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1762-UM002 - Rockwell Automation

1. 10 Hz 3 50 Hz 60 Hz 2 1 0 300 200 100 0 100 200 300 400 Thermocouple Temperature C 11 10 9 8 7 10 Hz 50 Hz 4 60 Hz 3 2 1 0 600 400 200 0 200 400 600 800 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 A 22 Specifications Figure A 18 Module Accuracy at 25 C 77 F Ambient for Type T Thermocouple Using 250 500 and 1 kHz Filter 100 80 gt 60 250 Hz g 500 Hz amp 1000 Hz 20 0 300 200 100 0 100 200 300 400 Thermocouple Temperature C 160 140 120 100 250 Hz a 80 500 Hz 60 1000 Hz 40 20 0 600 400 200 0 200 400 600 800 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 Appendix B Two s Complement Binary Numbers The processor memory stores 16 bit binary numbers Two s complement binary is used when performing mathematical calculations internal to the processor Analog input values from the analog modules are returned to the processor in 16 bit two s complement binary format For positive numbers the binary notation and two s complement binary notation are identical As indicated in the figure on the next page each position in the number has a decimal value beginning at the right with 2 and ending at the left with 215 Each position can be 0 or 1 in
2. To Select Make these bit settings 15 14 133 12 11 10 9 8 7 6 5 43 2 1 0 E S as Filter 10 Hz 1 1 0 6 Frequency f 69 Hz 0 0 0 0 50 Hz 0 0 1 1 250Hz 0 1 1 3 500 Hz 1 0 0 4 1 kHz 1 0 1 5 Open Upscale 0 0 0 Seu Downscale 0 1 32 Hold Last State 1 0 64 Zero 1 1 96 Tempera Degrees C 0 0 ture Units Degrees F 1 128 Input Thermocouple 0 01070 0 Type J Thermocouple K 0 0 0 256 Thermocouple T 0 0 1 0 512 Thermocouple E 0 0 1 E 768 Thermocouple R 0 1 01 0 b 1024 Thermocouple S 0 1 0 1280 Thermocouple B 0 1 1 0 1536 Thermocouple N 0 1 1 1792 Thermocouple C 1 0 0 0 2048 50 to 50 mV 1 0 0 2304 100 to 100 mV 1 0 1 0 2560 Data Raw 0 0 0 0 Format Proportional Engineering 0 0 1 4096 Units Engineering 1 0 0 16384 Units X 10 Scaled for PID 0 1 0 8192 Percent Range 0 1 1 12288 Enable Disable 0 0 Channel Enable 1 32768 1 Default values are in bold type and are indicated by zero bit settings For example the default filter frequency is 60Hz 2 Anattempt 0 write any non valid spare bit configuration into any selection field results in a module configuration error Publication 1762 UM002A EN P July 2002 3 6 Module Data Status and Channel Configuration Enabling or Disabling a Channel Bit 15 You can enable or disable each of the four channels individually using bit 15 The module only scans enabled chan
3. E 250 Hz E 500 Hz E 1000 Hz 400 200 0 200 400 600 800 1000 1200 1400 Temperature C 200 180 zi 160 140 2 100 500 Hz 80 1000 Hz 3 60 40 20 0 500 0 500 1000 1500 2000 2500 Temperature F Publication 1762 UM002A EN P July 2002 Effective Resolution C Effective Resolution F 2 5 2 0 1 5 1 0 0 5 0 0 Module Data Status and Channel Configuration 3 27 Figure 3 14 Effective Resolution Versus Input Filter Selection for Type R Thermocouples Using 10 50 and 60 Hz Filters 10 Hz 50 Hz 60 Hz 200 400 600 800 1000 1200 1400 1600 1800 Temperature C z 10 Hz 50 Hz 60 Hz 500 1000 1500 2000 2500 3000 3500 Temperature F Publication 1762 UM002A EN P July 2002 3 28 X Module Data Status and Channel Configuration Figure 3 15 Effective Resolution Versus Input Filter Selection for Type R Thermocouples Using 250 500 and 1k Hz Filters 250 200 El 500 Hz 100 1000Hz 59 0 0 200 400 600 800 1000 1200 1400 1600 1800 Temperature C 400 350 300 S 250 250 Hz amp 200 500 Hz 150 1000Hz 100 duce eee Fandom 50 0 aS ES Eg ERISQUE 0 500 1000 1500 2000 2500 3000 3500 Temperature F Pu
4. 0 4 0 3 10 Hz 0 2 50 Hz 60 Hz 0 1 0 400 200 0 200 400 600 800 1000 1200 Temperature C 0 7 0 6 0 5 j 10 Hz 50 Hz d 60 Hz 0 2 0 1 0 400 0 400 800 1200 1600 2000 Temperature F Publication 1762 UM002A EN P July 2002 3 22 Module Data Status and Channel Configuration Figure 3 9 Effective Resolution Versus Input Filter Selection for Type J Thermocouples Using 250 500 and 1k Hz Filters 60 50 a 250 Hz 3 30 500 Hz g 1000H m 000 Hz 4g 0 400 200 0 200 400 600 800 1000 1200 Temperature C 120 100 g 8 250 Hz Z 60 500 Hz 9 1000H 4 000 Hz 20 0 400 0 400 800 1200 1600 2000 Temperature F Publication 1762 UM002A EN P July 2002 Module Data Status and Channel Configuration 3 23 Figure 3 10 Effective Resolution Versus Input Filter Selection for Type K Thermocouples Using 10 50 and 60 Hz Filters 5 5 5 0 _ 4 5 4 0 S 3 5 10 Hz g 3 0 50 Hz E T 60 Hz 2 1 5 10 0 5 0 0 400 200 0 200 400 600 800 1000 1200 Temperature C 10 0 9 0 8 0 7 0 g 50 50 Hz 40 60 Hz 33 0 s 20 1 0 0 0 500 0 500 1000 1500 2000 2500 Temperature F Publication 1762 UM002A EN P July 2002 3 24 Module Data Stat
5. Input Data File The input data table allows you to access module read data for use in the control program via word and bit access The data table structure is shown in table below EET a Oe 0 SGN Analog Input Data Channel 0 1 SGN Analog Input Data Channel 1 2 SGN Analog Input Data Channel 2 3 SGN Analog Input Data Channel 3 4 Reserved 0C4 0C3 OC2 OC1 OCO Reserved S4 83 2 1 S0 5 UO 00 Ul 01 U2 02 U3 03 U4 04 Reserved Input Data Values Publication 1762 UM002A EN P July 2002 Data words 0 through 3 correspond to channels 0 through 3 and contain the converted analog input data from the input device The most significant bit bit 15 is the sign bit SGND General Status Bits S0 to S4 Bits SO through S3 of word 4 contain the general status information for channels 0 through 3 respectively Bit S4 contains general status information for the CJC sensor If set 1 these bits indicate an error Cover or under range open circuit or input data not valid condition associated with that channel The data not valid condition is described below Input Data Not Valid Condition The general status bits SO to S3 also indicate whether or not the input data for a particular channel 0 through 3 is being properly converted valid by the module This invalid data condition can occur bit set when the download of a new configuration to a channel is accepted by the module proper configuration but before th
6. 70 60 50 CN 250 Hz 9 800 Hz E Hm 1000 Hz 20 10 0 400 200 0 200 400 600 800 1000 1200 1400 Thermocouple Temperature C oa 250 Hz 3 500 Hz g 1000 Hz 500 0 500 1000 1500 2000 2500 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 2 5 2 0 Accuracy C 0 5 0 0 Accuracy F NNWWO FS B oO cic cc o oo ccc c Specifications A 17 Figure A 13 Module Accuracy at 25 C 77 F Ambient for Type R Thermocouple Using 10 50 and 60 Hz Filter 10 Hz 50 Hz 60 Hz 200 400 600 800 1000 1200 1400 1600 1800 Thermocouple Temperature C 10 Hz 50 Hz 60 Hz 500 1000 1500 2000 2500 3000 3500 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 A 18 Specifications Figure A 14 Module Accuracy at 25 C 77 F Ambient for Type R Thermocouple Using 250 500 and 1 kHz Filter 140 120 100 o 250 Hz B j 500 Hz z 5 1000 Hz 40 20 0 0 200 400 600 800 1000 1200 1400 1600 1800 Thermocouple Temperature C 250 200 v 150 250 Hz S 500 Hz 2 100 1000 Hz 0 a ERIT RRETETUETDET es ee GV II RE a 0 500 Publication 1762 UM002A EN P July 2002
7. CJC Update Time Ch 0 ADC Self Calibration Time 53 ms 53 ms 53 ms 53 ms 103 ms 315 ms Module Scan 2 Ch 0 Update Time Ch 1 Update Time Ch 2 Update Time CJC Update Time Ch 0 Offset Time 53 ms 53 ms 53 ms 53 ms 53 ms 265 ms Channel 1 and Channel 2 no scan impact No autocalibration cycle is required for Channels 1 and 2 because they are configured to use the same Input Filter as Channel 0 Module Scan 3 Ch 0 Update Time Ch 1 Update Time Ch 2 Update Time CJC Update Time C C ADC Self Calibration Time 53 ms 53 ms 53 ms 53 ms 103 ms 315 ms After the above cycles are complete the module returns to scans without autocalibration for approximately 5 minutes At that time the autocalibration cycle repeats Module Data Status and Channel Configuration 3 37 Impact of Autocalibration on Module Startup During Mode Change Regardless of the selection of the Enable Disable Cyclic Calibration function an autocalibration cycle occurs automatically on a mode change from Program to Run and on subsequent module startups initialization for all configured channels During module startup input data is not updated by the module and the General Status bits SO to S5 are set to 1 indicating a Data Not Valid condition The amount of time it takes the module to startup is dependent on channel filter frequency selections as indicated in Table 3 5 Channel Update Time on page 3 34 The f
8. exposed junction thermocouple uses a measuring junction that Thermocouple does not have a protective metal sheath A thermocouple with this junction type provides the fastest response time but leaves thermocouple wires unprotected against corrosive or mechanical damage Measuring Junction with No Sheath As shown in the next illustration using an exposed junction thermocouple can result in removal of channel to channel isolation Isolation is removed if multiple exposed thermocouples are in direct contact with electrically conductive process material 1762 IT4 Conductive Material Multiplexer Publication 1762 UM002A EN P July 2002 D 4 Using Thermocouple Junctions To prevent violation of channel to channel isolation For multiple exposed junction thermocouples do not allow the measuring junctions to make direct contact with electrically conductive process material Preferably use a single exposed junction thermocouple with multiple ungrounded junction thermocouples Consider using all ungrounded junction thermocouples instead of the exposed junction type Publication 1762 UM002A EN P July 2002 Module Addressing Input Image File Appendix E Module Configuration Using MicroLogix 1200 and RSLogix 500 This appendix examines the 1762 IT4 module s addressing scheme and describes module configuration using RSLogix 500 and a MicroLogix 1200 controller The following memory ma
9. 2000 500 400 300 250 Hz 500 Hz 200 1000 Hz Effective Resolution F SS Sse 0 a DERIT T 500 1000 1500 2000 2500 3000 Temperature F 100 Publication 1762 UM002A EN P July 2002 3500 Effective Resolution C Effective Resolution F Module Data Status and Channel Configuration 3 17 Figure 3 4 Effective Resolution Versus Input Filter Selection for Type C Thermocouples Using 10 50 and 60 Hz Filters 0 8 0 7 0 6 0 5 0 4 0 3 10 Hz 50 Hz 60 Hz 0 2 0 1 0 0 0 400 800 1200 1600 2000 Temperature C 1 6 1 4 1 2 1 0 0 8 0 4 10 Hz 50 Hz 60 Hz 0 2 0 0 0 500 X 1000 1500 2000 2500 3000 3500 4000 Temperature F Publication 1762 UM002A EN P July 2002 3 18 Module Data Status and Channel Configuration Figure 3 5 Effective Resolution Versus Input Filter Selection for Type C Thermocouples Using 250 500 and 1k Hz Filters 180 160 S 140 s 1 250 Hz m dU 800 Hz E A 1000 Hz S 60 im 40 20 0 0 400 800 1200 1600 2000 2400 Temperature C 350 300 250 E 250 Hz 200 E 500 Hz S 1000 Hz amp 100 0 EESE TES ET TT T E R 500 1000 1500 200
10. F Thermocouple T 270 C to 230 C 454 F to 382 F 5 4 C 9 8 F 7 0 C 12 6 F 0 3500 C C 0 3500 F F Thermocouple K 230 C to 1370 C 382 F to 1 C 1 8 F 1 5 C 2 7 F 0 4995 C C 0 4995 F F 2498 F Thermocouple K 270 C to 225 C 454 F to 373 F 7 5 C 13 5 F 10 C 18 F 0 0378 C C 0 0378 F F Thermocouple E 210 C to 1000 C 346 F to 0 5 C 0 9 F 0 8 C 1 5 F 0 0199 C C 0 0199 F F 1832 F Thermocouple E 270 C to 210 C 454 F to 346 F 4 2 C 7 6 F 6 3 C 11 4 F 0 2698 C C 0 2698 F F Thermocouple R 1 7 C 3 1 F 2 6 C 4 7 F 0 0613 C C 0 0613 F F Thermocouple S 1 7 C 3 1 F 2 6 C 4 7 F 0 0600 C C 0 0600 F F Thermocouple C 1 8 C 4 3 3 F 3 5 C 4 6 3 F 0 0899 C C 0 0899 F F Thermocouple B 3 0 C 5 4 F 4 5 C 8 1 F 0 1009 C C 0 1009 F F 50 mV 15 uV 25 uV 0 44uV C 0 80uV F 100 mV 20 uV 30 uV 0 69uV C 01 25uV F 1 The module uses the National Institute of Standards and Technology NIST ITS 90 standard for hermocouple linearization 2 Accuracy and temperature drift information does not include the affects of errors or drift in the cold junction compensation circuit 3 Accuracy is dependent upon the analog digital converter output rate selection data format and 4 Temperature drift
11. 1 2 1 0 0 8 10 Hz 0 6 50 Hz NM 60 Hz 0 4 0 0 400 0 400 800 1200 1600 2000 2400 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 A 12 Specifications Figure A 8 Module Accuracy at 25 C 77 F Ambient for Type J Thermocouple Using 250 500 and 1 kHz Filter c1 250 Hz 500 Hz 1000 Hz Accuracy C N N e c ce c ce 400 200 0 200 400 600 800 1000 1200 Thermocouple Temperature C ao N O c c e 250 Hz 500 Hz 1000 Hz e co e Accuracy F 400 0 400 800 1200 1600 2000 2400 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 Accuracy C Accuracy F 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 0 0 16 0 14 0 12 0 10 0 8 0 6 0 4 0 2 0 0 0 Specifications A 13 Figure A 9 Module Accuracy at 25 C 77 F Ambient for Type K Thermocouple Using 10 50 and 60 Hz Filter 10 Hz 50 Hz 60 Hz 400 200 0 200 400 600 800 1000 1200 1400 Thermocouple Temperature C 10 Hz 50 Hz 60 Hz 500 0 500 1000 1500 2000 2500 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 A 14 Specifica
12. 100 Cyberport Road Hong Kong Tel 852 2887 4788 Fax 852 2508 1846 Publication 1762 UM002A EN P July 2002 Copyright 2002 Rockwell Automation All rights reserved Printed in the U S A
13. 4 The 1976 Provisional 0 5 to 30 K Temperature Scale Metrologia 15 65 68 1979 5 ASTM American Society for Testing and Materials Manual on the use of thermocouples in temperature measurement Special Tech Publ 470B edited by Benedict R P Philadelphia ASTM 1981 258p 6 Hansen M Anderko K Constitution of binary alloys New York McGraw Hill Book Co 1958 7 ASTM American Society for Testing and Materials Standard E230 87 1992 Annual Book of ASTM Standards Vol 14 03 Philadelphia ASTM 1992 102 230 8 Sparks L L Powell R L Hall W J Reference tables for low temperature thermocouples Natl Bur Stand U S Monogr 124 1972 June 61p 9 Starr C D Wang T P Effect of oxidation on stability of thermocouples Proceedings of the American Society for Testing and Materials Vol 63 1185 1194 1963 10 Roeser W E Dahl A I Reference tables for iron constantan and copper constantan thermocouples J Res Natl Bur Stand U S 20 337 355 RP1080 1938 March 11 Dahl A I Stability of base metal thermocouples in air from 800 to 2200 F J Res Natl Bur Stand U S 24 205 224 RP1278 1940 February 12 Sparks L L Powell R L Low temperatures thermocouples KP normal silver and copper versus Au 0 02 at Fe and Au 0 07 at 96 Fe J Res Natl Bur Stand U S 76A 3 263 283 1972 May June 13 Burley N A Hess R M Howie C F Coleman J A The
14. 537 546 29 Bentley R E Changes in Seebeck coefficient of Pt and Pt 10 Rh after use to 1700C in high purity polycrystalline alumina Int J Thermophys 6 1 83 99 1985 30 McLaren E H Murdock E G New considerations on the preparation properties and limitations of the standard thermocouple for thermometry Temperature Its Measurement and Control in Science and Industry Vol 4 Plumb H H ed Pittsburgh Instrument Society of America 1972 1543 1560 31 McLaren E H Murdock E G The properties of Pt PtRh thermocouples for thermometry in the range 0 1100 C I Basic measurements with standard thermocouples National Research Council of Canada Publication APH 2212 NRCC 17407 1979 Publication 1762 UM002A EN P July 2002 C 20 Thermocouple Descriptions Publication 1762 UM002A EN P July 2002 32 McLaren E H Murdock E G The properties of Pt PtRh thermocouples for thermometry in the range 0 1100 C II Effect of heat treatment on standard thermocouples National Research Council of Canada Publication APH 2213 NRCC 17408 1979 33 McLaren E H Murdock E G Properties of some noble and base metal thermocouples at fixed points in the range 0 1100 C Temperature Its Measurement and Control in Science and Industry Vol 5 Schooley J F ed New York American Institute of Physics 1982 953 975 34 Bentley R E Jones T P Inhomogeneities in type S thermocouples when used to 1064
15. Determining Effective Resolution and Range Publication 1762 UM002A EN P July 2002 The cut off frequency for each channel is defined by its filter frequency selection Choose a filter frequency so that your fastest changing signal is below that of the filter s cut off frequency The cut off frequency should not be confused with the update time The cut off frequency relates to how the digital filter attenuates frequency components of the input signal The update time defines the rate at which an input channel is scanned and its channel data word is updated Selecting Enable Disable Cyclic Calibration Word 4 Bit 0 Cyclic calibration functions to reduce offset and gain drift errors due to temperature changes within the module By setting word 4 bit 0 to 0 you can configure the module to perform calibration on all enabled channels Setting this bit to 1 disables cyclic calibration You can program the calibration cycle to occur whenever you desire for systems that allow modifications to the state of this bit via the ladder program When the calibration function is enabled bit 0 a calibration cycle occurs once for all enabled channels If the function remains enabled a calibration cycle occurs every five minutes thereafter The calibration cycle of each enabled channel is staggered over several module scan cycles within the five minute period to limit impact on the system response speed See Effects of Autocalibration on Module Up
16. conventional closed end protecting tubes is set at 1260 C by the ASTM 7 for 3 25 mm diameter thermoelements Their maximum upper temperature limit is defined by the melting temperature of the thermoelements which are nominally 1410 C for type NP and 1340 C for type NN 5 The thermoelectric stability and physical life of type N thermocouples when used in air at elevated temperatures will depend upon factors such as the temperature the time at temperature the diameter of the thermoelements and the conditions of use Their thermoelectric stability and oxidation resistance in air have been investigated and compared with those of type K thermocouples by Burley 16 by Burley and others 13 44 47 by Wang and Starr 17 43 48 49 by McLaren and Murdock 33 by Bentley 19 and by Hess 50 Type N thermocouples in general are subject to the same environmental restrictions as types E and K They are not recommended for use at high temperatures in sulfurous reducing or alternately oxidizing and reducing atmospheres unless suitably protected with protecting tubes They also should not be used in vacuum at high temperatures for extended times because the chromium and silicon in the positive thermoelement a nickel chromium silicon alloy vaporize out of solution and alter the Publication 1762 UM002A EN P July 2002 C 10 Thermocouple Descriptions Publication 1762 UM002A EN P July 2002 calibration In addition their use in
17. given in the ASTM standard 7 for protected type S thermocouples applies to AWG 24 0 51 mm wire This temperature limit applies to thermocouples used in conventional closed end protecting tubes and it is intended only as a rough guide to the user It does not apply to thermocouples having compacted mineral oxide insulation This section describes Copper Versus Copper Nickel Alloy thermocouples called type T thermocouples This type is one of the oldest and most popular thermocouples for determining temperatures within the range from about 370 C down to the triple point of neon 248 5939 C Its positive thermoelement TP is typically copper of high electrical conductivity and low oxygen content that conforms to ASTM Specification B3 for soft or annealed bare copper wire Such material is about 99 95 percent pure copper with an oxygen content varying from 0 02 to 0 07 percent depending upon sulfur content and with other impurities totaling about 0 01 percent Above about 200 C the thermoelectric properties of type TP thermoelements which satisfy the above conditions are exceptionally uniform and exhibit little variation between lots Below about 200 C the thermoelectric properties are affected more strongly by the presence of dilute transition metal solutes particularly iron The negative thermoelement TN or EN is a copper nickel alloy known ambiguously as constantan The word constantan refers to a Thermocouple Descriptions C
18. nicrosil versus nisil thermocouple A critical comparison with the ANSI standard letter designated base metal thermocouples Temperature Its Measurement and Control in Science and Industry Publication 1762 UM002A EN P July 2002 C 18 Thermocouple Descriptions Publication 1762 UM002A EN P July 2002 Vol 5 Schooley J F ed New York American Institute of Physics 1982 1159 1166 14 Potts J F Jr McElroy D L The effects of cold working heat treatment and oxidation on the thermal emf of nickel base thermoelements Herzfeld C M Brickwedde F G Dahl A I Hardy J D ed Temperature Its Measurement and Control in Science and Industry Vol 3 Part 2 New York Reinhold Publishing Corp 1962 243 264 15 Burley N A Ackland R G The stability of the thermo emf temperature characteristics of nickel base thermocouples Jour of Australian Inst of Metals 12 1 23 31 1967 16 Burley N A Nicrosil and nisil Highly stable nickel base alloys for thermocouples Temperature Its Measurement and Control in Science and Industry Vol 4 Plumb H H ed Pittsburgh Instrument Society of America 1972 1677 1695 17 Wang T P Starr C D Electromotive force stability of nicrosil nisil Journal of Testing and Evaluation 8 4 192 198 1980 18 Starr C D Wang T P Effect of oxidation on stability of thermocouples Proceedings of the American Society for Testing and Materials Nol 6
19. re install it by connecting it across the pair of CJC terminals Publication 1762 UM002A EN P July 2002 2 14 Installation and Wiring Calibration Publication 1762 UM002A EN P July 2002 The thermocouple module is initially calibrated at the factory The module also has an autocalibration function When an autocalibration cycle takes place the module s multiplexer is set to system ground potential and an A D reading is taken The A D converter then sets its internal input to the module s precision voltage source and another reading is taken The A D converter uses these numbers to compensate for system offset zero and gain span errors Autocalibration of a channel occurs whenever a channel is enabled You can also program your module to perform cyclic calibration cycles every five minutes See Selecting Enable Disable Cyclic Calibration Word 4 Bit 0 on page 3 14 To maintain optimal system accuracy periodically perform an autocalibration cycle IMPORTANT The module does not convert input data while the calibration cycle is in progress following a change in configuration Module scan times are increased by up to 112 ms during cyclic autocalibration Module Memory Map Input Image File Accessing Input Image File Data Chapter J Module Data Status and Channel Configuration After installing the 1762 IT4 thermocouple mV input module you must configure it for operation using the programmin
