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1746-6.22, SLC 500™ Thermocouple/mV Analog Input

1. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Channel Channel Disable 0 Status Channel Enable 1 Thermocouple Type J 0 0 0 0 Thermocouple Type K 0 0 0 1 Thermocouple Type T 0 0 1 0 Thermocouple TypeE 0 0 1 1 Thermocouple Type R 0 1 0 0 Thermocouple TypeS 0 1 0 1 Thermocouple Type B 0 1 1 0 Input Thermocouple Type N 0 1 1 1 Type 50 mV 1 0 0 0 100 mV 1 0 0 1 Invalid 1 0 1 0 Invalid 1 0 1 1 Invalid 1 1 0 0 Invalid 1 1 0 1 Invalid 1 1 1 0 CJ C temperature 1 1 1 1 Engineering Units x 1 0 0 Data Engineering Units x 10 0 1 Format Scaled for PID 1 0 Proportional counts 1 1 Zero on open circuit 0 0 Open Max on open circuit 0 1 Circuit Min on open circuit 1 0 Disabled 1 1 Temperature Degrees C 0 Units Degrees F 1 10 Hz input filter 0 0 Channel 50 Hz input filter 0 1 filter frequency 60 Hz input filter 1 0 250 Hz input filter 1 1 Open circuit o error 0 error Open circuit detected 1 Under range o error 0 error Under range condition 1 Over range OE ITOF 0 error Over range condition 1 Channel o error 0 error Channel error 1 Note It takes one timing cycle to complete an update Refer to Chapter 3 for module update times Publication 1746 6 22 4 14 Channel Configuration Data and Status Publication 1746 6 22 Explanations of the status conditions follow Channel Status Bit 0 The channel status bit indicates operational state of the channel When the channel
2. BTW DONE NT8 CONFIGURED BT20 1 B3 0 JE LS jt DN 4 If the NT8 is configured read the 8 input words into N12 0 N12 7 using repeating BTR s NT8 CONFIGURED BTR TRIGGER B3 0 BT20 0 BTR J E Mt Block Transfer Read CEND 4 EN Module Type Generic Block Transfer Rack 001 CDN gt Group 0 Module 0 L CER2 Control Block BT20 0 Data File N12 0 Length 8 Continuous No CEND gt Publication 1746 6 22 Module and Channel Diagnostics Chapter 6 Troubleshooting Your Module This chapter describes troubleshooting with channel status and module status LEDs It explains the types of conditions that might cause the module to flag an error and suggests what corrective action you could take Topics include module and channel diagnostics LED indicators Interpreting I O error codes troubleshooting flowchart The module operates at two levels module level channel level Module level operation includes functions such as powerup configuration and communication with the SLC processor Channel level operation includes functions such as data conversion and open circuit detection The module performs internal diagnostics at both levels and immediately indicates detected error conditions with either of its status LEDs See the LED troubleshooting tables on page 6 2 for LED operation Module Diagnostics at Powerup At module powerup the module performs a series of internal diagnostic tests If the mo
3. 1 Type B thermocouple cannot be represented in engineering units x1 F above 3276 7 F Software treats it as over range error 2 When millivolts are selected the temperature setting is ignored Analog input data is the same for either C or F selection Publication 1746 6 22 Channel Configuration Data and Status 1746 NT8 Thermocouple Module Channel Data Word Resolution Data Format 4 9 Input Engineering Units x 10 Engineering Units x 1 Scaled for PID Proportional Counts Type Celsius Fahrenheit Celsius Fahrenheit Celsius Fahrenheit Celsius Fahrenheit J 1 C step 1 F step 1 C step 1 F step 0 0592 C step 0 1066 F step 0 0148 C step 0 0266 F step K 1 C step 1 F step 1 C step 1 F step 0 1001 C step 0 1802 F step 0 0250 C step 0 0450 F step T 1 C step 1 F step 1 C step 1 F step 0 0409 C step 0 0736 F step 0 0102 C step 0 0184 F step E 1 C step 1 F step 1 C step 1 F step 0 0775 C step 0 1395 F step 0 0194 C step 0 0349 F step R 1 C step 1 F step 1 C step 1 F step 0 1079 C step 0 1942 F step 0 0270 C step 0 0486 F step S 1 C step 1 F step 1 C step 1 F step 0 1079 C step 0 1942 F step 0 0270 C step 0 0486 F step B 1 C step 1 F step 1 C step 1 F step 0 0928 C step 0 1670 F step 0 0232 C step 0 0417 F step N 1 C step 1
4. Channel Channel Status LED s Status LED s off on Channelis not Channel is enabled enabled and working word bit 0 1 Retry Enable channel if desired by setting channel cont status word bits CJC fault has 12 through 15 pope Channel error Check configuration word bits 1 Bit15 ine ee ps gt e configuration and m gt setli entre bits 12 through 14 Check that wiring is secure are set to zero Retry at both CJ Cs and that the temperature within the enclosure is in the range s limits of the CJ C sens r Over range condition exists The input signal is greater Yes than the high scale limit for i Bitl4 gt thechannelorthe CJC gt set 1 connections Correct and s probl lt ls problem ie retry corrected s problem corrected Under range condition exists The input signal is Bit 13 less than the low scale limit gt set i gt for the channel or the CJC F gt connections Correct and retry No Contact your local An open circuit condition Contact your local Allen Bradley Bit 12 is present Check channel Allen Bradley istributor an wiring for open or istributor distribut set 1 dCJC ff 7 distribut loose connections Retry Publication 1746 6 22 Preventive Maintenance Safety Considerations Chapter Maint
5. extract the drain wire and signal wires remove the foil shield bundle the input cables with a cable strap 4 Connect pairs of drain wires together Channels 0 and 1 Channels 2 and 3 Channels 4 and 5 Channels 6 and 7 Keep drain wires as short as possible 5 Connect the drain wires to the shield inputs of the terminal block if appropriate for thermocouple used Channel 0 and 1 drain wires to pin 5 e Channel 2 and 3 drain wires to pin 10 Channel 4 and 5 drain wires to pin 15 Channel 6 and 7 drain wires to pin 20 6 Connect the signal wires of each channel to the terminal block Important Only after verifying that your connections are correct for each channel trim the lengths to keep them short Avoid cutting leads too short Publication 1746 6 22 Installing And Wiring Your Module 2 9 7 Connect TBI chassis ground connector to the nearest chassis mounting bolt with 14 gauge wire Looking at the face of the module TB1 is near the lower part of the terminal block on the primary side of the PCB LaL as aa Connect ground wire to TB1 before installing module 8 At the sensor end of cables from thermocouple mV devices remove the drain wire and foil shield apply shrink wrap as an option connect to mV devices keeping the leads short Important If noise persists try grounding the opposite end of the cable Ground one end only Publi
6. 2 62 HZ Signal Attenuation with 50 Hz Input Filter 30 40 50 60 Hz Signal Frequency 3dB 4 0T 20 40 60 80 100 120 140 160 180 200 Amplitude in dB r 50 13 1 Hz 100 150 200 250 300 Hz Signal Frequency Publication 1746 6 22 3 6 Things To Consider Before Using Your Module Publication 1746 6 22 Signal Attenuation with 60 Hz Input Filter 3dB 4 0r 20 40 60 80 Amplitude in dB 100 120 440 160 180 200 0 60 120 180 240 300 360 Hz 15 7 Hz Signal Frequency Signal Attenuation with 250 Hz Input Filter 3dB _Or 20 40 60 80 r 100 Amplitude in dB 120 140 160 180 200 0 250 500 750 1000 1250 1500 Hz 65 5 Hz Signal Frequency Channel Step Response The channel filter frequency determines the channel s step response The step response is time required for the analog input signal to reach 95 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 table on page 3 5 shows the step response for each filter frequency Update Time Channel 0 Disabled Calculate Previous Things To Consider Before Using Your Module 3 7 The thermocouple modul
7. Publication 1746 6 22 7 2 Maintaining Your Module And Safety Considerations Publication 1746 6 22 Standing Clear Of Machinery When troubleshooting a problem with any SLC 500 system have all personnel remain clear of machinery The problem may be intermittent and the machine may move unexpectedly Have someone ready to operate an emergency stop switch ATTENTION Possible Equipment Operation Never reach into a machine to actuate a switch Also remove all electrical power at the main power disconnect switches before checking electrical connections or inputs outputs causing machine motion Failure to observe these precautions can cause personal injury or equipment damage Safety Circuits Circuits installed on machinery for safety reasons like over travel limit switches stop push buttons and interlocks should always be hard wired to the master control relay These circuits should also be wired in series so that when any one circuit opens the master control relay is de energized thereby removing power Never modify these circuits to defeat their function Serious injury or equipment damage may result ATTENTION Explosion Hazard Substitution of components may impair suitability for Class 1 Division 2 Do not disconnect equipment unless power has been switched off or the area is known to be non hazardous When in hazardous locations turn off power before replacing or wiring modules Note This equipmen
8. Allen Bradley SLC 500 User Thermocouple mV Analog Input Module Manual Catalog Number 1746 NT8 Important User Information Because of the variety of uses for the products described in this publication those responsible for the application and use of this control equipment 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 The illustrations charts sample programs and layout examples shown in this guide 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 the 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 in this publication Reproduction of the contents of this copyrighted publication in whole or part without written permission of Rockwell Automation is prohibited Throughout this manual we us
9. F step 1 C step 1 F step 0 0793 C step 0 1428 F step 0 0198 C step 0 0357 F step 50 mv 0 1mV step 0 1mV step 0 01mV step 0 01mV step 6 104uV step 6 104yV step 1 526uV step 1 526yV step 100 mv 0 1mV step 0 1mV step 0 01mV step 0 01mV step 12 21uV step 12 21yV step 3 052uV step 3 052yV step CJC Sensor 1 C step 1 F step 1 C step 1 F step 0 0079 C step 0 0143 F step 0 0020 C step 0 0036 F step 1 When millivolts are selected the tempera ure setting is ignored Analog input data is the same for either C or F selection Important Data resolution is not equivalent to data accuracy Input accuracy of 50 uV may span multiple steps for PID and Proportional Counts data types As an example a Type B thermocouple temperature range of 0 to 1820 C provides a voltage input range of 0 to 13 82mV to the 1746 NT8 This is a very small input range and when it is scaled to PID or proportional counts ranges a small input change results in many counts being changed Select Open Circuit State Bits 7 and 8 The open circuit bit field lets you define the state of the channel data word when an open circuit condition is detected for that channel This feature can be disabled by selecting the disable option An open circuit condition occurs when the thermocouple itself or its extension wire is physically separated or open This can happen if the wire gets cut or disconnected from terminal
10. General Considerations Publication 1746 6 22 When using the BAS or KE module to supply power to a 1747 AIC Link Coupler the link coupler draws its power through the module The higher current drawn by the AIC at 24V dc is shown in the table as BASn BAS networked and KEn KE networked Be sure to use these current draw values if the application uses the BAS or KE module in this way Most applications require installation in an industrial enclosure to reduce the effects of electrical interference Thermocouple inputs are highly susceptible to electrical noises due to the small amplitudes of their signal microvolt C Group your modules to minimize adverse effects from radiated electrical noise and heat Consider the following conditions when selecting a slot for the thermocouple module Position the module inaslot away from sources of electrical noise such as hard contact switches relays and AC motor drives away from modules which generate significant radiated heat such as the 32 point I O modules In addition route shielded twisted pair thermocouple or millivolt input wiring away from any high voltage I O wiring Remember that in a modular system the processor or communications adapter always occupies the first slot of the rack Installing And Wiring Your Module 2 5 Module Installation and Removal ATTENTION Possible Equipment Operation Before installing or removing your module always disconnect power from
11. program instructions required to generate the electronic signals that control your application If you do not contact your local Allen Bradley representative for the proper training before using these products This manual covers the 1746 NT8 thermocouple millivolt analog input module It contains the information you need to install wire use and maintain these modules It also provides diagnostic and troubleshooting help should the need arise Publication 1746 6 22 P 2 Preface Related Allen Bradley Documents Publication 1746 6 22 The following table lists several Allen Bradley documents that may help you as you use these products Publication Number Title 1747 2 30 SLC 500 System Overview SGI 1 1 Application Considerations for Solid State Controls 177041 oC es UH Controller Grounding and 1747 62 Installation amp Operation Manual for Modular Hardware S tyle Programmable Controllers 1147 621 Installation amp Operation Manual for Fixed Hardware Style Programmable Controllers 1747 6 15 SLC 500 Instruction Set Reference Manual ABT 1747 TS G001 SLC 500 Software P rogrammers s Quick Reference Guide 174T NP 002 Allen Bradley HHT Hand Held Terminal User Manual 1747 NM009 Getting Started Guide for HHT Hand Held Terminal SD499 Allen Bradley P ublication Index AG 7 1 Allen Bradley Industrial Automation Glossary To obtain a copy of any of the Allen Bradley documents listed c
