Allen-Bradley SLC 500 User Manual
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Allen-Bradley SLC 500 User Manual

4-channel thermocouple/mv input module
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SLC™ 500
4-Channel
Thermocouple/mV
Input Module
(Catalog Number 1746-NT4,
Series B)
User Manual

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Summary of Contents for Allen-Bradley SLC 500

  • Page 1 SLC™ 500 4-Channel Thermocouple/mV Input Module (Catalog Number 1746-NT4, Series B) User Manual...
  • Page 2 Important User Information Solid state equipment has operational characteristics differing from those of electromechanical equipment. Safety Guidelines for the Application, Installation and Maintenance of Solid State Controls (Publication SGI-1.1 available from your local Rockwell Automation sales office or online at http://www.ab.com/manuals/gi) describes some important differences between solid state equipment and hard-wired electromechanical devices.
  • Page 3 Summary of Changes The information below summarizes the changes to this manual since the last printing. To help you find new and updated information in this release of the manual, we have included change bars as shown to the right of this paragraph.
  • Page 4 Summary of Changes Publication 1746-UM007C-EN-P - July 2004...

  • Page 5: Table Of Contents

    Table of Contents Preface Who Should Use this Manual..... . . P-1 Purpose of this Manual ......P-1 Related Documentation .
  • Page 6 Table of Contents Effective Resolution ......4-4 Channel Cut-Off Frequency ..... 4-5 Channel Step Response .
  • Page 7 Table of Contents Chapter 7 Module Diagnostics and Module Operation vs Channel Operation ....7-1 Power-up Diagnostics ......7-1 Troubleshooting Channel Diagnostics .
  • Page 8 Table of Contents (Copper vs. Copper-Nickel <Constantan>) ..C-3 E Type Thermocouple......C-4 (Nickel-Chromium vs.

  • Page 9: Who Should Use This Manual

    This manual describes the procedures you use to install, wire, and troubleshoot your 4-channel thermocouple/mV module. This manual: • explains how to install and wire your module • gives you an overview of the SLC 500 programmable controller system Refer to your programming software user documentation for more information on programming your SLC 500 programmable controller.

  • Page 10: Related Documentation

    Read this Document Document Number In-depth information on the SLC Instruction Set. SLC 500 Instruction Set Reference Manual 1747-RM001 A description on how to install and use your Modular SLC 500 SLC 500 Modular Hardware Style User 1747-UM011 programmable controller. Manual A description on how to install and use your Fixed SLC 500 Installation &...

  • Page 11: Your Questions Or Comments On This Manual

    Preface If you would like a manual, you can: • download an electronic version from the internet at: – www.theautomationbookstore.com – http://www.ab.com/manuals • order a printed manual by: – contacting your local distributor or Rockwell Automation representative – visiting www.theautomationbookstore.com –...
  • Page 12 Preface Publication 1746-UM007C-EN-P - July 2004...

  • Page 13: General Description

    The thermocouple/mV module receives and stores digitally converted thermocouple and/or millivolt (mV) analog data into its image table for retrieval by all fixed and modular SLC 500 processors. The module supports connections from any combination of up to four thermocouple or mV analog sensors.

  • Page 14: Hardware Features

    Hardware Features The thermocouple module fits into any single-slot, except the processor slot (0), in either an SLC 500 modular system or an SLC 500 fixed system expansion chassis (1746-A2). It is a Class 1 module (uses 8 input words and 8 output words). It interfaces to thermocouple types J, K, T, E, R, S, B, and N, and supports direct ±50 mV and ±100...

  • Page 15: General Diagnostic Features

    The thermocouple module communicates to the SLC 500 processor through the parallel backplane interface and receives +5V dc and +24V dc power from the SLC 500 power supply through the backplane. No external power supply is required. You may install as many thermocouple modules in your system as the power supply can support.

  • Page 16: System Operation

    During this time the module status LED remains off. If no faults are found during the power-up diagnostics, the module status LED is turned on. Channel Data Word Channel Status Word Thermocouple SLC 500 Input Thermocouple or mV Processor Module Analog Signals...