20. the module status LED remains off and a module error is reported to the controller If module status Indicated Corrective action LED is condition On Proper Operation No action required Off Module Fault Cycle power If condition persists replace the module Call your local distributor or Rockwell Automation for assistance When an input channel is enabled the module performs a diagnostic check to see that the channel has been properly configured In addition the channel is tested on every scan for configuration errors over range and under range and open circuit conditions Invalid Channel Configuration Detection Whenever a channel configuration word is improperly defined the module reports an error See pages 4 4 to 4 6 for a description of module errors Over or Under Range Detection Whenever the data received at the channel word is out of the defined operating range an over range or under range error is indicated in input data word 5 Possible causes of an out of range condition include The temperature is too hot or too cold for the type of thermocouple being used The wrong thermocouple is being used for the input type selected or for the configuration that was programmed The input device is faulty The signal input from the input device is beyond the scaling range Publication 1762 UM002A EN P July 2002 4 4 Diagnostics and Troubleshooting Non critical vs Critical Module
21. 0 1 mV units The resolution of the engineering units x 10 data format is dependent on the range selected and the filter selected See Determining Effective Resolution and Range on page 3 14 Scaled for PID The value presented to the controller is a signed integer with 0 representing the lower input range and 416383 representing the upper input range To obtain the value the module scales the input signal range to a 0 to 16383 range which is standard to the PID algorithm for the MicroLogix 1200 and other Allen Bradley controllers e g SLC For example if type J thermocouple is used the lowest temperature for the thermocouple is 210 C which corresponds to 0 counts The highest temperature in the input range 1200 C corresponds to 16383 counts Percent Range Input data is presented to the user as a percent of the specified range The module scales the input signal range to a 0 to 10000 range For example using a type J thermocouple the range 210 C to 1200 C is represented as 096 to 10096 See Determining Effective Resolution and Range on page 3 14 Selecting Input Type Bits 11 through 8 Bits 11 through 8 in the channel configuration word indicate the type of thermocouple or millivolt input device Each channel can be individually configured for any type of input Module Data Status and Channel Configuration 3 9 Selecting Temperature Units Bit 7 The module supports two different linearized scaled ranges
22. 10 30 VDC 1762 1016 16 Input 10 30 VDC 1762 048 8 Output 120 240 VAC 1762 088 8 Dutput TRANS SRC 10 50 VDC 1762 0816 16 Dutput TRANS SRC 10 50 VDC 8 Dutput Relay 16 Dutput RLY 240 VAC 4 Channel Thermocouple Input Module 4 Channel RTD Resistance Input Module Other Requires 1 0 Card Type ID Read IO Config 0 Bul1752 MicroLogix 1200 Series C 1 17524T4 4 Channel Thermocouple Input Module Help Hide All Cards Module Configuration Using MicroLogix 1200 and RSLogix 500 E 5 The 1762 IT4 module is installed in slot 1 To configure the module double click on the module slot The general configuration screen appears Module 1 1762 IT4 4 Channel Thermocouple Input Module xi Expansion General Configuration Chan 0 2 Chan 3 Cal Generic Extra Data Config Vendor ID Product Type Product Cade Series Major Rev MinorRev Input Words Output Words Extra Data Length Ignore Configuration Error Cancel Apply Help wie Configuration options for channels 0 to 2 are located on a separate tab from channel 3 as shown below To enable a channel click its Enable box so that a check mark appears in it For optimum module performance disable any channel that is not hardwired to a real input Then choose your Data Format Input Type Filter Frequency Open Circuit response and Units for each channel Module 1 1762 IT4 4 C
23. 15 family of copper nickel alloys containing anywhere from 45 to 60 percent copper These alloys also typically contain small percentages of cobalt manganese and iron as well as trace impurities of other elements such as carbon magnesium silicon etc The constantan for type T thermocouples usually contains about 55 percent copper 45 percent nickel and small but thermoelectrically significant amounts about 0 1 percent or larger of cobalt iron or manganese It should be emphasized that type TN or EN thermoelements are NOT generally interchangeable with type JN thermoelements although they are all referred to as constantan In order to provide some differentiation in nomenclature type TN or EN is often referred to as Adams or RP1080 constantan and type JN is usually referred to as SAMA constantan The thermoelectric relations for type TN and type EN thermoelements are the same that is the voltage versus temperature equations and tables for platinum versus type TN thermoelements apply to both types of thermoelements over the temperature range recommended for each thermocouple type However if should not be assumed that type TN and type EN thermoelements may be used interchangeably or that they have the same commercial initial calibration tolerances The low temperature research 8 by members of the NBS Cryogenics Division showed that the type T thermocouple may be used down to liquid helium temperatures about 4K but that
24. 3 31 Figure 3 18 Effective Resolution Versus Input Filter Selection for Type T Thermocouples Using 10 50 and 60 Hz Filters 300 200 100 0 100 200 300 400 Temperature C 10 Hz 50 Hz 60 Hz 600 400 200 0 200 400 600 800 Temperature F Publication 1762 UM002A EN P July 2002 3 32 Module Data Status and Channel Configuration Figure 3 19 Effective Resolution Versus Input Filter Selection for Type T Thermocouples Using 250 500 and 1k Hz Filters 120 100 E 250 Hz 2 60 500 Hz m 1000Hz S 40 20 0 300 200 100 0 100 200 300 400 Temperature C 250 Hz 8 500 Hz 2 1000Hz 600 400 Publication 1762 UM002A EN P July 2002 200 0 200 Temperature F 400 600 800 Module Data Status and Channel Configuration 3 33 Determining Module Update Time Table 3 4 Effective Resolution vs Input Filter Selection for Millivolt Inputs Filter Frequency 50mV 100mV 10 Hz 6 uV 6 uV 50 Hz 9 uV 12 uV 60 Hz 9 uV 12 uV 250 Hz 125 uV 150 uV 500 Hz 250 uV 300 uV 1 kHz 1000 uV 1300 uV TIP The resolutions provided by the filters apply to the raw proportional data format only gt The module update time is defined as the time req
25. C 77 F Gov eet re Rote ea a A 3 ACCUFACI TE oap e E SEEM 2 6 ESSE ES A TS AP A 4 Accuracy Versus Thermocouple Temperature and Filter CULL Y a uv id repre dent a p Lt deep s Mae Spo Add A 5 Appendix B Positive Decimal Values catene MC ER ee a B 1 Negative Decimal Values 0 00000 eee eee B 2 Appendix C International Temperature Scale of 1990 C 1 Type B Thermocouples noanoa va Wa e a a X C 1 Type E Thermocouples eite E eade Uer e eas S C 3 Type J Thermocouples 2g aedis acd t e qr vo d roe T cded C 5 Type K Thermocouples oona E Gah tet abies C 7 Type N Thermocouples etse o CLERC Cd C 9 Type R Thermocouples 242 3 Np Cre Tufts een C 11 Type S Thermocouples 6 Cua uid arepla Qs uy ta hood qs C 12 Type T Thermocouples ule Vas ode ue dri ee a PS RS C 14 References e poe vu ace auedot uw sr baci eos 38 onde eod C 17 Appendix D Using a Grounded Junction Thermocouple D 1 Using an Ungrounded Isolated Junction Thermocouple D 2 Using an Exposed Junction Thermocouple D 3 Publication 1762 UM002A EN P July 2002 Table of Contents iv Module Configuration Using MicroLogix 1200 and RSLogix 500 Publication 1762 UM002A EN P July 2002 Appendix E Module Addressifid s cua A rad E ieee Ash ale deine ee RR 1762 T4 Configuration lle J4 2 kx ae kad aa ees Configuration Using RSLogix 500 Version 5 50 or Higher Generic Extra Data Configuration Configurat
26. C High Temperatures High Pressures 12 33 45 1980 35 Rhys D W Taimsalu P Effect of alloying additions on the thermoelectric properties of platinum Engelhard Tech Bull 10 41 47 1969 36 Cochrane J Relationship of chemical composition to the electrical properties of platinum Engelhard Tech Bull 11 58 71 1969 Also in Temperature Its Measurement and Control in Science and Industry Vol 4 Plumb H H ed Pittsburgh Instrument Society of America 1972 1619 1632 37 Aliotta J Effects of impurities on the thermoelectric properties of platinum Inst and Control Systems 106 107 March 1972 38 Burns G W Gallagher J S Reference tables for the Pt 30 percent Rh versus Pt 6 percent Rh thermocouple J Res Natl Bur Stand U S 70C 89 125 1966 39 Ehringer H Uber die lebensdauer von PtRh thermoelementen Metall 8 596 598 1954 40 Acken J S Some properties of platinum rhodium alloys Res Natl Bur Stand U S 12 249 RP650 1934 41 Hendricks J W McElroy D L High temperature high vacuum thermocouple drift tests Environmental Quarterly 34 38 March 1967 42 Zysk E D Platinum metal thermocouples Temperature Its Measurement and Control in Science and Industry Vol 3 Herzfeld C M ed New York Reinhold Publishing Corp 1962 Part 2 pp 135 156 43 Starr C D Wang T P A new stable nickel base thermocouple Journal of Testing and Evaluation 4
27. a series of input values corresponding to digital codes For an ideal analog input the values lie in a straight line spaced by inputs corresponding to 1 LSB Linearity Glossary G 3 is expressed in percent full scale input See the variation from the straight line due to linearity error exaggerated in the example below Actual Transfer Function LSB Least significant bit The LSB represents the smallest value within a string of bits For analog modules 16 bit two s complement binary codes are used in the I O image For analog inputs the LSB is defined as the rightmost bit of the 16 bit field bit 0 The weight of the LSB value is defined as the full scale range divided by the resolution module scan time same as module update time module update time The time required for the module to sample and convert the input signals of all enabled input channels and make the resulting data values available to the processor multiplexer An switching system that allows several signals to share a common A D converter normal mode rejection differential mode rejection A logarithmic measure in dB of a device s ability to reject noise signals between or among circuit signal conductors The measurement does not apply to noise signals between the equipment grounding conductor or signal reference structure and the signal conductors number of significant bits The power of two that represents the total number
28. and Range Determining Module Update Time 5 eer Ree eas Effects of Autocalibration on Module Update Time Calculating Module Update Time Impact of Autocalibration on Module Startup During Mode CHASES scr ger tea 2 s C pede aeo ees Chapter 4 Safety Considera OB cob o YR 4 or at RADO Ua Indicator LIgBtS unus see Bar doit ae ee FT eet o Ed Stand Clear of EdquippdenLb s cu qucd sce oe od Program Alteration s aw eke doy qd Ove Reb KE ROLL Safety CCUG oS sq aTSPIT SRCRFCHREATSPAYEE SS Specifications Two s Complement Binary Numbers Thermocouple Descriptions Using Thermocouple Junctions Table of Contents iii Module Operation vs Channel Operation 4 2 Power up Diagnostics plica ER AC 4 3 Channel Diagnostics 8 P bu pe me T Ee RF ES 4 3 Invalid Channel Configuration Detection 4 3 Over or Under Range Detecul n 4s osx 4 3 Open Circuit DAECHON w 27s 9a Shes FESS eS eo 4 4 Non critical vs Critical Module Errors 4 4 Module Error Definition Table 4 4 Module BHOE Field cass oua 53 aoe Wa eS Meek ES 4 4 Extended Error Information Field 4 5 Error COdES 0 bias Dydd edad gies Ae bead gut dees aur eate a 4 6 Contacting Rockwell Automation 0 4 7 Appendix A General Specifications n s p edioe d t RF Hordes A 1 Input Specifications 9g ed E AC qe eee axe CCP i CEN A 2 Repeatability at 25
29. connection to the reference cold junction A temperature difference between the junctions must exist for the device to function update time see module update time Numerics 3 dB frequency 3 12 A A D definition G 1 abbreviations G 1 accuracy A 4 vs temperature and filter frequency A 5 A 22 analog input module overview 1 1 4 1 attenuation cut off frequency 3 12 definition G 1 autocalibration module update time 3 34 B bus connector definition G 1 bus interface 1 4 C calibration 1 6 calibration cyclic 3 14 channel definition G 1 channel configuration 3 4 channel configuration word 3 4 channel diagnostics 4 3 channel status LED 1 4 channel update time definition G 1 CJC definition G 1 CJC sensor general status bits 3 2 module operation 1 5 CJC sensors error indication 3 3 input frequency 3 11 open circuit condition 3 9 over range flag 3 3 under range flag 3 3 CMRR See common mode rejection ratio Index common mode rejection 3 11 definition G 1 specification A 2 common mode rejection ratio definition G 1 specification A 2 common mode voltage definition G 1 common mode voltage range definition G 1 specification A 2 common mode voltage rating 3 11 configuration errors 4 5 configuration word definition G 1 contacting Rockwell Automation 4 7 cut off frequency 3 12 definition G 2 D data not valid condition 3 2 data word definition G 2 dB definition G 2 deci
30. does not violate any of the restrictions mentioned above For most general applications they may be used with the heat treatment given by the wire manufacturers However when the highest accuracy is sought additional preparatory heat treatments may be desirable in order to enhance their performance Details on this and other phases of the use and behavior of type KP thermoelements EP is the same as KP are given in publications by Pots and McElroy 14 by Burley and Ackland 15 by Burley 16 by Wang and Starr 17 18 by Bentley 19 and by Kollie et al 20 ASTM Standard E230 87 in the 1992 Annual Book of ASTM Standards 7 specifies that the initial calibration tolerances for type E commercial thermocouples be 1 7 C or 0 5 percent whichever is greater between 0 C and 900 C and 1 7 C or 1 percent whichever is greater between 200 C and 0 C Type E thermocouples can also be supplied to meet special tolerances which are equal to 1 C or 0 4 percent whichever is greater between 0 C and 900 C and 1 C or 0 5 percent whichever is greater between 200 C and 0 C Type E thermocouple materials are normally supplied to meet the tolerances specified for temperatures above 0 C The same materials however Thermocouple Descriptions C 5 Type J Thermocouples may not satisfy the tolerances specified for the 200 C to 0 C range If materials are required to meet the tolerances below 0 C this should be specified
31. is enabled and there are no channel errors When the channel is disabled the channel data word is cleared 0 dB decibeD A logarithmic measure of the ratio of two signal levels digital filter A low pass filter incorporated into the A D converter The digital filter provides very steep roll off above it s cut off frequency which provides high frequency noise rejection effective resolution The number of bits in a channel configuration word that do not vary due to noise filter A device that passes a signal or range of signals and eliminates all others filter frequency The user selectable frequency for a digital filter full scale The magnitude of input over which normal operation is permitted full scale range The difference between the maximum and minimum specified analog input values for a device gain drift Change in full scale transition voltage measured over the Operating temperature range of the module input data scaling Data scaling that depends on the data format selected for a channel configuration word Scaling is selected to fit the temperature or voltage resolution for your application input image The input from the module to the controller The input image contains the module data words and status bits linearity error Any deviation of the converted input or actual output from a straight line of values representing the ideal analog input An analog input is composed of
32. of completely different digital codes to which an analog signal can be converted or from which it can be generated overall accuracy The worst case deviation of the digital representation of the input signal from the ideal over the full input range is the overall accuracy Overall accuracy is expressed in percent of full scale repeatability The closeness of agreement among repeated measurements of the same variable under the same conditions resolution The increment of change represented by one unit For example the resolution of engineering units x1 is 0 1 and the resolution of raw proportional data is equal to maximum_value minimum_value 65534 Publication 1762 UM002A EN P July 2002 Glossary G 4 Publication 1762 UM002A EN P July 2002 sampling time The time required by the A D converter to sample an input channel status word Contains status information about the channel s current configuration and operational state You can use this information in your ladder program to determine whether the channel data word is valid step response time The time required for the channel data word signal to reach a specified percentage of its expected final value given a full scale step change in the input signal thermocouple A temperature sensing device consisting of a pair of dissimilar conductors welded or fused together at one end to form a measuring junction The free ends are available for
33. purity of 99 98 percent shall be alloyed with platinum of 99 99 percent purity to produce the positive thermoelement which typically contains 10 00 0 05 percent rhodium by weight The consensus standard 21 describes the purity of commercial type S materials that are used in many industrial thermometry applications and that meet the calibration tolerances described later in this section It does not cover however the higher purity reference grade materials that traditionally were used to construct thermocouples used as standard instruments of the IPTS 68 as transfer standards and reference thermometers in various laboratory applications and to develop reference functions and tables 27 28 The higher purity alloy material typically contains less than 500 atomic ppm of impurities and the platinum less than 100 atomic ppm of impurities 27 Difference between such high purity commercial material and the platinum thermoelectric reference standard Pt 67 are described in 27 and 28 A reference function for the type S thermocouple based on the ITS 90 and the SI volt was determined recently from new data obtained in an international collaborative effort involving eight national laboratories The results of this international collaboration were reported by Burns et al 28 The new function was used to compute the reference table given in this monograph Thermocouple Descriptions C 13 Research 27 demonstrated that type S thermocou
34. resolution 3 17 3 18 temperature range 1 1 type E accuracy A 9 A 10 description C 3 effective resolution 3 19 3 20 temperature range 1 1 type J accuracy A 11 A 12 description C 5 effective resolution 3 21 3 22 temperature range 1 1 type K accuracy A 13 A 14 description C 7 effective resolution 3 23 3 24 temperature range 1 1 type N accuracy A 15 A 16 description C 9 effective resolution 3 25 3 26 temperature range 1 1 type R accuracy A 17 A 18 description C 11 effective resolution 3 27 3 28 temperature range 1 1 type S accuracy A 19 A 20 description C 12 effective resolution 3 29 3 30 temperature range 1 1 type T accuracy A 21 A 22 description C 14 effective resolution 3 31 3 32 temperature range 1 1 Publication 1762 UM002A EN P July 2002 4 Index U W under range flag bits 3 3 wiring 2 1 update time 3 33 modules 2 11 update time See channel update time routing considerations 2 4 update time See module update time Publication 1762 UM002A EN P July 2002 www rockwellautomation com Power Control and Information Solutions Headquarters Americas Rockwell Automation 1201 South Second Street Milwaukee WI 53204 2496 USA Tel 1 414 382 2000 Fax 1 414 382 4444 Europe Middle East Africa Rockwell Automation Vorstlaan Boulevard du Souverain 36 1170 Brussels Belgium Tel 32 2 663 0600 Fax 32 2 663 0640 Asia Pacific Rockwell Automation Level 14 Core F Cyberport 3
35. the DIN rail mounting area of the module against the DIN rail The latch will momentarily open and lock into place Publication 1762 UM002A EN P July 2002 2 6 Installation and Wiring Use DIN rail end anchors Allen Bradley part number 1492 EA35 or 1492 EAH35 for environments with vibration or shock concerns End Anchor TIP For environments with extreme vibration and shock concerns use the panel mounting method D described below instead of DIN rail mounting Panel Mounting Use the dimensional template shown below to mount the module The preferred mounting method is to use two M4 or 48 panhead screws per module M3 5 or 6 panhead screws may also be used but a washer may be needed to ensure a good ground contact Mounting screws are required on every module For more than 2 modules number of modules 1 x 40 4 mm 1 59 in 14 5 L e Og a A Cn co m g S g MicroLogix 1200 Expansion 1 0 MicroLogix 1200 Expansion 1 0 MicroLogix 1200 Expansion 1 0 To co gt Two o1 IR MicroLogix 1200 NOTE h 5 Hole spacing tolerance B v 0 4 mm 0 016 in ce 1 59 c C oa c1 E E c Eg Publication 1762 UM002A EN P July 2002 Installation and Wiring 2 7 System Assembly The expansion I O module is attached to the controller or another I O m
36. wires specified by the thermocouple manufacturer Using the incorrect type of thermocouple extension wire or not following the correct polarity will cause invalid readings To ensures optimum accuracy limit overall cable impedance by keeping a cable as short as possible Locate the module as close to input devices as the application permits Grounding ATTENTION The possibility exists that a grounded or exposed thermocouple can become shorted to a potential greater than that of the thermocouple itself Due to possible shock hazard take care when wiring grounded or exposed thermocouples See Appendix D Using Thermocouple Junctions This product is intended to be mounted to a well grounded mounting surface such as a metal panel Additional grounding connections from the module s mounting tabs or DIN rail Gf used are not required unless the mounting surface cannot be grounded Under normal conditions the drain wire shield should be connected to the metal mounting panel earth ground Keep shield connection to earth ground as short as possible Ground the shield drain wire at one end only The typical location is as follows For grounded thermocouples or millivolt sensors this is at the sensor end For insulated ungrounded thermocouples this is at the module end Contact your sensor manufacturer for additional details Installation and Wiring 2 9 If it is necessary to connect the shield d