12. 0 Module Input Image Data Status Word Channel Status Checking Publication 1746 6 22 l e 0 le l e 2 l e 3 le 4 I e 5 l e 6 I e 7 15 Channel 0 Channel Data Status Word Channel 1 Channel Data Status Word Channel 2 Channel Data Status Word Channel 3 Channel Data Status Word Channel 4 Channel Data Status Word Channel 5 Channel Data Status Word Channel 6 Channel Data Status Word Channel 7 Channel Data Status Word You can use the information provided in the status word to determine if the input configuration data for any channel is valid per your configuration in O e 0 through O e 7 The channel status can be analyzed bit by bit In addition to providing information about an enabled or disabled channel each bit s status 0 or 1 tells you how the input data from the thermocouple or millivolt analog sensor connected to a specific channel will be translated for your application The bit status also informs you of any error condition and can tell you what type of error occurred A bit by bit examination of the status word is provided in the chart on the following page Channel Configuration Data and Status 4 13 Channel 0 7 Status Word I e 0 through I e 7 Bit Definitions
13. 1 0 CDN Preset 60 Accum 20 UM 60 seconds start CJ C check cycle by changing Channel 0 configuration word and latching Checking CJ C bit B3 CJC CYCLE TMR DN NT8 CONFIGURATION T11 0 MOV 0004 F Move DN Source N10 8 32737 lt Dest O 1 0 32767 CHECKING CJC B3 6 CL 4 Publication 1746 6 22 Programming Examples 5 5 Wait 7 seconds for Channel 0 to accept CJ C configuration and provide a data value time depends on module configuration CHECKING CJC CJC_CFG_TMR B3 6 TON 0005 lE Timer On Delay CEND 4 Timer TII Time Base 1 0 CDN2 Preset TS Accum 0 lt Copy CJ C Temperature I 1 0 into CJ C register N10 12 CJC CFG TMR DN CJC TEMP TII B3 0 MOV 0006 HE OSR Move DN 4 Source I1 0 3744 Dest N10 12 329 Move Channel 0 s regular configuration word into the Channel 0 configuration word and start timer to ensure word has been accepted prior to taking the thermocouple temperature readings CJC CFG TMR DN NT8 CONFIGURATION TII MOV 0007 JE Move DN Source N10 0 32767 lt Dest O 1 0 32767 lt REG_CFG_TMR TON Timer On Delay CEN gt Timer T11 2 Time Base 1 0 lt DN gt Preset 7 lt Accum 0 lt When CJC check cycle is completed T11 2 DN is set reset the Checking CJ C Bit B3 100 REG CFG TMR DN CHECKING CJC T11 2 B3 6 0008 E CU DN 4 0009 CE
14. 3 The accuracies specified as follows include errors due to the cold junction compensation for thermocouples and hardware and software errors associated with the system The hardware and software errors include calibration of the system and non linearity of the ADC For the sake of the calculations the resolution of the ADC was assumed to be at least 16 bits use of the 10 Hz 50 Hz and 60 Hz filter frequencies Note The 250 Hz frequency should not be applied to thermocouple inputs See table on page 3 4 Millivolt For millivolt inputs the error is 30 uV typical at 25 C and 120 uV maximum over temperature for the 10 Hz 50 Hz and 60 Hz filter frequencies The 250 Hz filter frequency accuracy is highly dependent upon operating environment and may be worse in noisy environments As with any high precision analog input device system grounding does affect the accuracy of the readings Care should be taken to ensure that the proper filter frequency has been selected based on the environmental conditions in which the module is to be used CJC compensation does not affect the millivolt inputs in terms of accuracy The following diagrams are provided to give a measure of system accuracy using test data from a single test module The tests recorded deviation between measured and expected values This data was taken over an entire range of the thermocouple or millivolt range as applicable and over the module s temperature ra
15. 400 C 454 F to 752 F B 300 C to 1820 C 572 C to 3308 F E 270 C to 1000 C 454 F to 1832 F R 0 C to 1768 C 32 F to 3214 F S 0 C to 1768 C 32 F to 3214 F N 0 C to 1300 C 32 F to 2372 F CJ C Sensor 25 C to 105 C 13 F to 221 F Millivolt Input Ranges 50 to 50 mV 100 to 100 mV Publication 1746 6 22 1 2 Module Overview Publication 1746 6 22 Channel Status LEDs Green Module Status esce r LED Green Removable CJC Sensors Cable Tie Slots Terminal wa Each input channel is individually configured for a specific input device and provides open circuit over range and under range detection and indication Hardware Features The module fits into any single slot for I O modules in either an SLC 500 modular system or an SLC 500 fixed system expansion chassis 1746 A2 except the zero slot which is reserved for the processor It is aClass 1 module using 8 input words and 8 output words The module contains a removable terminal block providing connections for eight thermocouple and or analog input devices On the terminal block are two cold junction compensation CJC sensors that compensate for the cold junction at ambient temperature It should also be noted there are no output channels on the module Configure the module with software rather than with jumpers or switches Important There is a jumper JP1 on the circuit board The module is
16. 5VDC Amps 24VDC Amps 0 120 0 070 Considerations for a Modular System Place your module in any slot of an SLC 500 modular or modular expansion chassis except for the left most slot slot 0 reserved for the SLC processor or adapter modules When using the module with a modular system add the values shown above to the requirements of all other modules in the SLC to prevent overloading the chassis power supply Refer to the SLC 500 Modular Hardware Style Instruction and Operating Manual publication 1747 6 2 Installing And Wiring Your Module 2 3 Fixed I O Chassis I O Module Compatibility The following chart depicts the range of current combinations supported by the fixed I O expansion chassis To use it find the backplane current draw and operating voltage for both modules being used in the chassis These specifications are found in the table alongside the chart Next plot each of the currents on the chart below If the point of intersection falls within the operating region the combination is valid If not the combination cannot be used in a 2 slot fixed I O chassis Module Current Draw Power Supply Loading 1 0 Module 5V 24V VO Module 5V 24V BAS 150 040 IKE 150 040 BASn 150 125 KEn 150 125 DCM 360 000 NI4 025 085 450 N OA16and FIO4I 055 150 NI8 200 100 0 455 FI
17. B 1060 C 1940 F 2 7 C 4 86 F N 500 C 932 F 1 3 C 2 34 F Publication 1746 6 22 A 6 Module Specifications The following table provides the total error expected over the temperature range of the module 0 to 60 C for each thermocouple based upon the type and the given reference point at the extremes of the temperature range 0 or 60 C The calculations are based on maximum hardware software error and maximum CJC inaccuracy over temperature Thermocouple Type haii o Error J 275 C 527 F 3 0 C 5 4 F K 550 C 1022 F 3 0 C 5 4 F T 65 C 149 F 3 4 C 6 12 F E 365 C 689 F 2 5 C 4 5 F R 885 C 1625 F 6 5 C 11 7 F S 885 C 1625 F 7 2 C 12 96 F B 1060 C 1940 F 8 4 C 15 12 F N 500 C 932 F 3 0 C 5 4 F The diagrams that follow for each thermocouple type give data for a sample module over the input range of the thermocouple over temperature Thermocouples are usually parabolic in their uV to C curves Normally at the ends of any given thermocouple range the ratio of change in temperature increases as a result of a change in voltage In other words at the ends a smaller change in voltage results in a larger change in C The data that follows gives an idea of a sample module s error over the thermocouple range versus at a single reference point as provided with the tables above Note Th
18. CJC sensors Terminal Block Release Screws CJ C Sensors gt _ 3 Recommended Torque wiring screws 0 25 Nm 2 2 in Ib release screws 0 25 Nm 2 2 in Ib CJ C Sensors gt qg Terminal Block 4 Release Screws ATTENTION Possible Equipment Operation Before wiring your module always disconnect power from the SLC 500 system and from any other source to the module Failure to observe this precaution can cause unintended equipment operation and damage Wiring Your Module Installing And Wiring Your Module 2 7 Follow these guidelines to wire your input signal cables Power input and output I O wiring must be in accordance with Class 1 Division 2 wiring methods Article 501 4 b of the National Electrical Code NFPA 70 and in accordance with the authority having jurisdiction Route thermocouple and millivolt signal wires as far as possible from sources of electrical noise such as motors transformers contactors and ac devices As a general rule allow at least 6 in about 15 2 cm of separation for every 120V ac of power Routing the field wiring in a grounded conduit can reduce electrical noise further If the field wiring must cross ac or power cables ensure that they cross at right angles For high immunity to electrical noise use Belde
19. Configure eight channels of a thermocouple module residing in slot 3 of 1746 chassis Configure each channel with the same parameters Channel Configuration 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 A A A A Configure Channel for NN ae Enable Bit e Type K Thermocouple Input e Engineering Units X 10 e Zero if Open Circuit e Fahrenheit e 10 Hz Filter Frequency e Not Used e Data Word The following procedure transfers configuration data and sets the channel enable bits of all eight channels with a single File Copy instruction Publication 1746 6 22 5 2 Programming Examples Procedure 1 Create integer file N10 Integer file N10 should contain eight elements N10 0 through N10 7 2 Using the programming software enter the configuration parameters for all eight thermocouple channels into data file locations N10 0 through N10 7 Data table for initial programming address 15 data 0 address 15 data 0 N10 0 1000 0010 0010 0011 N10 1 1000 0010 0010 0011 N10 2 1000 0010 0010 0011 N10 3 1000 0010 0010 0011 N10 4 1000 0010 0010 0011 N10 5 1000 0010 0010 0011 N10 6 1000 0010 0010 0011 N10 7 1000 0010 0010 0011 Press a key or enter value N10 3 0 1 offline no forces binary data decimal addr File EXMPL CHANGE SPECIFY NEXT PREV RADIX ADDRESS FILE FILE F1 F5 F7 F8 3
20. Table of Contents Module Specifications Appendix A Electrical Specifications 152 2 30 pce bot vet bte A 1 Physical Specifications es titi ard tbe gra e S as A 1 Environmental Specifications 00 cece eee A 2 Input Specifications 42s voee b etre k beady ede A 2 DverallAGCUIaC V soos er bna eru Ep VUES dus A 2 MilliVOlL dada ed Seed eu act d ce eb PEE CRT A 3 Thermocouples corsa e err i ts A 5 Using Grounded Junction Ungrounded Junction and Exposed Junction Thermocouples Appendix B Thermocouple Types s u ve rae ae E n an B 1 Grounded unction sua eo 1d oer v ela dd E B 2 Ungrounded Insulated J unction sss B 2 Exposed unction ise vea ter ben eant B 2 ISOIGUON aus s dodo tb tap tet dads B 2 Grounded J unction Thermocouples aaa sisse B 3 Exposed J unction Thermocouples 005 B 4 Glossary Index Publication 1746 6 22 Who Should Use This Manual What This Manual Covers Preface Read this preface to familiarize yourself with this user manual This preface covers who should use this manual what this manual provides related Allen Bradley documents common techniques used in this manual Allen Bradley support Use this manual if you design install program or maintain a control system that uses Allen Bradley Small Logic Controllers SLC You should have a basic understanding of SLC 500 products You should also understand electronic process control and the ladder
21. an error in the configuration word or an error has occurred while acquiring the A D data value If during the auto calibration process the module detects an out of range condition for the filter frequency selected for the channel the channel error bit is set An out of range condition occurring during auto calibration would be the result of an overly noisy environment whereby the module cannot maintain accuracy specifications thus flagging an error The error bit is cleared when the error condition is resolved The channel data word is not updated during a period of auto calibration filter frequency tolerance errors Publication 1746 6 22 Chapter 5 Programming Examples Earlier chapters explained how the configuration word defines the way a channel operates This chapter shows the programming required to configure the module It also provides you with segments of ladder logic specific to unique situations that might apply to your programming requirements The example segments include basic example automatic monitoring thermocouples and CJC sensors verifying channel configuration changes interfacing to the PID instruction monitoring channel status bits e PLC 5 example with NT8 in remote I O rack Basic Example To enter data into the channel configuration word O e 0 through O e 7 when the channel is disabled bit 0 0 follow these steps Refer to the table on page 4 4 for specific configuration details Example
22. and Information Group Technical Communication Dept A602V T122 P O Box 2086 Milwaukee WI 53201 2086 Publication 1746 6 22 General Description Chapter 1 Module Overview This chapter describes the thermocouple mv input module and explains how the SLC 500 processor reads thermocouple or millivolt analog input data from the module Read this chapter to familiarize yourself further with your thermocouple mV analog input module This chapter covers general description and hardware features e an overview of system and module operation block diagram of channel input circuits This module is designed exclusively to mount into 1746 I O racks for use with SLC 500 fixed and modular systems The module stores digitally converted thermocouple mV analog data in its image table for retrieval by all fixed and modular SLC 500 processors The module supports connections from any combination of up to eight thermocouple mV analog sensors Input Ranges The following tables define thermocouple types and associated temperature ranges and the millivolt analog input signal ranges that each of the module s input channels support To determine the practical temperature range of your thermocouple refer to the specifications in appendix A Thermocouple Temperature Ranges Type C Temperature Range F Temperature Range J 210 C to 760 C 346 F to 1400 F K 270 C to 1370 C 454 F to 2498 F T 270 C to