  • Page 17: Module Operation

    Thermocouple Compatibility The thermocouple module is fully compatible with all SLC 500 fixed and modular controllers. It is compatible with all NBS MN-125 standard types J, K, T, E, R, S, and B thermocouple sensors and extension wire;...
  • Page 18 Overview Input Circuit Block Diagram Input Circuit Block Diagram Terminal Block Module Circuitry CJCA Sensor Open Circuit Detection Channel 0 Shield ungrounded thermocouple User-Selected Filter Frequency Channel 1 Shield grounded Analog to within Digital Digital thermocouple Digital Multiplexer Value Filter Convertor Channel 2 Shield...

  • Page 19: Linear Millivolt Device Compatibility

    Overview The possibility exists that grounded or exposed ATTENTION thermocouples can become shorted to a potential greater than that of the thermocouple itself. Due to possible shock hazard, care should be taken when wiring these types of thermocouples. Refer to Appendix D for more details.
  • Page 20 Overview Publication 1746-UM007C-EN-P - July 2004...

  • Page 21: Required Tools And Equipment

    This chapter can help you to get started using the NT4 4-channel thermocouple/mV module. The procedures are based on the assumption that you have an understanding of SLC 500 products. You should understand electronic process control and be able to interpret the ladder logic instructions required to generate the electronic signals that control your application.

  • Page 22: Installation Procedures

    • For modular style systems, calculate the total load on the system power supply using the procedure described in the SLC 500 Modular Hardware Style User Manual (Publication Appendix A Number 1747-UM011) or the SLC 500 Modular Chassis and Power Supplies Technical Data (Specifications) (Publication Number 1746-TD003).
  • Page 23 Quick Start for Experienced Users Insert the 1746-NT4 module into the chassis Reference Make sure system power is off; then insert the thermocouple input module into your 1746 Chapter 3 chassis. In this example procedure, local slot 1 is selected. (Installation and Wiring) Never install, remove, or wire modules with power...
  • Page 24 Quick Start for Experienced Users Connect the thermocouple wires Reference Connect thermocouple wires to channel 0 on the module’s terminal block. Make sure both cold Chapter 3 (Installion and junction compensation (CJC) assemblies are securely attached. Wiring Ground the shield drain wire at one end only. The preferred location is to the same point as the Appendix D sensor ground reference.
  • Page 25 Configuration, Data, and Status) Appendix B (NT4 Configuration Worksheet) SLC 500 Controller Data Files Output Image Input Image (8 words) Address 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Channel 0 Configuration Word Word 0 O:1.0...
  • Page 26 (Channel will be processed for your application. In this procedure the addressing reflects the location of Configuration, the module as slot 1. Data, and Status) Chapter 6 SLC 500 Controller (Ladder Data Files Programming Input Image Output Image Examples) (8 words)
  • Page 27 7. Status) Chapter 6 (Ladder Programming Examples) Chapter 8 (Application Examples) SLC 500 Controller Data Files Input Image Output Image (8 words) Word 0 Channel 0 Data Word Word 1 Channel 1 Data Word Word 2...
  • Page 28 Quick Start for Experienced Users Publication 1746-UM007C-EN-P - July 2004...

  • Page 29: Compliance To European Union Directives

    Chapter Installation and Wiring This chapter provides: • Compliance to European Union Directives • Electrostatic Discharge • NT4 Power Requirements • Module Location in Chassis • Module Installation and Removal • Terminal Wiring • Thermocouple Calibration Compliance to European If this product has the CE mark it is approved for installation within the European Union and EEA regions.

  • Page 30: Electrostatic Discharge

    Installation and Wiring Electrostatic Discharge Electrostatic discharge can damage semiconductor devices inside this module if you touch backplane connector pins. Guard against electrostatic damage by observing the precautions listed next. Electrostatic discharge can degrade performance or ATTENTION cause permanent damage. Handle the module as stated below.

