUPLE INPUT MODULE .........................16

FIGURE 5 : MEMORY MAPPING OF THERMOCOUPLE INPUT MODULE .............................................16

FIGURE 6 : CONNECTION DIAGRAM OF THERMOCOUPLE INPUT MODULE .......................................20


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

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

a) Any engineer who is responsible for the planning, design andconstruction of automatic equipment using the product associated withthis manual should be of a competent nature, trained and qualified tothe local and national standards required to fulfill that role. Theseengineers should be fully aware of all aspects of safety with regards toautomated equipment.

b) Any commissioning or service engineer must be of a competent nature,trained and qualified to the local and national standards required to fulfillthat job. These engineers should also be trained In the use andmaintenance of the completed product. This Includes being completelyfamiliar with all associated documentation for the said product. Allmaintenance 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 and coordinated manner in compliance to establishedsafety practices. The operators should also be familiar withdocumentation, which is connected with the actual operation of thecompleted equipment.

Note: The term-completed equipment refers to a third party constructeddevice, which contains or uses the product associated with this manual.Note on the Symbol used in this ManualAt various times through out this manual certain symbols will be used tohighlight points of Information, which are Intended to ensure the userspersonal safety and protect the integrity of equipment. Whenever any of thefollowing symbols are encountered its associated.

Note must be read and understood. Each of the symbols used is listedbelow; with a brief description of its meaning.

Warning !

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

Warning !

The specifications of product and contents of manual are subject to changewithout notice.


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1. Module Overview

This chapter describes the followingThermocouple Input Module Overview

LED IndicationsGeneral Specifications

1.1 Thermocouple Input Module Overview

This thermocouple input module converts thermocouple input mV values intoequivalent temperature values of 0.1C resolution with cold junctioncompensation and linearization. This is sigma - delta type A/D conversion. Itprovides 8 non-isolated channels, 16-bit resolution ADC. The individualchannel can be configured for specific type of thermocouple input. Thethermocouple types along with temperature ranges are given in below table.

Thermocouple Type C Temperature rangeJ -210.0 to +760.0

K -270.0 to +1370.0T -270.0 to +400.0

E -270.0 to +1000.0

R 0.0 to +1760.0S 0.0 to +1760.0

B 0.0 to +1820.0N -270.0 to +1300.0

The parameters and commands those are transferred to the module foradvanced processing are Thermocouple input type Return value in case of open circuit Averaging Channel enable / disable Maximum minimum 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 Open circuit detection CJC fault

This is an intelligent module with on-board processor and memory. The datatransfer between CPU module and thermocouple input module takes placeby 'READ_W' and 'WRITE_W' functions in application program. The modulestatus is available in input image and commands can be issued throughoutput image.


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The figure 1 on next page shows front view of 8 channels thermocouple inputmodule

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

TC0+

TC1+

TC0-

TC1-

SHIELD0

SHIELD1

TC2+

TC3+

TC2-

TC3-

SHIELD2

SHIELD3

TC4+

TC5+

TC4-

TC5-

SHIELD4SHIELD5

TC6+

TC7+

TC6-

TC7-

SHIELD6

SHIELD7

+ 24 V

0 V

EARTH

NO 24 V SUPPLY

CPU FAULT

CJC FAULT

CH0

CH1

CH2

CH3

CH4

CH5

CH6

CH7

4310ANALOG INTPUT

8 CH T/C

Figure 1 : Front View of Thermocouple Input Module

The module provides LED indications on the front. Brief information aboutchannel can be written on the front door. Behind front door, 38-pin removableterminal block is provided for interfacing. The wiring details are shown onbackside of front door.

Front ShieldPlate

Terminal Block

Fixing Screw

in RemovableTerminal Block

Connection

Details LabelFront Door

IO Label

LED

Indications

ChannelStatusLEDs

ModuleStatusLEDs

Terminal BlockFixing Screw

LM35CJC SensorPCB


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The thermocouple input module can be configured in any IO slot of the PLC.The number of thermocouple input modules is limited by back panel currentcapacity. In general a channel requires following information Dynamic configuration information Static configuration information

Data and Status information

In all, 22 words information per module is available.

1.2 LED Indications

The following table explains significance of 11 numbers of LEDs provided onthe module.

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

24 VDC supply to module absent1 No 24 V Supply Orange

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

Module in self testCPU watchdog faulty

2 CPU fault OrangeON

Module busyOFF CJC sensor OK.

CJC sensor short3 CJC Fault OrangeON

CJC sensor openOFF Channel not enabledON Channel enabled and healthy

Parameter mismatchInvalid configurationOver rangeUnder range

Open circuit

4Channel Status(Eight for eightchannels)

Green Flashingwith 10 Hzfrequency

CJC fault


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1.3 General Specifications

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

Number of Input channels 8Conversion Method Sigma delta with digital filter

J -210.0 C to +760.0 CK -270.0 C to +1370.0 CT -270.0 C to +400.0 CE -270.0 C to +1000.0 CR 0.0 to +1760.0 CS 0.0 to +1760.0 CB 0.0 to +1820.0 C

Thermocoupleinput types andoutput range

N -270.0 C to +1300.0 CTemperature resolution 0.1 CAccuracy 0.5 % of full scaleInput filter frequency 50 HzConversion time 60 ms per channelThermocouple linearization In steps of 10 C

Cold junction compensationLM 35 IC sensor mounted onterminal block itself

Channel to internalcircuit

1.5 kV opticalIsolation

Channel to channel NilInput Impedance 1 M Ohms

External supply requirement24 V DC, 100 mA(18 30 VDV including ripple)

External supply protection315 mA miniature glass fuse on

module Reverse polarity protection

Indications

No 24 V SupplyCPU faultCJC fault

Channel status (8)Back-plane current (5 V consumption) 250 mAIO points consumed 8 input bits and 8 output bitsTermination / Connection Removable 38 pin terminal blockOrdering code 4310


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2. Module Operation

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

Block Diagram Thermocouple Types and Range of Temperatures On-Board Processor Operations Module Information

At the time of application program development, the module can beconfigured using the programming software DOXMINI+ so that above specialfeatures can be used. Refer chapter 4 for configuration and programmingdetails.