23. block If either of the two CJC devices is removed from the terminal block any input channel configured for either a thermocouple or CJC temperature input is placed in an open circuit condition An input channel configured for millivolt input is not affected by CJC open circuit conditions The results of the data word in an open circuit condition depend upon the selection of bits 7 and 8 If zero is selected 00 the channel data word is forced to 0 during an open circuit condition Publication 1746 6 22 4 10 Channel Configuration Data and Status Publication 1746 6 22 Selecting maximum forces the 01 channel data word value to its full scale value during an open circuit condition The full scale value is determined by the selected input type and data format Selecting minimum forces the 10 channel data word value to its low scale value during an open circuit condition The low scale value is determined by the selected input type and data format Disabling the open circuit selection 11 may result in unintended operation on a failure Generally with the open circuit option disabled the data word remains unchanged The open circuit error bit and the channel LED flags the condition until the error is resolved For example if channel one is configured as a thermocouple type when the CJC breaks in an open circuit condition if open circuit detection is disabled the data word remains unchanged If the circuit selection is
24. enable bit is set in the configuration word the thermocouple module configures the selected channel and takes a data sample for the channel data word before setting this bit in the status word Input Type Status Bits 1 through 4 The input type bit field indicates what type of input signal you have configured for the channel This field reflects the input type defined in the channel configuration word Data Format Type Status Bits 5 and 6 The data format bit field indicates the data format you have defined for the channel This field reflects the data type selected in bits 5 and 6 of the channel configuration word Open Circuit Type Status Bits 7 and 8 The open circu1 f 9 1 d do1 d TJOf T co det type 979 TD o w 8 n c 1 yo 11 u ha 1 Channel Configuration Data and Status 4 15 Under Range Error Bit 13 This bit is set 1 whenever a configured channel detects an under range condition for the channel data An under range condition exists when the input value is equal to or below the specified lower limit of the particular sensor connected to that channel Over Range Error Bit 14 This bit is set 1 whenever a configured channel detects an over range condition for the channel data An over range condition exists when the input value is equal to or above the specified upper limit of the particular sensor connected to that channel Channel Error Bit 15 This bit is set 1 whenever a configured channel detects
25. image word should contain data or status Place a one in bit 15 if channel data is desired Place a zero in bit 15 if status is desired Build the channel configuration word for every channel on each thermocouple mV module repeating the procedures given in steps 1 through 8 Enter this configuration into your ladder program and download it to the thermocouple module Publication 1746 6 22 4 4 Channel Configuration Data and Status A detailed explanation appears in the following table Channel Configuration Word 0 e 0 through O e 7 Bit Definitions 15 14 13 12 11 10 8 7 6 5 4 3 2 1 0 Channel Enable Channel Disable 0 Channel Enable 1 Thermocouple Type J 0 0 0 0 Thermocouple Type K 0 0 0 1 Thermocouple Type T 0 0 1 0 Thermocouple TypeE 0 0 1 1 Thermocouple Type R 0 1 0 0 Thermocouple TypeS 0 1 0 1 Thermocouple Type B 0 1 1 0 Input Thermocouple Type N 0 1 1 1 Type 50 mV 1 0 0 0 100 mV 1 0 0 1 Invalid 1 0 1 0 Invalid 1 0 1 1 Invalid 1 1 0 0 Invalid 1 1 0 1 Invalid 1 1 1 0 CJ C temperature 1 1 1 1 Engineering Units x 1 0 0 Data Engineering Units x 10 0 1 Format Scaled for PID 1 0 Proportional counts 1 1 Zero on open circuit 0 0 ad Max on open circuit 0 1 Open Circuit Min on open circuit 1 0 Disabled 1 1 Temperature Degr
26. range The input signal range is proportional to your selected input and scaled into a 32 768 to 32 767 range Publication 1746 6 22 4 6 Channel Configuration Data and Status Publication 1746 6 22 Using Scaled for PID and Proportional Counts The thermocouple module provides eight options for displaying input channel data These are 0 1 F 0 1 C 1 F 1 C 0 01 mV 0 1 mV Scaled for PID and Proportional Counts The first six options represent real Engineering Units displayed by the 1746 NT8 and do not require explanation The Scaled for PID and Proportional Counts selections provide the highest NT8 display resolution but also require you to manually convert the channel data to real Engineering Units The equations below show how to convert from Scaled for PID to Engineering Units Engineering Units to Scaled for PID Proportional Counts to Engineering Units and Engineering Units to Proportional Counts To perform the conversions use the defined temperature or millivolt range for the channel s input type See the Channel Data Word Format table on page 4 7 The lowest possible value for an input type is Sy ow and the highest possible value is Sgyag Effective Resolutions The effective resolution for an input channel depends upon the filter frequency selected for that channel Scaling Examples Equation Solution Equation Solution Equation Solution Equation Solution Channel Configuration Da
27. shipped with the jumper in the up position as illustrated below Do not change the position of JP1 The jumper is used for test purposes only Side Label y INPUT UM gas His Door Label IZ 1746 NTE GIGA 4 CICA TTT BE SHEEEEEEEEEEEEEEE ICE Nou Pt t a h J umper Do Not Move Self Locking Tabs 1 Requires use of a Block Transfer when used in a remote rack with a 1747 ASB System Overview Module Overview 1 3 Hardware Features Thermocouple or mV A4 Channel Status Word Thermocouple SLC 500 npu Analog Signals Module Processar gt Channel Configuration Word Hardware Function Channel Status LED Indicators Display operating and fault status of channels 0 7 Module Status LED Displays operating and fault status of the module Side Label Nameplate Provides module information Removable Terminal Block Provides electrical connection to input devices Door Label Permits easy terminal identification Cable Tie Slots Secure and route wiring from module Self Locking Tabs Secure module in chassis slot Diagnostic LEDs The module contains diagnostic LEDs that help you identify the source of problems that may occur during power up or during normal operation Power up
28. 0 Dest 0 1 0 Length 8 After copying the Status Check configuration words start a 7 second timer T11 1 to allow the NT8 to update its 1 0 mage to the channel status words The time required for the NT8 to update its I O image is dependent on the NT8 l configuration Note the time required be greater than the channel update time including the autocalibration time NT8_CHECKING_STS NT8_STS_CNF_TMR B3 6 TON JE Timer On Delay CEN gt Timer Tiri Time Base 10 lt DN gt Preset 7 lt Accum 0 lt Publication 1746 6 22 5 10 Programming Examples After waiting for the NT8 to update its I O image check each channel s status error bits by masking off the appropriate bits and checking if these bits are set non zero If an error is detected set the appropriate channel status error bits B3 112 B3 119 Rung 5 checks channels 0 3 NT8 STS CNF TMR DN NT8 CHECK FLAGS T11 1 B3 6 MOV 0005 lE OSR Move DN 5 Source 0 0 lt Dest B3 7 0000000000000001 lt NT8_CH0_STS_FLAGS MVM Masked Move Source 1 1 0 0 lt Mask OFO000h 4096 Dest N10 20 4096 NT8 CHO STS FLAGS NT8 CH0 ERROR NEQ B3 7 Not Equal CL Source A N10 20 0 4096 lt Source B 0 0 lt NT8_CH1_STS_FLAGS MVM Masked Move Source Era 0 lt Mask OFO000h 4096 lt Dest N10 21 0 lt NT8_CH1_STS_FLAGS NT8_CH1_ERROR NEQ B3 7 Not Equal cL Sou
29. 0003 0004 Programming Examples 5 9 Monitoring Channel Status Bits Example During 1st program scan copy thermocouple channel configuration words N10 0 N10 7 to NT8 In addition initialize channel error registers N10 20 N10 27 and Error Flags B3 112 B3 119 NT8_CH_CNF S 1 COP J E Copy File 15 Source N10 0 Dest 0 1 0 Length 8 NT8_CHO_STS_FLAGS FLL Fill File TL Source 0 Dest N10 20 Length 8 CLR Clear Dest B3 7 0000000000000001 lt If the NT8 is not checking channel status store the thermocouple readings in the NT8 last channel reading registers METTE thes registers should be used in the remainder of the program e g for temperature control instead of the image location NT8 CHECKING STS ZNT8 LAST TEMP READ B3 6 COP t Copy File 4 Source 1 1 0 Dest N10 30 Length 8 T11 0 is a repeating 60 second timer which initiates the NT8 channel status check NT8 STS CHECK TMR DN NT8 STS CHECK TMR T11 0 TON Timer On Delay CEND DN Timer T11 0 Time Base 10 DN Preset 60 Accum 10 Every 60 seconds initiate a NT8 channel status check by latching the NT8 channel status checking bit and copying the Status check configuration words N10 10 N10 7 to the NT8 configuration words NT8_STS_CHECK_TMR DN NT8_CHECKING_STS T11 0 B3 6 JF L DN 4 NT8_CH_CNF COP Copy File Source N10 1
30. 7 Address 0 e 0 0 e 1 0 e2 0 e 3 0 e 4 0 e 5 0 e 6 0 e 7 l e 0 I e 1 I e 2 l e 3 I e 4 I e 5 I e 6 I e 7 Address 3 2 Things To Consider Before Using Your Module Module Addressing The following memory map shows you how the SLC processor s output and input tables are defined for the module Image Table Bit 15 Bit 0 Channel 0 Configuration Word Channel 1 Configuration Word Channel 2 Configuration Word Thermocouple Channel 3 Configuration Word SLC 5 0X Module Channel 4 Configuration Word Data Files Output acida Channel 5 Configuration Word Siok Scan Channel 6 Configuration Word Vndc EE Output Image Channel 7 Configuration Word Output Image 8 Words ppl Ste can ga TE bar etl edad ngut Image Input Image Words Channel 0 Data or Status Word Channel 1 Data or Status Word Channel 2 Data or Status Word Channel 3 Data or Status Word Channel 4 Data or Status Word Channel 5 Data or Status Word Channel 6 Data or Status Word Channel 7 Data or Status Word Bit 15 Bit 0 Publication 1746 6 22 Output Image Configuration Words Eight words of the SLC processor s output image table are reserved for the module Output image words 0 7 are used to configure the module s input channels 0 7 Each output image word configures a single channel and can be referred to as a configuration word Each word has a unique address based on the slot number assigned to the module Example Address If you want to configure channel 2 o
31. Auto calibration occurs immediately following configuration of a previously unselected filter frequency and generally every two minutes for all selected filter frequencies of the system The time required to perform auto calibration is defined as follows Auto calibration Time 250 Hz Filter 60 Hz Filter SOHzFilter 10 Hz Filter 325 msec 525 msec 585 msec 1 975 s CJC sensors are acquired at 60 Hz to maximize the trade offs between resolution and update rate For example if some channels are acquired at 250 Hz and some are acquired at 50 Hz then the total auto calibration time would be 25047 35m 60 Hz 525 msec 50 Hz 585 msec 1 435 sec Total During auto calibration input values are not updated Things To Consider Before Using Your Module 3 9 Response to Slot By writing to the status file in the modular SLC processor you can Disabling disable any chassis slot Refer to your SLC programming manual for the slot disable enable procedure ATTENTION POSSIBLE EQUIPMENT OPERATION Always understand the implications of disabling a module before using the slot disable feature Failure to observe this precaution can cause unintended equipment operation Input Response When a thermocouple slot is disabled the thermocouple module continues to update its input image table However the SLC processor does not read input from a module that is disabled Therefore when the processor disables the thermocoupl
32. ND2 Data Table for Configuration Changes address 15 data 0 address 15 data 0 N10 0 0000 0010 0010 0011 N10 8 0000 0010 0011 1111 N10 1 0000 0010 0010 0011 N10 2 0000 0010 0010 0011 N10 3 0000 0010 0010 0011 N10 4 0000 0010 0010 0011 N10 5 0000 0010 0010 0011 N10 6 0000 0010 0010 0011 N10 7 0000 0010 0010 0011 Publication 1746 6 22 5 6 Programming Examples Update Time Calculation Ch 0 Update Time 0 470 Ch 0 Open Circuit Check 0 045 Ch 1 Update Time 0 470 Ch 1 Open Circuit Check 0 045 Ch 2 Update Time 0 470 Ch 2 Open Circuit Check 0 045 Ch 3 Update Time 0 470 Ch 3 Open Circuit Check 0 045 Ch 4 Update Time 0 470 Ch 4 Open Circuit Check 0 045 Ch 5 Update Time 0 470 Ch 5 Open Circuit Check 0 045 Ch 6 Update Time 0 470 Ch 6 Open Circuit Check 0 045 Ch 7 Update Time 0 470 Ch 7 Open Circuit Check 0 045 CJ C Checking 0 290 Update Time 4 410 Autocalibration Time Calculation Auto Calibration for 10 Hz 1 975 Auto Calibration for 60 Hz 0 525 Total Auto Calibration 2 500 Max Time Between Updates 6 910 After a channel configuration word is changed by the ladder logic the module may not update the processor s input image until one update time later In order to ensure that the program is using the proper input data the ladder logic should wait one update time plus one calibration time to ensure that the new input data matches the channel configuratio