37. with autocalibration is slightly better than withou Publicat TIP autocalibration input noise For more detailed accuracy information see the accuracy graphs on pages A 5 through A 21 gt ion 1762 UM002A EN P July 2002 Accuracy C Accuracy F 4 0 3 5 3 0 2 5 2 0 1 5 1 0 0 5 0 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 0 0 Specifications A 5 Accuracy Versus Thermocouple Temperature and Filter Frequency The following graphs show the module s accuracy when operating at 25 C for each thermocouple type over the thermocouple s temperature range for each frequency The effect of errors in cold junction compensation is not included Figure A 1 Module Accuracy at 25 C 77 F Ambient for Type B Thermocouple Using 10 50 and 60 Hz Filter 10 Hz 50 Hz 60 Hz 200 600 800 1000 1200 1400 1600 1800 2000 Thermocouple Temperature C 10 Hz 50 Hz 60 Hz 500 1000 1500 2000 2500 3000 3500 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 A 6 Specifications Figure A 2 Module Accuracy at 25 C 77 F Ambient for Type B Thermocouple Using 250 500 and 1 kHz Filter 240 200 o 160 250 Hz 120 500 Hz 8 1000 H x 80 Z 40 0 200 400 600
38. 0 2500 3000 3500 4000 4500 Temperature F ce Publication 1762 UM002A EN P July 2002 Effective Resolution C Effective Resolution F Module Data Status and Channel Configuration 3 19 Figure 3 6 Effective Resolution Versus Input Filter Selection for Type E Thermocouples Using 10 50 and 60 Hz Filters 3 0 2 5 2 0 10 Hz 1 5 50 Hz 60 Hz 1 0 0 5 0 0 400 200 0 200 400 600 800 1000 Temperature C 3 0 10 Hz 2 5 50 Hz 2 0 60 Hz 500 0 500 1000 1500 2000 Temperature F Publication 1762 UM002A EN P July 2002 3 20 Module Data Status and Channel Configuration Figure 3 7 Effective Resolution Versus Input Filter Selection for Type E Thermocouples Using 250 500 and 1k Hz Filters 100 5 80 ed 500 Hz g 40 1000 Hz 20 0 400 200 0 200 400 600 800 1000 Temperature C E 250 Hz E 500 Hz E 1000Hz 500 0 500 1000 1500 2000 Temperature F Publication 1762 UM002A EN P July 2002 Effective Resolution C Effective Resolution F Module Data Status and Channel Configuration 3 21 Figure 3 8 Effective Resolution Versus Input Filter Selection for Type J Thermocouples Using 10 50 and 60 Hz Filters
39. 1 42 56 1976 Thermocouple Descriptions C 21 44 Burley N A Powell R L Burns G W Scroger M G The nicrosil versus nisil thermocouple properties and thermoelectric reference data Natl Bur Stand U S Monogr 161 1978 April 167p 45 Burley N A Jones T P Practical performance of nicrosil nisil thermocouples Temperature Measurement 1975 Billing B F Quinn T J ed London and Bristol Institute of Physics 1975 172 180 46 Burley N A Hess R M Howie C F Nicrosil and nisil new nickel based thermocouple alloys of ultra high thermoelectric stability High Temperatures High Pressures 12 403 410 1980 47 Burley N A Cocking J L Burns G W Scroger M G The nicrosil versus nisil thermocouple the influence of magnesium on the thermoelectric stability and oxidation resistance of the alloys Temperature Its Measurement and Control in Science and Industry Vol 5 Schooley J F ed New York American Institute of Physics 1982 1129 1145 48 Wang T P Starr C D Nicrosil nisil thermocouples in production furnaces in the 538 C 1000 F to 1177 C 2150 F range ISA Transactions 18 4 83 99 1979 49 Wang T P Starr C D Oxidation resistance and stability of nicrosil nisil in air and in reducing atmospheres Temperature Ils Measurement and Control in Science and Industry Vol 5 Schooley J E ed New York American Institute of Physics 1982 1147
40. 1 mm 370 C for AWG 24 or 28 0 51 mm or 0 33 mm and 320 C for AWG 30 0 25 mm These temperature limits apply to thermocouples used in conventional closed end protecting tubes and they are intended only as a rough guide to the user They do not apply to sheathed thermocouples having compacted mineral oxide insulation This section describes Nickel Chromium Alloy Versus Nickel Aluminum Alloy thermocouples called type K thermocouples This type is more resistant to oxidation at elevated temperatures than types E J or T thermocouples and consequently it finds wide application at temperatures above 500 C The positive thermoelement KP which is the same as EP is an alloy that typically contains about 89 to 90 percent nickel 9 to about 9 5 percent chromium both silicon and iron in amounts up to about 0 5 percent plus smaller amounts of other constituents such as carbon manganese cobalt and niobium The negative thermoelement KN is typically composed of about 95 to 96 percent nickel 1 to 1 5 percent silicon 1 to 2 3 percent aluminum 1 6 to 3 2 percent manganese up to about 0 5 percent cobalt and smaller amounts of other constituents such as iron copper and lead Also type KN thermoelements with modified compositions are available for use in special applications These include alloys in which the manganese and aluminum contents are reduced or eliminated while the silicon and cobalt contents are increased The low temperature
41. 1000 1500 2000 2500 3000 3500 Thermocouple Temperature F Accuracy C Accuracy F 2 5 2 0 1 5 1 0 0 5 0 0 4 5 4 0 3 5 3 0 2 5 2 0 1 5 1 0 0 5 0 0 Specifications A 19 Figure A 15 Module Accuracy at 25 C 77 F Ambient for Type S Thermocouple Using 10 50 and 60 Hz Filter 10 Hz 50 Hz 60 Hz 200 400 600 800 1000 1200 1400 1600 1800 Thermocouple Temperature C 10 Hz 50 Hz 60 Hz 500 1000 1500 2000 2500 3000 3500 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 A 20 Specifications Figure A 16 Module Accuracy at 25 C 77 F Ambient for Type S Thermocouple Using 250 500 and 1 kHz Filter 140 120 100 E 250 Hz 3 500 Hz gw 1000 Hz 40 20 0 0 200 400 600 800 1000 1200 1400 1600 1800 Thermocouple Temperature C 250 200 be 150 250 Hz 3 500 Hz 3 100 1000Hz 50 0 0 500 1000 1500 2000 2500 3000 3500 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 Accuracy C Accuracy F Specifications A 21 Figure A 17 Module Accuracy at 25 C 77 F Ambient for Type T Thermocouple Using 10 50 and 60 Hz Filter
42. 1157 50 Hess T G Nicrosil nisil high performance thermocouple alloys ISA Transactions 16 3 81 84 1977 51 Anderson R L Lyons J D Kollie T G Christie W H Eby R Decalibration of sheathed thermocouples Temperature Its Measurement and Control in Science and Industry Vol 5 Schooley J F ed New York American Institute of Physics 1982 977 1007 52 Bentley R E Morgan T L Ni based thermocouples in the mineral insulated metal sheathed format thermoelectric instabilities to 1100 C J Phys E Sci Instrum 19 262 268 1986 53 Wang T P Bediones D 10 000 hr stability test of types K N and a Ni Mo Ni Co thermocouple in air and short term tests in reducing atmospheres Temperature Its Measurement and Control in Science and Industry Vol 6 Schooley J F ed New York American Institute of Physics 1992 595 600 Publication 1762 UM002A EN P July 2002 C 22 Thermocouple Descriptions Publication 1762 UM002A EN P July 2002 54 Burley N A N CLAD N A novel advanced type N integrally sheathed thermocouple of ultra high thermoelectric stability High Temperatures High Pressures 8 609 616 1986 55 Burley N A A novel advanced type N integrally sheathed thermocouple of ultra high thermoelectric stability Thermal and Temperature Measurement in Science and Industry 3rd Int IMEKO Conf Sheffield Sept 1987 115 125 56 Burley N A N CLAD N A novel integr
43. 13 212 211 25 21 20 _ 915 _ 163844819244096420484324241 32768 30755 32768 2013 1x2 4 16384 16384 1x2 8192 8192 1x21 4096 4096 1x2 2048 2048 1x21 1024 1024 1x29 512 512 1x28 256 256 1x2 128 128 1x29 64 64 1x25 32 32 1x24 16 16 1x28 8 8 1x2 4 4 1x2 2 2 1x2 1 1 d Ae ae a t3 32767 L_1x215 32768 This position is always 1 for negative numbers Publication 1762 UM002A EN P July 2002 International Temperature Scale of 1990 Type B Thermocouples Appendix C Thermocouple Descriptions The information in this appendix was extracted from the NIST Monograph 175 issued in January 1990 which supersedes the IPTS 68 Monograph 125 issued in March 1974 NIST Monograph 175 is provided by the United States Department of Commerce National Institute of Standards and Technology The ITS 90 1 3 is realized maintained and disseminated by NIST to provide a standard scale of temperature for use in science and industry in the United States This scale was adopted by the International Committee of Weights and Measures CIPM at its meeting in September 1989 and it became the official international temperature scale on January 1 1990 The ITS 90 supersedes the IPTS 68 75 2 and the 1976 Provisional 0 5 K to 30 K Temperature Scale EPT 76 4 The adoption of the ITS 90 removed several
44. 2 Chan Output Analog 4 Chan Input 8 Input 10 30 VDC 16 Input 10 30 VDC 8 Dutput 120 240 VAC 8 Dutput TRANS SAC 10 50 VDC 16 Output TRANS SRC 10 50 VDC 8 Output Relay 16 Output RLY 240 VAC 4 Channel Thermocouple Input Module 4 Channel RTD Resistance Input Module Other Requires 1 0 Card Type ID R This screen allows you to manually enter expansion modules into expansion slots or to automatically read the configuration of the controller To read the existing controller configuration click on the Read IO Config button Publication 1762 UM002A EN P July 2002 E 4 Module Configuration Using MicroLogix 1200 and RSLogix 500 Publication 1762 UM002A EN P July 2002 A communications dialog appears identifying the current communications configuration so that you can verify the target controller If the communication settings are correct click on Read IO Config Read IO Configration from Online Processor x Driver Route Processor Node fas DF1 1 gt flocal fi Decimal 1 Octal Last Configured cx 1 Node 1d local Reply Timeout fio Sec Who Active Cancel Help The actual I O configuration is displayed In this case it matches our manual configuration 1 0 Configuration r Current Cards Available Fiter AEE 8 Input 79 132 VAC Analog 2 Chan Input 2 Chan Output 1 762 1F 4 Analog 4 Chan Input 1762 108 8 Input
45. 3 1185 1194 1963 19 Bentley R E Short term instabilities in thermocouples containing nickel based alloys High Temperatures High Pressures 15 599 611 1983 20 Kollie T G Horton J L Carr K R Herskovitz M B Mossman C A Temperature measurement errors with type K Chromel vs AlumeD thermocouples due to short ranged ordering in Chromel Rev Sci Instrum 46 1447 1461 1975 21 ASTM American Society for Testing and Materials Standard E1159 87 1992 Annual Book of ASTM Standards Vol 14 03 Philadelphia ASTM 1992 388 389 22 Bedford R E Ma C K Barber C R Chandler T R Quinn T J Burns G W Scroger M New reference tables for platinum 10 rhodium platinum and platinum 1396 rhodium platinum thermocouples Temperature Its Measurement and Control in Science and Industry Vol 4 Part 3 p 1585 Plumb H H ed Pittsburgh Instrument Society of America 1972 23 Burns G W Strouse G F Mangum B W Croarkin M C Guthrie W F Chattle M New reference functions for platinum 1396 rhodium versus platinum type R and platinum 30 rhodium versus platinum 696 rhodium type B thermocouples based on the ITS 90 in Thermocouple Descriptions C 19 Temperature Its Measurement and Control in Science and Industry Vol 6 Schooley J F ed New York American Institute of Physics 1992 559 564 24 Glawe G E Szaniszlo A J Long term drift of some noble and
46. 64 F to 1832 F 0 1 C 0 18 F Thermocouple E 270 C to 220 C 454 F to 364 F 1 0 C 1 8 F Thermocouples S and R 0 4 C 0 72 F Thermocouple C 0 2 C 0 36 F Thermocouple B 0 7 C 1 26 F 50 mV 6 uV 100 mV 6 uV 1 Repeatability is the ability of the input module to register the same reading in successive measurements for the same input signal 2 Repeatability at any other temperature in the 0 to 60 C 32 to 140 F range is the same as long as the temperature is stable Publication 1762 UM002A EN P July 2002 A 4 Specifications Accuracy With Autocalibration Enabled Without Autocalibration Accuracy 3 for 10 Hz 50 Hz and 60 Maximum Temperature Drift 4 1 Hz Filters max Input Type at 25 C 77 F at 0 to 60 C at 0 to 60 C 32 to 140 F Ambient 32 to 140 F Ambient Ambient Thermocouple J 210 C to 1200 C 346 F to 2192 F 0 6 C 1 1 F 0 9 C 1 7 F 0 0218 C C 0 0218 F F Thermocouple N 200 C to 1300 C 328 F to 2372 F 1 C 1 8 F x1 5 C 42 7 F 0 0367 C C 40 0367 F F Thermocouple N 210 C to 200 C 346 F to 328 F 1 2 C 2 2 F 1 8 C 4 3 3 F 0 0424 C C 40 0424 F F Thermocouple T 230 C to 400 C 382 F to amp 752 F 1 C 1 8 F x1 5 C 2 7 F 0 0349 C C 0 0349 F
47. 800 1000 1200 1400 1600 1800 2000 Thermocouple Temperature C 400 350 300 250 250 Hz S 200 500 Hz lt 150 1000 Hz 100 50 0 500 1000 1500 2000 2500 3000 3500 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 Accuracy C Accuracy F 1 8 1 6 1 4 1 2 1 0 0 8 0 6 0 4 0 2 0 0 3 5 3 0 2 5 2 0 1 5 1 0 0 5 0 0 Specifications A 7 Figure A 3 Module Accuracy at 25 C 77 F Ambient for Type C Thermocouple Using 10 50 and 60 Hz Filter 10 Hz 50 Hz 60 Hz 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 Thermocouple Temperature C 10 Hz 50 Hz 60 Hz 500 1000 1500 2000 2500 3000 3500 4000 4500 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 A 8 Specifications Figure A 4 Module Accuracy at 25 C 77 F Ambient for Type C Thermocouple Using 250 500 and 1 kHz Filter 100 90 80 70 60 E 250 Hz 50 500 Hz 40 1000 Hz 30 20 Accuracy C 0 400 800 1200 1600 2000 2400 Thermocouple Temperature C 250 Hz 500 Hz 1000 Hz 60 Accuracy F 0 SS SSS E IDEE SES e ET E 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Thermocouple
48. AWG 12 18 and 22 type TP thermoelements during 30 hours of Publication 1762 UM002A EN P July 2002 C 16 Thermocouple Descriptions Publication 1762 UM002A EN P July 2002 heating in air at 500 C At this temperature the type TN thermoelements have good resistance to oxidation and exhibit only small voltage changes heated in air for long periods of time as shown by the studies of Dahl 11 Higher operating temperatures up to at least 800 C are possible in inert atmospheres where the deterioration of the type TP thermoelement is no longer a problem The use of type T thermocouples in hydrogen atmospheres at temperatures above about 370 C is not recommended since type TP thermoelements may become brittle Type T thermocouples are not well suited for use in nuclear environments since both thermoelements are subject to significant changes in composition under thermal neutron irradiation The copper in the thermoelements is converted to nickel and zinc Because of the high thermal conductivity of type TP thermoelements special care should be exercised when using the thermocouples to ensure that the measuring and reference junctions assume the desired temperatures ASTM Standard E230 87 in the 1992 Annual Book of ASTM Standards 7 specifies that the initial calibration tolerances for type T commercial thermocouples be 1 C or 0 75 percent whichever is greater between 0 C and 350 C and 1 C or 1 5 percent whichever is g
49. Allen Bradley MicroLogix 1200 Thermocouple mV Input Module Catalog Number 1762 IT4 User Manual LII ITI I LA I en Rockwell Automation E Por Important User Information Because of the variety of uses for the products described in this publication those responsible for the application and use of these products must satisfy themselves that all necessary steps have been taken to assure that each application and use meets all performance and safety requirements including any applicable laws regulations codes and standards In no event will Allen Bradley be responsible or liable for indirect or consequential damage resulting from the use or application of these products Any illustrations charts sample programs and layout examples shown in this publication are intended solely for purposes of example Since there are many variables and requirements associated with any particular installation Allen Bradley does not assume responsibility or liability to include intellectual property liability for actual use based upon the examples shown in this publication Allen Bradley publication SGI 1 1 Safety Guidelines for tbe Application Installation and Maintenance of Solid State Control available from your local Allen Bradley office describes some important differences between solid state equipment and electromechanical devices that should be taken into consideration when applying products such as those described i
50. Errors Module Error Definition Table Table 4 1 Module Error Table Don t Care Bits 15 14 13 12 11 Open Circuit Detection On each scan the module performs an open circuit test on all enabled channels Whenever an open circuit condition occurs the open circuit bit for that channel is set in input data word 6 Possible causes of an open circuit include the input device is broken a wire is loose or cut the input device is not installed on the configured channel A thermocouple is installed incorrectly Non critical module errors are typically recoverable Channel errors over range or under range errors are non critical Non critical error conditions are indicated in the module input data table Critical module errors are conditions that may prevent normal or recoverable operation of the system When these types of errors occur the system typically leaves the run or program mode of operation until the error can be dealt with Critical module errors are indicated in Table 4 3 Extended Error Codes on page 4 6 Analog module errors are expressed in two fields as four digit Hex format with the most significant digit as don t care and irrelevant The two fields are Module Error and Extended Error Information The structure of the module error data is shown below Module Error Extended Error Information 10 9 8 1 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
51. Hex Digit 4 Hex Digit 3 Hex Digit 2 Hex Digit 1 Publication 1762 UM002A EN P July 2002 Module Error Field The purpose of the module error field is to classify module errors into three distinct groups as described in the table below The type of error determines what kind of information exists in the extended error information field These types of module errors are typically reported Diagnostics and Troubleshooting 4 5 in the controller s I O status file Refer to your controller manual for details Table 4 2 Module Error Types Error Type Module Error Description Field Value Bits 11 through 9 binary No Errors 000 No error is present The extended error field holds no additional information Hardware 001 General and specific hardware error codes are Errors specified in the extended error information field Configuration 010 Module specific error codes are indicated in the Errors extended error field These error codes correspond to options that you can change directly For example the input range or input filter selection Extended Error Information Field Check the extended error information field when a non zero value is present in the module error field Depending upon the value in the module error field the extended error information field can contain error codes that are module specific or common to all 1769 analog modules TIP If no errors are present in the module error field the
52. Module ATTENTION To prevent shock hazard care should be taken when wiring the module to analog signal sources Before wiring any module disconnect power from the system power supply and from any other source to the module After the module is properly installed follow the wiring procedure on page 2 12 using the proper thermocouple extension cable or Belden 8761 for non thermocouple applications Publication 1762 UM002A EN P July 2002 2 12 Installation and Wiring Cut foil shield and drain wire signal wire signal wire drain wire foil shield signal wire signal wire To wire your module follow these steps 1 At each end of the cable strip some casing to expose the individual wires 2 Trim the signal wires to 2 inch 5 cm lengths Strip about 3 16 inch 5 mm of insulation away to expose the end of the wire ATTENTION Be careful when stripping wires Wire fragments that fall into a module could cause damage at power up 3 At one end of the cable twist the drain wire and foil shield together bend them away from the cable and apply shrink wrap Then earth ground at the preferred location based on the type of sensor you are using See Grounding on page 2 8 4 At the other end of the cable cut the drain wire and foil shield back to the cable and apply shrink wrap 5 Connect the signal wires to the terminal block Connect the other end of the cable to the analog input device 6
53. NN LUTE Lr 8r n Se sur LE cede b att t sur S LAU E s Terminal Block Layout d pre Gym pem aea AT Labeling the Terminals ebore PL Gane AG d eEELS Wiring the Finger Safe Terminal Block Wire Size and Terminal Screw Torque Terminal Door labeboessiq44 9elYvv54 99 hoses ES Wiring the IOUS 16 apo X dolci tpe QR RR OE doe eg Wiring DIA BTA c ia dedos TP MOOR A homo ope Cold Junction Compensation eva Ver era x Ex EXU Calibration enn a p e 24 dh ert Hes qot sera po Chapter 3 Module Memory Map z cues eer x LET ERES Accessing Input Image File Data 4o oc Oe ic Input D ta File osa potuero ned De Men end Input Data Values oo dew e deco im vedete ed General Status Bits SO to 4 liliis Open Circuit Flag Bits OCO to OC iussus Over Range Flag Bits O0 to O4 0 Under Range Flag Bits U0 to U4 Configuring Channels ca cux Ho Ex PEO MESS X xu Configuration Data File e ean yim d bes ees t Channel CoDMITSU EA OD segun Foo ed oe dC bos Enabling or Disabling a Channel Bit 15 Selecting Data Formats Bits 14 through 12 Selecting Input Type Bits 11 through 8 Selecting Temperature Units Bit 7 Cui Rad Determining Open Circuit Response Bits 6 and 5 Selecting Input Filter Frequency Bits 2 through 0 Selecting Enable Disable Cyclic Calibration GS Ost ob BID e ope usb emt tree nad d dtd Determining Effective Resolution
54. Range 0 to 55 C 32 F to 131 F Value See Accuracy on page A 4 CJC Accuracy 1 3 C 42 34 F Maximum Overload at Input Terminals 35V dc continuous Input Group to Bus Isolation 720V dc for 1 minute qualification test 30V ac 30V dc working voltage Input Channel Configuration via configuration software screen or the user program by writing a unique bit pattern into the module s configuration file Module OK LED On module has power has passed internal diagnostics and is communicating over the bus Off Any of the above is not true Channel Diagnostics Over or under range and open circuit by bit reporting Vendor D Code 1 Product Type Code 10 Product Code 64 1 Maximum current input is limited due to input impedance Input Type Thermocouple J Repeatability for 10 Hz Filter 0 1 C 0 18 F Thermocouple N 110 C to 1300 C 166 F to 2372 F 0 1 C 0 18 F Thermocouple N 210 C to 110 C 346 F to 166 F 0 25 C 0 45 F Thermocouple T 170 C to 400 C 274 F to 752 F 0 1 C 0 18 F Thermocouple T 270 C to 170 C 454 F to 274 F 1 5 C 2 7 F Thermocouple K 270 C to 1370 C 454 F to 2498 F 0 1 C 0 18 F Thermocouple K 270 C to 170 C 454 F to 274 F 2 0 C 3 6 F Thermocouple E 220 C to 1000 C 3