  • Page 31: Module Location In Chassis

    In the table: • AN "x" indicates a valid combination. • No symbol indicates an invalid combination. • A "+" indicates an external power supply (refer to the SLC 500 4-Channel Analog I/O Modules User Manual, publication 1746-UM005 for more information).
  • Page 32 Installation and Wiring 1746- 5V dc Amps 24V dc Amps IM16 0.085 0.185 OA16 0.370 OAP12 0.370 0.050 IB16 0.085 0.050 IV16 0.085 IG16 0.140 0.135 OV16 0.270 0.135 OBP8 0.135 OG16 0.180 0.045 0.045 0.085 0.090 OW16 0.170 0.180 0.030 0.025 0.060...

  • Page 33: General Considerations

    Installation and Wiring 1746- 5V dc Amps 24V dc Amps NO4V 0.055 0.145 ITB16 0.085 ITV16 0.085 IC16 0.085 0.150 0.040 0.150 0.145 OBP16 0.250 OVP16 0.250 0.060 0.040 0.050 0.050 HSTP1 0.020 General Considerations Most applications require installation in an industrial enclosure to reduce the effects of electrical interference.

  • Page 34: Terminal Block Removal

    Installation and Wiring Terminal Block Removal Never install, remove, or wire modules with power ATTENTION applied to the chassis or devices wired to the module. To remove the terminal block: 1. Loosen the two terminal block release screws. 2. Grasp the terminal block at the top and bottom and pull outward and down.

  • Page 35: Module Removal Procedure

    Installation and Wiring 3. Cover all unused slots with the Card Slot Filler, Catalog Number 1746-N2. Top and Bottom Module Release(s) Card Guide Module Removal Procedure 1. Press the releases at the top and bottom of the module and slide the module out of the chassis slot.

  • Page 36: Wiring Considerations

    Installation and Wiring (Terminal Block Spare Part Catalog Number 1746-RT32) Release Screw CJC A+ Channel 0+ CJC Assembly CJC A Channel 0 Shield Channel 1+ Shield Channel 1 Shield Channel 2+ Shield Channel 2 Shield Channel 3+ CJC B Channel 3 CJC Assembly CJC B+ Analog Common...
  • Page 37 Installation and Wiring • To ensure proper operation and high immunity to electrical noise, always use Belden 8761 (shielded, twisted pair) or ™ equivalent wire for millivolt sensors or shielded, twisted pair thermocouple extension lead wire specified by the thermocouple manufacturer for the thermocouple type you are using.
  • Page 38 25 ohms (12.5 one-way) will produce 0.3 mV of error. To reduce error, use large gage wire with less resistance for long wire runs. • Follow system grounding and wiring guidelines found in your SLC 500 Modular Hardware Style User Manual (publication 1747-UM011). Publication 1746-UM007C-EN-P - July 2004...

  • Page 39: Wiring Input Devices To The Nt4

    Installation and Wiring 3-11 Wiring Input Devices to the NT4 After the thermocouple module is properly installed in the chassis, follow the wiring procedure below using the proper thermocouple extension cable, or Belden 8761 for non-thermocouple applications. Cable (Cut foil shield and drain wire;...

  • Page 40: Cold Junction Compensation (Cjc)

    3-12 Installation and Wiring Cold Junction Compensation (CJC) Do not remove or loosen the cold junction ATTENTION compensating thermistor assemblies located between the two upper and lower CJC terminals on the terminal block. Both thermistor assemblies are critical to ensure accurate thermocouple input readings at each channel.

  • Page 41: Thermocouple Calibration

    Installation and Wiring 3-13 Thermocouple Calibration The thermocouple module is initially calibrated at the factory. The module also has an auto calibration function. Auto calibration compensates for offset and gain drift of the A/D converter caused by temperature change within the module. An internal, high precision, low drift voltage and system ground reference is used for this purpose.
  • Page 42 3-14 Installation and Wiring Publication 1746-UM007C-EN-P - July 2004...

  • Page 43: Chapter 4 Module Id Code

    Chapter Preliminary Operating Considerations This chapter explains how the thermocouple module and the SLC processor communicate through the module’s input and output image. It lists the preliminary setup and operation required before the thermocouple module can function in a 1746 I/O system. Topics include: •...

  • Page 44: Module Addressing

    Preliminary Operating Considerations Module Addressing The following memory map shows you how the output and input image tables are defined for the thermocouple module. Bit 15 Bit 0 Address O:e.0 Channel 0 Configuration Word Word 0 Channel 1 Configuration Word Word 1 O:e.1 O:e.2...