33. O4V 055 120 NIO4I 055 145 400 HS 300 000 NIO4V 055 115 HSTP1 200 000 NO4I 055 195 350 IA 035 000 NO4V 055 145 A8 050 000 NR4 050 050 2 IA16 085 000 INT4 060 040 250 OWl6andlA16 IB8 050 000 OA16 370 000 Cunent 180 255 mA B16 085 000 OA8 185 000 aV de ag de E B32 106 000 OAP12 370 000 IC16 085 000 OB8 135 000 150 a ted from G16 140 000 OB16 280 000 i Poux IH16 085 000 OB16E 135 000 M4 035 000 0832 452 000 50 IM8 050 000 OBP8 135 000 M16 085 000 OBP16 250 000 IN16 085 000 0G16 180 000 50 100 150 200 104 030 025 OV8 135 000 Current mA at 24V 108 060 045 OV16 210 000 Example Plot IN16 and NIO4V iss 13 UTE iia am IN16 0 085 at 5V dc and 0A at 24V dc HT LIEN Le poe a a NIO4V 0 055A at 5V dc and 0 115A at 24V dc ITV16 085 000 OW16 A70 180 1 Add current draws of both modules at 5V dc to get 0 14 IV8 050 000 OW4 045 045 140mA V16 085 000 OW8 485 090 2 Plotthis point on the chart above 140mA at5V dc V32 106 000 0X8 085 090 3 Add current draws of both modules at 24V dc to get 4 5 0 115A 115mA Plot current draw at 24V dc 115mA at 24V dc Note the point of intersection on the chart above marked x This combination falls within the valid operating region for the fixed I O chassis Important The1746 NO4lI and 1746 NO4V analog output modules may require an external power supply Publication 1746 6 22 2 4 Installing And Wiring Your Module
34. Program a rung in your ladder logic to copy the contents of integer file N10 to the eight consecutive output words of the thermocouple module beginning with O 3 0 Initial programming example During the first pass send the channel configuration data to the thermocouple module First Pass s3NT8 CONFIGURATION Sil COP 0000 qJ E Copy File 15 Source N10 0 Dest 0 3 0 Length 8 0001 C END 2 On power up bit S 1 15 is set for the first program scan During the first program scan the configuration data in N10 0 through N10 7 will be sent to the 1746 NT8 channel configuration words Publication 1746 6 22 Automatic Monitoring Thermocouples and CJC Sensors Verifying Channel Configuration Changes Programming Examples 5 8 The following example explains how to change data in the channel configuration word when the channel is currently enabled Example Execute a dynamic configuration change to channel 0 of the thermocouple module located in slot 1 of a 1746 chassis Periodically e g every 60 seconds change from monitoring an external type K thermocouple to monitoring the CJC sensors mounted on the terminal block The CJC reading gives a good indication of what the temperature is inside the control cabinet Finally set channel 0 back to type K thermocouple Important During configuration alteration the state of each modified channel can not be determined until after one module update time N
35. Reconfiguration WINGS cm PKT 3 8 Auto Calibration eee ene a aa ne toa Listes ee atus 3 8 Response to Slot Disabling cece eee eee aes 3 9 IIBUERCSDONS Ort seri see roter 3 9 Output Response osa nota ett hae ates 3 9 Chapter 4 Channel Configuration 08r Eee oie eve ee ed 4 1 Channel Configuration Procedure 0005 4 2 Select Channel Enable Bit0 cee ae 4 5 Select Input Types Bits 1 through 4 4 5 Select Data Format Bits 5 and 6 issus 4 5 Using Scaled for PID and Proportional Counts s aaura geek ye teeta se 4 6 Effective Resolutions 0cse cece aes 4 6 Scaling Examples scorta ele so RA aas 4 7 Select Open Circuit State Bits 7and8 4 9 Select Temperature Units Bit9 08 4 10 Select Channel F ilter Frequency BISA Oa sl e aca uterine eer g uraia vera cia 4 10 Unused Bits Bits 12 through 14 4 11 Select Input Image Type Bit 15 05 4 11 Channel Data Status Word cc cece eee eens 4 12 Channel Status Checking cc cece cece eeues 4 12 Channel Status Bi 21r vei e tese 4 14 Input Type Status Bits 1 through 4 4 14 Data Format Type Status Bits 5 and6 4 14 Open Circuit Type Status Bits 7and8 4 14 Temperature Units Type Status Bit9 4 14 Programming Examples Troubleshooting Your Module Maintaining Your Module And Safety Considerations Table
36. Status tueri Then Take this Corrective Action LED is On Poki i5 No action required Examine error bits in status word The module f bit 12 1 the input has an open circuit SUE IE f bit 13 1 the input value is under On ob under range I bit 14 1 the input value is over condition over range TECHN E HNR range condition f bit 1521 the channel has a diagnostic channel error The module is in Off Cannel or the No action is required disabled Publication 1746 6 22 Troubleshooting Your Module 6 3 Channel status LEDs Green The channel status LED operates with status bits in the channel status word to indicate the following faults detected by the module invalid channel configuration anopen circuit input out of range errors selected filter frequency data acquisition or auto calibration errors When the module detects any of the following fault conditions it causes the channel status LED to flash and sets the corresponding fault bit in the channel status word Channel fault bits bits 12 through 15 and channel status LEDs are self clearing when fault conditions are corrected Open circuit Detection Bit 12 If open circuit detection is enabled for an input channel the module tests the channel for an open circuit condition each time it scans its input Open circuit detection is always performed for the CJC inputs Possible causes of an open circuit include broken thermocouple or CJC sensor the
37. aining Your Module And Safety Considerations Read this chapter to familiarize yourself with preventive maintenance safety considerations The National Fire Protection Association NFPA recommends maintenance procedures for electrical equipment Refer to article 70B of the NFPA for general safety related work practices The printed circuit boards of your module must be protected from dirt oil moisture and other airborne contaminants To protect these boards install the SLC 500 system in an enclosure suitable for its operating environment Keep the interior of the enclosure clean and whenever possible keep the enclosure door closed Also regularly inspect the terminal connections for tightness Loose connections may cause a malfunctioning of the SLC system or damage to the components ATTENTION Possible Loose Connections Before inspecting connections always ensure that incoming power is OFF Failure to observe this precaution can cause personal injury and equipment damage Safety is always the most important consideration Actively think about the safety of yourself and others as well as the condition of your equipment The following are some things to consider Indicator Lights When the module status LED on your module is illuminated your module is receiving power Activating Devices When Troubleshooting Never reach into a machine to activate a device the machine may move unexpectedly Use a wooden stick
38. and channel diagnostics are explained in Chapter 6 Testing Your Module The module communicates with the SLC 500 processor and receives 5V dc and 24V dc power from the system power supply through the parallel backplane interface No external power supply is required You may install as many thermocouple modules in the system as the power supply can support Each module channel can receive input signals from a thermocouple or a mV analog input device You configure each channel to accept either one When configured for thermocouple input types the module converts analog input voltages into cold junction compensated and linearized digital temperature readings The module uses National Institute of Standards and Technology NIST ITS 90 for thermocouple linearization When configured for millivolt analog inputs the module converts analog values directly into digital counts The module assumes that the mV input signal is linear System Operation At power up the module checks its internal circuits memory and basic functions During this time the module status LED remains off If the module finds no faults it turns on its module status LED Channel Data Word Publication 1746 6 22 1 4 Module Overview Publication 1746 6 22 After completing power up checks the module waits for valid channel configuration data from your SLC ladder logic program channel status LEDs are off After channel configuration da
39. annels 0 7 respectively dependent on bit in configuration word O e 0 7 configuration data for channels 0 7 respectively See Module Addressing on page 3 1 to see the module s image table Within 12 5V Block Diagram Terminal Block Module Overview Module Circuitry CJ CA Sensor ungrounded B2 thermocouple O Shield to 2 e Shield Q4 ded T rounde ermocouple e Shield o je Shield gl CJCB Sensor ultiplexer User Selected Filter Frequency 1 5 Analog to pj ital s Digital Digital Converter Fifter Value Analo round Important When using multiple thermocouples the potential between any two channels cannot exceed the channel to channel differential voltage 12 5 volts For more information see Appendix B Publication 1746 6 22 1 6 Module Overview Linear Millivolt Device Compatibility A large number of millivolt devices may be used with the 1746 NT8 module For this reason we do not specify compatibility with any particular device However millivolt applications often use strain gage bridges A resistive voltage divider using fixed resistors is recommended for this application The circuit diagram below shows how this connection is made guain age Bridge Voc variable 1746 NT8 i Channel L i i Input U
40. ary Publication 1746 6 22 Digital filter A low pass filter of the A D converter The digital filter provides high frequency noise rejection Effective resolution The number of bits in the channel data word that do not vary due to noise Full scale error gain error The difference in slope between the actual and ideal analog transfer functions Full scale range FSR The difference between the maximum and minimum specified analog values Gain drift The change in full scale transition voltage measured over the operating temperature range of the module Input data scaling Depends on the data format that you select for the channel data word You can select from scaled for PID or Engineering Units for millivolt thermocouple or CJC inputs which you must compute to fit your application s temperature or voltage resolution Local system A control system with I O chassis within several feet of the processor and using 1746 C7 or 1746 C9 ribbon cable for communication LSB least significant bit The bit that represents the smallest value within a string of bits The weight of this value is defined as the full scale range divided by the resolution Multiplexer A switching system that allows several input 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 circ
41. atus Bits Publication 1746 6 22 The following example shows how to monitor the open circuit error bits of each channel and set an alarm in the processor if one of the thermocouples opens An open circuit error can occur if the thermocouple breaks one of the thermocouple wires gets cut or disconnected from the terminal block or if the CJC sensors are not installed or are damaged Important If a CJC input is not installed or is damaged all enabled thermocouple alarms are set and all enabled thermocouple channel LEDs flash The example shows how to automatically switch between reading the channel status words and channel sensor data words Specifically this example shows a simple method of utilizing a timer to periodically switch between reading the channel status and data words The program utilizes a timer accumulator value to determine when to set up the configuration words and when to read in the channel status and channel data information The channel status information is copied from the I 2 0 to I 2 7 registers into registers N7 10 to N7 17 The channel data information is copied from I 2 0 to I 2 7 into registers N7 0 to N7 7 This allows sensor data and channel status information to be accessed at any time from these registers However when the module channels are configured to read sensor data the channel status words as reflected in N7 10 to N7 17 are not being dynamically updated and vice versa 0000 0001 0002
42. backplane 12 5V dc continuous between channels LED Indicators 9 green status indicators one for each of 8 channels and one for module status odule ID Code 3533 Recommended Cable for thermocouple inputs for mV inputs Appropriate shielded twisted pair thermocouple extension wire Belden 8761 or equivalent aximum Wire Size One 14 AWG wire or two 22 AWG wires per terminal 1 Refer to the thermocouple manufacturer for the correct extention wire Publication 1746 6 22 A 2 Module Specifications Environmental Specifications Input Specifications Publication 1746 6 22 Operating Temperature 0 C to 60 C 32 F to 140 F Storage Temperature 40 C to 85 C 40 F to 185 F Relative Humidity 5 to 95 without condensation Certification UL amp CUL approved Hazardous Environment Classification Class Division 2 Hazardous Environment Groups A B C D EMC CE compliant Type of Input S electable Thermocouple Type J 210 C to 760 C 346 F to 1400 F Thermocouple Type K 270 C to 1370 C 454 F to 2498 F Thermocouple Type T 270 C to 400 C 454 F to 752 F Thermocouple Type E 270 C to 1000 C 454 F to 1832 F Thermocouple Type R 0 C to 1768 C 32 F to 3214 F Thermocouple Type S 0 C to 1768 C 32 F to 3214 F Thermoc
43. cables 2 1 Reach us now at www rockwellautomation com Wherever you need us Rockwell Automation brings together leading brands in industrial automation including Allen Bradley controls Reliance Electric power transmission products Dodge mechanical power transmission components and Rockwell Software Rockwell Automation s unique flexible approach to helping customers achieve a competitive advantage is supported by thousands of authorized partners distributors and system integrators around the world Americas Headquarters 1201 South Second Street Milwaukee WI 53204 USA Tel 1 414 382 2000 Fax 1 414 382 4444 Rockwell European Headquarters SA NV avenue Herrmann Debroux 46 1160 Brussels Belgium Tel 32 2 663 06 00 Fax 32 2 663 06 40 Asia Pacific Headquarters 27 F Citicorp Centre 18 Whitfield Road Causeway Bay Hong Kong Tel 852 2887 4788 Fax 852 2508 Automation Publication 1746 6 22 July 1999 1999 Rockwell International Corporation All rights reserved Printed in the U S A