55. Repeat steps 1 through 5 for each channel on the module TIP See Appendix D Using Thermocouple Junctions for additional information on wiring grounded gt ungrounded and exposed thermocouple types Publication 1762 UM002A EN P July 2002 Installation and Wiring 2 13 Wiring Diagram CJC grounded thermocouple sensor ungrounded thermocouple within 10V dc grounded thermocouple TIP When using an ungrounded thermocouple the shield must be connected to ground at the module E end IMPORTANT When using grounded and or exposed thermocouples that are touching electrically conductive material the ground potential between any two channels cannot exceed 10V de or temperature readings will be inaccurate Cold Junction To obtain accurate readings from each of the channels the temperature between the thermocouple wire and the input channel must be compensated for A cold junction compensating thermistor has been integrated in the terminal block The thermistor must remain installed to retain accuracy Compensation Matinee Do not remove or loosen the cold junction compensating thermistor assembly This assembly is critical to ensure accurate thermocouple input readings at each channel The module will operate in the thermocouple mode but at reduced accuracy if the CJC sensor is removed See Determining Open Circuit Response Bits 6 and 5 on page 3 9 If the thermistor assembly is accidentally removed
56. Standard Part 2 Industrial Environment This product is intended for use in an industrial environment Publication 1762 UM002A EN P July 2002 2 2 Installation and Wiring Power Requirements General Considerations Publication 1762 UM002A EN P July 2002 Low Voltage Directive This product is tested to meet Council Directive 73 23 EEC Low Voltage by applying the safety requirements of EN 61131 2 Programmable Controllers Part 2 Equipment Requirements and Tests For specific information required by EN61131 2 see the appropriate sections in this publication as well as the following Allen Bradley publications e Industrial Automation Wiring and Grounding Guidelines for Noise Immunity publication 1770 4 1 e Automation Systems Catalog publication B113 The module receives power through the bus interface from the 5V dc 24V dc system power supply The maximum current drawn by the module is shown in the table below Module Current Draw at 5V dc at 24V dc 40 mA 50 mA 1762 I O is suitable for use in an industrial environment when installed in accordance with these instructions Specifically this equipment is intended for use in clean dry environments Pollution degree 2 and to circuits not exceeding Over Voltage Category II IEC 60664 1 1 Pollution Degree 2 is an environment where normally only non conductive pollution occurs except that occasionally a temporary conductivity caused b
57. Step Response The selected channel filter frequency determines the channel s step response The step response is the time required for the analog input signal to reach 100 of its expected final value given a full scale step change in the input signal This means that if an input signal changes faster than the channel step response a portion of that signal will be attenuated by the channel filter The channel step response is calculated by a settling time of 3 x 1 filter frequency Filter Frequency Step Response 10 Hz 303 ms 50 Hz 63 ms 60 Hz 53 ms 250 Hz 15 ms 500 Hz 9 ms 1 kHz 7 ms Publication 1762 UM002A EN P July 2002 3 12 Module Data Status and Channel Configuration Publication 1762 UM002A EN P July 2002 Channel Cut Off Frequency The filter cut off frequency 3 dB is the point on the frequency response curve where frequency components of the input signal are passed with 3 dB of attenuation The following table shows cut off frequencies for the supported filters Table 3 3 Filter Frequency versus Channel Cut off Frequency Filter Frequency Cut off Frequency 10 Hz 2 62 Hz 50 Hz 13 1 Hz 60 Hz 15 7 Hz 250 Hz 65 5 Hz 500 Hz 131 Hz 1 kHz 262 Hz All input frequency components at or below the cut off frequency are passed by the digital filter with less than 3 dB of attenuation All frequency components above the cut off frequency are increasingly attenuated as shown in t
58. Temperature F Publication 1762 UM002A EN P July 2002 Specifications A 9 Figure A 5 Module Accuracy at 25 C 77 F Ambient for Type E Thermocouple Using 10 50 and 60 Hz Filter 5 0 4 0 i a 3 0 10 Hz S 50 Hz 2 20 60 Hz 1 0 0 0 400 200 0 200 400 600 800 1000 Thermocouple Temperature C 9 0 8 0 7 0 2 09 10Hz g i 80 Hz m 60 Hz 2 0 1 0 NS 500 0 500 1000 1500 2000 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 A 10 Specifications Figure A 6 Module Accuracy at 25 C 77 F Ambient for Type E Thermocouple Using 250 500 and 1 kHz Filter 70 60 50 P ag 250 Hz a 500 Hz gw 1000 Hz 20 10 0 400 200 0 200 400 600 800 1000 Thermocouple Temperature C u 250 Hz a 500 Hz 1000 Hz 500 0 500 1000 1500 2000 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 Accuracy C Accuracy F Specifications A 11 Figure A 7 Module Accuracy at 25 C 77 F Ambient for Type J Thermocouple Using 10 50 and 60 Hz Filter 0 7 0 6 0 5 10 Hz 0 4 50 Hz 60 Hz 0 3 0 2 0 1 0 400 200 0 200 400 600 800 1000 1200 Thermocouple Temperature C
59. actors as the temperature the time at temperature the diameter of the thermoelements and the conditions of use The ASTM Manual 5 indicates that type K thermocouples should not be used at high temperatures in sulfurous reducing or alternately oxidizing and reducing atmospheres unless suitably protected with protecting tubes They also should not be used in vacuum at high temperatures for extended times because the chromium in the positive thermoelement a nickel chromium alloy vaporizes out of solution and alters the calibration In addition avoid their use in atmospheres that promote green rot corrosion 9 of the positive thermoelement Such corrosion results from the preferential oxidation of chromium in atmospheres with low but not negligible oxygen content and can lead to a large decrease in the thermoelectric voltage of the thermocouple with time The effect is most serious at temperatures between 800 C and 1050 C Both thermoelements of type K thermocouples are reasonably stable thermoelectrically under neutron irradiation since the resulting changes in their chemical compositions due to transmutation are small The KN thermoelements are somewhat less stable than the KP thermoelements in that they experience a small increase in the iron content accompanied by a slight decrease in the manganese and cobalt contents ASTM Standard E230 87 in the 1992 Annual Book of ASTM Standards 7 specifies that the initial calibration t
60. ad wire and the module terminal block the cold junction common mode rejection For analog inputs the maximum level to which a common mode input voltage appears in the numerical value read by the processor expressed in dB common mode rejection ratio CMMR The ratio of a device s differential voltage gain to common mode voltage gain Expressed in dB CMRR is a comparative measure of a device s ability to reject interference caused by a voltage common to its input terminals relative to ground CMRR 20 Log o V1 V2 common mode voltage The voltage difference between the negative terminal and analog common during normal differential operation common mode voltage range The largest voltage difference allowed between either the positive or negative terminal and analog common during normal differential operation configuration word Word containing the channel configuration information needed by the module to configure and operate each channel Publication 1762 UM002A EN P July 2002 Glossary 6 2 Publication 1762 UM002A EN P July 2002 cut off frequency The frequency at which the input signal is attenuated 3 dB by a digital filter Frequency components of the input signal that are below the cut off frequency are passed with under 3 dB of attenuation for low pass filters data word A 16 bit integer that represents the value of the input channel The channel data word is valid only when the channel
61. al compatibility with the thermoelements also has been investigated by Burley 54 56 and by Bentley 57 60 Neither thermoelement of a type N thermocouple is extremely sensitive to minor differences in heat treatment provided that the treatment does not violate any of the restrictions mentioned above For most general applications they may be used with the heat treatment routinely given by the wire manufacturer Bentley 61 62 however has reported reversible changes in the Seebeck coefficient of type NP and NN thermoelements when heated at temperatures between 200 C and 1000 C These impose limitations on the accuracy obtainable with type N thermocouples The magnitude of such changes was found to depend on the source of the thermoelements Consequently when the highest accuracy and stability are sought selective testing of materials as well as special preparatory heat treatments beyond those given by the manufacturer will usually be necessary Bentley s articles 61 62 should be consulted for guidelines and details ASTM Standard E230 87 in the 1992 Annual Book of ASTM Standards 7 specifies that the initial calibration tolerances for type N commercial thermocouples be 2 2 C or 0 75 percent whichever is greater between 0 C and 1250 C Type N thermocouples can also be supplied to meet special tolerances that are equal to approximately Thermocouple Descriptions C 11 Type R Thermocouples one half the standard toler
62. ally sheathed thermocouple optimum design rationale for ultra high thermoelectric stability Temperature Its Measurement and Control in Science and Industry Vol 6 Schooley J F ed New York American Institute of Physics 1992 579 584 57 Bentley R E The new nicrosil sheathed type N MIMS thermocouple an assessment of the first production batch Mater Australas 18 6 16 18 1986 58 Bentley R E Russell Nicrosil sheathed mineral insulated type N thermocouple probes for short term variable immersion applications to 1100 C Sensors and Actuators 16 89 100 1989 59 Bentley R E Irreversible thermoelectric changes in type K and type N thermocouple alloys within nicrosil sheathed MIMS cable J Phys D 22 1908 1915 1989 60 Bentley R E Thermoelectric behavior of Ni based ID MIMS thermocouples using the nicrosil plus sheathing alloy Temperature Its Measurement and Control in Science and Industry Vol 6 Schooley J F ed New York American Institute of Physics 1992 585 590 61 Bentley R E Thermoelectric hysteresis in nicrosil and nisil Phys E Sci Instrum 20 1368 1373 1987 62 Bentley R E Thermoelectric hysteresis in nickel based thermocouple alloys Pbys D 22 1902 1907 1989 Using a Grounded Junction Thermocouple Appendix D Using Thermocouple Junctions This appendix describes the types of thermocouple junctions available and explains the trade offs in using th
63. ances given above Tolerances are not specified for type N thermocouples below 0 C The suggested upper temperature limit of 1260 C given in the ASTM standard 7 for protected type N thermocouples applies to AWG 8 3 25 mm wire It decreases to 1090 C for AWG 14 1 63 mm 980 C for AWG 20 0 81 mm 870 C for AWG 24 or 28 0 51 mm or 0 33 mm and 760 C for AWG 30 0 25 mm These temperature limits apply to thermocouples used in conventional closed end protecting tubes and they are intended only as a rough guide to the user They do not apply to thermocouples having compacted mineral oxide insulation This section describes Platinum 13 percent Rhodium Alloy Versus Platinum thermocouples called type R thermocouples This type is often referred to by the nominal chemical composition of its positive RP thermoelement platinum 13 percent rhodium The negative RN thermoelement is commercially available platinum that has a nominal purity of 99 99 percent 21 An industrial consensus standard ASTM E1159 87 specifies that rhodium having a nominal purity of 99 98 percent shall be alloyed with platinum of 99 99 percent purity to produce the positive thermoelement which typically contains 13 00 0 05 percent rhodium by weight This consensus standard 21 describes the purity of commercial type R materials that are used in many industrial thermometry applications and that meet the calibration tolerances described later in this section It d
64. are number See the label on the processor hardware types in the system including all I O modules fault code if the processor is faulted Publication 1762 UM002A EN P July 2002 4 8 Diagnostics and Troubleshooting Publication 1762 UM002A EN P July 2002 General Specifications Specifications Specification Dimensions Appendix A Value 90 mm height x 87 mm depth x 40 mm width height including mounting tabs is 110 mm 3 54 in height x 3 43 in depth x 1 58 in width height including mounting tabs is 4 33 in Approximate Shipping Weight with carton 220g 0 53 Ibs Storage Temperature 40 C to 85 C 40 F to 185 F Operating Temperature 0 C to 55 C 32 F to 131 F Operating Humidity 5 to 95 non condensing Operating Altitude 2000 meters 6561 feet Vibration Operating 10 to 500 Hz 5G 0 030 in peak to peak Relay Operation 2G Shock Operating 30G 11 ms panel mounted 20G 11 ms DIN rail mounted Relay Operation 7 5G panel mounted 5G DIN rail mounted Non Operating 40G panel mounted 30G DIN rail mounted Recommended Cable Belden 8761 shielded for millivolt inputs Shielded thermocouple extension wire for the specific type of thermocouple you are using Follow thermocouple manufacturer s recommendations Agency Certification e C UL certified under CSA C22 2 No 142 e UL 508 listed e CE compliant for all applicable dir
65. atmospheres with low but not negligible oxygen content is not recommended since it can lead to changes in calibration due to the preferential oxidation of chromium in the positive thermoelement Nevertheless Wang and Starr 49 studied the performances of type N thermocouples in reducing atmospheres as well as in stagnant air at temperatures in the 870 C to 1180 C range and found them to be markedly more stable thermoelectrically than type K thermocouples under similar conditions The performance of type N thermocouples fabricated in metal sheathed compacted ceramic insulated form also has been the subject of considerable study Anderson and others 51 Bentley and Morgan 52 and Wang and Bediones 53 have evaluated the high temperature thermoelectric stability of thermocouples insulated with magnesium oxide and sheathed in Inconel and in stainless steel Their studies showed that the thermoelectric instabilities of such assemblies increase rapidly with temperature above 1000 C It was found also that the smaller the diameter of the sheath the greater the instability Additionally thermocouples sheathed in Inconel showed substantially less instability above 1000 C than those sheathed in stainless steel Bentley and Morgan 52 stressed the importance of using Inconel sheathing with a very low manganese content to achieve the most stable performance The use of special Ni Cr based alloys for sheathing to improve the chemical and physic
66. ats If you select the raw proportional data format for a channel the data word will be a number between 32767 and 32767 For example if a type J thermocouple is selected the lowest temperature of 210 C corresponds to 32767 counts The highest temperature of 1200 C corresponds to 32767 See Determining Effective Resolution and Range on page 3 14 Engineering Units x 1 When using this data format for a thermocouple or millivolt input the module scales the thermocouple or millivolt input data to the actual engineering values for the selected millivolt input or thermocouple type It expresses temperatures in 0 1 C or 0 1 F units For millivolt inputs the module expresses voltages in 0 01 mV units Use the engineering units x 10 setting to produce temperature readings in whole degrees Celsius or b Fahrenheit The resolution of the engineering units x 1 data format is dependent on the range selected and the filter selected See Determining Effective Resolution and Range on page 3 14 Publication 1762 UM002A EN P July 2002 3 8 Module Data Status and Channel Configuration Publication 1762 UM002A EN P July 2002 Engineering Units x 10 When using a thermocouple input with this data format the module scales the input data to the actual temperature values for the selected thermocouple type With this format the module expresses temperatures in 1 C or 1 F units For millivolt inputs the module expresses voltages in
67. bel See dB definition of terms G 1 differential mode rejection See normal mode rejection digital filter definition G 2 E effective resolution at available filter frequencies 3 14 3 33 definition G 2 electrical noise 2 4 EMC Directive 2 1 error codes 4 6 error definitions 4 4 errors configuration 4 5 critical 4 4 extended error information field 4 5 hardware 4 5 module error field 4 4 non critical 4 4 European Union Directives 2 1 extended error codes 4 6 Publication 1762 UM002A EN P July 2002 2 Index extended error information field 4 5 F fault condition at power up 1 4 filter definition G 2 filter frequency definition G 2 effect on effective resolution 3 14 effect on noise rejection 3 10 effect on step response 3 11 selecting 3 10 full scale definition G 2 full scale range definition G 2 G gain drift definition G 2 general status bits 3 2 grounding 2 8 H hardware errors 4 5 heat considerations 2 4 input data formats engineering units x 1 3 7 engineering units x 10 3 8 percent range 3 8 raw proportional data 3 7 scaled for PID 3 8 input data scaling definition G 2 input filter selection 3 10 input image definition G 2 input module channel configuration 3 4 enable channel 3 6 Publication 1762 UM002A EN P July 2002 input module status general status bits 3 2 over range flag bits 3 3 under range flag bits 3 3 input type range selection 3 8 installation grou
68. blication 1762 UM002A EN P July 2002 Effective Resolution C Effective Resolution F 1 4 1 2 1 0 0 8 0 6 0 4 0 2 0 0 2 5 2 0 0 5 0 0 Module Data Status and Channel Configuration 3 29 Figure 3 16 Effective Resolution Versus Input Filter Selection for Type S Thermocouples Using 10 50 and 60 Hz Filters 10 Hz 50 Hz 60 Hz 200 400 600 800 1000 1200 1400 1600 1800 Temperature C 10 Hz 50 Hz 60 Hz 500 1000 1500 2000 2500 3000 3500 Temperature F Publication 1762 UM002A EN P July 2002 3 30 Module Data Status and Channel Configuration Figure 3 17 Effective Resolution Versus Input Filter Selection for Type S Thermocouples Using 250 500 and 1k Hz Filters 250 200 S 3 500Hz LE g 100 1000 Hz 50 0 0 200 400 600 800 1000 1200 1400 1600 1800 Temperature C 400 350 300 250 250 Hz 200 500 Hz 150 1000 Hz ii 100 ce ee rec ENSIS 50 0 _ SSS cp Rp wap 0 500 1000 1500 2000 2500 3000 3500 Temperature F Publication 1762 UM002A EN P July 2002 Effective Resolution C Effective Resolution F 2 5 10Hz 2 0 50 Hz 1 5 60 Hz 1 0 6 0 5 0 4 0 3 0 2 0 0 0 Module Data Status and Channel Configuration
69. blications that contain important information about MicroLogix 1200 systems For Read this document Document number A user manual containing information on how to install MicroLogix M 1200 User Manual 1762 UM001 use and program your MicroLogix 1200 controller An overview of the MicroLogix 1200 System including MicroLogix M 1200 Technical Data 1762 TD001 1762 Expansion 1 0 Information on the MicroLogix 1200 instruction set MicroLogix 1200 and MicroLogix 1500 Programmable 1762 RM001 Controllers Instruction Set Reference Manual In depth information on grounding and wiring Allen Bradley Programmable Controller Grounding and 1770 4 1 Allen Bradley programmable controllers Wiring Guidelines If you would like a manual you can e download a free electronic version from the internet at www theautomationbookstore com purchase a printed manual by contacting your local distributor or Rockwell Automation representative visiting www theautomationbookstore com and placing your order calling 1 800 963 9548 USA Canada or 001 330 725 1574 Outside USA Canada Conventions Used in This The following conventions are used throughout this manual Manual Bulleted lists dike this one provide information not procedural steps e Numbered lists provide sequential steps or hierarchical information Italic type is used for emphasis Publication 1762 UM002A EN P July 2002 Rockwell Automation S
70. date Time on page 3 34 The effective resolution for an input channel depends upon the filter frequency selected for that channel The following graphs provide the effective resolution for each of the range selections at the six available frequencies These graphs do not include the affects of unfiltered input noise Choose the frequency that most closely matches your requirements Effective Resolution C Effective Resolution F Module Data Status and Channel Configuration 3 15 Figure 3 2 Effective Resolution Versus Input Filter Selection for Type B Thermocouples Using 10 50 and 60 Hz Filters 2 5 2 0 1 5 10 Hz 50 Hz 1 0 60 Hz 0 5 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Temperature C 4 5 4 0 3 5 3 0 10Hz 2 5 50 Hz a 60 Hz 1 5 1 0 0 5 0 0 500 1000 1500 2000 2500 3000 3500 Temperature F Publication 1762 UM002A EN P July 2002 3 16 Module Data Status and Channel Configuration Figure 3 3 Effective Resolution Versus Input Filter Selection for Type B Thermocouples Using 250 500 and 1k Hz Filters 350 300 250 250 Hz 200 500 Hz 150 1000 Hz Effective Resolution C 100 50 E 0 IEEE ESI mr IR IM 200 400 600 800 1000 1200 1400 1600 1800 Temperature C 600
71. deficiencies and limitations associated with IPTS 68 Temperatures on the ITS 90 are in closer agreement with thermodynamic values than were those of the IPTS 68 and EPT 76 Additionally improvements have been made in the non uniqueness and reproducibility of the temperature scale especially in the temperature range from t68 630 74 C to 1064 43 C where the type S thermocouple was the standard interpolating device on the IPTS 68 For additional technical information regarding ITS 90 refer to the NIST Monograph 175 This section discusses Platinum 30 percent Rhodium Alloy Versus Platinum 6 percent Rhodium Alloy thermocouples commonly called type B thermocouples This type is sometimes referred to by the nominal chemical composition of its thermoelements platinum 30 percent rhodium versus platinum 6 percent rhodium or 30 6 The positive BP thermoelement typically contains 29 60 0 2 percent rhodium and the negative BN thermoelement usually contains 6 12 0 02 percent rhodium The effect of differences in rhodium content are described later in this section An industrial consensus standard 21 CASTM E1159 87 specifies that rhodium having a purity of 99 98 percent shall be alloyed with platinum of 99 99 percent purity to produce the thermoelements This consensus standard 21 describes Publication 1762 UM002A EN P July 2002 C 2 Thermocouple Descriptions Publication 1762 UM002A EN P July 2002 the purity of commerc