  • Page 45: Input Image-Data Words And Status Words

    Preliminary Operating Considerations Chapter 5, Channel Configuration, Data, and Status, gives you detailed bit information about the data content of the configuration word. Input Image-Data Words and Status Words The 8-word, thermocouple module input image (defined as the input from the thermocouple module to the CPU) represents data words and status words.

  • Page 46: Channel Filter Frequency Selection

    Preliminary Operating Considerations Channel Filter Frequency The thermocouple module uses a digital filter that provides high frequency noise rejection for the input signals. The digital filter is Selection 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.

  • Page 47: Channel Cut-Off Frequency

    Preliminary Operating Considerations 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 defined as the point on the input channel frequency response curve where frequency components of the input signal are passed with 3 dB of attenuation.

  • Page 48: Channel Step Response

    Preliminary Operating Considerations 250 Hz Filter Notch Fre quen cy Frequency Response -3 dB Amplitude (in dB) 1000 1250 1500 Frequency 65.5 Hz 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 100% of its expected final value.

  • Page 49: Update Time

    Preliminary Operating Considerations Update Time The thermocouple module 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.

  • Page 50: Update Time Calculation Example

    Preliminary Operating Considerations 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 •...

  • Page 51: Channel Turn-On, Turn-Off, And Reconfiguration Times

    Preliminary Operating Considerations Channel Turn-On, Turn-Off, The table below gives you the turn-on, turn-off, and reconfiguration times for enabling or disabling a channel. and Reconfiguration Times Description Duration Turn-On Time The time it takes to set the Requires up to one module status bit (transition from 0 to update time plus one of the 1) in the status word, after...

  • Page 52: Response To Slot Disabling

    4-10 Preliminary Operating Considerations Response to Slot Disabling By writing to the status file in your modular SLC processor you can disable any chassis slot. Refer to your programming device‘s manual for the slot disable/enable procedure. Always understand the implications of disabling a ATTENTION thermocouple module before using the slot disable feature.

  • Page 53: Channel Configuration

    Chapter Channel Configuration, Data, and Status This chapter examines the channel configuration word and the channel status word bit by bit, and explains how the module uses configuration data and generates status during operation. This chapter includes: • Channel Configuration •...

  • Page 54: Channel Configuration Procedure

    Channel Configuration, Data, and Status Channel Configuration The channel configuration word consists of bit fields, the settings of which determine how the channel will operate. This procedure looks Procedure at each bit field separately and helps you configure a channel for operation.
  • Page 55 Channel Configuration, Data, and Status 8. Build the channel configuration word for every channel on each thermocouple/mV module repeating the procedures given in steps 1-7. 9. Following the steps outlined in chapter 2, Quick Start for Experienced Users, or in chapter 6, Ladder Programming Examples, enter this configuration data into your ladder program and copy it to the thermocouple module.
  • Page 56 Channel Configuration, Data, and Status Bit(s) Define To Select Make these bit settings in the Channel Configuration Word Input type Thermocouple Type J Thermocouple Type K Thermocouple Type T Thermocouple Type E Thermocouple Type R Thermocouple Type S Thermocouple Type B Thermocouple Type N 50mV 100mV...

  • Page 57: Select Input Type (Bits 0-3)

    Channel Configuration, Data, and Status Select Input Type (Bits 0-3) 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 ±100 mV analog input signals.

  • Page 58: Using Scaled-For-Pid And Proportional Counts

    Channel Configuration, Data, and Status 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 provided/displayed by the 1746-NT4, and do not require explanation.