2.1 Block Diagram

Block diagram of thermocouple input module is shown below.

CPUModule

/Analog toDigitalConverter

OPTICAL

I

SOLATION

Cold junctionCompensationInput Circuit

On board

Processor

Memory forConfiguration,Data, Status

Information

ModuleInterfaceCircuit

WatchDog

Amplifier

Multiplexer

Channel 0InputCircuit

Channel 7InputCircuit

DC-to-DCConverter

+15 V

-15 V

+5 V

-5 V

+ 24 VDC

24 V GND

Earth

ature GlassFuse

GND

No 24 V Supply Signal

Supply forADC Circuit

TC7+TC7-SHIELD7

TC0+

TC0-

SHIELD0

PCB withLM35 asCJC Sensor

+ 5 V

GND


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Figure 2 : Block diagram of Thermocouple Input module

The module provides eight analog to digital channels for thermocouple input.CPU bus is optically isolated from ADC circuit. The analog to digital converteroperates on serial data from the channels. The cold junction compensation

sensor signal and enabled channel input signals are multiplexed and thenamplified for ADC input. Thus sigma-delta (/ ) ADC converts only enabledanalog channels to digital value one by one. The converted count for eachchannel is manipulated by on-board processor. It has following functions.

Cold junction compensation Scaling Linearization Averaging

Thus cold junction compensated, scaled and linearized temperature readingis transferred 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 and updateschannel data information.

The channels can be independently enabled or disabled. Each channel inputcircuit has open circuit detection mechanism. On-board processor detectssignals, which are out of range of selected input type. The CJC sensor faultsare detected by module. All this information is available to main CPU.

The dynamic configuration, static configuration, data, status information isavailable in dual port RAM on the module. The configuration of all channelsis transferred to the module memory using WRITE_W function in theapplication program. Similarly data and status of all channels can be read byREAD_W function in the application program.

The module requires external 24 V for ADC circuit operation. Internally DC-to-DC converter generates 15 VDC and 5 VDC as required by eachchannel. If 24 VDC is absent or on-board glass fuse is blown, modulegenerates 'No 24 V Supply' signal for main CPU. The fuse protection forexternal 24 VDC supply is provided on module.


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2.2 Thermocouple types and range of temperatures

This section describes the thermocouple types and data range oftemperatures supported by module.

Type Material mV signal C temperature rangeJ Iron Vs Constantan (Copper-Nickel) -8.096 to 42.922 -210.0 to +760.0

KChromel (Nickel-Chromium VsAlumel (Nickel-Aluminium)

-6.458 to 54.807 -270.0 to +1370.0

T Copper Vs Constantan (Copper-Nickel) -6.258 to 20.869 -270.0 to +400.0

EChromel (Nickel-Chromium) VsConstantan (Copper-Nickel)

-9.835 to 76.358 -270.0 to +1000.0

R Platinum Vs Platinum-13% Rhodium 0.000 to 21.108 0.0 to +1768.0S Platinum Vs Platinum-10% Rhodium 0.000 to 18.698 0.0 to +1768.0

BPlatinum- 6% Rhodium Vs Platinum-30%Rhodium

0.000 to 13.814 0.0 to +1820.0

NNickel-14.2% Chromium-1.4% Silicon VsNickel-4.4% Silicon-0.1% Magnesium

-3.990 to 47.502 -200.0 to +1300.0

2.3 On-Board Processor Operations

The thermocouple input module is intelligent module with on-boardprocessor. The functions of on-board processor are explained below.

2.3.1 Power On Operations

After power ON, if 24 V supply to module is absent or on-board fuse is blownthen on-board processor sets Ix.1 bit of input image. After power ON, thisprocessor checks the hardware called as self test. During self-test and if

hardware error is detected, Ix.1 bit is set. Also CPU fault LED on front panelis put ON indicating that module is not accessible. During module operation,if module hardware is found faulty or watchdog error is detected, Ix.1 bit isset.

If the module hardware is OK, Ix.1 bit is cleared. Module starts CJC sensorsignal conversion by default and waits for static and dynamic configurationfrom the CPU module. After reception of valid configuration of thermocoupleinput channels, the module starts sampling and digital conversion cycle ofenabled channels. For more details of IO image 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 this case,

CPU module does not read the channel data and status.


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2.3.2 Analog to Digital Conversion

The module samples a thermocouple input channel and converts mV input toits digital value one by one. After power on, first CJC sensor signal issampled and conversion is started. After that as shown in the figure below,

only enabled channels are converted. If any error like invalid configuration isdetected, channel is not converted. The disabled channels or channels witherror detected are bypassed retaining earlier values.After one channel conversion, module initiates next channel conversion.During this conversion period, module processes converted data of previouschannel. This process includes applying CJC compensation, scaling,linearization and averaging. Thus the processed data for previous channel ismade available during this period. After converting all healthy channels,processed data and status information of all the channels is transferred torespective memory area on the module. This cycle continues. Thus when theprocessor module performs READ_W operation, it reads either old or newinformation i.e. data and status of channels.

Figure 3 : ADC Conversion Cycle

The module takes certain time to sample all enabled channels and convertinto digital value. The required time is the module update time. The factorsaffecting module update time is number of channels enabled. The moduleupdate time is minimum when only one channel is enabled. Likewise themodule update time is maximum when all channels are enabled. The moduleincorporates a digital low pass filter to reject noise on the input signal. Forthermocouple inputs, it is fixed to 50 Hz. It provides better noise rejection forlow filter frequencies.