72. e source of problems that may occur during power up or during normal channel operation The LED indicates both status and power Power up and channel diagnostics are explained in Chapter 4 Diagnostics and Troublesbooting The modules communicate to the controller through the bus interface The modules also receive 5 and 24V dc power through the bus interface System Operation At power up the module performs a check of its internal circuits memory and basic functions During this time the module status LED remains off If no faults are found during power up diagnostics the module status LED is turned on After power up checks are complete the module waits for valid channel configuration data If an invalid configuration is detected the module generates a configuration error Once a channel is properly configured and enabled it continuously converts the thermocouple or millivolt input to a value within the range selected for that channel Each time a channel is read by the input module that data value is tested by the module for an over range under range open circuit or input data not valid condition If such a condition is detected a unique bit is set in the channel status word The channel status word is described in Input Data File on page 3 2 Using the module image table the controller reads the two s complement binary converted thermocouple or millivolt data from the module This typically occurs at the end of the
73. e A D converter can provide valid properly configured data to the MicroLogix 1200 controller The following information highlights the bit operation of the Data Not Valid condition 1 The default and module power up bit condition is reset 0 2 The bit condition is set 1 when a new configuration is received and determined valid by the module The set 1 bit condition Module Data Status and Channel Configuration 3 3 remains until the module begins converting analog data for the previously accepted new configuration When conversion begins the bit condition is reset 0 The amount of time it takes for the module to begin the conversion process depends on the number of channels being configured and the amount of configuration data downloaded by the controller TIP If the new configuration is invalid the bit function remains reset 0 and the module posts a configuration error See Configuration m Errors on page 4 5 3 If A D hardware errors prevent the conversion process from taking place the bit condition is set 1 Open Circuit Flag Bits OCO to OC4 Bits OCO through OC3 of word 4 contain open circuit error information for channels 0 through 3 respectively Errors for the CJC sensor are indicated in OC4 The bit is set 1 when an open circuit condition exists See Open Circuit Detection on page 4 4 for more information on open circuit operation Over Range Flag Bits 00 to 04 Over range bits for channels 0 t
74. ectives e C Tick marked for all applicable acts Hazardous Environment Class Class I Division 2 Hazardous Location Groups A B C D UL 1604 C UL under CSA C22 2 No 213 Radiated and Conducted Emissions EN50081 2 Class A Publication 1762 UM002A EN P July 2002 A 2 Specifications Input Specifications Publication 1762 UM002A EN P July 2002 Specification Electrical EMC Value The module has passed testing at the following levels e ESD Immunity EN61000 4 2 e 4 kV contact 8 kV air 4 kV indirect e Radiated Immunity EN61000 4 3 e 10 V m 80 to 1000 MHz 80 amplitude modulation 900 MHz keyed carrier e Fast Transient Burst EN61000 4 4 e 2 kV dkHz e Surge Immunity EN61000 4 5 e 1kV galvanic gun e Conducted Immunity EN61000 4 6 e 10V 0 15 to 80MHz 2 1 Conducted Immunity frequency range may be 150 kHz to 30 MHz if the Radiated Immunity frequency range is 30 to 1000 MHz 2 For grounded thermocouples the 10V level is reduced to 3V Specification Number of Inputs Value 4 input channels plus 1 CJC sensor Resolution 15 bits plus sign Bus Current Draw max 40 mA at 5V dc 50 mA at 24V dc Heat Dissipation 1 5 Total Watts The Watts per point plus the minimum Watts with all points energized Converter Type Delta Sigma Response Speed per Channel Input filter and configuration dependen
75. ed channel 1 X403 010 000000011 Invalid input type selected channel 2 X404 010 000000100 Invalid input type selected channel 3 X405 010 0 0000 0101 Invalid filter selected channel 0 X406 010 000000110 Invalid filter selected channel 1 X407 010 0 0000 0111 Invalid filter selected channel 2 X408 010 000001000 Invalid filter selected channel 3 X409 010 0 0000 1001 Invalid format selected channel 0 X40A 010 000001010 Invalid format selected channel 1 X40B 010 0 0000 1011 Invalid format selected channel 2 X40C 010 000001100 Invalid format selected channel 3 X40D 010 000001101 An unused bit has been set for channel 0 X40E 010 000001110 An unused bit has been set for channel 1 X40F 010 000001111 An unused bit has been set for channel 2 X410 010 0 0001 0000 An unused bit has been set for channel 3 X411 010 0 0001 0001 Invalid module configuration register 1 Xrepresents the Don t Care digit Publication 1762 UM002A EN P July 2002 Diagnostics and Troubleshooting 4 7 Contacting Rockwell If you need to contact Rockwell Automation for assistance please Automation have the following information available when you call a clear statement of the problem including a description of what the system is actually doing Note the LED state also note data and configuration words for the module list of remedies you have already tried processor type and firmw
76. ell as the condition of your equipment is of primary importance The following sections describe several safety concerns you should be aware of when troubleshooting your control system ATTENTION Never reach into a machine to actuate a switch because unexpected motion can occur and cause injury Remove all electrical power at the main power disconnect switches before checking electrical connections or inputs outputs causing machine motion Indicator Lights When the green LED on the module is illuminated it indicates that power is applied to the module and that it has passed its internal tests Publication 1762 UM002A EN P July 2002 4 2 Diagnostics and Troubleshooting Module Operation vs Channel Operation Publication 1762 UM002A EN P July 2002 Stand Clear of Equipment When troubleshooting any system problem have all personnel remain clear of the equipment The problem could be intermittent and sudden unexpected machine motion could occur Have someone ready to operate an emergency stop switch in case it becomes necessary to shut off power Program Alteration There are several possible causes of alteration to the user program including extreme environmental conditions Electromagnetic Interference EMD improper grounding improper wiring connections and unauthorized tampering If you suspect a program has been altered check it against a previously saved master program Safety Circuits Circuits
77. em with the 1762 IT4 thermocouple mV analog input module ATTENTION Take care when choosing a thermocouple junction and connecting it from the environment to the module If you do not take adequate precautions for a given thermocouple type the electrical isolation of the module might be compromised Available thermocouple junctions are grounded ungrounded isolated exposed With a grounded junction thermocouple the measuring junction is physically connected to the protective sheath forming a completely sealed integral junction If the sheath is metal or electrically conductive there is electrical continuity between the junction and sheath The junction is protected from corrosive or erosive conditions The response time approaches that of the exposed junction type described in Using an Exposed Junction Thermocouple on page D 3 Measuring Junction Metal Sheath Connected to Sheath IN Extension Wire N Publication 1762 UM002A EN P July 2002 D 2 Using Thermocouple Junctions Using an Ungrounded Isolated Junction Thermocouple Publication 1762 UM002A EN P July 2002 The shield input terminals for a grounded junction thermocouple are connected together and then connected to chassis ground Use of this thermocouple with an electrically conductive sheath removes the thermocouple signal to chassis ground isolation of the module In addition if multiple grounded junction therm
78. ements although they are all referred to as constantan In order to provide some differentiation in nomenclature type JN is often referred to as SAMA constantan Type J thermocouples are recommended by the ASTM 5 for use in the temperature range from 0 C to 760 C in vacuum oxidizing reducing or inert atmospheres If used for extended times in air above 500 C heavy gauge wires are recommended because the oxidation rate is rapid at elevated temperatures Oxidation normally causes a gradual decrease in the thermoelectric voltage of the thermocouple with time Because iron rusts in moist atmospheres and may become brittle type J thermocouples are not recommended for use below 0 C In addition they should not be used unprotected in sulfurous atmospheres above 500 C The positive thermoelement iron is relatively insensitive to composition changes under thermal neutron irradiation but does exhibit a slight increase in manganese content The negative thermoelement a copper nickel alloy is subject to substantial composition changes under thermal neutron irradiation since copper is converted to nickel and zinc Iron undergoes a magnetic transformation near 769 C and an alpha gamma crystal transformation near 910 C 6 Both of these transformations especially the latter seriously affect the thermoelectric properties of iron and therefore of type J thermocouples This behavior and the rapid oxidation rate of iron are the main reas
79. en temperatures n b p about 20 3K where their Seebeck coefficient is about 8mV C They may even be used down to liquid helium temperatures 4 2 K although their Seebeck coefficient becomes quite low only about 2mV C at 4K Both thermoelements of type E thermocouples have a relatively low thermal conductivity good resistance to corrosion in moist atmospheres and reasonably good homogeneity For these three reasons and their relatively high Seebeck coefficients type E thermocouples have been recommended 8 as the most useful of the letter designated thermocouple types for low temperature measurements For measurements below 20K the non letter designated thermocouple KP versus gold 0 07 is recommended The properties of this thermocouple have been described by Sparks and Powell 12 Type E thermocouples also have the largest Seebeck coefficient above 0 C for any of the letter designated thermocouples For that reason they are being used more often whenever environmental conditions permit Publication 1762 UM002A EN P July 2002 C 4 Thermocouple Descriptions Publication 1762 UM002A EN P July 2002 Type E thermocouples are recommended by the ASTM 5 for use in the temperature range from 200 C to 900 C in oxidizing or inert atmospheres If used for extended times in air above 500 C heavy gauge wires are recommended because the oxidation rate is rapid at elevated temperatures About 50 years ago Dahl 11 studied the
80. ency that you choose for a module channel determines the amount of noise rejection for the inputs A lower frequency 50 Hz versus 500 Hz provides better noise rejection and increases effective resolution but also increases channel update time A higher filter frequency provides lower noise rejection but decreases the channel update time and effective resolution When selecting a filter frequency be sure to consider cut off frequency and channel step response to obtain acceptable noise rejection Choose a filter frequency so that your fastest changing signal is below that of the filter s cut off frequency Module Data Status and Channel Configuration 3 11 Common Mode Rejection is better than 115 dB at 50 and 60 Hz with the 50 and 60 Hz filters selected respectively or with the 10Hz filter selected The module performs well in the presence of common mode noise as long as the signals applied to the user positive and negative input terminals do not exceed the common mode voltage rating 10V of the module Improper earth ground may be a source of common mode noise Transducer power supply noise transducer circuit noise or process variable irregularities may also be sources of normal mode noise The filter frequency of the module s CJC sensors is the lowest filter frequency of any enabled thermocouple type to maximize the trade offs between effective resolution and channel update time Effects of Filter Frequency on Channel
81. er designated thermocouples It offers higher thermoelectric stability in air above 1000 C and better air oxidation resistance than types E J and K thermocouples The positive thermoelement NP is an alloy that typically contains about 84 percent nickel 14 to 14 4 percent chromium 1 3 to 1 6 percent silicon plus small amounts usually not exceeding about 0 1 percent of other elements such as magnesium iron carbon and cobalt The negative thermoelement NN is an alloy that typically contains about 95 percent nickel 4 2 to 4 6 percent silicon 0 5 to 1 5 percent magnesium plus minor impurities of iron cobalt manganese and carbon totaling about 0 1 to 0 3 percent The type NP and NN alloys were known originally 16 as nicrosil and nisil respectively The research reported in NBS Monograph 161 showed that the type N thermocouple may be used down to liquid helium temperatures about 4K but that its Seebeck coefficient becomes very small below 20K Its Seebeck coefficient at 20K is about 2 5uV K roughly one third that of type E thermocouples which are the most suitable of the letter designated thermocouples types for measurements down to 20K Nevertheless types NP and NN thermoelements do have a relatively low thermal conductivity and good resistance to corrosion in moist atmospheres at low temperatures Type N thermocouples are best suited for use in oxidizing or inert atmospheres Their suggested upper temperature limit when used in
82. extended error information field is set pe to Zero Hardware Errors General or module specific hardware errors are indicated by module error code 001 See Table 4 3 Extended Error Codes on page 4 6 Configuration Errors If you set the fields in the configuration file to invalid or unsupported values the module generates a critical error Table 4 3 Extended Error Codes on page 4 6 lists the possible module specific configuration error codes defined for the modules Publication 1762 UM002A EN P July 2002 4 6 Diagnostics and Troubleshooting Error Codes Table 4 3 Extended Error Codes The table below explains the extended error code Error Type Hex Module ExtendedError Error Description Equivalent Error Information Code Code Binary Binary No Error X000 000 000000000 No Error General Common X200 001 000000000 General hardware error no additional information parare Enar X201 001 0 0000 0001 Power up reset state Hardware Specific X300 001 100000000 General hardware error no additional information Error X301 001 1 0000 0001 Microprocessor hardware error X302 001 100000010 A D Converter error X303 001 100000011 Calibration error Module Specific X400 010 000000000 General configuration error no additional information ees X401 010 000000001 Invalid input type selected channel 0 X402 010 000000010 Invalid input type select
83. for thermocouples degrees Celsius C and degrees Fahrenheit F Bit 7 is ignored for millivolt input types or when raw proportional scaled for PID or percent data formats are used IMPORTANT If you are using engineering units x 1 data format and degrees Fahrenheit temperature units thermocouple types B and C cannot achieve full scale temperature with 16 bit signed numerical representation An over range error will occur for the configured channel if it tries to represent the full scale value The maximum representable temperature is 3276 7 F Determining Open Circuit Response Bits 6 and 5 An open circuit condition occurs when an input device or its extension wire is physically separated or open This can happen if the wire is cut or disconnected from the terminal block TIP If the CJC sensor is removed from the module terminal block its open circuit bit is set 1 and the module continues to calculate thermocouple m readings at reduced accuracy If an open CJC circuit is detected at power up the module uses 25 C as the sensed temperature at that location If an open CJC circuit is detected during normal operation the last valid CJC reading is used An input channel configured for millivolt input is not affected by CJC open circuit conditions See Open Circuit Detection on page 4 4 for additional details Bits 6 and 5 define the state of the channel data word when an open circuit condition is detected for the correspond
84. g software compatible with the controller for example RSLogix 500 Once configuration is complete and reflected in the ladder logic you need to operate the module and verify its configuration This chapter contains information on the following module memory map accessing input image file data configuring channels determining effective resolution and range determining module update time The module uses six input words for data and status bits input image and five configuration words Memory Map Channel 0 Data Word Channel 1 Data Word Input Image Channel 2 Data Word B words Channel 3 Data Word General Open Circuit Status Bits Over Under range Bits p RE EE LL ccEERS Bit 15 Bit 0 Word 0 Word 1 Word 2 Word 3 Word 4 bits 0 to 4 and 8 to 12 Word 5 bits 6 to 15 The input image file represents data words and status words Input words 0 through 3 hold the input data that represents the value of the analog inputs for channels 0 through 3 These data words are valid only when the channel is enabled and there are no errors Input words 4 and 5 hold the status bits To receive valid status information the channel must be enabled You can access the information in the input image file using the programming software data files input screen Publication 1762 UM002A EN P July 2002 3 2 Module Data Status and Channel Configuration
85. hannel Thermocouple Input Module x Expansion General Configuration Chan 0 2 Chan 3 Cal Generic Extra Data Config r Word Channel 0 Data Format Input Type Filter Hz T Chan Enabled Raw Proportional zl Type J z feo Hz z Open Circuit Units Upscale Y r Word Channel 1 Data Format Input Type Filter Hz Chan Enabled Raw Proportional z Type J X 60Hz v Open Circuit Units Upscale z ET r Word Channel 2 fs Data Format Input Type Filter Hz Chan Enabled Raw Propartional zl Type J v 60Hz v Open Circuit Units Upscale z ac X w P Word Channel 3 Chan Enabled Module 1 1762 IT4 4 Channel Thermocouple Input Module 3 x Expansion General Configuration Chan 0 2 Chan 3 Cal Generic Extra Data Config Data Format Input Type Filter Hz Raw Proportional z ype J z co Haly Open Circuit Units Upscale z E Cancel Apply Help For a complete description of each of these parameters and the choices available for each of them see Configuration Data File on page 3 4 Publication 1762 UM002A EN P July 2002 E 6 Module Configuration Using MicroLogix 1200 and RSLogix 500 The Cal tab contains a check box for disabling cyclic calibration See Selecting Enable Disable Cyclic Calibration Word 4 Bit 0 on page 3 14 for more information Module 1 1762 IT4 4 Channel Thermocouple Input Modt Expansion General C
86. he graphs on page 3 13 Module Data Status and Channel Configuration 3 13 Figure 3 1 Frequency Response Graphs 10 Hz Input Filter Frequency 50 Hz Input Filter Frequency 0 E 0 20 h 40 40 60 80 Ss B 0 10 amp 100 co 120 120 140 449 160 460 180 190 200 L fi fi fi L 200 i L n fi fi L L 0 10 20 30 40 50 60 0 50 100 150 200 250 300 Y Y 2 62 Hz Freq uency Hz 13 1 Hz Frequency Hz 60 Hz Input Filter Frequency 250 Hz Input Filter Frequency 0 L 3 dB 0 3dB 20 20 3 40 ET amp n 80 8 H 038 S am S o w 12 a2 H co 8 i 140 E 160 460 180 E 200 sd 0 60 120 180 240 300 360 0 250 500 750 900 1150 1300 Y 15 72 Hz Frequency Hz 65 5 Hz Frequency Hz 500 Hz Input Filter Frequency 1000 Hz Input Filter Frequency 0 3 dB 0 20 3 40 40 o 60 8 NE Ss 100 5 100 c E ed S am wod2 Mw C a 160 160 180 180 200 200 meai aaaea aaaeeeaa aai aa 0 500 1000 1500 2000 2500 3000 0 1K m 3K m 5K ek Y Y 131Hz 262 Hz Frequency Hz Frequency Hz Publication 1762 UM002A EN P July 2002 3 14 Module Data Status and Channel Configuration
87. he scan diagram on the previous page The cyclic calibration time only applies when cyclic calibration is enabled and active If enabled the cyclic calibration is staggered over several scan cycles once every five minutes to limit the overall impact to module update time Effects of Autocalibration on Module Update Time The module s autocalibration feature allows it to correct for accuracy errors caused by temperature drift over the module operating temperature range 0 to 55 C Autocalibration occurs automatically on a system mode change from Program to Run for all configured channels or if any online configuration change is made to a channel In addition you can configure the module to perform autocalibration every 5 minutes during normal operation or you can disable this feature using the Enable Disable Cyclic Calibration function default is enabled This feature allows you to implement a calibration cycle anytime at your command by enabling and then disabling this bit If you enable the cyclic autocalibration function the module update time increases when the autocalibration occurs To limit its impact on the module update time the autocalibration function is divided over multiple module scans The first enabled channel receives an A D converter ADC self calibration and a channel offset calibration over the course of two module scans The time added to the module update time depends on the filter selected for the channel as show
88. hrough 3 and the CJC sensor are contained in word 5 even numbered bits They apply to all input types When set D the over range flag bit indicates an input signal that is at the maximum of its normal operating range for the represented channel or sensor The module automatically resets 0 the bit when the data value falls below the maximum for that range Under Range Flag Bits U0 to U4 Under range bits for channels 0 through 3 and the CJC sensor are contained in word 5 odd numbered bits They apply to all input types When set 1 the under range flag bit indicates an input signal that is at the minimum of its normal operating range for the represented channel or sensor The module automatically resets 0 the bit when the under range condition is cleared and the data value is within the normal operating range Publication 1762 UM002A EN P July 2002 3 4 Module Data Status and Channel Configuration Configuring Channels After module installation you must configure operation details such as thermocouple type temperature units etc for each channel Channel configuration data for the module is stored in the controller configuration file which is both readable and writable The configuration data file is shown below Bit definitions are provided in Channel Configuration on page 3 4 Detailed definitions of each of the configuration parameters follow the table Configuration Data File The default value of the config