44. cation 1746 6 22 2 10 Installing And Wiring Your Module Terminal Block Diagram with Input Cable LL CJCA Secure Thermocouple or mV Cable Channel 0 I gt Channel 0 Shield for CHO and CH1 s Channel 1 Channel 1 Channel 24 i Channel 2 ys Shield for CH2 and CH3 H______ Channel 3 i Channel 3 is Channel 4 gt Channel 4 Ls Shield for CH4 and CH5 Channel 54 ds Channel 5 J Channel 6 L gt Channel 6 L gt Shield for CH6 and CH7 Channel 74 Channel 7 L CJC B gt CjJCB Recommended Torque TB1 0 3 to 0 5 Nm 2 5 to 4 5 in Ib The module also has a ground terminal TB1 which should be grounded to a chassis mounting bolt with 14 gauge wire Cold Junction Compensation CJC ATTENTION Possible Equipment Operation Do not remove or loosen the cold junction compensating temperature transducers located on the terminal block Both CJCs are required to ensure accurate thermocouple input readings at each channel The module will not operate in thermocouple mode if a CJC is not connected Failure to observe this precaution can cause unintended equipment operation and damage Publication 1746 6 22 Installing And Wi
45. d ji i L L L L Channel 3 Channel Configuration Word L J L L L L Channel 4 Channel Configuration Word L J L L 1 1 Channel 5 Channel Configuration Word J L L L T T T 1 r T T T Channel 6 Channel Configuration Word Channel 7 Channel Configuration Word L e slot number of the module Publication 1746 6 22 4 2 Channel Configuration Data and Status Channel Configuration Procedure Publication 1746 6 22 The configuration word default settings are all zero Next we describe how you set configuration bits of a channel configuration word to set up the following channel parameters data format such as engineering units counts or scaled for PID how the channel should respond to a detected open input circuit filter frequency selection temperature units in C or F whether the channel is enabled or disabled whether status or data information is selected for the module s input image table The channel configuration word consists of bit fields the settings of which determine how the channel operates This procedure looks at each bit field separately and helps configure a channel for operation Refer to the chart on page 4 4 and the bit field descriptions that follow for complete configuration information 1 Determine which channels are used in your program and enable them Place a one in bit 0 if the channel is to be enabled Place a zero in bit 0 if the channel is to be disabl
46. d channel temp 1000 F Want to calculate Proportional C ounts equivalent From Channel Data Word Format table 5 oy 454 F and Syigy 1832 F Publication 1746 6 22 4 8 Channel Configuration Data and Status 1746 NT8 Thermocouple Module Channel Data Word Format Data Format Input Engineering Units x10 Engineering Units x1 Scaled for Proportional Type Celsius Fahrenheit Celsius Fahrenheit PD Counts J 210 to 760 346 to 1400 2100 to 7600 3460 to 14000 0 to 16383 32768 to 32767 K 270 to 1370 454 to 2498 2700 to 13700 4540 to 24980 0 to 16383 32768 to 32767 T 270 to 400 454 to 752 2700 to 44000 4540 to 7520 0 to 416383 32768 to 32767 E 270 to 1000 454 to 1832 2700 to 10000 4540 to 18320 0 to 16383 32768 to 32767 R 0 to 1768 32 to 3214 0 to 17680 320 to 32140 0 to 16383 32768 to 32767 S 0 to 41768 32 to 2372 0 to 17680 320 to 32140 0 to 16383 32768 to 32767 B 300 to 1820 572 to 3308 3000 to 18200 5720 to 3276 7 0 to 416383 32768 to 32767 N 0 to 1300 32 to 2372 0 to 13000 320 to 23720 0 to 16383 32768 to 32767 50 mv 500 to 500 500 to 500 5000 to 5000 5000 to 5000 0 to 16383 32768 to 32767 100 mv 1000 to 1000 1000to 1000 10000 to 1000 10000 to 10000 0 to 16383 32768 to 32767 CJC Sensor 25 to 105 13 to 221 250 to 1050 130 to 2210 0 to 16383 32768 to 32767
47. dule detects a failure the module status LED remains off Channel Diagnostics When a channel is enabled the module checks for a valid configuration Then on each scan of its inputs the module checks for out of range and open circuit fault conditions of its inputs including the CJC input When the module detects a failure of any channel diagnostic test it causes the channel status LED to blink and sets the corresponding channel fault bit bits 12 15 of the channel status word Channel fault bits and LEDs are self clearing when fault conditions are corrected Publication 1746 6 22 6 2 Troubleshooting Your Module Important If you clear the channel enable bit the channel status LED Indicators bits are reset The module has nine LEDs as shown below eight channel status LEDs numbered to correspond with each channel one module status LED INPUT om lt LED for Module Status Sus Pere Module BIC 4 Thermocouple mV LED Troubleshooting Tables Module status LED If Module Status LED Then Take this Corrective Action IS The module is On operating properly No action required The module is turned T Cycle power If the condition persists call your off s mM d local Allen Bradley distributor for assistance Flashing dan eens Check jumper 1position Module status and Channel status LED If Module
48. e data was recorded at 60 Hz Values at 10 Hz and 50 Hz would be comparable Publication 1746 6 22 Degrees C Deviation Degrees C Deviation Module Specifications A 7 Thermocouple J Deviations Over Temp 4 5 3 5 4 2 5 4 Channel Delta 0 5 4 0 ge 0 96 6d f ed ELE Degrees C TC Input Thermocouple K Deviations Over Temp 4 54 3 5 4 2 5 4 Channel Delta 0 5 4 HEHE EEE HE EEE EE EH EE EEE d 90 eee 6 e GO 96 6 Oe 4 0 SELES Degrees C TC Input Publication 1746 6 22 A 8 Module Specifications Thermocouple T Deviations Over Temp E 6 2 Po 2 0 1 A 3 3 3 3 34 9 3 3 94 94 9 PPL HLP HP THK OHH HL OHE HE Degrees C TC Input Thermocouple E Deviations Over Temp 8 74 64 54 5 E 44 Channel Delta o P gt 24 14d 0 REE EEE EEE EEE EEE 4 d 9 9 9 64 HEFL EE EKFHEEEHESE Degrees C TC Input Publication 1746 6 22 Degrees C Deviation Degrees C Deviation Module Specifications A 9 Thermocouple R Deviations Over Temp 0 Channel Delta 66 6 6 6 6 6 6 6 0 9 o o Degrees C TC Input Thermocouple S Deviations Over Temp CP 6 O60 6 P 6 6 9 0 Z Degrees C TC Input Channel Data Publication 1746 6 22 A 10 Module Specifications Thermocouple B Deviation
49. e enabled Module update time 290 msec 470 msec 470 msec 470 msec 470 msec 470 msec 470 msec 470 msec 470 msec 4 05 sec Update Time Calculation Example The following example shows how to calculate the module update time for the given configuration Channel 0 configured for 250 Hz filter frequency enabled Channel 1 configured for 250 Hz filter frequency enabled Channel 2 configured for 50 Hz filter frequency enabled Channel 3 through 7 disabled Publication 1746 6 22 3 8 Things To Consider Before Using Your Module Channel Turn On Turn Off and Reconfiguration Times Auto Calibration Publication 1746 6 22 Using the values from the table on page 3 7 add the sum of all enabled channel sample times plus one CJC update time Channel 0 sampling time 66 msec Channel 1 sampling time 66 msec Channel 2 sampling time 140 msec CJ C update time 290 msec Module updatetime 562mse The time required for the module to recognize a new configuration for a channel is generally one module update time plus 890 usec per newly configured channel If the filter frequency selected for the newly enabled configured channel is new to the module then auto calibration is performed following configuration recognition Turn off time requires up to one module update time Reconfiguration time is the same as turn on time Auto calibration is performed by the module to correct for drift errors over temperature
50. e module slot the module inputs appearing in the processor image table remain in their last state and the module s updated image table is not read When the processor re enables the module slot the current state of the module inputs are read by the processor during the subsequent scan Output Response The SLC processor may change the thermocouple module output data configuration as it appears in the processor output image However this data is not transferred to the thermocouple module The outputs are held in their last state When the slot is re enabled the data in the processor image is transferred to the thermocouple module Publication 1746 6 22 Channel Configuration 15 4 Chapter Channel Configuration Data and Status Read this chapter to configure each input channel check each input channel s configuration and status Channel configuration words appear in the SLC processor s output image table as shown below Words 0 7 correspond to module channels 0 7 After module installation configure each channel to establish the way the channel operates e g thermocouple type temperature units etc Configure the channel by setting bits in the configuration word using your programming device The SLC configuration words are shown below SLC Output Image Configuration Words Channel 0 Channel Configuration Word Channel 1 Channel Configuration Word Channel 2 Channel Configuration Wor
51. e notes to make you aware of safety considerations ATTENTION Identifies information about practices or circumstances that can lead to personal injury or death property damage or economic loss Attention statements help you to e identify a hazard e avoid a hazard e recognize the consequences Important Identifies information that is critical for successful application and understanding of the product PLC PLC 2 PLC 3 and PLC 5 are registered trademarks of Rockwell Automation SLC SLC 500 SLC 5 01 SLC 5 02 SLC 5 03 SLC 5 04 and SLC 5 05 are registered trademarks of Rockwell Automation Belden is a trademark of Belden Inc Preface Module Overview Installing And Wiring Your Module Table of Contents Who Should Use This Manual 2 euer EL o P 1 What This Manual Covers m o Ya e c EE aen P 1 Related Allen Bradley Documents n nunnana anaana P 2 Common Techniques Used in this Manual P 3 Allen Bradley Support 2 252 2522 dace etate e aes P 3 Local Product Support robs uud me SO cR te Ee P 3 Technical Product Assistance cece eee eae P 3 Your Questions or Comments on this Manual P 3 Chapter 1 General Descriplions cs 1 quac ski REED CURES 1 1 INPUERGNGES shoei tutes eve daas ris diese eris 1 1 Hardware Features src iE EECPEX2 RE eee es 1 2 Diagnostic LEDS 2 quo oaeeez aate e ERE E RE d 1 3 System OVeIVIBW 14 coco Wo Tre Rod teh o Konto te URS 1 3 System Operation uou o cet
52. e update time is defined as 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 SLC processor It can be calculated by adding the sum of all enabled sample times plus a CJC update time Channel Calculate Previous Channel 1 Disabled Channel 2 Disabled Channel 7 Disabled Sample Sample Channel 1 Channel 2 Calculate Previous The following table shows the channel sampling time for each filter frequency It also gives the CJC update time Sample Channel 7 Calculate Previous Channel Sampling Time Channel Sampling Time for Each Filter Frequency all values 1 msec Channel Sampling Time CJC Update Time 250 Hz Filter 60 Hz Filter 50 Hz Filter 10 Hz Filter 290 msec 66 msec 125 msec 140 msec 470 msec The times above include a settling time necessary between input channel readings The sampling times for filter frequencies listed do not include a 45 msec open circuit detection time utilized when the channel is configured for open circuit detection CJC open circuit detection does not require the additional 45 msec settling time The fastest module update time occurs when only one channel with a 250 Hz filter frequency is enabled Module update time 290 msec 66 msec 356 msec The slowest module update time occurs when eight channels each using a 10 Hz filter frequency ar
53. econd timer to wait for the NT NT8 CH5 STS FLAGS 0 lt Source B 0 0 lt NT8 CH5 ERROR NEQ B3 7 Not Equal CL Source A N10 25 5 NT8_CH6_STS_FLAGS NT8_CH6_STS_FLAGS MVM Masked Move Source L1 6 0 lt Mask OF000h 4096 Dest N10 26 0 lt 0 lt Source B 0 0 lt NT8 CH6 ERROR NEQ B3 7 Not Equal CL Source A N10 26 6 NT8_CH7_STS_FLAGS NT8_CH7_STS_FLAGS MVM Masked Move Source EL 0 lt Mask OF000h 4096 Dest N10 27 0 lt 0 lt Source B 0 0 lt NT8_CH7_ERROR NEQ B3 7 Not Equal CL Source A N10 27 7 s copy the regular NT8 channel configuration words into the NT8 I O to change its I O image back to the regular channel configuration Again the time required by the NT8 to change its I O image is dependent on the NT8 configuration NT8 STS CNF TMR DN NT8_CH_CNF TII COP JE Copy File DN Source N10 0 Dest 0 1 0 Length 8 Programming Examples 5 13 NT8 REG CNF TMR TON Timer On Delay t CEN gt Timer T11 2 Time Base L0 CDN 5 Preset 7 Accum 0 lt After the NT8 has restored its normal I O image clear the NT8 checking status bit B3 100 NT8 REG CNF TMR DN NT8 CHECKING STS T11 2 B3 6 0008 lE U gt DN 4 0009 CEND gt PLC 5 Exam ple with The following example shows sample ladder logic when using a PLC NT8 in Re
54. ed Determine the input device type J K etc thermocouple or mV for a channel and enter its respective four digit binary code in bit field 1 through 4 of the channel configuration word Select a data format for the data word Your selection determines how the analog input value from the A D converter will be expressed in the data word Enter your two digit binary code in bit field 5 and 6 of the channel configuration word Determine the desired state for the channel data word if an open circuit condition is enabled and detected for that channel Enter the two digit binary code in bit field 7 and 8 of the channel configuration word If the channel is configured for thermocouple inputs determine if the channel data word should read in degrees Fahrenheit or degrees Celsius and enter a one or a zero in bit 9 of the configuration word If the channel is configured for a mV analog sensor enter a zero in bit 9 Determine the desired input filter frequency for the channel and enter the two digit binary code in bits 10 and 11 of the channel configuration word A lower filter frequency increases the channel update time but also increases the noise rejection and channel resolution A higher filter frequency decreases the channel update time but also decreases the noise rejection and effective resolution 10 Channel Configuration Data and Status 4 3 Ensure that bits 12 through 14 contain zeros Determine whether the channel input