Channel 0

disabled /error detection

Channel 1


Channel 2


Channel 3


Channel 7disabled /

error detection

Channel 6disabled /

error detection

Channel 5disabled /

error detection

Channel 4disabled /

error detection

CJC ChannelConversion

hannel 0Conversion

Channel 1Conversion

Channel 2Conversion

Channel 3Conversion

Update allchannel dataand status

hannel 7Conversion

Channel 6Conversion

Channel 5Conversion

Channel 4Conversion


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2.3.3 Cold Junction Compensation

Cold Junction Compensation (CJC) is necessary when making temperaturemeasurements using thermocouples. The thermocouple itself works on theprinciple that an electrical potential exists at the junction of two dissimilar

metals. The amount of this potential varies with temperature. When using athermocouple, the voltage across the thermocouple is measured andaccordingly the temperature is calculated.

CJC becomes necessary because the junction between each end of thethermocouple and thermocouple input module (terminal block) also adds apotential difference to the actual thermocouple voltage. When thethermocouple wires are connected to the terminal block, two morethermocouple junctions are formed, because the terminals are made of adifferent material (copper) than the thermocouple wires. These extrajunctions (called cold junctions), develop their own voltage, which alters thevoltage generated by the actual thermocouple. To compensate for this addedpotential, it is necessary to know the temperature at the junction between thethermocouple and terminal block. This temperature is measured using anextra CJC sensor. This is a temperature sensor other than a thermocouple.The sensors used here is IC (integrated circuit) sensors LM 35, which isdirectly, mounted on terminal block between terminal numbers 4, 6 and 8 asshown in chapter 3.2.15 VDC for the sensor LM35 is provided bythermocouple input module. The sensor provides 0 to 70 mV for 0 to 70 Ctemperature.

To make actual thermocouple temperature measurement, the voltage fromthe thermocouple and CJC sensor is measured considering them as differentchannel inputs as explained in chapter 2.3.2.Then CJC sensor temperaturereading is compensated from thermocouple channel temperature reading.Thus the effect of cold junctions is negated. This compensated reading isthen scaled and linearized to get actual temperature.

2.3.4 Scaling

The mV signal from thermocouples is scaled for equivalent temperature asper reference tables provided by standards. For the same, refer appendix 1.

2.3.5 Linearization

Thermocouple signals are not linear e.g. 10 percent change in athermocouple voltage does not correspond to a 10 percent change in itstemperature. Therefore linearization of thermocouple signal is necessary toget equivalent temperature. Also, each thermocouple type requires different

linearization.

In thermocouple input module linearization is performed by flexible softwaremethods. This is done with look up table in steps of 10 C for eachthermocouple type. ADC count is mapped within its 10 C temperature rangeand equivalent temperature is calculated considering line equation.


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2.3.6 Averaging

The module provides user selectable averaging facility so that stable value isavailable for processing and necessary control action. The module samplesand converts enabled channels one by one. The module keeps digital valueinto different memory locations. Depending on the averaging count, the

module performs averaging of those many previous readings and updateschannel data information.

Thus if the averaging counts of channel 0, 1 and 2 are 0, 4 and 8respectively, then initially data of channel 0, 1 and 2 are updated after 1, 4and 8 conversion cycles respectively. After that, it gets updated in everycycle. One conversion cycle means sampling and converting all enabledchannels as explained in chapter 2.3.2.Thus combination of filter frequencyand averaging count can be selected to get optimum channel update timeand stable temperature reading.

2.4 Module Information

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

Input Output Image Mapping Memory Mapping Commands Module Status Bits

2.4.1 Input Output Image Mapping

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

CPU module

1.1.1.1.1Input ImageNo 24 V Supply Ix.0Invalid Configuration Ix.1Set Points Exceeded Ix.2Out of Range Ix.3Open Circuit Ix.4CJC Fault Ix.5

CPU Fault Ix.7

Thermocouple Input module

ModuleInterface

circuit

Channel 4

Output ImageStatic ConfigurationWrite

Qx.0

Input Scan

Logic Scan

SLOT

ENO

IMM_IN

EN

Output Scan

Logic Scan

SLOT

ENOIMM_OUT

ENChannel 5

Channel 6

Channel 7

Channel 0

Channel 1

Channel 2

Channel 3


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Figure 4 : Input Output Image Mapping of Thermocouple Input Module

The module consumes 8 input bits (1 byte) of input image and 8 output bits(1 byte) of output image in the CPU module. CPU reads the status of module

in input scan. CPU writes user commands to module in output scan. Forimmediate updation of input and output image in application program,IMM_IN and IMM_OUT functions can be used in application programwhenever required. For the details refer chapter 2.4.3 and 2.4.4.

2.4.2 Memory Mapping

The memory mapping related to thermocouple input module is shown infigure below.

Figure 5 : Memory Mapping of Thermocouple Input Module

The configuration (grouped as static and dynamic) from PLC variable areae.g. memory or page is transferred to module memory when WRITE_Wfunction gets executed in application program i.e. in logic scan. The module

Logic Scan

CPU module17 words hold channel dynamic information

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 of 8channels

Channel 0 Static Configuration MW50

Channel 7 Static Configuration MW64

9 words hold data for 8 channels and CJCChannel 0 Data MW100

Channel 7 Data MW114CJC Data MW116

5 words hold status of 8 channelsChannel Set Point Status MW118Channel Configuration Status MW120Channel Input Range Status MW122Channel Open Circuit Status MW124CJC Sensor Status MW126

SLOT

DATA

LEN

ADDR

ENOWRITE W

EN

Logic Scan

SLOT

DATA

LEN

ADDR

ENO

READ W

EN

Thermocouple Input module

17 words hold channel dynamic information of8 channels

Channel 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 8channels

Channel 0 Static Configuration MMW96

Channel 7 Static Configuration MMW110

9 words hold data for 8 channels and CJC

Channel 0 Data MMW128

Channel 7 Data MMW142CJC Data MMW144

5 words hold status of 8 channelsChannel Set Point Status MMW146Channel Configuration Status MMW148Channel Input Range Status MMW150Channel Open Circuit Status MMW152CJC Sensor Status MMW154


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takes action on static configuration information only when static configurationwrite command is issued. This can be issued by setting Qx.0 bit of outputimage. In case of dynamic configuration information, the module detects anychange in configuration cyclically and if any valid change is detected, it takesappropriate action. After power on, the module starts converting CJC sensorinput channel. The module starts its channel conversion operation only afterreceiving valid configuration. If channel configuration is modified or channelis enabled / disabled, it takes effect only in the subsequent conversion cycle.The channel 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 CJC reading (ambient temperature)and status information can be read from the module using READ_W function.