89. ial type B materials that are used in many industrial thermometry applications that meet the calibration tolerances described later in this section Both thermoelements will typically have significant impurities of elements such as palladium iridium iron and silicon 38 Studies by Ehringer 39 Walker et al 25 26 and Glawe and Szaniszlo 24 have demonstrated that thermocouples in which both legs are platinum rhodium alloys are suitable for reliable temperature measurements at high temperatures Such thermocouples have been shown to offer the following distinct advantages over types R and S thermocouples at high temperatures 1 improved stability 2 increased mechanical strength and 3 higher operating temperatures The research by Burns and Gallagher 38 indicated that the 30 6 thermocouple can be used intermittently for several hours up to 1790 C and continuously for several hundred hours at temperatures up to about 1700 C with only small changes in calibration The maximum temperature limit for the thermocouple is governed primarily by the melting point of the Pt 6 percent rhodium thermoelement which is estimated to be about 1820 C by Acken 40 The thermocouple is most reliable when used in a clean oxidizing atmosphere air but also has been used successfully in neutral atmospheres or vacuum by Walker et al 25 26 Hendricks and McElroy 41 and Glawe and Szaniszlo 24 The stability of the thermocouple at high te
90. ing channel The module overrides the actual input data depending on the option that you specify when it detects an open circuit The open circuit options are explained in the table on page 3 10 Publication 1762 UM002A EN P July 2002 3 10 Module Data Status and Channel Configuration Publication 1762 UM002A EN P July 2002 Table 3 2 Open Circuit Response Definitions Response Definition Option Upscale Sets the input data value to full upper scale value of channel data word The full scale value is determined by the selected input type and data format Downscale Sets the input data value to full lower scale value of channel data word The low scale value is determined by the selected input type and data format Last State Sets the input data value to the last input value prior to the detection of the open circuit Zero Sets the input data value to 0 to force the channel data word to 0 Selecting Input Filter Frequency Bits 2 through 0 The input filter selection field allows you to select the filter frequency for each channel and provides system status of the input filter setting for channels 0 through 3 The filter frequency affects the following as explained later in this chapter noise rejection characteristics for module inputs channel step response channel cut off frequency effective resolution module update time Effects of Filter Frequency on Noise Rejection The filter frequ
91. installed on the machine for safety reasons like over travel limit switches stop push buttons and interlocks should always be hard wired to the master control relay These devices must be wired in series so that when any one device opens the master control relay is de energized thereby removing power to the machine Never alter these circuits to defeat their function Serious injury or machine damage could result The module performs diagnostic operations at both the module level and the channel level Module level operations include functions such as power up configuration and communication with a MicroLogix 1200 controller Channel level operations describe channel related functions such as data conversion and over or under range detection Internal diagnostics are performed at both levels of operation When detected module error conditions are immediately indicated by the module status LED Both module hardware and channel configuration error conditions are reported to the controller Channel over range or under range and open circuit conditions are reported in the module s input data table Module hardware errors are typically reported in the controller s I O status file Refer to your controller manual for details Diagnostics and Troubleshooting 4 3 Power up Diagnostics Channel Diagnostics At module power up a series of internal diagnostic tests are performed If these diagnostic tests are not successfully completed
92. ion Chan 0 2 Chan 3 Cal Offset Decimal Radix Cancel Apply Help Generic Extra Data Contig x Publication 1762 UM002A EN P July 2002 E 8 Module Configuration Using MicroLogix 1200 and RSLogix 500 Publication 1762 UM002A EN P July 2002 Glossary The following terms and abbreviations are used throughout this manual For definitions of terms not listed here refer to Allen Bradley s Industrial Automation Glossary Publication AG 7 1 A D Converter Refers to the analog to digital converter inherent to the module The converter produces a digital value whose magnitude is proportional to the magnitude of an analog input signal attenuation The reduction in the magnitude of a signal as it passes through a system bus connector A 16 pin male and female connector that provides electrical interconnection between the modules channel Refers to input interfaces available on the module s terminal block Each channel is configured for connection to a thermocouple or millivolt input device and has its own data and diagnostic status words channel update time The time required for the module to sample and convert the input signals of one enabled input channel and update the channel data word CJC Cold junction compensation CJC is the means by which the module compensates for the offset voltage error introduced by the temperature at the junction between a thermocouple le
93. ion Using RSLogix 500 Version 5 2 or Lower Glossary Index Who Should Use This Manual How to Use This Manual Preface Read this preface to familiarize yourself with the rest of the manual This preface covers the following topics e who should use this manual how to use this manual related publications e conventions used in this manual Rockwell Automation support Use this manual if you are responsible for designing installing programming or troubleshooting control systems that use Allen Bradley MicroLogix 1200 As much as possible we organized this manual to explain in a task by task manner how to install configure program operate and troubleshoot a control system using the 1762 IT4 Manual Contents If you want See An overview of the thermocouple mV input module Chapter 1 Installation and wiring guidelines Chapter 2 Module addressing configuration and status information Chapter 3 Information on module diagnostics and troubleshooting Chapter 4 Specifications for the input module Appendix A Information on understanding two s complement binary numbers Appendix B Thermocouple descriptions Appendix C Information on using the different types of thermocouple junctions Appendix D An example of configuration using RSLogix 500 Appendix E Publication 1762 UM002A EN P July 2002 Preface 2 Related Documentation The table below provides a listing of pu
94. its Seebeck coefficient becomes quite small below 20K Its Seebeck coefficient at 20K is only about 5 6uUV K being roughly two thirds that of the type E thermocouple The thermoelectric homogeneity of most type TP and type TN Cor EN thermoelements is reasonably good There is considerable variability however in the thermoelectric properties of type TP thermoelements below about 70K caused by variations in the amounts and types of impurities present in these nearly pure materials The high thermal conductivity of the type TP thermoelements can also be troublesome in precise applications For these reasons type T thermocouples are generally unsuitable for use below about 20K Type E thermocouples are recommended as the most suitable of the letter designated thermocouple types for general low temperature use since they offer the best overall combination of desirable properties Type T thermocouples are recommended by the ASTM 5 for use in the temperature range from 200 C to 370 C in vacuum or in oxidizing reducing or inert atmospheres The suggested upper temperature limit for continuous service of protected type T thermocouples is set at 370 C for AWG 14 1 63 mm thermoelements since type TP thermoelements oxidize rapidly above this temperature However the thermoelectric properties of type TP thermoelements are apparently not grossly affected by oxidation since negligible changes in the thermoelectric voltage were observed at NBS 10 for
95. le is free of all metal fragments When wiring the terminal block keep the finger safe cover in place 1 Route the wire under the terminal pressure plate You can use the stripped end of the wire or a spade lug The terminals will accept a 6 35 mm 0 25 in spade lug 2 Tighten the terminal screw making sure the pressure plate secures the wire Recommended torque when tightening terminal screws is 0 904 Nm 8 in lbs 3 After wiring is complete remove the debris shield TIP If you need to remove the finger safe cover insert a screw driver into one of the square wiring holes and gently pry the cover off If gt you wire the terminal block with the finger safe cover removed you will not be able to put it back on the terminal block because the wires will be in the way Publication 1762 UM002A EN P July 2002 Installation and Wiring 2 11 Wire Size and Terminal Screw Torque Each terminal accepts up to two wires with the following restrictions Wire Type Wire Size Terminal Screw Torque Solid Cu 90 C 194 F 14 to 22 AWG 0 904 Nm 8 in Ibs Stranded Cu 90 C 194 F 16 to 22 AWG 0 904 Nm 8 in Ibs Terminal Door Label A removable write on label is provided with the module Remove the label from the door mark your unique identification of each terminal with permanent ink and slide the label back into the door Your markings ID tag will be visible when the module door is closed Wiring the
96. mperatures has been shown by Walker et al 25 26 to depend primarily on the quality of the materials used for protecting and insulating the thermocouple High purity alumina with low iron content appears to be the most suitable material for the purpose Type B thermocouples should not be used in reducing atmospheres nor those containing deleterious vapors or other contaminants that are reactive with the platinum group metals 42 unless suitably protected with nonmetallic protecting tubes They should never be used in metallic protecting tubes at high temperatures The Seebeck coefficient of type B thermocouples decreases with decreasing temperature below about 1600 C and becomes almost negligible at room temperature Consequently in most applications the reference junction temperature of the thermocouple does not need to be controlled or even known as long as it between 0 C and 50 C For example the voltage developed by the thermocouple with the reference junction at 0 C undergoes a reversal in sign at about 42 C and between 0 C and 50 C varies from a minimum of 2 6uV near 21 C to a maximum of 2 3uV at 50 C Therefore in use if the reference junction of the thermocouple is within the range 0 C to 50 C then a 0 C reference junction temperature can be assumed and the error introduced will not exceed 3uV At temperatures above Thermocouple Descriptions C 3 Type E Thermocouples 1100 C an additional measurement err
97. n in Table 3 6 on page 3 35 Each additional enabled channel receives 1 During an online configuration change input data for the affected channel is not updated by the module Module Data Status and Channel Configuration 3 35 separate ADC self calibration and offset calibration cycles only if their filter configurations are different than those of previously calibrated channels Following all input channel calibration cycles the CJC sensor channel receives a separate ADC self calibration cycle The time added to this cycle is determined by the filter setting for the CJC which is set to the lowest filter setting of any input configured as a thermocouple If no enabled input channel is configured for a thermocouple no CJC calibration cycle occurs See Table 3 6 below for channel and CJC sensor ADC self calibration times as well as channel offset calibration times Table 3 6 Calibration Time Type of Calibration 10Hz 50Hz 60Hz 250Hz 500Hz 1kHz ADC self calibration 603 123 103 27 15 9 Channels 0 through 3 Offset calibration 303 63 53 15 9 6 Channels 0 through 3 ADC self calibration 603 123 103 27 15 9 CJC sensor Calculating Module Update Time To determine the module update time add the individual channel update times for each enabled channel and the CJC update time if any of the channels are enabled as thermocouple inputs EXAMPLE f Two Channels Enabled for Millivolt Inputs Chan
98. n this publication Reproduction of the contents of this copyrighted publication in whole or part without written permission of Rockwell Automation is prohibited Throughout this publication notes may be used to make you aware of safety considerations The following annotations and their accompanying statements help you to identify a potential hazard avoid a potential hazard and recognize the consequences of a potential hazard Identifies information about practices or circumstances that can cause an explosion in a hazardous environment which may lead to personal injury or death property damage or economic loss ATTENTION Identifies information about practices or circumstances that can lead to personal injury or death property damage or economic loss IMPORTANT Identifies information that is critical for successful application and understanding of the product Overview Installation and Wiring Table of Contents Preface Who Should Use This Manual llle P 1 How to Use This Manual 22 aet S reU eres P 1 Manual Contents 232 s soo ere oer doi eee e P 1 Related Docimentatloti ss qa ge mx be Fe Eee YES P 2 Conventions Used in This Manual P 2 Rockwell Automation Support o oo d ues date et P 3 Local Product SUODOB u a que a a p Er d e de D Sd P 3 Technical Product Assistance sorge yere p P 3 Your Questions or Comments on the Manual P 3 Chapter 1 General De
99. nding 2 8 heat and noise considerations 2 4 International Temperature Scale 1990 C 1 ITS 90 C 1 L LED 4 1 linearity error definition G 2 LSB definition G 3 millivolt inputs range 1 2 module error field 4 4 module scan time definition G 3 module status data not valid 3 2 module update time 3 33 definition G 3 multiplexer definition G 3 negative decimal values B 2 noise rejection 3 10 normal mode rejection definition G 3 number of significant bits definition G 3 0 open circuit detection 4 4 error bits 3 3 operation system 1 4 out of range detection 4 3 overall accuracy definition G 3 over range flag bits 3 3 P positive decimal values B 1 power up diagnostics 4 3 power up sequence 1 4 program alteration 4 2 R resolution definition G 3 S safety circuits 4 2 sampling time definition G 4 scan time G 3 specifications A 1 status word definition G 4 step response effects of filter frequency 3 11 step response time definition G 4 system operation 1 4 T terminal door label 2 11 thermocouple accuracy A 4 definition G 4 descriptions C 1 exposed junction D 3 grounded junction D 1 junction types D 1 repeatability A 3 ungrounded junction D 2 using junctions D 1 troubleshooting safety considerations 4 1 Index 3 two s complement binary numbers B 1 type B accuracy A 5 A 6 description C 1 effective resolution 3 15 3 16 temperature range 1 1 type C accuracy A 7 A 8 effective
100. nel 0 Input 50 mV with 60 Hz filter Channel 1 Input 50 mV with 500 Hz filter From Table 3 5 Channel Update Time on page 3 34 Module Update Time Ch 0 Update Time Ch 1 Update Time 53 ms 9 ms 62 ms Publication 1762 UM002A EN P July 2002 3 36 Module Data Status and Channel Configuration EXAMPLE 2 Three Channels Enabled for Different Inputs Publication 1762 UM002A EN P July 2002 Channel 0 Input Type J Thermocouple with 10 Hz filter Channel 1 Input Type J Thermocouple with 60 Hz filter Channel 2 Input 100 mV with 250 Hz filter From Table 3 5 Channel Update Time on page 3 34 Module Update Time Ch 0 Update Time Ch 1 Update Time Ch 2 Update Time CJC Update Time uses lowest thermocouple filter selected 303 ms 53 ms 15 ms 303 ms 674 ms 3 Three Channels Enabled for Different Inputs with Cyclic Calibration Enabled Channel 0 Input Type T Thermocouple with 60 Hz Filter Channel 1 Input Type T Thermocouple with 60 Hz Filter Channel 2 Input Type J Thermocouple with 60 Hz Filter From Table 3 5 Channel Update Time on page 3 34 Module Update Time without an Autocalibration Cycle Ch 0 Update Time Ch 1 Update Time Ch 2 Update Time CJC Update Time uses lowest thermocouple filter selected 53 ms 53 ms 53 ms 53 ms 212 ms Module Update Time during an Autocalibration Cycle Module Scan 1 Ch 0 Update Time Ch 1 Update Time Ch 2 Update Time
101. nels Enabling a channel forces it to be recalibrated before it measures input data Disabling a channel sets the channel data word to zero TIP When a channel is not enabled 0 no input is provided to the controller by the A D converter This speeds up the response of the active channels p improving performance Selecting Data Formats Bits 14 through 12 This selection configures channels 0 through 3 to present analog data in any of the following formats Raw Proportional Data Engineering Units x 1 Engineering Units x 10 Scaled for PID Percent Range Table 3 1 Channel Data Word Format Data Format e Engineering Units x1 Engineering Units x10 Scaled for PID Raw Proportion Percent ec oF ec oF al Data Range J 2100 to 12000 3460 to 421920 210 to 1200 346 to 2192 0 to 16383 32767 to 432767 0 to 10000 K 2700 to 413700 4540 to 24980 270 to 1370 454 to 2498 0 to 16383 32767 to 32767 0 to 10000 T 2700 to 4000 4540 to 7520 270 to 400 454 to 752 0 to 16383 32767 to 432767 0 to 10000 E 2700 to 10000 4540 to 418320 270 to 1000 454 to 1832 0 to 16383 32767 to 32767 0 to 10000 R 0 to 17680 320 to 32140 0 to 1768 32 to 3214 0 to 16383 32767 to 32767 0 to 10000 S 0 to 417680 320 to 32140 0 to 1768 32 to 3214 0 to 416383 32767 to 432767 0 to 10000 B 3000 to 18200 45720 to 32767 300
102. ocouple wires Both thermoelements of type S thermocouples are sensitive to impurity contamination In fact type R thermocouples were developed essentially because of iron contamination effects in some British platinum 10 percent rhodium wires The effects of various impurities on the thermoelectric voltages of platinum based thermocouple materials have been described by Rhys and Taimsalu 35 by Cochrane 36 and by Aliotta 37 Impurity contamination usually causes negative changes 25 26 29 in the thermoelectric voltage of the thermocouple with time the extent of which will depend upon the type and amount of chemical contaminant Such changes were shown to be due mainly to the platinum thermoelement 25 26 29 Volatilization of the rhodium from the positive thermoelement for the vapor transport of rhodium from the positive thermoelement to the pure platinum negative thermoelement also will cause negative drifts in the thermoelectric voltage Bentley 29 demonstrated that the vapor transport of rhodium can be virtually eliminated at 1700 C by using a single length of twin bore tubing to insulate the thermoelements and that contamination of the thermocouple by impurities transferred from the alumina insulator can be reduced by heat treating the insulator prior to its use McLaren and Murdock 30 33 and Bentley and Jones 34 thoroughly studied the performance of type S thermocouples in the range 0 C to 1100 C They described how thermall
103. ocouples are used the module channel to channel isolation is removed since there is no isolation between signal and sheath sheaths are tied together It should be noted that the isolation is removed even if the sheaths are connected to chassis ground at a location other than the module since the module is connected to chassis ground 1762 IT4 Multiplexer Metal sheath with Electrical Continuity to Thermocouple Signal Wires Rockwell Automation recommends that a grounded junction thermocouple have a protective sheath made of electrically insulated material for example ceramic An alternative is to float the metal sheath with respect to any path to chassis ground or to another thermocouple metal sheath Thus the metal sheath must be insulated from electrically conductive process material and have all connections to chassis ground broken Note that a floated sheath can result in a less noise immune thermocouple signal An ungrounded isolated junction thermocouple uses a measuring junction that is electrically isolated from the protective metal sheath This junction type is often used in situations when noise will affect readings as well as situations using frequent or rapid temperature cycling For this type of thermocouple junction the response time is longer than for the grounded junction Using Thermocouple Junctions D 3 Measuring Junction Isolated from Sheath LLL Using an Exposed Junction
104. odule by means of a ribbon cable after mounting as shown below Use the pull loop on the connector to disconnect modules Do not pull on the ribbon cable ATTENTION EXPLOSION HAZARD In Class I Division 2 applications the bus connector must be fully seated and the bus connector cover must be snapped in place In Class I Division 2 applications all modules must be mounted in direct contact with each other as shown on page 2 5 If DIN rail mounting is used an end stop must be installed ahead of the controller and after the last 1762 I O module Field Wiring Connections General Power and input wiring must be in accordance with Class 1 Division 2 wiring methods Article 501 4 b of the National Electric Code NFPA 70 and in accordance with the authority having jurisdiction Channels are isolated from one another by 10 Vdc maximum e If multiple power supplies are used with analog millivolt inputs the power supply commons must be connected Publication 1762 UM002A EN P July 2002 2 8 Installation and Wiring Publication 1762 UM002A EN P July 2002 Terminal Block Do not tamper with or remove the CJC sensor on the terminal block Removal of the sensor reduces accuracy For millivolt sensors use Belden 8761 shielded twisted pair wire Cor equivalent to ensure proper operation and high immunity to electrical noise For a thermocouple use the shielded twisted pair thermocouple extension lead