  • Page 59: Scaling Examples

    Channel Configuration, Data, and Status Scaling Examples Scaled-for-PID to Engineering Units Equation: Engr Units Equivalent = S LOW + [ (S HIGH - S LOW ) x (Scaled-for-PID value displayed / 16384) ] • Assume type J input type, scaled-for-PID display type, channel data = 3421.
  • Page 60 Channel Configuration, Data, and Status Proportional Counts to Engineering Units Equation: Engr Units Equivalent = S LOW + { (S HIGH - S LOW ) x [ ( Proportional Counts value displayed + 32768) / 65536 ] } • Assume type E input type, proportional counts display type, channel data = 21567.
  • Page 61 Channel Configuration, Data, and Status 1746-NT4 Thermocouple Module – Channel Data Word Format Input Type Data Format Engineering Units x 10 Engineering Units x 1 Scaled–for– Proportional Counts ° Celsius ° Fahrenheit ° Celsius ° Fahrenheit -210 to 760 -346 to 1400 -2100 to 7600 -3460 to 14000 0 to 16383...

  • Page 62: Select Open Circuit State (Bits 6 And 7)

    5-10 Channel Configuration, Data, and Status Select Open Circuit State (Bits 6 and 7) 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 is active for thermocouple input types, millivolt input types, and CJC device input.

  • Page 63: Select Temperature Units (Bit 8)

    Channel Configuration, Data, and Status 5-11 Select Temperature Units (Bit 8) 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.

  • Page 64: Select Channel Enable (Bit 11)

    5-12 Channel Configuration, Data, and Status Select Channel Enable (Bit 11) You use the channel enable bit to enable a channel. The thermocouple module only scans those channels that are enabled. To optimize module operation and minimize throughput times, unused channels should be disabled by setting the channel enable bit to zero.

  • Page 65: Channel Status Checking

    Channel Configuration, Data, and Status 5-13 Channel Status Checking The channel status word is a part of the thermocouple module’s input image. Input words 4-7 correspond to and contain the configuration status of thermocouple channels 0, 1, 2, and 3 respectively. You can use the data 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.3.
  • Page 66 5-14 Channel Configuration, Data, and Status Bit(s) Define These bit settings Indicate this 0–3 Input type Thermocouple Type J Thermocouple Type K Thermocouple Type T Thermocouple Type E Thermocouple Type R Thermocouple Type S Thermocouple Type B Thermocouple Type N 50 mV 100 mV Invalid...

  • Page 67: Status Conditions

    Channel Configuration, Data, and Status 5-15 If the channel for which you are seeking status is IMPORTANT disabled (bit O:e.x/11 = 0), all bit fields are cleared. The status word for any disabled channel is always 0000 0000 0000 0000 regardless of any previous setting that may have been made to the configuration word.

  • Page 68: Temperature Units Type Status (Bit 8)

    5-16 Channel Configuration, Data, and Status Temperature Units Type Status (Bit 8) The temperature units field indicates the state of the temperature units bit in the configuration word (bit 8). Channel Filter Frequency (Bits 9 and 10) The channel filter frequency bit field reflects the filter frequency you selected in the configuration word.

  • Page 69: Over-Range Error (Bit 14)

    Channel Configuration, Data, and Status 5-17 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 above the specified upper limit of the particular sensor connected to that channel.
  • Page 70 5-18 Channel Configuration, Data, and Status Publication 1746-UM007C-EN-P - July 2004...

  • Page 71: Initial Programming

    Chapter Ladder Programming Examples Earlier chapters explained how the configuration word defines the way a channel operates. This chapter shows the programming required to enter the configuration word into the processor memory. It also provides you with segments of ladder logic specific to unique situations that might apply to your programming requirements.

  • Page 72: Procedure

    Ladder Programming Examples Example - Configure four channels of a thermocouple module residing in slot 3 of a 1746 chassis. Configure each channel with the same parameters. Bit Number Bit Setting Configures Channel For: • Type K Thermocouple Input • Engineering Units 10 •...

  • Page 73: Dynamic Programming

    Ladder Programming Examples Dynamic Programming 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 2 of the thermocouple module located in slot 3 of a 1746 chassis. Change from monitoring an external type K thermocouple to monitoring the CJC sensors mounted on the terminal block.

  • Page 74: Verifying Channel Configuration Changes

    Ladder Programming Examples Verifying Channel When executing a dynamic channel configuration change, there will always be a delay from the time the ladder program makes the change Configuration Changes to the time the NT4 gives you a data word using that new configuration information.