2.4.3 Commands

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

program. CPU writes commands in output image area of module in outputscan. The module reads output image area cyclically and takes appropriateaction. If 'IMM_OUT' function is executed in logic scan for a particular slot, itstops current logic scan, executes output scan for defined slot and resumeslogic scan again. This is useful when ever immediate updation of outputimage is needed. The functions of output image bits are given below

No.Bit

AddressCommand Status Description

ONIt gives command to module to accept staticconfiguration or change static configuration asper contents of module memory words MMW#96 to MMW#110.

1 Qxx.0Write staticconfiguration

OFF Write static command is OFF.

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


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2.4.4 Module Status Bits

As discussed in chapter 2.4.1,input image bits are used as module statusindications. User can check the module status through application program.The module writes status in its input image area cyclically. The CPU reads

this input image area in input scan. If 'IMM_IN' function is executed in logicscan for a particular slot, it stops current logic scan, executes input scan fordefined slot and resumes logic scan again. This is useful when everimmediate updation of input image is needed. The functions of input imagebits are given below

No.Bit

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.0Module NotReady

OFF

Module healthy and ready

Not Applicable

Invalid static configurationON

Parameter mismatchValid static configuration

2 Ixx.1InvalidConfiguration

OFFValid parameters

MMW #148

Any channel temperature readingabove high set point

ONAny channel temperature readingbelow low set point

3 Ixx.2Set pointexceeded

OFFAll channel temperature readingswithin high and low set points

MMW #146

Over range for any enabledchannels/s.

ONUnder range for any enabledchannels/s.4 Ixx.3 Out of Range

OFFAll enabled channel inputs arewithin specified range

MMW #150

ONOpen circuit for any enabledchannels/s.

5 Ixx.4 Open CircuitOFF

All enabled channel inputs areconnected

MMW #152

CJC sensor openONCJC sensor short

6 Ixx.5 CJC fault

OFF CJC sensor healthy

MMW #154

Module CPU watch dog faultON

Module not ready7 Ixx.6 CPU Fault

OFF Module healthy and ready

Not Applicable

Note xxis slot number in which module is fixed.Ixx.6 is reserved and should not be used.

Whenever accessing the module, user must check the module status bit Ix.0.If any error condition is detected in input image, check corresponding modulememory word to get more details to locate exact problem.


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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

3231

30

35

36

37

38

34

TC0+

TC1+

TC0-

TC1-SHIELD0

SHIELD1

TC2+

TC3+

TC2-

TC3-

SHIELD2

SHIELD3

TC4+

TC5+

TC4-

TC5-

SHIELD4

SHIELD5

TC6+

TC7+

TC6-

TC7-

SHIELD6

SHIELD7

+ 24 V

0 V

EARTH

Figure 6 : Connection diagram of Thermocouple Input Module

In figure, thermocouples are connected to channel 0 and 7. For interfacingthermocouples, 38-pin terminal block is provided. Thermocouple input isconnected to TCn+and TCn-terminals, where nis a channel number. Forhealthy working, ensure correct polarity of thermocouple element. It isensured that all the three connections of a thermocouple element come inline on terminal block for easy connectivity. Thermocouple 1 is connected toterminal cumbers 12, 14 and 16. Thermocouple 2 is to be connected toterminal numbers 13, 15 and 17. Thermocouple 8 is to be connected to

Thermocouple 1

Thermocouple 8

nect this shieldto Earthbusbar.

Connect this shieldto SHIELDterminal.

+ 24 VDC

GND

EARTH


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terminal numbers 31, 33 and 35. Ensure that thermocouple element isisolated tip type only.

Being susceptible to industrial noise, mill volt signal from thermocouple is tobe carried out on the field through shielded cable. Connect shield on moduleside to 'SHIELDn' terminal provided on terminal block. For eachthermocouple input separate 'SHIELDn' terminal is provided. Other end of

shield should be earthed.

For functioning of thermocouple input module, external 24 VDC supply isrequired. Connect 24 VDC supply between terminals 36 (+ 24 V) and 37 (0V). 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, powercontactors, etc i.e. high voltage wiring should be kept separate and apartfrom thermocouple signals.

Digital Input wiring and Digital Output wiring (especially, relay output andAC output) should be separately bundled and kept as apart as possiblefrom thermocouple signals.

Thermocouple signals should be carried through shielded cables.

Outside control panel

Following guidelines to be observed outside control panel.

Depending upon the type of modules used in PLC, separate ducts should beprovided 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 powercables, etc over long distances

Ensure that cables carrying analog signals cross at right angles to powercables so that minimum length of cable will be in close vicinity of powercables.

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 thermocouple input module andtransferring information with thermocouple input module. This information isuseful for application program development. The module configuration

consists of Slot configuration and Channel configuration

4.1 Slot Configuration

The thermocouple input module provides 8 thermocouple input channels,which can be independently operated. Configuring the slot for thermocoupleinput module is just like any other discrete IO module only. The programmingand documentation 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. The

output image is used for writing user commands to module. For more details,refer chapter 2.4.3 and 2.4.4.

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

Power SupplyModule

CPU Module Slot 0

32 DC InputModule

I0.0 to I0.7I1.0 to I1.7

I2.0 to I2.7I3.0 to I3.7

Slot 1

32 DC OutputModule

Q4.0 toQI4.7Q5.0 to Q5.7

Q6.0 to Q6.7Q7.0 to Q7.7

Slot 2

ThermocoupleInput Module

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

Slot 3

16 DC OutputModule

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. Thermocouple 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 isshown below.