105. oes not cover however the higher purity reference grade materials that traditionally were used to construct thermocouples used as transfer standards and reference thermometers in various laboratory applications and to develop reference functions and tables 22 23 The higher purity alloy material typically contains less than 500 atomic ppm of impurities and the platinum less than 100 atomic ppm of impurities 22 Differences between such high purity commercial material and the platinum thermoelectric reference standard Pt 67 are described in 22 and 23 A reference function for the type R thermocouple based on the ITS 90 and the SI volt was determined recently from new data obtained in a collaborative effort by NIST and NPL The results of this international collaboration were reported by Burns et al 23 The function was used to compute the reference table given in this monograph Type R thermocouples have about a 12 percent larger Seebeck coefficient than do Type S thermocouples over much of the range Type R thermocouples were not standard interpolating instruments on the IPTS 68 for the 630 74 C to gold freezing point range Other than these two points and remarks regarding history and composition all of the precautions and restrictions on usage given in the section on type S thermocouples also apply to type R thermocouples Glawe and Publication 1762 UM002A EN P July 2002 C 12 Thermocouple Descriptions Type S Thermoco
106. olerances for type K commercial thermocouples be 2 2 C or 0 75 percent whichever is greater between 0 C and 1250 C and 2 2 C or 2 percent whichever is greater between 200 C and 0 C In the 0 C to 1250 C range type K thermocouples can be supplied to meet special tolerances that are equal to approximately one half the standard tolerances given above Type K thermocouple materials are normally supplied to meet the tolerances specified for temperatures above 0 C However the same materials may not satisfy the tolerances specified for the 200 C to 0 C range If materials are required to meet the tolerances below 0 C this should be specified when they are purchased The suggested upper temperature limit of 1260 C given in the ASTM standard 7 for protected type K thermocouples applies to AWG 8 3 25 mm wire It decreases to 1090 C for AWG 14 1 63 mm 980 C for AWG 20 0 81 mm 870 for AWG 24 or 28 0 51 mm or 0 33 mm and 760 C for AWG 30 0 25 mm These temperature limits apply to thermocouples used in conventional closed end protecting tubes and they are intended only as a rough guide to the user They do not apply to thermocouples having compacted mineral oxide insulation Thermocouple Descriptions C 9 Type N Thermocouples This section describes Nickel Chromium Silicon Alloy Versus Nickel Silicon Magnesium Alloy thermocouples commonly referred to as type N thermocouples This type is the newest of the lett
107. ollowing is an example calculation of module startup time EXAMPLE 1 Two Channels Enabled for Different Inputs Channel 0 Input Type T Thermocouple with 60 Hz filter Channel 1 Input Type J Thermocouple with 60 Hz filter Module Startup Time Ch OADC Self Calibration Time Ch 0 Offset Time CJC Self Calibration Time 103 ms 53 ms 103 ms 259 ms 2 Three Channels Enabled Two with Different Inputs Channel 0 Input Type T Thermocouple with 60 Hz filter Channel 1 Input Type J Thermocouple with 60 Hz filter Channel 2 Input Type K Thermocouple with 50 Hz filter Module Startup Time Channel 0 ADC Self Calibration Time Channel 0 Offset Time Channel 2 ADC Self Calibration Time Channel 2 Offset Time CJC Self Calibration Time 103 ms 53 ms 123 ms 63 ms 103 ms 445 ms Publication 1762 UM002A EN P July 2002 3 38 X Module Data Status and Channel Configuration Publication 1762 UM002A EN P July 2002 Safety Considerations Chapter Diagnostics and Troubleshooting This chapter describes troubleshooting the thermocouple mV input module This chapter contains information on safety considerations while troubleshooting internal diagnostics during module operation module errors contacting Rockwell Automation for technical assistance Safety considerations are an important element of proper troubleshooting procedures Actively thinking about the safety of yourself and others as w
108. on 1762 UM002A EN P July 2002 1 6 Overview Publication 1762 UM002A EN P July 2002 Module Field Calibration The module provides autocalibration which compensates for offset and gain drift of the A D converter caused by a temperature change within the module An internal high precision low drift voltage and system ground reference is used for this purpose The input module performs autocalibration when a channel is initially enabled In addition you can program the module to perform a calibration cycle once every 5 minutes See Selecting Enable Disable Cyclic Calibration Word 4 Bit 0 on page 3 14 for information on configuring the module to perform periodic autocalibration Compliance to European Union Directives Chapter 2 Installation and Wiring This chapter tells you how to determine the power requirements for the modules avoid electrostatic damage install the module wire the module s terminal block wire input devices This product is approved for installation within the European Union and EEA regions It has been designed and tested to meet the following directives EMC Directive The 1762 IT4 module is tested to meet Council Directive 89 336 EEC Electromagnetic Compatibility CEMC and the following standards in whole or in part documented in a technical construction file e EN 50081 2 EMC Generic Emission Standard Part 2 Industrial Environment EN 50082 2 EMC Generic Immunity
109. onfiguration Chan 0 2 Chan 3 Cal Generic Extra Data Config Disable cyclic module calibration Generic Extra Data Configuration This tab redisplays the configuration information entered on the 1762 IT4 configuration screen in raw data format As explained on page E 7 you can enter the configuration information using this tab instead of using the Chan 0 2 and Chan 3 tabs You do not have to enter data in both places Publication 1762 UM002A EN P July 2002 Module Configuration Using MicroLogix 1200 and RSLogix 500 E 7 Configuration Using RSLogix 500 Version 5 2 or Lower If you do not have version 5 5 or higher of RSLogix 500 you can still configure your module using the Generic Extra Data Configuration dialog The 1762 IT4 uses six 16 bit binary numbers to configure each of its four channels To properly configure and enable input channel 1 for the setting in the table below add the decimal values given to each of the six parameters These decimal values are listed in the configuration table on page 3 5 Table 5 2 1762 IT4 Parameter Decimal Values Parameter Setting Decimal Value Filter Frequency 250 Hz 3 Open Circuit Hold Last State 64 Temperature Units Degrees F 128 Input Type Thermocouple S 1280 Data Format Engineering Units x 10 16384 Enable Channel Enable 32768 Total 14909 Enter this value into the Generic Extra Data Config tab Expansion General Configurat
110. onfigured on board each module as engineering units x 1 engineering units x 10 scaled for PID percent of full scale raw proportional data Filter Frequencies The module uses a digital filter that provides high frequency noise rejection for the input signals The filter is programmable allowing you to select from six different filter frequencies for each channel e 10 Hz e 50 Hz e 60 Hz e 250 Hz e 500 Hz e 1000 Hz Hardware Features Channels are wired as differential inputs A cold junction compensation CJC sensor is attached to the terminal block to enable accurate readings from each channel The sensor compensates for offset voltages introduced into the input signal as a result of the cold junction where the thermocouple wires are connected to the module Overview 1 3 The illustration below shows the module s hardware features Item Description 1a upper panel mounting tab 1b lower panel mounting tab power diagnostic LED module door with terminal identification label bus connector cover terminal block DIN rail latch pull loop 2 3 5 6 flat ribbon cable with bus connector female 7 8 9 Publication 1762 UM002A EN P July 2002 1 4 Overview System Overview Publication 1762 UM002A EN P July 2002 General Diagnostic Features The module contains a diagnostic LED that helps you identify th
111. ons why iron versus constantan thermocouples are not recommended as a standardized type above 760 C If type J thermocouples are taken to high temperatures especially above 900 C they will lose the accuracy of their calibration when they are recycled to lower temperatures If type J thermocouples are used in air at temperatures above 760 C only the largest wire AWG 8 3 3 mm should be used and they should be held at the measured temperature for 10 to 20 minutes before readings are taken The thermoelectric voltage of the type J thermocouples may change by as much as 40uV or 0 6 C equivalent per minute when first brought up to temperatures near 900 C ASTM Standard E230 87 in the 1992 Annual Book of ASTM Standards 7 specifies that the initial calibration tolerances for type J commercial thermocouples be 2 2 C or 0 75 percent whichever is greater between 0 C and 750 C Type J thermocouples can also be supplied to meet special tolerances which are equal to approximately one half the standard tolerances given above Tolerances are not specified for type J thermocouples below 0 C or above 750 C Thermocouple Descriptions C 7 Type K Thermocouples The suggested upper temperature limit of 760 C given in the above ASTM standard 7 for protected type J thermocouples applies to AWG 8 3 25 mm wire For smaller diameter wires the suggested upper temperature limit decreases to 590 C for AWG 14 1 63 mm 480 C for AWG 20 0 8
112. or of 34V about 0 3 C would be insignificant in most instances ASTM Standard E230 87 in the 1992 Annual Book of ASTM Standards 7 specifies that the initial calibration tolerances for type B commercial thermocouples be 0 5 percent between 870 C and 1700 C Type B thermocouples can also be supplied to meet special tolerances of 0 25 percent Tolerances are not specified for type B thermocouples below 870 C The suggested upper temperature limit of 1700 C given in the ASTM standard 7 for protected type B thermocouples applies to AWG 24 0 51 mm wire This temperature limit applies to thermocouples used in conventional closed end protecting tubes and it is intended only as a rough guide to the user It does not apply to thermocouples having compacted mineral oxide insulation This section describes Nickel Chromium Alloy Versus Copper Nickel Alloy thermocouples known as type E thermocouples This type and the other base metal types do not have specific chemical compositions given in standards rather any materials whose emf temperature relationship agrees with that of the specified reference table within certain tolerances can be considered to be a type E thermocouple The positive thermoelement EP is the same material as KP The negative thermoelement EN is the same material as TN The low temperature research 8 by members of the NBS Cryogenics Division showed that type E thermocouples are very useful down to liquid hydrog
113. ough configuring your 1762 IT4 thermocouple mV input module with RSLogix 500 programming software assumes your module is installed as expansion I O in a MicroLogix 1200 system and that RSLinx is properly configured and a communications link has been established between the MicroLogix processor and RSLogix 500 Module Configuration Using MicroLogix 1200 and RSLogix 500 E 3 Start RSLogix and create a MicroLogix 1200 application The following screen appears Ed RSLogix 500 UNTITLED File Edit View Search Comms Tools Window Help Dase 6t ae oof s amp SIpmg amp rig OFFLINE ba Driver unknown B 43 Project H 0 Help No Forces 3 Forces Enabled i oix FERE IE H TT JE YE lt gt 40 45 abl aes Node 1o L gt N User Ket X Tmericourter A noioe K Compare H Controller Program Files H 0 Data Files H Force Files m Custom Data Monitors Custom Graphical Monitors Recipe Monitors C Trends EL Database File 2 For Help press F1 2 0000 APP READ 7 While offline double click on the IO Configuration icon under the controller folder and the following IO Configuration screen appears 1 0 Configuration Read I0 Config 0 Bul 1762 1762T4 MicroLogix 1200 Series C 4 Channel Thermocouple Input Module Help Hide All Cards r Current Cards Available Fite a 8 Input 79 132 VAC Analog 2 Chan Input
114. p shows the input image table for the module Detailed information on the image table is located in Chapter 3 Memory Map Input Image is eee Bit 15 Bit 0 Word 0 Word 1 Word 2 Word 3 Word 4 bits 0 to 4 and 8 to 12 Word 5 bits 6 to 15 For example to obtain the general status of channel 2 of the module located in slot e use address I e 6 2 Slot Word Bit Input File Type gt x A Element Delimiter Word Delimiter Bit Delimiter Publication 1762 UM002A EN P July 2002 E 2 Module Configuration Using MicroLogix 1200 and RSLogix 500 Configuration Using RSLogix 500 Version 5 50 or Higher Publication 1762 UM002A EN P July 2002 1762 IT4 Configuration File The configuration file contains information you use to define the way a specific channel functions The configuration file is explained in more detail in Configuring Channels on page 3 4 The configuration file is modified using the programming software configuration screen For an example of module configuration using RSLogix 500 see Configuration Using RSLogix 500 Version 5 50 or Higher on page E 2 Table 5 1 Software Configuration Channel Defaults Parameter Default Setting Disable Enable Channel Disable Filter Frequency 60 Hz Input Type Thermocouple Type J Data Format Raw Proportional Temperature Units C Open Circuit Response Upscale Disable Cyclic Calibration Enable This example takes you thr
115. ples can be used from 50 C to the platinum melting point temperature They may be used intermittently at temperatures up to the platinum melting point and continuously up to about 1300 C with only small changes in their calibrations The ultimate useful life of the thermocouples when used at such elevated temperatures is governed primarily by physical problems of impurity diffusion and grain growth which lead to mechanical failure The thermocouple is most reliable when used in a clean oxidizing atmosphere air but may be used also in inert gaseous atmospheres or in a vacuum for short periods of time However type B thermocouples are generally more suitable for such applications above 1200 C Type S thermocouples should not be used in reducing atmospheres nor in those containing metallic vapor such as lead or zinc nonmetallic vapors such as arsenic phosphorus or sulfur or easily reduced oxides unless they are suitably protected with nonmetallic protecting tubes Also they should never be inserted directly into a metallic protection tube for use at high temperatures The stability of type S thermocouples at high temperatures gt 1200 C depends primarily upon the quality of the materials used for protection and insulation and has been studied by Walker et al 25 26 and by Bentley 29 High purity alumina with low iron content appears to be the most suitable material for insulating protecting and mechanically supporting the therm
116. program scan or when commanded by the control program If the controller and the module determine that the data transfer has been made without error the data is used in the control program Overview 1 5 Module Operation When the module receives a differential input from an analog device the module s circuitry multiplexes the input into an A D converter The converter reads the signal and converts it as required for the type of input The module also continuously samples the CJC sensor and compensates for temperature changes at the terminal block cold junction between the thermocouple wire and the input channel See the block diagram below A D 4 Thermocouple mV Converter Inputs n e 5 5 lt e S amp a a e N 5 2 e 2 z g Lum eo cC rz 6 om co N T x 2 o CJC Sensor p DS S i o a 5 D E x9 o xn Each channel can receive input signals from a thermocouple or millivolt analog input device depending upon how you configured the channel When configured for thermocouple input types the module converts the analog input voltages into cold junction compensated and linearized digital temperature readings The module uses the National Institute of Standards and Technology NIST ITS 90 standard for linearization for all thermocouple types Q K T E R S B N When configured for millivolt inputs the module converts the analog values directly into digital counts Publicati
117. r pins Do not touch circuit components inside the module e If available use a static safe work station e When not in use keep the module in its static shield box Publication 1762 UM002A EN P July 2002 2 4 Installation and Wiring Publication 1762 UM002A EN P July 2002 Remove Power ETT Remove power before removing or installing this module When you remove or install a module with power applied an electrical arc may occur An electrical arc can cause personal injury or property damage by sending an erroneous signal to your system s field devices causing unintended machine motion causing an explosion in a hazardous environment causing permanent damage to the module s circuitry Electrical arcing causes excessive wear to contacts on both the module and its mating connector Worn contacts may create electrical resistance Selecting a Location Reducing Noise Most applications require installation in an industrial enclosure to reduce the effects of electrical interference Analog inputs are highly susceptible to electrical noise Electrical noise coupled to the analog inputs will reduce the performance accuracy of the module Group your modules to minimize adverse effects from radiated electrical noise and heat Consider the following conditions when selecting a location for the analog module Position the module away from sources of electrical noise such as hard contact switches
118. rain wire at the module end connect it to earth ground using a panel or DIN rail mounting screw Refer to Industrial Automation Wiring and Grounding Guidelines Allen Bradley publication 1770 4 1 for additional information Noise Prevention Route field wiring away from any other wiring and as far as possible from sources of electrical noise such as motors transformers contactors and ac devices As a general rule allow at least 15 2 cm 6 in of separation for every 120V of power Routing field wiring in a grounded conduit can reduce electrical noise If field wiring must cross ac or power cables ensure that they Cross at right angles To limit the pickup of electrical noise keep thermocouple and millivolt signal wires as far as possible from power and load lines If noise persists for a device try grounding the opposite end of the cable shield You can only ground one end at a time Wiring Terminal Block Layout Labeling the Terminals A write on label is provided with the module Mark the identification of each terminal with permanent ink and slide the label back into the door Publication 1762 UM002A EN P July 2002 2 10 Installation and Wiring Wiring the Finger Safe Terminal Block Be careful when stripping wires Wire fragments ATTENTION ATTENTION that fall into a module could cause damage when power is applied Once wiring is complete ensure the modu
119. reater between 200 C and 0 C Type T thermocouples can also be supplied to meet special tolerances which are equal to approximately one half the standard tolerances given above Type T thermocouple materials are normally supplied to meet the tolerances specified for temperatures above 0 C However the same materials may not satisfy the tolerances specified for the 200 C to 0 C range If materials are required to meet the tolerances below 0 C this should be specified when they are purchased The suggested upper temperature limit of 370 C given in the ASTM standard 7 for protected type T thermocouples applies to AWG 14 1 63 mm wire It decreases to 260 C for AWG 20 0 81 mm 200 C for AWG 24 or 28 0 51 mm or 0 33 mm and 150 C for AWG 30 0 25 mm These temperature limits apply to thermocouples used in conventional closed end protecting tubes and they are intended only as a rough guide to the user They do not apply to thermocouples having compacted mineral oxide insulation References Thermocouple Descriptions C 17 1 Preston Thomas H The International Temperature Scale of 1990 ITS 90 Metrologia 27 3 10 1990 ibid p 107 2 The International Practical Temperature Scale of 1968 Amended Edition of 1975 Metrologia 12 7 17 1976 3 Mangum B W Furukawa G T Guidelines for realizing the International Temperature Scale of 1990 ITS 90 Natl Inst Stand Technol Tech Note 1265 1990 August 190 p
120. refractory metal thermocouples at 1600K in air argon and vacuum Temperature Its Measurement and Control in Science and Industry Vol 4 Plumb H H ed Pittsburgh Instrument Society of America 1972 1645 1662 25 Walker B E Ewing C T Miller R R Thermoelectric instability of some noble metal thermocouples at high temperatures Rev Sci Instrum 33 1029 1040 1962 26 Walker B E Ewing C T Miller R R Study of the instability of noble metal thermocouples in vacuum Rev Sci Instrum 36 601 606 1965 27 Bedford R E Ma C K Barber C R Chandler T R Quinn T J Burns G W Scroger M New reference tables for platinum 10 rhodium platinum and platinum 1396 rhodium platinum thermocouples Temperature Its Measurement and Control in Science and Industry Vol 4 Plumb H H ed Pittsburgh Instrument Society of America 1972 1585 1603 28 Burns G W Strouse G F Mangum B W Croarkin M C Guthrie W F Marcarino P Battuello M Lee H K Kim J C Gam K S Rhee C Chattle M Arai M Sakurai H Pokhodun A I Moiseeva N P Perevalova S A de Groot M J Zhang J Fan K Wu S New reference functions for platinum 1096 rhodium versus platinum type S thermocouples based on the ITS 90 Part I and Part Il in Temperature Its Measurement and Control in Science and Industry Vol 6 Schooley J F ed New York American Institute of Physics 1992
121. relays and AC motor drives away from modules which generate significant radiated heat Refer to the module s heat dissipation specification In addition route shielded twisted pair analog input wiring away from any high voltage I O wiring Installation and Wiring 2 5 Mounting ATTENTION Do not remove protective debris strip until after the module and all other equipment near the module is mounted and wiring is complete Once wiring is complete and the module is free of debris carefully remove protective debris strip Failure to remove strip before operating can cause overheating Minimum Spacing Maintain spacing from enclosure walls Side wireways adjacent equipment etc Allow 50 8 mm 2 in of space on all sides for adequate ventilation as shown MicroLogix 1200 Side 17620 lg E 1762 1 0 1762 0 Bottom r gt ENIM 1762 expansion I O may be mounted horizontally only ATTENTION During panel or DIN rail mounting of all devices be sure that all debris metal chips wire strands etc is kept from falling into the module Debris that falls into the module could cause damage when power is applied to the module DIN Rail Mounting The module can be mounted using the following DIN rails 35 x 7 5 mm EN 50 022 35 x 7 5 or 35 x 15 mm EN 50 022 35 x 15 Before mounting the module on a DIN rail close the DIN rail latch Press