55. ees c Units Degrees F2 10 Hz input filter 0 0 Channel 50 Hz input filter 0 1 filter 1 frei 60 Hz njut nigr 1 0 250 Hz input filter 1 1 Unused 0 0 0 Unused Invalid 1 1 1 Inputlmage Status Word 0 Type Data Word 1 1 Forengineering units x1 values are expressed in 0 1 degrees or 0 01 mV For engineering units x10 values are expressed in 1 0 degree or 0 1 mV 2 When millivolt input type is selected the bit setting for temperature units is ignored 3 Ensure unused bits 12 through 14 are always set to zero Publication 1746 6 22 Channel Configuration Data and Status 4 5 Select Channel Enable Bit 0 Use the channel enable bit to enable a channel The thermocouple module only scans enabled channels To optimize module operation and minimize throughput times unused channels should be disabled by setting the channel enable bit to zero default value When set 1 the channel enable bit is used by the module to read the configuration word information selected While the enable bit is set modification of the configuration word may lengthen the module update time for one cycle If any change is made to the configuration word the change is reflected in the status word before new data is valid described on page 4 11 While the channel enable bit is cleared 0 the associated channel data status word values are cleared After the channel enable bit is set 1 the associated channel data status word remains cleared until t
56. ex Publication 1746 6 22 Installing the module 2 1 J J unction exposed B 1 B 4 grounded B 1 B 3 ungrounded B 1 L LED indicators 6 1 Low scale value 4 10 LSB G 2 Maintenance 7 1 Millivolt analog input signal ranges 1 1 Module Addressing 1 4 3 2 diagnostics 6 1 ID code 3 1 level operation 6 1 status LED 6 4 N Normal mode rejection G 2 O Open circuit bit field 4 9 4 14 condition 4 9 4 10 detection 1 4 6 3 error 4 14 error bits 5 8 Out of range condition 4 15 Over range condition 1 4 error 4 10 4 15 P Preventive maintenance 7 1 Programming 3 2 3 3 3 4 3 6 3 7 3 9 4 5 4 6 4 9 4 10 4 14 4 15 Proportional counts 4 5 4 6 Proportional counts to engineering units 4 7 R Range full scale G 2 millivolt analog input signal 1 1 temperature 1 1 Resolution G 2 G 3 S Safety 7 1 Circuits 7 2 considerations 7 1 Sampling time G 2 Scaled for PID 4 5 4 6 5 7 Scaled for PID to engineering units 4 Shipping 2 6 2 8 2 10 Signal attenuation G 1 Static shielded container 2 6 2 8 2 10 3 2 3 3 3 4 3 6 3 7 3 9 4 5 4 6 4 9 4 10 4 14 4 15 Status G 3 Step response time G 3 T Temperature ranges 1 1 units bit 4 10 units field 4 14 Terminal block removal 2 6 Troubleshooting 6 1 6 2 6 5 contacting Allen Bradley P 3 U Under range condition 1 4 error 4 15 Ungrounded junction B 1 Update time G 2 Useful resolution G 3 W Wiring signal
57. he thermocouple module sets the channel status bit bit 0 in the channel status word Select Input Types Bits 1 through 4 The input type bit field lets you configure the channel for the type of input device you have connected to the module Valid input devices are types J K T E R S B and N thermocouple sensors and 50 mV and x100mV analog input signals The channel can also be configured to read the cold junction temperature calculated for that specific channel When the cold junction compensation CJC temperature is selected the channel ignores the physical input signal Select Data Format Bits 5 and 6 The data format bit field lets you define the expressed format for the channel data word contained in the module input image The data types are engineering units scaled for PID and proportional counts The engineering units allow you to select from two resolutions x1 or x10 For engineering units x1 values are expressed in 0 1 degrees or 0 01mV For engineering units x10 values are expressed in 1 0 degrees or 0 1mV Use the x10 setting to produce temperature readings in whole degrees Celsius or Fahrenheit The scaled for PID value is the same for millivolt thermocouple and CJC input types The input signal range is proportional to your selected input type and scaled into a 0 through 16 383 range which is standard to the SLC PID algorithm The proportional counts are scaled to fit the defined temperature or voltage
58. i aac pared aoro ie co es 1 3 Module Operation Cos s be Mee ee eee a et eas 1 4 Module Addressing 5 5 13 x cm ex hec oo cede 1 4 Block Diag rales c5 date stets s Y te afe boss 1 5 Linear Millivolt Device Compatibility 000 ee 1 6 Chapter 2 Electrostatic Damage ca cucine m re e VE ren set 2 1 Power Requirements oes oe vo inca ea sich aca ea 2 2 Considerations for a Modular System 0 2 2 Fixed I O Chassis I O Module Compatibility 2 3 General Considerations cc ccc cece cece eens 2 4 Module Installation and Removal ccc eee e eeu 2 5 Terminal Block Removal iiss pic hats eh eh es 2 6 Wiring Your Module as eres tite a iere Lute a Edere 2 7 Preparing and Wiring the Cables 08 2 8 Cold J unction Compensation CJ C sss 2 10 Publication 1746 6 22 ii Table of Contents Things To Consider Before Using Your Module Channel Configuration Data and Status Publication 1746 6 22 Chapter 3 Mod le TDW Gre M RT 3 1 Module Addressing scuto o nct e bn ete 3 2 Output Image Configuration Words 5 3 2 Input Image Data Words and Status Ino APRI mate are A teeta ease eeu AL 3 3 Channel Filter Frequency Selection issus 3 3 Channel Cut Off Frequency 3 4 Channel Step Response rosa rio E esce doce d 3 6 Update Time ut epoca are a rites iar P QUU e fet 3 7 Update Time Calculation Example sss 3 7 Channel Turn On Turn Off and
59. jection and channel resolution A larger filter frequency decreases the noise rejection but also decreases the channel update time and channel resolution Guidelines for filter frequency are listed below Channel Configuration Data and Status 4 11 e 250 Hz setting provides minimal noise filtering 60 Hz setting provides 60 Hz AC line noise filtering 50 Hz setting provides 50 Hz AC line noise filtering 10 Hz setting provides both 50 Hz and 60 Hz AC line noise filtering When a CJC input type is selected filter frequency is ignored To maximize the speed versus resolution trade off CJC inputs are sampled at 60 Hz Unused Bits Bits 12 through 14 Bits 12 14 are not defined Ensure these bits are always cleared 0 Select Input Image Type Bit 15 The input image type bit allows you to select data or status information in the channel s input image word When set 1 the module places channel data in the corresponding input image word When the bit is cleared 0 the module places channel status in the corresponding input image word Publication 1746 6 22 4 12 Channel Configuration Data and Status Channel Data Status Word The actual thermocouple or millivolt input data values or channel status reside in I e 0 through I e 7 of the thermocouple module input image file The data values present depend on the input type and data formats you have selected When an input channel is disabled its data word is reset
60. junction style provides the fastest response time but leaves the thermocouple wires unprotected against corrosive or mechanical damage Publication 1746 6 22 B 2 Using Grounded Junction Ungrounded Junction and Exposed Junction Thermocouples The following illustrations show each of the three 3 thermocouple types Grounded Junction Measuring Junction is Metal Sheath connected to sheath Extension Wire N Ungrounded Insulated Junction Measuring Junction is isolated from sheath Exposed Junction Measuring Junction has no sheath Isolation The 1746 NT8 module provides the following electrical isolation e 12 5V dc electrical isolation channel to channel e 500V dc electrical isolation channel to chassis ground e 500V dc electrical isolation channel to backplane Care must be taken when choosing a thermocouple type and connecting it to the 1746 NT8 module from the environment being measured If adequate precautions are not taken for a given thermocouple type the electrical isolation of the 1746 NT8 module may be compromised Publication 1746 6 22 Using Grounded Junction Ungrounded Junction and Exposed Junction Thermocouples B 3 Grounded Junction Thermocouples As shown in the following illustration on page B 3 the shield input terminals are internally connected together which are then connected to chassis ground Using grounded junction thermocouples with electrically conductive sheaths removes the ther
61. mm l itum fixed fixed Note The resistors should be selected to ensure that the differential input voltage is less than or equal to 100 mV Publication 1746 6 22 Electrostatic Damage Chapter 2 Installing And Wiring Your Module Read this chapter to install and wire your module This chapter covers avoiding electrostatic damage determining power requirements installing the module wiring signal cables to the module s terminal block Electrostatic discharge can damage semiconductor devices inside this module if you touch backplane connector pins Guard against electrostatic damage by observing the following precautions ATTENTION Electrostatically Sensitive Components Before handling the module touch a grounded object to rid yourself of electrostatic charge Handle the module from the front away from the backplane connector Do not touch backplane connector pins Keep the module in its static shield container when not in use or during shipment Failure to observe these precautions can degrade the module s performance or cause permanent damage Publication 1746 6 22 2 2 Installing And Wiring Your Module Power Requirements Publication 1746 6 22 The module receives its power through the SLC 500 chassis backplane from the fixed or modular 5 VDC 24 VDC chassis power supply The maximum current drawn by the module is shown in the table below Maximum Current Drawn by the Module
62. mocouple signal to chassis ground isolation of the module This is inherent to the thermocouple construction In addition if multiple grounded junction thermocouples are used the module s channel to channel isolation is removed since there is no isolation between signal and sheath and the 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 1746 NT8 MUXES Grounded junction with nonconductive protective sheath CHO Metal sheath with electrical continuity m to thermocouple signal wires floating ground connection For grounded junction thermocouples it is recommended that they have protective sheaths made of electrically insulated material e g ceramic or the metal protective sheaths be floated The metal sheaths would need to be floated with respect to any path to chassis ground or to another thermocouple metal sheath This means the metal sheath must be insulated from electrically conductive process material and have all connections to chassis ground broken It should be noted that a floated sheath may result in a less noise immune thermocouple signal Publication 1746 6 22 B 4 Using Grounded Junction Ungrounded Junction and Exposed Junction Thermocouples Publication 1746 6 22 Exposed Junction Thermocouples Recommended wiring for exposed junctio
63. modules processor modules and power supplies CJC Cold Junction Compensation The means by which the module compensates for the offset voltage error introduced by the temperature at the junction between the thermocouple lead wire and the input terminal block the cold junction Common mode rejection ratio CMRR 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 terminal relative to ground Common mode voltage The voltage difference between the negative terminal and analog common during normal differential operation Configuration word Contains the channel configuration information needed by the module to configure and operate each channel Information is written to the configuration word through the logic supplied in your ladder program Cut off frequency The frequency at which the input signal is attenuated 3 dB by the 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 dB decibel A logarithmic measure of the ratio of two signal levels Data word A 16 bit integer that represents the value of the analog input channel The channel data word is valid only when the channel is enabled and there are no channel errors Publication 1746 6 22 G 2 Gloss
64. mote I O 5 controller to control the module in remote rack across the Remote I Rack O network The PLC 5 must use Block transfer reads and writes to communicate with the 1746 NT8 module in a remote rack Note the example provides code which will reconfigure the module if the PLC 5 senses are remote rack fault Also the PLC 5 processor uses the exact same configuration words as the SLC 500 processors Publication 1746 6 22 5 14 Programming Examples During the first scan clear the NT8 Configurated bit B3 4 to initiate the NT8 configuration process First scan orSFC step NT8 CONFIGURED S B3 0 JE D 15 4 If the NT8 is configured and a rack fault occurs clear the NT8 Configured bit B 3 4 to initiate the NT8 configuration process NT8_CONFIGURED RIO RACKI FLT B3 0 MVM J F Masked Move 4 Source N30 2 256 lt Mask OFH 15 Dest N11 3 0 lt RIO_RACK1_FLT NT8_CONFIGURED NEQ B3 0 Not Equal CUD Source A N11 3 4 0 Source B 0 0 Until the NT8 is configured send the 8 configuration words N12 10 17 to the NT8 using repeating BTW s NT8 CONFIGURED NT8 BTW EN NT8 BTW B3 0 BT20 1 BTW 3t 3t Block Transfer Write CEN gt 4 EN Module Type Generic Block Transfer Rack 001 CDN Group 0 Module 0 L ER2 Control Block BT20 1 Data File N12 10 Length 8 Continuous No When the NT8 is configured latch the NT8 Configured bit B3 4