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 Output

Module (4732)

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

Slot 2Thermocouple

InputModule (4310)

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

Slot 316 DC Output

Module (4716)

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


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Input module in first slot 0 consumes IB0 to IB3 of input image. Outputmodule in slot 1 consumes QB0 to QB3 of output image. The analog inputmodule consumes IB4 of input image and QB4 of output image.16 DCOutput module in slot 3 consumes QB5 and QB6 of output image.

4.2 Channel Configuration

The thermocouple input module can be configured in any slot of PLC. Itprovides 8 non-isolated channels. These channels can be independentlyconfigured for different types of thermocouple 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 ofthermocouple.

Dynamic configuration This information does not affect basic functioningof channel. This information is changed during run time e.g. high and lowlimit for temperature reading.

4.2.1 Static Configuration

After power ON the configuration of one or more channels can be transferredto the module using WRITE_W function. The global variables, memory orpage can be used to hold channel configuration. The channel staticconfiguration information includes Thermocouple input type Filter frequency (fixed to 50 Hz for thermocouple inputs) Return value on open circuit and

Averaging

This information is transferred to module memory by using 'WRITE_Wfunction. The module takes action on this information when staticconfiguration write command is issued (on rising edge of Qx.0 bit). After thatonly static configuration or change in static configuration is effective.

This static configuration information is to be stored in bit form in one word foreach channel. The following table gives information to be stored. The validcombination of bits must be set.

Module memory words MMW #96 to MMW #110 are module memory wordsfor 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 0J thermocouple 0 0 0 0 0K thermocouple 0 0 0 0 1T thermocouple 0 0 0 1 0E thermocouple 0 0 0 1 1R thermocouple 0 0 1 0 0

Input type

S thermocouple 0 0 1 0 1


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

Invalid 1 1 1 1 150 Hz 0 0 0

Invalid 0 0 1Filter

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

Returnvalue onOpencircuit &CJC fault

Invalid 1 1

16 0 08 0 14 1 0

Avg.Samples

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 word

MMW #110 Channel 7 static configuration word

Input type

The thermocouple input module supports different types of inputs. The inputsinclude J type thermocouple K type thermocouple T type thermocouple

E type thermocouple R type thermocouple S type thermocouple B type thermocouple N type thermocouple

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. One out offour filter frequencies can be selected.

Bit 7 Bit 6 Bit 5 Filter Frequency Update time for a Channel0 0 0 50 Hz 60 ms0 0 1 60 Hz 50 ms0 1 0 250 Hz 12 ms0 1 1 500 Hz 6 ms

This is in built function of ADC. The filter frequency affects noise rejection onincoming thermocouple milli- volt signal. A lower filter frequency increases


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noise rejection. Also it affects channel update time. So select a filterfrequency considering acceptable noise and channel update time.

Return value on open circuit and CJC fault

Next two bits, bit 8 and bit 9 define the value of the channel temperature

reading when the open circuit is detected for that channel or CJC fault (CJCsensor open or short) is detected.

Bit9 Bit8 Open Circuit value

0 0 Zero0 1 Upper scale1 0 Lower scale1 1 Invalid

In such open circuit 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 Samples

0 0 160 1 81 0 41 1 No

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

explained in chapter 2.3.2.Thus combination of filter frequency andaveraging count can be selected to get optimum channel update time andstable temperature reading.

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

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_Wfunction. The module detects change in dynamic configuration information inits own scan. If valid change is detected, appropriate action is initiated anddynamic configuration or change in dynamic configuration is effectiveimmediately.

Channel Enable


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The eight bits in module memory word MMW #0 defines the enable status ofthe all the channels. If it is 0 channel is disabled and if it is 1 channel isenable. The module samples only enabled channels and converts into digitalvalue. Thus enabling only used channels can minimize the channel updatetime. If a particular channel is important at particular instance, all otherchannels can be disabled temporarily and only one channel conversion can

be carried out to get fast response.

MMW #0 Channel enable / disable word

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

Disable 0Ch 7

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

Bit 0 of MMW #0 is enable / disable bit for channel 1. Bit 7 of MMW #0 isenable / disable bit for channel 8.

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 channel temperaturereadings available in 0.1 C resolution. If channel temperature is above highset point, corresponding high bit in MMW #146 is set. If channel temperatureis below low set point, corresponding bit in MMW # 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 changed as per input typeselection. These user settings are compared with input type selected for achannel. If settings are not within range of that input type, Ixx.1 bit is madeON indicating invalid configuration. Refer MMW #148 to point out faultychannel configuration. If high set point for a channel is less than that of low

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.


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4.3 Channel Information

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

4.3.1 Channel Data

Module memory words MMW #128 to MMW #142 are module memory wordsfor channel temperature readings. MMW #144 holds CJC sensor reading.This is nothing but ambient temperature. The temperature reading resolutionis 0.1 C. For enabled channels, this information is updated cyclically inmodule. The data is read and stored using READ_W function in applicationprogram.

Thermocouple Type C Temperature rangeJ -210.0 to +760.0K -270.0 to +1370.0T -270.0 to +400.0E -270.0 to +1000R 0.0 to +1768.0S 0.0 to +1768.0B 0.0 to +1820.0N -200.0 to +1300.0

4.3.2 Channel Status

Channel status information is available in MMW #146 to MMW #154 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 0

< Min. limit 1

< Max. limit 0> Max. limit 1

> Min. limit 0

Ch 7

< 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 above highset point. It becomes OFF when temprature reading is below high set point.Low bit becomes ON when temerature reading is below low set point. Itbecomes OFF when temprature reading is above low set point.


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Similarly next two bits gives high and low point status of cahnnel 1 and so on.

Channel configuration status

Module memory word MMW #148 holds status of validity of configuration andparameters for all the channels.

MMW #148 Channel configuration and parameter mismatch status

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

Ch 0Config. Invalid 1

Config. valid 0Ch 7

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

Bit 0 of MMW #148 gives channel 0 configuration status and bit 7 of MMW#148 gives channel 7 configuration status.