122. represents such a small fraction of the total production of commercial iron wire that the producers do not control the chemical composition to maintain constant thermoelectric properties Instead instrument companies and thermocouple fabricators select material most suitable for the thermocouple usage The total and specific types of impurities that occur in commercial iron change with time location of primary ores and methods of smelting Many unusual lots have been selected in the past for example spools of industrial iron wire and even scrapped rails from an elevated train line At present iron wire that most closely fits these tables has about 0 25 percent manganese and 0 12 percent copper plus other minor impurities The negative thermoelement for type J thermocouples is a copper nickel alloy known ambiguously as constantan The word constantan has commonly referred to copper nickel alloys containing anywhere from 45 to 60 percent copper plus minor impurities of carbon cobalt iron and manganese Constantan for type J thermocouples usually contains about 55 percent copper 45 percent nickel and a small but thermoelectrically significant amount of cobalt iron and manganese about 0 1 percent or more It should be Publication 1762 UM002A EN P July 2002 C 6 Thermocouple Descriptions Publication 1762 UM002A EN P July 2002 emphasized that type JN thermoelements are NOT generally interchangeable with type TN or EN thermoel
123. research 8 by members of the NBS Cryogenics Division showed that the type K thermocouple may be used down to liquid helium temperatures about 4K but that its Seebeck coefficient becomes quite small below 20K Its Seebeck coefficient at 20K is only about 4uV K being roughly one half that of the type E thermocouple which is the most suitable of the letter designated thermocouples types for measurements down to 20K Type KP and type KN thermoelements do have a relatively low thermal conductivity and good resistance to corrosion in moist atmospheres at low temperatures The thermoelectric homogeneity of type KN thermoelements however was found 8 to be not quite as good as that of type EN thermoelements Type K thermocouples are recommended by the ASTM 5 for use at temperatures within the range 250 C to 1260 C in oxidizing or inert atmospheres Both the KP and the KN thermoelements are subject to deterioration by oxidation when used in air above about 750 C but even so type K thermocouples may be used at temperatures up to about 1350 C for short periods with only small changes in calibration Publication 1762 UM002A EN P July 2002 C 8 Thermocouple Descriptions Publication 1762 UM002A EN P July 2002 When oxidation occurs it normally leads to a gradual increase in the thermoelectric voltage with time The magnitude of the change in the thermoelectric voltage and the physical life of the thermocouple will depend upon such f
124. sctiptioDoo ura o qe er d o Doe etaed rpm 1 1 Thermocouple mV Inputs and Ranges 1 1 Data Formats llle 1 2 Filter Frequencies lt ui gars e roux erro Por oa Sales 1 2 Hardware Features es XR by 8 Eee Sv ea Pease eee 635 1 2 General Diagnostic Feat res c aya pese DR Pest 1 4 System OVERVIEW rra quod ace dee Reed quet oen b de bel d n 1 4 System Operator eda d rr ay eee SP PARSE 1 4 Module Operation vae seg ea dng pes EX RC ETERE SS 1 5 Module Field Calibration 34 4 dRkpAS I Le UPS 1 6 Chapter 2 Compliance to European Union Directives 2 1 EMC Directive feds cee ke Sa eR CERYU E 2 1 Low Voltage Directive sees bacs ceo ato a 2 2 Power Requirements llle 2 2 General Considerations ee uo Sears ci ex ac adde a 2 2 Hazardous Location Considerations 2 3 Prevent Electrostatic Discharge osse 2 3 Remove Power x ease da EN GG 4 RIDE ER 2 4 Selecting a Location n sedg Wo pu tu gutes 2 4 Mounting A aor ips vestib dee a d ptite tn ded lr fedis 2 5 Minimum Spacing xc u uc ek s wy pote 2 5 DIN Rail MOUNDE o IS 4 ky Pah ee a A Sta ewe 2 5 Panel MOUBIBE Gun tu auaa aaa 2 6 Syster Assem Blye se tnea Ea eed esee e Et RC Qd 2 7 Field Wiring Connections 4 ace eee oce OLI e RC Uo 2 7 Publication 1762 UM002A EN P July 2002 Table of Contents ii Module Data Status and Channel Configuration Diagnostics and Troubleshooting Publication 1762 UM002A EN P July 2002
125. t See Fffects of Filter Frequency on Noise Rejection on page 3 10 Rated Working Voltage 30V ac 30V dc Common Mode Voltage Range 10V maximum per channel Common Mode Rejection 115 dB minimum at 50 Hz with 10 Hz or 50 Hz filter 115 dB minimum at 60 Hz with 10 Hz or 60 Hz filter Normal Mode Rejection Ratio 85 dB minimum at 50 Hz with 10 Hz or 50 Hz filter 85 dB minimum at 60 Hz with 10 Hz or 60 Hz filter Maximum Cable Impedance 25 Q for specified accuracy Input Impedance 10M Q Open circuit Detection Time 7 ms to 1 515 seconds Calibration The module performs autocalibration upon power up and whenever a channel is enabled You can also program the module to calibrate every five minutes 1 Rated working voltage is the maximum continuous voltage that can be applied at the input terminal including the input signal and the value that floats above ground potential for example 30V dc input signal and 20V dc potential above ground 2 For proper operation both the plus and minus input terminals must be within 10V dc of analog common 3 Open circuit detection time is equal to the module scan time which is based on the number of enabled channels the filter frequency of each channel and whether cyclic calibration is enabled Specifications A 3 Repeatability at 25 C 77 F 2 Specification Module Error over Full Temperature
126. the processor memory A 0 indicates a value of 0 a 1 indicates the decimal value of the position The equivalent decimal value of the binary number is the sum of the position values Positive Decimal Values The far left position is always 0 for positive values As indicated in the figure below this limits the maximum positive decimal value to 32767 all positions are 1 except the far left position For example 0000 1001 0000 1110 211 28 23 22 21 20484256484442 2318 0010 0011 0010 1000 213 29 28 25 23 _ 81924512425643248 9000 1x24 16384 16384 1x21 28192 8192 1x21 4096 4096 1x2 2048 2048 1x2 0 1024 1024 1x29 512 512 1x28 256 256 1x2 128 128 1x26 64 64 1x25 32 32 1x2 16 16 1x25 8 8 1x2 4 4 1x2 22 2 1x2 1 1 0 1 3 14d 1d d 1d 1 1 1 1 1 1 1 1 1 32767 L 0x215 0 This position is always 0 for positive numbers Publication 1762 UM002A EN P July 2002 B 2 Two s Complement Binary Numbers Negative Decimal Values In two s complement notation the far left position is always 1 for negative values The equivalent decimal value of the binary number is obtained by subtracting the value of the far left position 32768 from the sum of the values of the other positions In the figure below all positions are 1 the value is 32767 32768 1 For example 1111 1000 0010 0011 214 2
127. thermoelectric stability of EP and EN type alloys when heated in air at elevated temperatures His work should be consulted for details More recent stability data on these alloys in air were reported by Burley et al 13 Type E thermocouples should not be used at high temperatures in sulfurous reducing or alternately reducing and oxidizing atmospheres unless suitably protected with protecting tubes They also should not be used in vacuum at high temperatures for extended times because the chromium in the positive thermoelement a nickel chromium alloy vaporizes out of solution and alters the calibration In addition their use in atmospheres that promote green rot corrosion of the positive thermoelement should be avoided Such corrosion results from the preferential oxidation of chromium in atmospheres with low but not negligible oxygen content and can lead to a large decrease in the thermoelectric voltage of the thermocouple with time The effect is most serious at temperatures between 800 C and 1050 C The negative thermoelement a copper nickel alloy is subject to composition changes under thermal neutron irradiation since the copper is converted to nickel and zinc Neither thermoelement of type E thermocouples is very sensitive to minor changes in composition or impurity level because both are already heavily alloyed Similarly they are also not extremely sensitive to minor differences in heat treatment provided that the treatment
128. tions 100 90 Figure A 10 Module Accuracy at 25 C 77 F Ambient for Type K Thermocouple Using 250 500 and 1 kHz Filter 80 70 60 250 Hz 50 500 Hz 40 Accuracy C 30 1000 Hz 20 10 400 160 140 200 0 200 400 600 800 Thermocouple Temperature C 1000 1200 1400 120 100 250 Hz 80 500 Hz Accuracy F 60 1000 Hz 40 20 500 Publication 1762 UM002A EN P July 2002 0 500 Thermocouple Temperature F 1000 1500 2000 2500 Specifications A 15 Figure A 11 Module Accuracy at 25 C 77 F Ambient for Type N Thermocouple Using 10 50 and 60 Hz Filter N A ce 10 Hz 50 Hz 60 Hz Accuracy C T o co eO o Oo N 400 200 0 200 400 600 800 1000 1200 1400 Thermocouple Temperature C n2 on Io e 10 Hz 50 Hz 60 Hz c Accuracy F ce ce c1 ce ce 500 0 500 1000 1500 2000 2500 Thermocouple Temperature F Publication 1762 UM002A EN P July 2002 A 16 Specifications Figure A 12 Module Accuracy at 25 C 77 F Ambient for Type N Thermocouple Using 250 500 and 1 kHz Filter
129. to 1820 4572103308 Oto 16383 32767 to 32767 0 to 10000 N 2100 to 13000 3460 to 23720 210 to 1300 346t0 42372 Oto 16383 32767 to 432767 0 to 10000 p 0 to 423150 13201032767 0t042315 432to 4199 Oto 16383 32767 to 432767 0 to 10000 50mV 5000 to 450007 500 to 5002 0 to 16383 32767 to 432767 0 to 10000 100 mV 40000 to 10000 1000 to 1000 0 to 16383 32767 to 432767 0 to 10000 1 Type B and C thermocouples cannot be represented in engineering units x1 F above 3276 7 F therefore it will be treated as an over range error 2 When millivolts are selected the temperature setting is ignored Analog input date is the same for C or F selection Publication 1762 UMO002A EN P July 2002 Module Data Status and Channel Configuration 3 7 The engineering units data formats represent real engineering temperature units provided by the module to the controller The raw proportional m counts scaled for PID and percent of full scale data formats may yield the highest effective resolutions but may also require that you convert channel data to real engineering units in your control program Raw Proportional Data The value presented to the controller is proportional to the selected input and scaled into the maximum data range allowed by the bit resolution of the A D converter and filter selected The raw proportional data format also provides the best resolution of all the data form
130. tures system and module operation calibration The thermocouple mV input module supports thermocouple and millivolt signal measurement It digitally converts and stores thermocouple and or millivolt analog data from any combination of up to four thermocouple or millivolt analog sensors Each input channel is individually configurable via software for a specific input device data format and filter frequency and provides open circuit over range and under range detection and indication Thermocouple mV Inputs and Ranges The table below defines thermocouple types and their associated full scale temperature ranges The second table lists the millivolt analog input signal ranges that each channel will support To determine the practical temperature range your thermocouple supports see the specifications in Appendix A Thermocouple Type C Temperature Range F Temperature Range J 210 to 1200 C 346 to 2192 F K 270 to 1370 C 454 to 2498 F T 270 to 400 C 454 to 752 F E 270 to 1000 C 454 to 1832 F R 0 to 1768 C 32 to 3214 F S 0 to 1768 C 32 to 3214 F B 300 to 1820 C 572 to 3308 F N 210 to 1300 C 346 to 2372 F C 0 to 2315 C 32 to 4199 F Publication 1762 UM002A EN P July 2002 12 Overview Publication 1762 UM002A EN P July 2002 Millivolt Input Type Range 50 mV 50 to 50 mV 100 mV 100 to 100 mV Data Formats The data can be c
131. uired for the module to sample and convert the input signals of all enabled input channels and provide the resulting data values to the processor Module update time can be calculated by adding the sum of all enabled channel s times The module sequentially samples the enabled channels in a continuous loop as shown below Channel 0 Disabled Channel 1 Disabled Channel 2 Disabled Sample Channel 0 Enabled Enabled Sample Channel 1 Sample Enabled Channel 2 to Channel 3 Disabled No Thermocouple ive Sample Channel 3 Enabled TC Enabled Sample CJC Calibration Not Ac Perform Calibration Calibration Active Publication 1762 UM002A EN P July 2002 3 34 Module Data Status and Channel Configuration Publication 1762 UM002A EN P July 2002 Channel update time is dependent upon the input filter selection The following table shows the channel update times Table 3 5 Channel Update Time Filter Frequency Channel Update Time 10 Hz 303 ms 50 Hz 63 ms 60 Hz 53 ms 250 Hz 15ms 500 Hz 9 ms 1 kHz 7 ms The CJC input is only sampled if one or more channels are enabled for any thermocouple type The CJC update time is equal to the largest channel update time of any of the enabled thermocouple inputs types In that case a single CJC update is done per scan See t
132. uples Publication 1762 UM002A EN P July 2002 Szaniszlo 24 and Walker et al 25 26 have determined the effects that prolonged exposure at elevated temperatures gt 1200 C in vacuum air and argon atmospheres have on the thermoelectric voltages of type R thermocouples ASTM Standard E230 87 in the 1992 Annual Book of ASTM Standards 7 specifies that the initial calibration tolerances for type R commercial thermocouples be 1 5 C or 0 25 percent whichever is greater between 0 C and 1450 C Type R thermocouples can be supplied to meet special tolerances of 0 6 C or 0 1 percent whichever is greater The suggested upper temperature limit 1480 C given in the ASTM standard 7 for protected type R thermocouples applies to AWG 24 0 51 mm wire This temperature limit applies to thermocouples used in conventional closed end protecting tubes and it is intended only as a rough guide to the user It does not apply to thermocouples having compacted mineral oxide insulation This section describes Platinum 10 percent Rhodium Alloy Versus Platinum thermocouples commonly known as type S thermocouples This type is often referred to by the nominal chemical composition of its positive SP thermoelement platinum 10 percent rhodium The negative SN thermoelement is commercially available platinum that has a nominal purity of 99 99 percent 21 An industrial consensus standard ASTM E1159 87 specifies that rhodium having a nominal
133. upport Preface 3 Rockwell Automation offers support services worldwide with over 75 Sales Support Offices 512 authorized distributors and 260 authorized Systems Integrators located throughout the United States alone plus Rockwell Automation representatives in every major country in the world Local Product Support Contact your local Rockwell Automation representative for sales and order support product technical training warranty support support service agreement Technical Product Assistance If you need to contact Rockwell Automation for technical assistance please review the information in Chapter 4 Diagnostics and Troubleshooting first Then call your local Rockwell Automation representative Your Questions or Comments on the Manual If you find a problem with this manual please notify us If you have any suggestions for how this manual could be made more useful to you please contact us at the address below Rockwell Automation Automation Control and Information Group Technical Communication Dept A602V P O Box 2086 Milwaukee WI 53201 2086 Publication 1762 UM002A EN P July 2002 Preface 4 Publication 1762 UM002A EN P July 2002 General Description Chapter 1 Overview This chapter describes the 1762 IT4 Thermocouple mV Input Module and explains how the module reads thermocouple or millivolt analog input data Included is information about the module s hardware and diagnostic fea
134. uration data is represented by zeros in the data file The structure of the channel configuration file is shown below Word 15 14 8 7 6 0 Bit Enable Data Format Input Type Tem perature Open Circuit Not Not Filter Frequency 0 Channel Channel 0 Channel 0 Units Condition Used Used Channel 0 0 Channel 0 Channel 0 Enable Data Format Input Type Jem perature Open Circuit Not Not Filter Frequency 1 Channel Units Condition Channel 1 Channel 1 Used Used Channel 1 1 Channel 1 Channel 1 Enable Data Format Input Type Tem perature Open Circuit Not Not Filter Frequency 2 Channel Channel 2 Channel 2 Units Condition Used Used Channel 2 2 Channel 2 Channel 2 Enable Data Format Input Type Tem perature Open Circuit Not Not Filter Frequency 3 Channel Units Condition Channel 3 Channel 3 Used Used Channel 3 3 Channel 3 Channel 3 Enable Disable 4 Reserved Cyclic Calibration Publication 1762 UM002A EN P July 2002 The structure and bit settings are shown in Channel Configuration on page 3 4 Channel Configuration Each channel configuration word consists of bit fields the settings of which determine how the channel operates See the table below and the descriptions that follow for valid configuration settings and their meanings Module Data Status and Channel Configuration 3 5
135. us and Channel Configuration Figure 3 11 Effective Resolution Versus Input Filter Selection for Type K Thermocouples Using 250 500 and 1k Hz Filters 120 100 g 8 250Hz 2 00 500Hz S 1000 Hz B 40 20 0 400 200 0 200 400 600 800 1000 1200 Temperature C 220 200 E 180 e 160 S 140 250 Hz s 120 100 500 Hz 80 1000 Hz 60 40 20 0 500 0 500 1000 1500 2000 2500 Temperature F Publication 1762 UM002A EN P July 2002 Effective Resolution C Effective Resolution F Module Data Status and Channel Configuration 3 25 Figure 3 12 Effective Resolution Versus Input Filter Selection for Type N Thermocouples Using 10 50 and 60 Hz Filters 0 8 0 7 0 6 0 5 10 Hz 0 4 50 Hz 0 3 60 Hz 0 2 0 1 0 0 400 200 0 200 400 600 800 1000 1200 1400 Temperature C 1 4 1 2 1 0 0 8 0 6 0 4 0 2 0 0 10 Hz 50Hz 60 Hz 500 0 500 1000 1500 2000 2400 Temperature F Publication 1762 UM002A EN P July 2002 3 26 X Module Data Status and Channel Configuration Figure 3 13 Effective Resolution Versus Input Filter Selection for Type N Thermocouples Using 250 500 and 1k Hz Filters
136. when they are purchased The suggested upper temperature limit 870 C given in the ASTM standard 7 for protected type E thermocouples applies to AWG 8 3 25 mm wire It decreases to 650 C for AWG 14 1 63 mm 540 C for AWG 20 0 81 mm 430 C for AWG 24 or 28 0 51 mm or 0 33 mm and 370 C for AWG 30 0 25 mm These temperature limits apply to thermocouples used in conventional closed end protecting tubes and they are intended only as a rough guide to the user They do not apply to thermocouples having compacted mineral oxide insulation This section discusses Iron Versus Copper Nickel Alloy SAMA thermocouples called type J thermocouples A type J thermocouple is one of the most common types of industrial thermocouples because of its relatively high Seebeck coefficient and low cost It has been reported that more than 200 tons of type J materials are supplied annually to industry in this country However this type is least suitable for accurate thermometry because there are significant nonlinear deviations in the thermoelectric output of thermocouples obtained from different manufacturers These irregular deviations lead to difficulties in obtaining accurate calibrations based on a limited number of calibration points The positive thermoelement is commercially pure 99 5 percent Fe iron usually containing significant impurity levels of carbon chromium copper manganese nickel phosphorus silicon and sulfur Thermocouple wire
137. y condensation shall be expected 2 Over Voltage Category Il is the load level section of the electrical distribution system At this level transient voltages are controlled and do not exceed the impulse voltage capability of the product s insulation 3 Pollution Degree 2 and Over Voltage Category Il are International Electrotechnical Commission IEC designations Installation and Wiring 2 3 Hazardous Location Considerations This equipment is suitable for use in Class I Division 2 Groups A B C D or non hazardous locations only The following WARNING statement applies to use in hazardous locations WARNING EXPLOSION HAZARD e Substitution of components may impair suitability for Class I Division 2 Do no replace components or disconnect equipment unless power has been switched off or the area is known to be non hazardous Do not connect or disconnect components unless power has been switched off or the area is known to be non hazardous This product must be installed within an enclosure All wiring must comply with N E C article 501 4 b Prevent Electrostatic Discharge ATTENTION Electrostatic discharge can damage integrated circuits or semiconductors if you touch bus connector pins Follow these guidelines when you handle the module Touch a grounded object to discharge static potential Wear an approved wrist strap grounding device Do not touch the bus connector or connecto
138. y reversible effects such as quenched in point defects mechanical stresses and preferential oxidation of rhodium in the type SP thermoelement cause chemical Publication 1762 UM002A EN P July 2002 C 14 Thermocouple Descriptions Type T Thermocouples Publication 1762 UM002A EN P July 2002 and physical inhomogeneities in the thermocouple and thereby limit its accuracy in this range They emphasized the important of annealing techniques The positive thermoelement is unstable in a thermal neutron flux because the rhodium converts to palladium The negative thermoelement is relatively stable to neutron transmutation Fast neutron bombardment however will cause physical damage which will change the thermoelectric voltage unless it is annealed out At the gold freezing point temperature 1064 18 C the thermoelectric voltage of type S thermocouples increases by about 340uV about 3 percent per weight percent increase in rhodium content the Seebeck coefficient increases by about 4 percent per weight percent increase at the same temperature ASTM Standard E230 87 in the 1992 Annual Book of ASTM Standards 7 specifies that the initial calibration tolerances for type S commercial thermocouples be 1 5 C or 0 25 percent whichever is greater between 0 C and 1450 C Type S thermocouples can be supplied to meet special tolerances of 0 6 C or 0 1 percent whichever is greater The suggested upper temperature limit 1480 C

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