65. n 8761 shielded twisted pair or equivalent wire for millivolt sensors or use shielded twisted pair thermocouple extension lead wire specified by the thermocouple manufacturer Using the incorrect type of convention thermocouple extension wire or not following the correct polarity may cause invalid readings Ground the shield drain wire at only one end of the cable The preferred location is at the shield connections on the terminal block Refer to IEEE Std 518 Section 6 4 2 7 or contact your sensor manufacturer for additional details Keep all unshielded wires as short as possible Excessive tightening can strip a screw Tighten screws to 0 25 Nm 2 2 in Ib or less based on UL 1059 CSA C22 2 No 158 VDE 0110B 2 79 standards Follow system grounding and wiring guidelines found in your SLC 500 Modular Installation and Operation Manual publication 1747 6 2 modular or 1747 6 21 fixed Publication 1746 6 22 2 8 Installing And Wiring Your Module Preparing and Wiring the Cables To prepare and connect cable leads and drain wires follow these steps Remove foil shield and drain wire Signal Wires from sensor end of the cable Drain Wire Signal Wires 1 Ateach end of the cable strip some casing to expose individual wires 2 Trim signal wires to 5 inch lengths beyond the cable casing Strip about 3 16 inch 4 76 mm of insulation to expose the ends of the wires 3 At the module end of the cables
66. n requested The above table shows how to calculate the update time and autocalibration time for the channel configuration being used Publication 1746 6 22 Interfacing to the PID Instruction Programming Examples 5 7 The thermocouple module was designed to interface directly to the SLC 5 02 or later processor PID instruction without the need for an intermediate scale operation Example Use 1746 NT8 channel data as the process variable in the PID instruction 1 Select scaled for PID as the data type in the channel configuration word 2 Specify the thermocouple channel data word as the process variable for the PID instruction In this example the value 32701 8043 H is the numeric equivalent of configuration word N10 0 for channel 0 It is configured for a type K thermocouple scaled for PID zero the signal for an open circuit 10 Hz C and channel enabled Programming for PID Control Example Program Listing f f Initialize NT8 First Pass Bit Channel 0 sil MOV J E MOVE L 15 Source N10 0 Dest O 3 0 PID PID Control Block N11 Process Variable I Control Variable N11 Control Block Length SCL SCALE Source N11 23 Rate 10000 Offset Dest The Rate and Offset parameters should be set per your application The Destination will typically be an analog output channel Publication 1746 6 22 5 8 Programming Examples Monitoring Channel St
67. n the module located in slot 4 in the SLC chassis your address would be O 4 2 B O Slot Word 4 2 E Chapter 4 Channel Configuration Data and Status gives you detailed bit information about the data content of the configuration word Channel Filter Frequency Selection Things To Consider Before Using Your Module 3 3 Input Image Data Words and Status Words Eight words of the SLC processor s input image table are reserved for the module Input image words are multiplexed since each channel has one data word and one status word The corresponding configuration word selects whether the channel status or channel data is in the input image word Status bits for a particular channel reflect the configuration settings that you entered into the configuration output image word for that channel To receive valid status the channel must be enabled and the module must have stored a valid configuration word for that channel Each input image word has a unique address based on the slot number assigned to the module Example Address To obtain the status data word of channel 2 input word 2 of the module located in slot 4 in the SLC chassis use address I 4 2 lot File Type ay EA l Pius 1 4 2 Word Element Delimiter Chapter 4 Channel Configuration Data and Status gives you detailed bit information about the content of the data word and the status word The thermocouple module uses a digital filter tha
68. n thermocouples is shown in the following illustration Using exposed junction thermocouples may result in removal of channel to channel isolation This may occur if multiple exposed thermocouples are in direct contact with electrically conductive process material To prevent violation of channel to channel isolation For multiple exposed thermocouples do not allow the measuring junction of the thermocouple to make direct contact with electrically conductive process material Use all ungrounded junction thermocouple instead of the exposed junction type 1746 NT8 MUXES Conductive Material CHO Exposed junction with shielded cable Nonconductive Material Exposed junction with shielded cable Glossary You should understand the following terms and abbreviations before using this guide A D Refers to analog to digital conversion The conversion produces a digital value whose magnitude is proportional to the instantaneous magnitude of an analog input signal Attenuation The reduction in magnitude of a signal as it passes through a system The opposite of gain Channel Refers to one of eight small signal analog input interfaces to the modules s terminal block Each channel is configured for connection to a thermocouple or DC millivolt mV input device and has its own configuration and status words Chassis A hardware assembly that houses devices such as I O modules adapter
69. nge 0 60 C The maximum deviation for each thermocouple temperature or millivolt range was plotted Publication 1746 6 22 A 4 Module Specifications uV Err 100mV Span Prop Cts 60 Hz 0 C 50 00 45 00 40 00 35 00 30 00 25 00 uV Error 20 00 uV Deviation 15 00 10 00 0 00 D SIE LP EIE IIF ut mV Input uV Err 100mV Span Prop Cts 60 Hz 25 C 50 00 45 00 40 00 35 00 30 00 25 00 uV Error 20 00 uV Deviation 15 00 10 00 5 00 0 00 mV Input Publication 1746 6 22 uV Deviation 90 00 80 00 70 00 60 00 50 00 40 00 30 00 20 00 10 00 0 00 PEES 2 BL gg s Module Specifications A 5 uV Err 100mV Span Prop Cts 60 Hz 60 C UV Error IEE 999 LOGOS SOM LEER PP Pe Ss mV Input Thermocouple The following table provides the total error expected of the thermocouple based on the thermocouple type and the given reference point at 25 C The calculations assumed typical hardware software error and typical CJC accuracy at 25 C Thermocouple Reference Thermocouple Type Point Error J 275 C 527 F 1 4 C 2 52 F K 550 C 1022 F 1 5 C 2 7 F T 65 C 149 F 1 3 C 2 34 F E 365 C 689 F 1 0 C 1 8 F R 885 C 1625 F 3 6 C 6 48 F S 885 C 1625 F 3 4 C 6 12 F
70. of Contents iii Channel Filter Frequency Bits 10 and 11 ode DUCERE ne ORA 4 14 Open Circuit Error BIET2 ucc iore pep ES 4 14 Under Range Error Bit 13 ssssusun 4 15 Over Range Error Bit 14 suus 4 15 Channel Error Bit 15 vi ocu ce etc 4 15 Chapter 5 Basic EXaliDle ereire cernar tient tat ees seats 5 1 Procedure urinni bue nn p n ened te Canet 5 2 Automatic Monitoring Thermocouples and CJ C Sensors aaua 5 3 Verifying Channel Configuration Changes sausau 5 3 Interfacing to the PID Instruction unuau anaana 5 7 Monitoring Channel Status Bits aaa 5 8 PLC 5 Example with NT8 in Remote I O Rack 5 14 Chapter 6 Module and Channel Diagnostics ssssusse 6 1 Module Diagnostics at Powerup cc eee eee 6 1 Channel Diagnostics bese teh etes eene 6 1 LE Dilndicators icin des edema UTR EURO BUS 6 2 LED Troubleshooting Tables 00000 6 2 Channel status LEDs Green cc e cree eae 6 3 Open circuit Detection Bit 12 000 e 6 3 Out of R ange Detection Bit 13 for Under Range bit 14 for Over Range cc cece e eee 6 3 Channel Error BitI5 sae SM au e ob ae ota sect 6 4 Module Status LED Green cece eee 6 4 Interpreting YO Error Codes cece cece eens 6 4 Chapter 7 Preventive Maintenance ccc ee ese eee ee ene 7 1 Safety Considerations scd etr score dat V extus 7 1 Publication 1746 6 22 iv
71. ontact your local Allen Bradley office or distributor Common Techniques Used in this Manual Allen Bradley Support Preface P 3 The following conventions are used throughout this manual Bulleted lists such as this one provide information not procedural steps Numbered lists provide sequential steps or hierarchical information Textin this font indicates words or phrases you should type Key names appear in bold capital letters within brackets for example ENTER Allen Bradley 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 Allen Bradley representatives in every major country in the world Local Product Support Contact your local Allen Bradley representative for sales and order support product technical training warranty support support service agreements Technical Product Assistance If you need to contact Allen Bradley for technical assistance please review the information in the Troubleshooting chapter first Then call your local Allen Bradley representative Your Questions or Comments on this Manual If you find a problem with this manual please notify us of it on the enclosed Publication Problem Report If you have any suggestions for how this manual could be made more useful to you please contact us at the address below Allen Bradley Control
72. ote N10 2 1 through N10 2 4 have the input type for type K Thermocouple 0001 N10 8 1 through N10 8 4 have the input type for CJC Temperature Sensor 1111 When executing a dynamic channel configuration change there is always a delay from the time the ladder program makes the change to the time the 1746 NTS supplies a data word using that new configuration information Also the ladder program should use the thermocouple temperature data location N10 20 for thermocouple temperature readings and data location N10 12 for CJC temperature readings Publication 1746 6 22 5 4 Programming Examples During the first pass send the channel configuration data to the thermocouple module First Pass NT8 CONFIGURATION Su COP 0000 sal Copy File 15 Source N10 0 Dest 0 1 0 Length 8 CHECKING_CJC B3 6 CU 4 If DEA C copy Channel 0 temperature data into data location for use Temperature control logic should use N10 20 rather than the TC input image I 1 0 to eliminate problems during CJ C checking CHECKING_CJC CHO TEMP B3 6 MOV 0001 it Move 4 Source I1 0 3744 Dest N10 20 3744 Copy temperature data from Channels 1 7 to data registers for use cun 0002 Copy File Source 1 1 1 Dest N10 21 Length 7 Repeating 60 seconds timer T11 0 which starts the CJ C check cycle CJC CYCLE TMR DN CJC CYCLE TMR T11 0 TON 0003 iE Timer On Delay CEN 2 DN Timer T11 0 Time Base
73. ouple Type B 300 C to 1820 C 572 F to 3308 F Thermocouple Type N 0 C to 1300 C 32 F to 2372 F Millivolt 50mV dc to 50mV dc Millivolt 100mV dc to 100mV dc Thermocouple Linearization NIST ITS 90 standard Cold J unction Compensation Accuracy 1 72 C 25 C to 105 C Input Impedence Greater than 10MQ Temperature Scale Selectable C or F and 0 1 C or 0 1 F DC Millivolt Scale Selectable 0 1 mV or 0 01 mV Open Circuit Detection Selectable Upscale Downscale Zero or Disabled Time to Detect Open Circuit One channel cycle time Input Step Response 0 to 95 in 400 msec 10 Hz Display Resolution See Channel Data Word Resolution table on page 4 8 Overall Module Accuracy at 25 C 77 F See Module Accuracy Tables page A 3 Overall Module Accuracy See Module Accuracy Tables page A 3 Overall Module Drift See Module Accuracy Tables page A 3 Module Update Time Dependent upon enabled channels see Update Time page 3 7 Channel Tum Off Time Up to one module update time Overall Accuracy The accuracy of the module is determined by many aspects of the hardware and software functionality of the module The following discussion explains what the user can expect in terms of accuracy based on the thermocouple and millivolt inputs for the 1746 NT8 module Module Specifications A
74. rce A N10 21 1 0 lt Source B 0 0 lt NT8_CH2_STS_FLAGS MVM Masked Move Source L12 0 lt Mask OFO000h 4096 Dest N10 22 0 lt Publication 1746 6 22 Programming Examples 5 11 NT8 CH2 STS FLAGS NT8 CH2 ERROR NEQ B3 7 Not Equal CL Source A N10 22 2 0 lt Source B 0 0 lt NT8_CH3_STS_FLAGS MVM Masked Move Source 13 0 lt Mask OF000h 4096 Dest N10 23 0 lt NT8_CH3_STS_FLAGS NT8_CH3_ERROR NEQ B3 7 Not Equal L Source A N10 23 3 0 lt Source B 0 0 lt After waiting for the NT8 to update its I O image check each channel s status error bits by masking off the appropriate bits and checking if these bits are set non zero If an error is detected set the appropriate channel status error bits B3 112 B3 119 Rung 6 checks channels 4 7 NT8 STS CNF TMR DN NT8 CHECK FLAGS2 NT8 CH4 STS FLAGS 0006 T11 1 B3 6 MVM JE jOSR Masked Move DN 6 Source L14 0 lt Mask OF000h 4096 Dest N10 24 0 lt NT8_CH4_STS_FLAGS NT8 CH4 ERROR NEQ B3 7 Not Equal CL Source A N10 24 4 0 lt Source B 0 0 lt NT8_CH5_STS_FLAGS MVM Masked Move Source ELS 0 lt Mask OF000h 4096 Dest N10 25 0 lt Publication 1746 6 22 5 12 Programming Examples 0007 Publication 1746 6 22 After updating the error status registers and fla image Begin 7 s
75. ring Your Module 2 11 To obtain accurate readings from each of the channels the cold junction temperature temperature at the module s terminal junction between the thermocouple wire and the input channel must be compensated for Two cold junction compensating sensors have been integrated in the removable terminal block They must remain installed Publication 1746 6 22 Module ID Code Chapter 3 Things To Consider Before Using Your Module This chapter explains how the module and the SLC processor communicate through the processor s I O image tables It also describes the module s input filter characteristics Topics discussed include module ID code module addressing channel filter frequency selection channel turn on turn off and reconfiguration times response to slot disabling The module ID code is unique number assigned to each 1746 I O module The ID code defines for the processor the type of I O module and the number of words used in the processor s I O image table The module ID code for the 1746 NT8 module is 3533 No special I O configuration is required The module ID automatically assigns the correct number of input and output words Publication 1746 6 22 Word 0 Word 1 Word 2 Word 3 Word 4 Word 5 Word 6 Word 7 Word 0 Word 1 Word 2 Word 3 Word 4 Word 5 Word 6 Word