Configuration bit is ON when

Static configuration for a channel is invalid i.e.if bit 4 to bit 0 are 01000 to 11111if bit 5 to bit 7 are 100 to 111In dynamic configuration

if high set point is not within specified input rangeif low set point is not within specified input rangeif high set point < low set point

In all these cases, Ixx.1 bit becomes ON. Corresponding green channel LEDstarts 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 0

Under range 1

< Over range 0Over range 1> Under range 0

Ch 7

Under range 1

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 over rangeand under range status of channel 1 and so on.The input ranges are as given below.


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Thermocouple Type mV signal C Temperature rangeJ -8.096 to 42.922 -210 to +760K -6.458 to 54.807 -270 to +1370T -6.258 to 20.869 -270 to 400E -9.835 to 76.358 -270 to 1000R 0.000 to 21.108 0 to 1768S 0.000 to 18.698 0 to 1768B 0.000 to 13.814 0 to 1820N -3.990 to 47.502 -200 to 1300

Over range bit becomes ON when thermocouple input is above specifiedinput signal. Under range bit becomes ON when thermocouple input isbelow specified input signal. In all these cases, corresponding greenchannel LED starts flashing.

Open Circuit Error

MMW #152 stores open circuit 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 0Open circuit 1

Input connected 0Ch 7

Open circuit 1Res - 0 0 0 0 0 0 0 0

Bit 0 of MMW #152 holds status of channel 0. It becomes ON if channel 0 isconfigured and input signal is not connected. Bit 1 of MMW #152 holds statusof channel 1. In ADC conversion cycle, first open circuit status for configuredchannel is checked. If open circuit is detected, channel is bypassed and

return value in case of open circuit is stored as channel temperature reading.Bit 9 and bit 8 of static configuration word of a channel decides return valueas zero, upper scale or lower scale considering safety in control action.

If open circuit error bit is set for a channel, corresponding channel LED(green color) on module starts flashing.

CJC status

MMW #154 stores cold junction compensation sensor channel status ofindividual channels.

Item Description 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0Sensor not shorted 0Short

Circuit Sensor shorted 1Sensor Connected 0Open

Circuit CJC Sensor Open 1Res - 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Bit 0 of MMW #154 is CJC sensor short circuit bitBit 1 of MMW #154 is open circuit status bit


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The behavior in case of CJC fault is similar to that of any thermocouple inputchannel. In case of fault, 'CJC fault' indication (yellow) on front side ofmodule becomes ON.

4.4 Programming with Nexgen 4000 CPU

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

The WRITE_W function below shows data transfer from the CPU module'smemory to thermocouple input module memory. The details of transfer are -

Thermocouple 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 thermocouple input module in slot 2 is #96

'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. Thermocouple input module is not accessible to CPU module

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

| |#2 -|SLOT |

| |MW50 -|DATA |

| |#8 -|LEN |

| |#96 -|ADDR |

| |-------------------

So 8 words (MW50 to MW64) information from CPU memory is transferred tothe memory at address #96 onwards of thermocouple input module fitted inslot 2.

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

Thermocouple input module is configured in slot 2 of PLC

Address on the thermocouple 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'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 ifParameters of function are invalid or not within specified range.Thermocouple input module is not accessible to CPU module


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

#2 -|SLOT || |

#128 -|ADDR || |

#8 -|LEN || |

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

So 8 words (MMW128 to MMW142) information on thermocouple input

module fitted in slot #2 are transferred to the CPU memory words (MW100 toMW114).

Example of basic application program is given below. For the same, referNexgen PLC configuration shown in chapter 4.1.

In the configuration, following points are to be noted.

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 if for

one or more channels, configuration is invalid.

I 8.2 is a maximum minimum set point status bit as 'Set point Exceeded' bit.I 8.2 is set if for one or more configured channels, input signal is below orabove limits set.

I 8.3 is a thermocouple input range status bit as 'Out of Range' bit. I 8.3 is setif for one or more configured channels, input signal is below or abovespecified range.

I 8.4 is a open circuit status bit as 'Open Circuit ' bit. I 8.4 is set if for one ormore configured channels, input is not connected.

I 8.5 is a CJC status bit as 'CJC Fault ' bit. I 8.5 is set if CJC sensor mounteddirectly on top side of terminal block is open or short.

Q 8.0 is a command for 'Static Configuration Write'. When this bit is set byuser, thermocouple input module accepts static configuration available inmodule memory words MMW#96 to MMW#110 and configures the moduleaccordingly for input type, filter, return value for open circuit and number ofaveraging samples.


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

While developing application program, first check whether the module ishealthy. For the same, check 'Module Error' bit S 4.2 and 'Module Not Ok' bitI8.0. If any bit is set, declare respective fault. In this case, module is notaccessible. If both are OFF, then only enable 'WRITE_W' and 'READ_W'functions for thermocouple input module.

The static configuration information consists of basic attributes like input type(J, K, T, E, R, S, B and N), filter (50 Hz, 60 Hz, 250 Hz, 500 Hz), return valuein case of open circuit of input signal (zero, upper scale, lower scale) and no.of averaging samples ( 1, 4, 8, 16 ). This configuration is to be transferred tomodule memory MMW#96 to MMW#110, if all the 8 channels are used. Inthis example, channels are configured for T type of thermocouple 50 Hz filter Return value is of upper scale in case of open circuit of input signal No. of averaging samples is 8

For this configuration, the value $0902 should be written to respectivemodule memory word.

Static Configuration Word 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 1 0

So MW50 to MW 64 should contain $0902, for the configuration required.This information is transferred to thermocouple module memory MMW#96 toMMW#110, when 'WRITE_W' function is executed.

When 'WRITE_W' function is executed successfully, ENO output becomesON, When ENO is ON, set 'Static Configuration Write' command bit informingthe module to accept the static configuration or change in configuration.Once this information is transferred to module, it is valid as long as PLCpower 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.

Reserved Returnvalue ofupperscale

Avg. of4Samples

50 HzFilter

T typeThermocoupleinput


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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 forone scan duration. If this bit is not ON even if function enable conditions areON, 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 condition M0.6with interlocks of Module Error bit S4.2 and 'Module Not Ok' bit I8.0.