  • Page 75: Interfacing To The Pid Instruction

    Ladder Programming Examples Interfacing to the PID The thermocouple module was designed to interface directly to the SLC 5/02 or later processor PID instruction without the need for an Instruction intermediate scale operation. Example - Use NT4 channel data as the process variable in the PID instruction.

  • Page 76: Monitoring Channel Status Bits

    Ladder Programming Examples Monitoring Channel Status This example shows how you could monitor the open circuit error bits of each channel and set an alarm in the processor if one of the Bits 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 thermistors are not installed or are damaged.

  • Page 77: Invoking Autocalibration

    Ladder Programming Examples Invoking Autocalibration Autocalibration of a channel occurs whenever a channel is enabled, or when a change is made to its input type or filter frequency. You can also command your module to perform an autocalibration cycle by disabling a channel, waiting for the status bit to change state (1 to 0) and then re-enabling that channel.
  • Page 78 Ladder Programming Examples Example - Command the NT4 to perform an autocalibration of channel 0. The NT4 is in slot 3. Program Listing Rung 2:0 Condition for Channel 0 Enable Autocalibration O:3.0 [OSR] Channel 0 Flag Rung 2:0 Channel 0 Status Channel 0 Flag Channel 0 Enable O:3.0...

  • Page 79: Module Operation Vs Channel Operation

    Chapter Module Diagnostics and Troubleshooting This chapter describes troubleshooting using the channel status LEDs as well as the module status LED. It explains the types of conditions that might cause an error to be reported and gives suggestions on how to resolve the problem. This chapter includes: •...

  • Page 80: Channel Diagnostics

    Module Diagnostics and Troubleshooting Channel Diagnostics When a channel is enabled (bit 11 = 1), a diagnostic check is performed to see that the channel has been properly configured. In addition the channel is tested for out-of-range and open-circuit faults on every scan.

  • Page 81: Led Indicators

    Module Diagnostics and Troubleshooting LED Indicators The thermocouple module has five LEDs. Four of these are channel status LEDs numbered to correspond to each of the thermocouple’s input channels, and one is a module status LED. INPUT CHANNEL Channel LEDs STATUS MODULE STATUS Module Status LED...

  • Page 82: Channel Status Leds (Green)

    Module Diagnostics and Troubleshooting Channel Status LEDs (Green) The channel LED is used to indicate channel status and related error information contained in the channel status word. This includes conditions such as: • normal operation • channel-related configuration errors • open circuit errors •...

  • Page 83: Out-Of-Range Detection

    Module Diagnostics and Troubleshooting Out-Of-Range Detection Whenever the data received at the channel data word is out of the defined operating range, an over-range or under-range error is indicated and bit 13 (under-range) or 14 (over-range) of the channel status word is set. Refer to the temperature ranges provided in the table on page 5-9 for a review of the temperature range limitations for your input device.

  • Page 84: Troubleshooting Flowchart

    Module Diagnostics and Troubleshooting Troubleshooting Flowchart Check LEDs on module. Channel Channel Channel Module Module Status LED Status LED Status LED(s) Status LED off Status LED on off. blinking Channel is Channel enabled Module fault Normal module and working not enabled. Fault condition operation...

  • Page 85: Replacement Parts

    Module Diagnostics and Troubleshooting Replacement Parts The NT4 module has the following replaceable parts: Part Catalog Number Replacement Terminal Block 1746-RT32 Replacement Terminal Cover 1746-R13 Series B 1746-NT4 Installation Instructions 1746-IN010 Contacting Rockwell If you need to contact Rockwell Automation for assistance, please have the following information available when you call: Automation •...
  • Page 86 Module Diagnostics and Troubleshooting Publication 1746-UM007C-EN-P - July 2004...

  • Page 87: Chapter 8 Basic Example

    Chapter Application Examples This chapter provides two application examples to help you use the thermocouple input module. They are defined as a: • basic example • supplementary example The basic example builds on the configuration word programming provided in chapter 6 to set up one channel for operation. This setup is then used in a typical application to display temperature.