76. rmocouple or CJC sensor wire cut or disconnected millivolt input wire cut or disconnected Out of Range Detection Bit 13 for Under Range bit 14 for Over Range The module tests all enabled channels for an out of range condition each time it scans its inputs Possible causes of an out of range condition include the temperature is too hot or too cold for the thermocouple being used atype B thermocouple may be registering a F value in Engineering Units x1 beyond the range allowed by the SLC processor beyond 32 767 for the data word a CJC sensor may be damaged or the temperature being detected by the CJC may be outside the CJC sensor range limits Publication 1746 6 22 6 4 Troubleshooting Your Module Troubleshooting Your Module Troubleshooting Flowchart Check LEDs on module Y module is seated properly in chassis Cycle power Is problem corrected No Contact your local Allen Bradley distributor Module Status Module Status Channel LED s off LED s on Status LED s flashing Y i Module fault Normal condition module Fault operation condition Check to see tha End Are faulted channel s configured for mV or thermocouple input Thermocouple Is more than one LED blinking No Check channel
77. s Over Temp Channel Delta Degrees C Deviation 9 606066 644d4B8 202 623 40 4980825028BgG 926 Degrees C TC Input Thermocouple N Deviations Over Temp 2 5 4 24 1 5 4 i Oo Channel Delta g ou 0 5 4 SPS HHO HE SES PEPPPEERPESESMSES Degrees C TC Input Publication 1746 6 22 Thermocouple Types Appendix B Using Grounded Junction Ungrounded Junction and Exposed Junction Thermocouples This appendix describes the types of thermocouples available and explains the trade offs in using them with the 1746 NT8 module There are three 3 types of thermocouple junctions Grounded Junction The measuring junction is physically connected to the protective sheath forming a completely sealed integral junction If the sheath is metal or electrically conductive then 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 Ungrounded Junction The measuring junction is electrically isolated from the protective metal sheath This may also be referred to as an insulated junction This type is often used where noise would affect the reading and for frequent or rapid temperature cycling The response time is longer than the grounded junction Exposed Junction The measuring junction does not have a protective metal sheath so it is exposed This
78. set at minimum the data word is set to the low scale value for the range and format Important Enabling the open circuit function adds approximately 45 msec to the channel update time Disabling the open circuit detection removes the time adder CJC sensors do not require the additional time thus it is recommended that when using a channel for CJC sensor acquisition the open circuit selection is enabled Select Temperature Units Bit 9 The temperature units bit lets you select temperature engineering units for thermocouple and CJC input types Units are either degrees Celsius C or degrees Fahrenheit F This bit field is only active for thermocouple and CJC input types It is ignored when millivolt inputs types are selected Important If you are using engineering units x1 mode and Fahrenheit temperature units i e 0 1 F the full scale temperature for thermocouple type B is not achievable with 16 bit signed numerical representation An over range error occurs for that channel if it tries to represent the full scale value The maximum representable temperature is 3276 7 F instead of 3308 F Select Channel Filter Frequency Bits 10 and 11 The channel filter frequency bit field lets you select one of four filters available for a channel The filter frequency affects the channel update time and noise rejection characteristics A smaller filter frequency increases the channel update time but also increases the noise re
79. t field channel filter frequency 4 14 data format 4 5 4 14 input type 4 5 4 14 open circuit 4 9 4 14 C Calibration A 1 Channel configuration 4 1 configuration word 4 2 4 4 data word 4 2 4 8 4 9 4 10 diagnostics 6 1 enable bit 4 5 error 4 15 6 4 filter frequency bit 4 10 filter frequency bit field 4 14 status bit 4 14 update time 4 2 Channel status LEDs 6 3 Cold junction compensation CJ C 2 10 Common mode rejection G 1 Condition open circuit 4 9 4 10 out of range 4 15 over range 1 4 under range 1 4 Configuration words G 1 contacting Allen Bradley for assistance P 3 Cutoff frequency G 1 D Data format bit field 4 5 4 14 Data resolution 4 9 Data word 4 2 G 1 G 2 Index l i Detection open circuit 6 3 determining 2 1 determining power requirements 2 1 Diagnostic information 6 4 LEDs 1 3 Drift G 2 E Effective resolution G 2 Electrical noise 2 7 Engineering units 4 5 4 6 to proportional counts 4 7 to scaled for PID 4 7 Error channel 4 15 full scale G 2 open circuit 4 14 over range 4 10 4 15 under range 4 15 Error codes 6 4 0 6 1 Exposed junction B 1 B 4 F Filter frequency 4 2 4 10 4 15 Full Scale error G 2 range G 2 G Gain drift G 2 Gain error G 2 Grounded junction B 1 B 3 H Hardware features 1 3 Hot swapping 2 5 I O error codes 6 1 6 4 Indicator lights 7 1 Input bit field 4 5 4 14 channel data 4 6 image type bit 4 11 Publication 1746 6 22 l ii Ind
80. t is suitable for use in Class 1 Division 2 groups A B C and D or non hazardous locations only Refer to your system s Installation amp Operation Manual for more information Electrical Specifications Physical Specifications Appendix A Module Specifications This appendix lists the specifications for the 1746 NT8 Thermocouple millivolt Input Module Backplane Current Consumption 120 mA at 5V dc 70 mA at 24Vdc Backplane Power Consumption FERE maximum 0 6W at 5V dc 1 68W at 24V C umber of Channels 8 backplane and channel to channel isolated JO Chassis Location Any I O module slot except 0 A D Conversion Method Sigma Delta Modulation nput Filtering Low pass digital filter with programmable notch filter frequencies ormal Mode Rejection between input and input Greater than 100 dB at 50 60 Hz Common Mode Rejection between input and ground Greater than 100 dB at 50 60 Hz Input Filter Cut Off Frequencies 2 6 Hz at 10 Hz filter frequency 13 1 Hz at 50 Hz filter frequency 15 72 Hz at 60 Hz filter frequency 65 5 Hz at 250 Hz filter frequency Greater than 100 dB at 50 60 Hz Calibration Module autocalibrates at power up and approximately every two minutes afterward Input Over voltage P rotection 30V dc continuous 600W pulsed for 1 msec Isolation 500V dc continuous between inputs and chassis ground and between inputs and
81. t provides high frequency noise rejection for the input signals The digital filter is programmable allowing you to select from four filter frequencies for each channel The digital filter provides the highest noise rejection at the selected filter frequency The graphs to follow show the input channel frequency response for each filter frequency selection Selecting a low value i e 10 Hz for the channel filter frequency provides the best noise rejection for a channel but it also increases the channel update time Selecting a high value for the channel filter frequency provides lower noise rejection but decreases the channel update time The following table shows the available filter frequencies cut off frequency step response and a DC effective resolution for each filter frequency Publication 1746 6 22 3 4 Things To Consider Before Using Your Module Publication 1746 6 22 Cut off frequency Step Response Time and Effective Resolution Based on Filter Frequency The step response is calculated by a 4 x l filter frequency settling time Channel Cut Off Frequency The channel filter frequency selection determines a channel s cut off frequency also called the 3 dB frequency The cut off frequency is Things To Consider Before Using Your Module 3 5 Signal Attenuation with 10 Hz Input Filter 3dB 4 0r 20 40 60 80 Amplitude in dB we mplt E 120 140 160 180 200 r
82. ta and Status 4 7 Scaled for PID to Engineering Units Engineering Units Equivalent 2S ow SHigh S_ow x Scaled for PID value displayed 16384 Assume type input type scaled for PID display type channel data 3421 Wantto calculate C equivalent From Channel Data Word Format table Sj oy 210 C and Syigy 760 C Engineering Units Equivalent 210 C 760 C 210 C x 3421 16384 7 46 C Engineering Units to Scaled for PID Scaled for P ID Equivalent 16384 x Engineering Units desired S gw SHig S ow Assume type input type scaled for P ID display type desired channel temp 344 C Want to calculate Scaled for P ID equivalent From Channel Data Word Format table Sj ow 210 C and Syigy 760 C Scaled for P ID Equivalent 16384 x 344 C 210 C 760 C 210 C 2 9357 Proportional Counts to Engineering Units aa Units Equivalent Si ow S uicu Si ow x Proportional Counts value displayed 32768 55 Assume type E input type proportional counts display type channel data 21567 Want to calculate F equivalent From Channel Data Word Format table Sj oy 454 F and Sui 1832 F Engineering Units Equivalent 454 F 1832 F 454 F x 21567 32768 65536 1441 3 F Engineering Units to Proportional Counts Proportional Counts Equivalent 65536 x Engineering Units desired Si gw Suigh S tow 32768 Assume type E input type proportional counts display type desire
83. ta is transferred and channel enable bits are set the enabled channel status LEDs turn on Then the channel continuously converts the thermocouple or millivolt input to a value within the range you selected for the channel Each time the module reads an input channel the module tests that data for a fault i e over range or under range condition If open circuit detection is enabled the module tests for an open circuit condition If it detects an open circuit over range or under range condition the module sets a unique bit in the channel status word and causes the channel status LED to flash The SLC processor reads the converted thermocouple or millivolt data from the module at the end of the program scan or when commanded by the ladder program After the processor and module determine that the data transfer was made without error the data can be used in your ladder program Module Operation The module s input circuitry consists of eight differential analog inputs multiplexed into an A D convertor The A D convertor reads the analog input signals and converts them to a digital value The input circuitry also continuously samples the CJC sensors and compensates for temperature changes at the cold junction terminal block Module Addressing The module requires eight words each in the SLC processor s input and output image tables Addresses for the module in slot e are as follows I e 0 7 thermocouple mV or status data for ch
84. the SLC 500 system and from any other source to the module in other words do not hot swap your module and disconnect any devices wired to the module Failure to observe this precaution can cause unintended equipment operation and damage ol _ 19 WA SEE eT N e Top and Bottom Module Release s uunu N To insert your module into the rack follow these steps 1 Before installing the module connect the ground wire to TB1 See figure on page 2 9 2 Align the circuit board of your module with the card guides at the top and bottom of the chassis 3 Slide your module into the chassis until both top and bottom retaining clips are secure Apply firm even pressure on your module to attach it to its backplane connector Never force your module into the slot 4 Cover all unused slots with the Card Slot Filler Allen Bradley part number 1746 N2 Publication 1746 6 22 2 6 Installing And Wiring Your Module Publication 1746 6 22 Terminal Block Removal To remove the terminal block 1 Loosen the two terminal block release screws To avoid cracking the terminal block alternate between screws as you remove them 2 Using a screwdriver or needle nose pliers carefully pry the terminal block loose When removing or installing the terminal block be careful not to damage the CJC sensors Terminal block diagram with
85. uit signal conductors but not between the equipment grounding conductor or signal reference structure and the signal conductors Remote system A control system where the chassis can be located several thousand feet from the processor chassis Chassis communication is via the 1747 SN Scanner and 1747 ASB Remote I O Adapter Resolution The smallest detectable change in a measurement typically expressed in engineering units e g 0 15 C or as number of bits For example a 12 bit value has 4 096 possible counts It can therefore be used to measure 1 part in 4096 Sampling time The time required by the A D converter to sample an input channel Glossary G 3 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 A D signal to reach 95 of its expected final value given a full scale step change in the input signal Update time The time for the module to sample and convert a channel input signal and make the resulting value available to the SLC processor Publication 1746 6 22 A Addressing 3 2 3 4 3 6 3 7 3 9 4 5 4 6 4 9 4 10 4 14 4 15 Allen Bradley P 3 contacting for assistance P 3 Analog to digital conversion G 1 Attenuation G 1 Avoiding electrostatic damage 2 1 B Bit channel status 4 14 Bi

1746-6.22, SLC 500™ Thermocouple/mV Analog Input

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1746-6.22, SLC 500&trade; Thermocouple/mV Analog Input

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1746-6.22, SLC 500™ Thermocouple/mV Analog Input