When 'WRITE_W' function is executed, the data $00FF is transferred to

module memory MMW#00. The maximum and minimum set points for eachchannel is transferred to module memory words MMW#02 to MMW#32 If'WRITE_W' function is executed successfully, M0.7 bit becomes ON. If thisbit is not ON even if function enable conditions are ON, declare fault and takeappropriate action.

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

| || |

#2 -|SLOT || || |

MW166 -|DATA || || |

#17 -|LEN || || |

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


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After transferring static and dynamic configuration information tothermocouple module memory, module starts functioning. Enable 'READ_W'function with 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 to

MW#114 respectively. CJC data i.e. ambient temperature reading isavailable in memory word MW#116.

If 'READ_W' function is executed successfully, M1.1 bit becomes ON. If thisbit is not ON even if function enable conditions are ON, declare fault and takeappropriate action.

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

| || |

#2 -|SLOT || || |

#128 -|ADDR || || |

#9 -|LEN || || |

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

To read the status of temperature readings for maximum and minimum setpoints, it is necessary to read MMW#146 when I8.2 bit 'Set point Exceeded'

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 under rangefor channel 0. Similarly, M127.6 is over range bit for channel 7 and M127.7 is


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for under range for channel 7. With this status, appropriate action can betaken for temperature control.

To read the status of each channel, read the status information when evercorresponding 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 CPU memorybits M118.0 to M118.7. M118.0 bit is ON if channel 0 configuration is invalid,M118.1 bit is ON if channel 1 configuration is invalid and so on. In this correctthe configuration of faulty channel. In case of invalid configuration forparticular channel, channel temperature reading becomes #0.

'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 || |-------------------


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When this 'READ_W' function is executed successfully, check CPU memorybits M120.0 to M121.7 for over range and under range status. M120.0 bit isON if channel 0 input signal is above specified range, M120.1 bit is ON ifchannel 0 input signal is below specified range and so on. In this case, takeproper action. For a particular channel, if input signal is above specifiedrange, channel temperature reading remains at maximum value. For T typethermocouple input, this is 400.0 C. For a particular channel, if input signalis below specified range, channel temperature reading remains at minimumvalue. For T type thermocouple input, this is -270.0 C.

'Open Circuit' bit I8.4 becomes ON, if one or more channel input isdisconnected. 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 CPU memorybits M122.0 to M122.7 for open circuit status. M122.0 bit is ON if channel 0input is open, M122.1 bit is ON if channel 1 input is open and so on. In thiscase, take proper action. For a particular channel, in case of open circuit,channel temperature reading is forced to value selected by user. In this case,it is upper scale value, which is 400.0 C for T type of thermocouple inputtype.'CJC Fault' bit I8.5 becomes ON, if CJC sensor is open or short. This CJCsensor is mounted directly on terminal block and terminal no. 4,6,8 are usedfor the same. To find out exact reason, read MMW#154 from module.

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

| || |

#2 -|SLOT || || |

#154 -|ADDR || || |

#1 -|LEN || || |

MW124 -|DATA || |-------------------


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When this 'READ_W' function is executed successfully, check CPU memorybits M124.0 and M124.1 for CJC sensor status. M124.0 bit is ON if CJCsensor is short and M122.1 bit is ON if CJC sensor is open. In this case, takeproper action. If CJC sensor fault is detected, all the channel temperaturereadings are forced to user selected value (the return value in case of opencircuit). In this case, it is upper scale value, which is 400.0 C for T type of

thermocouple input type.

4.5 Programming with Nexgen 5000 CPU

The configuration data in PLC variables is transferred to the Thermocoupleinput module when 'IM_Write function is executed. The data in the PLCvariables can be updated using operators like 'MOVE', arithmetic or anyother functions. The data from analog input module memory can betransferred to PLC variables when 'IM_Read' function is executed.

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

The Thermocouple 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, whenfunction is executed successfully. It is FALSE if

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


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So 8 words configuration information ( Static ) from CPU memory istransferred to the memory at address 96 onwards & 17 words configurationinformation ( Dynamic) from CPU memory is transferred to memory 0onwars of Thermocouple input 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_Rdy output becomes ON, when EN is ON and function is executedsuccessfully. ENO is OFF ifParameters 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, referNexgen PLC configuration shown in chapter 4.1. In the configuration,following points are to be 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 isobserved on module.

%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 isobserved.

_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 ishealthy. 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 not accessible. If both are OFF, then only enable 'IM_Write'and 'IM_Read functions for Thermocouple module.

Once Thermocouple input data is read successfully, the data can beprocessed as the application requirement. If anaolg input data read is to bedisplayed on HMI or SCADA, the varaible AIData should be mapped to anymemory varaible while declaration like

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

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

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

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


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5. Troubleshooting

In this chapter, following points related to thermocouple input module arediscussed.

LED Indications for diagnosticsFault Diagnostic

5.1 LED Indications for Diagnostics

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

No. LED Color Status Description

OFF 24 VDC supply to module healthy24 VDC supply to module absent1

No 24 VSupply

OrangeON

24 VDC circuit on-board glass fuse blown

OFFModule hardware healthy and module isreadyModule in self testCPU watchdog faulty

2 CPU fault OrangeON

Module busyOFF CJC sensor OK.

CJC sensor short3 CJC Fault OrangeON

CJC sensor openOFF Channel not enabledON Channel enabled and healthy

Parameter mismatchInvalid configurationOver rangeUnder rangeOpen circuit

4

ChannelStatus(Eight for eightchannels)

Green Flashingwith 10 Hzfrequency

CJC fault

5.2 Fault Diagnostic

This section explains various possibilities of faults related to thermocoupleInput Module and external interface and corrective action to 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 case canbe sorted out by on line monitoring of application program.


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Equipments required

The following equipments are required for fault diagnosis of thermocoupleinput module

Screw driverDigital Multi meter with measuring facility for

mV DC voltage.Continuity and resistance.Set up for on line monitoring of application program as follows.PC with DOXMINI+ softwarePC to Nexgen PLC Cable

The following diagnostic flow chart shows various possibilities of faults ifthermocouple module is not in operation as per requirement and correctiveaction 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?