  • Page 88: Channel Configuration

    Application Examples Channel Configuration Configure the thermocouple channel with the following setup: • type J thermocouple • °F - display to whole degree • zero data word in the event of an open circuit • 10 Hz input filter to reject high frequency noise and give good rejection of 60 Hz line noise Channel Configuration Worksheet (With Settings Established for Channel 0) Bit Number...
  • Page 89 Application Examples Program Listing Rung 2.0 Initialize Channel 0 of NT4 First Pass Bit MOVE Source N10:0 Dest O:3.0 Rung 2.1 Convert the channel 0 data word (degrees F) to BCD and write this to the LED display If channel 0 is ever disabled, a zero is written to the display. TO BCD Source I:3.0 Dest...

  • Page 90: Supplementary Example

    Application Examples Supplementary Example Application Setup (Four Channels °C °F) This example shows how to display the temperature of several different thermocouples at one annunciator panel. A selector switch (I:2/0) allows the operator to choose between displaying data in °C and °F.

  • Page 91: Channel Configuration

    Application Examples Channel Configuration Configuration setup for ambient thermocouple: • channel 0 • type T thermocouple • display temperature to tenths of a degree • zero data word in the event of an open circuit • 60 Hz input filter to provide 60 Hz line noise rejection Configuration setup for bath thermocouple: •...
  • Page 92 Application Examples Channel Configuration Worksheet (With Settings Established) Bit Number Channel 0 (Ambient) Channel 1 (Bath) Channel 2 (Steam) Channel 3 (Chilled H2O) • Input Type Select • Data Format Select • Open Circuit Select • Temperature Units Select • Filter Frequency Select •...

  • Page 93: Program Setup And Operation Summary

    Application Examples Program Setup and Operation Summary 1. Set up two configuration words in memory for each channel, one for °C and the other for °F. In addition, set up two configuration words to monitor the thermocouple’s CJC temperature. Monitoring the CJC temperature gives a good indication of the temperature inside of the control cabinet the SLC is mounted in.
  • Page 94 Application Examples Rung 2.0 If the degrees selector switch is turned to the Fahrenheit position, set up all four channels to read in degrees Fahrenheit. The default for channel 0 is to read the ambient temperature thermocouple. Degrees Configure NT4 Selector Switch - Channels Fahrenheit...
  • Page 95 Application Examples Rung 2.4 If the ambient/cabinet selector switch is turned to the ambient position and the degrees selector switch is in the Celsius position, configure channel 0 to read the ambient temperature thermocouple in degrees Celsius. Degrees Ambient/Cabinet Selector Switch - Selector Switch - Configure NT4 Celsius...
  • Page 96 8-10 Application Examples Rung 2.8 Convert the NT4 data words to BCD format and send to the LED displays. Write NT4 Ambient or Cabinet Temperature to Display TO BCD Source I:1.0 Dest O:3.0 Rung 2.9 Write NT4 Bath Temperature to Display TO BCD Source I:1.1 Dest...

  • Page 97: Electrical Specifications

    Appendix Specifications This appendix lists the specifications and input resolution curves for the 1746-NT4 4-Channel Thermocouple/mV Input Module. Electrical Specifications Specification Value Backplane Current 60 mA at 5V dc Consumption 40 mA at 24V dc Backplane Power 0.8W maximum (0.3W @ 5V dc, 0.5W @ 24V dc) Consumption Number of Channels 4 (backplane isolated)

  • Page 98: Physical Specifications

    Maximum Wire Size Two 14 AWG wires per terminal Maximum Cable Impedance 25 ohms maximum loop impedance, for <1LSB error Terminal Block Removable, Allen-Bradley spare part Catalog Number 1746-RT32 (1) Refer to the thermocouple manufacturer for the correct extension wire. Environmental Specifications...