Moduleworking 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 continue.

Diagnostic flow chart continue.

IO ERR LED

Status?

Module ErrorSystem bit Status ?

Fix module properly. Check expansioncable if it i9s 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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* The fuse should be replaced by sametype strictly

Rating - 315 mA, 250 V

Sub- miniature fuse link no. 372Make WICKMANN

Note For healthy operation of module always ensure that supply to module is withinspecified

range i.e. 18 VDC to 30 VDC includingripple.

Always ensure thatthermocouple elements are of isolated tip type.

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

C

Temperature readingOk?

Monitor binary data valuefor channel with PC basedProgramming Software

heck application program.Check for JMP, MCR-MEinterlocks if any.

.


Probably problem is onhermocouple element side.

Take proper action.


Diagnosis Over Contact MESSUNGSYSTEMS

YESNO

YESNO

YES NO


YESNO

Diagnosis Over


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6. Appendix 1

This section shows the reference tables for each thermocouple type. Eachtable gives mV signal from thermocouple and equivalent temperature.Reference Table - J Type Thermocouple (Iron vs. Copper-Nickel)

C mV C mV C mV C mV C mV C mV

-210 -8.096 -40 -1.961 130 6.909 300 16.327 470 25.720 640 35.470-200 -7.890 -30 -1.482 140 7.459 310 16.881 480 26.276 650 36.071-190 -7.659 -20 -0.995 150 8.010 320 17.434 490 26.834 660 36.675-180 -7.403 -10 -0.501 160 8.562 330 17.986 500 27.393 670 37.284-170 -7.123 0 0.000 170 9.115 340 18.538 510 27.953 680 37.896-160 -6.821 10 0.507 180 9.669 350 19.090 520 28.516 690 38.512-150 -6.500 20 1.019 190 10.224 360 19.642 530 29.080 700 39.132-140 -6.159 30 1.537 200 10.779 370 20.194 540 29.647 710 39.755-130 -5.801 40 2.059 210 11.334 380 20.745 550 30.216 720 40.382-120 -5.426 50 2.585 220 11.889 390 21.297 560 30.788 730 41.012-110 -5.037 60 3.116 230 12.445 400 21.848 570 31.362 740 41.645-100 -4.633 70 3.650 240 13.000 410 22.400 580 31.939 750 42.281-90 -4.215 80 4.187 250 13.555 420 22.952 590 32.519 760 42.919-80 -3.786 90 4.726 260 14.110 430 23.504 600 33.102 770 43.559

-70 -3.344 100 5.269 270 14.665 440 24.057 610 33.689-60 -2.893 110 5.814 280 15.219 450 24.610 620 34.279-50 -2.431 120 6.360 290 15.773 460 25.164 630 34.873


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Reference Table - K Type Thermocouple (Nickel-Chromium vs. Nickel-Aluminum)


-270 -6.458 10 0.397 290 11.795 570 23.629 850 35.313 1130 46.249-260 -6.441 20 0.798 300 12.209 580 24.055 860 35.718 1140 46.623-250 -6.404 30 1.203 310 12.624 590 24.480 870 36.121 1150 46.995-240 -6.344 40 1.612 320 13.040 600 24.905 880 36.524 1160 47.367-230 -6.262 50 2.023 330 13.457 610 25.330 890 36.925 1170 47.737

-220 -6.158 60 2.436 340 13.874 620 25.755 900 37.326 1180 48.105-210 -6.035 70 2.851 350 14.293 630 26.179 910 37.725 1190 48.473-200 -5.891 80 3.267 360 14.713 640 26.602 920 38.124 1200 48.838-190 -5.730 90 3.682 370 15.133 650 27.025 930 38.522 1210 49.202-180 -5.550 100 4.096 380 15.554 660 27.447 940 38.918 1220 49.565-170 -5.354 110 4.509 390 15.975 670 27.869 950 39.314 1230 49.926-160 -5.141 120 4.920 400 16.397 680 28.289 960 39.708 1240 50.286-150 -4.913 130 5.328 410 16.820 690 28.710 970 40.101 1250 50.644-140 -4.669 140 5.735 420 17.243 700 29.129 980 40.494 1260 51.000-130 -4.411 150 6.138 430 17.667 710 29.548 990 40.885 1270 51.355-120 -4.138 160 6.540 440 18.091 720 29.965 1000 41.276 1280 51.708-110 -3.852 170 6.941 450 18.516 730 30.382 1010 41.665 1290 52.060-100 -3.554 180 7.340 460 18.941 740 30.798 1020 42.053 1300 52.410-90 -3.243 190 7.739 470 19.366 750 31.213 1030 42.440 1310 52.759-80 -2.920 200 8.138 480 19.792 760 31.628 1040 42.826 1320 53.106-70 -2.587 210 8.539 490 20.218 770 32.041 1050 43.211 1330 53.451-60 -2.243 220 8.940 500 20.644 780 32.453 1060 43.595 1340 53.795-50 -1.889 230 9.343 510 21.071 790 32.865 1070 43.978 1350 54.138-40 -1.527 240 9.747 520 21.497 800 33.275 1080 44.359 1360 54.479-30 -1.156 250 10.153 530 21.924 810 33.685 1090 44.740 1370 54.819-20 -0.778 260 10.561 540 22.350 820 34.093 1100 45.119-10 -0.398 270 10.971 550 22.776 830 34.501 1110 45.4970 0.000 280 11.382 560 23.203 840 34.908 1120 45.873

6.1 Reference Table - T Type Thermocouple (Copper vs. Copper-Nickel)Monograph,


-270 -6.258 -150 -4.648 -30 -1.121 90 3.814 210 9.822 330 16.624

-260 -6.232 -140 -4.419 -20 -0.757 100 4.279 220 10.362 340 17.219-250 -6.180

ed-2002-016 8 channel thermocouple input module(4310).pdf

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