  • Page 99: Input Specifications

    Specifications Input Specifications Specification Value Type of Input (Selectable) 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) Thermocouple Type B 300°C to 1820°C (572°F to 3308°F)

  • Page 100: 1746-Nt4 Module Accuracy

    Specifications 1746-NT4 Module Accuracy Input Type Without Autocalibration With Autocalibration Maximum Error Maximum Error Temperature Drift @ 25°C @ 77°F (0°C-60°C) ±1.06°C ±1.91°F ±0.0193°C/°C, °F/°F ±1.72°C ±3.10°F ±0.0328°C/°C, °F/°F ±1.43°C ±2.57°F ±0.0202°C/°C, °F/°F ±0.72°C ±1.3°F ±0.0190°C/°C, °F/°F ±3.61°C ±6.5°F ±0.0530°C/°C, °F/°F ±3.59°C ±6.46°F ±0.0530°C/°C, °F/°F...
  • Page 101 Specifications ˚ ( C) Resolution Type J Thermocouple ( F) ˚ 250 Hz 50/60 Hz 10 Hz 3.20 0.40 0.20 5.76 0.72 0.36 2.40 0.30 0.15 4.32 0.54 0.27 1.60 0.20 0.10 2.88 0.36 0.18 0.80 0.10 0.05 1.44 0.18 0.09 0.00 111 2...
  • Page 102 Specifications ˚ ( C) Resolution ˚ ( F) Type N Thermocouple 250 Hz 50/60 Hz 10 Hz 0.10 1.60 0.20 2.88 0.36 0.18 0.08 1.28 0.16 2.30 0.29 0.14 0.96 0.12 0.06 1.73 0.22 0.1 1 0.64 0.08 0.04 1.15 0.14 0.07 0.02...
  • Page 103 Specifications ˚ ( C) Resolution ( F) ˚ Type S Thermocouple 250 Hz 50/60 Hz 10 Hz 6.79 1.20 12.22 2.16 1.08 4.53 0.80 8.15 1.44 0.72 2.26 0.40 4.07 0.72 0.36 1050 1200 1350 1500 1650 1800 1112 1382 1652 1922 2192 2462 2732 3002 3272...
  • Page 104 Specifications ˚ ( C) Resolution ˚ ( F) Type B Thermocouple 250 Hz 50/60 Hz 10 Hz 3.20 0.80 5.76 1.44 0.72 2.40 0.60 4.32 1.08 0.54 1.60 0.40 2.88 0.72 0.36 0.80 0.20 1.44 0.36 0.18 300 150 900 1050 1200 1350 1500 1650 1800 1950 508 238 32 842 1112 1382 1652 1922 2192 2462 2732 3002 3272 3542...

  • Page 105: Channel Configuration Procedure

    Appendix NT4 Configuration Worksheet The following configuration procedure and worksheet are provided to help you configure each of the channels on your thermocouple module. Channel Configuration The channel configuration word consists of bit fields, the settings of which determine how the channel will operate. This procedure looks Procedure at each bit field separately and helps you configure a channel for operation.
  • Page 106 NT4 Configuration Worksheet 3. Determine the desired state for the channel data word if an open circuit condition is detected for that channel. Enter the 2-digit binary code in bit field 6-7 of the channel configuration word. Bits 6 and 7 Open Circuit Select 00 = zero 01 = upscale...
  • Page 107 NT4 Configuration Worksheet 9. Enter the completed configuration words for each module into the summary worksheet on the following page. 10. Following the steps outlined in chapter 2 or in chapter 6, enter this configuration data into your ladder program and copy it to the thermocouple module.

  • Page 108: Channel Configuration Worksheet

    NT4 Configuration Worksheet Channel Configuration Worksheet Bit Number Channel 0 Channel 1 Channel 2 Channel 3 Input Type Select Data Format Select Open Circuit Select Temperature Units Select Filter Frequency Select Channel Enable Not Used Bit Definitions: Description Specification Bits 0-3 Input Type Select 0000 = J 0100 = R...

  • Page 109: Appendix C J Type Thermocouple

    Appendix Thermocouple Restrictions Following are some restrictions extracted from NBS Monograph 125 (IPTS-68) issued March 1974 on thermocouples J, K, T, E, R, and S. J Type Thermocouple (Iron vs. Copper-Nickel <Constantan>) The J thermocouple “is the least suitable for accurate thermometry because there are significant nonlinear deviations in the thermoelectric output from different manufacturers.

  • Page 110: K Type Thermocouple

    Thermocouple Restrictions “ASTM Standard E230-72 in the Annual Book of ASTM Standards [1972] specifies that the standard limits of error for Type J commercial thermocouples be ±2.2C between 0 and 277C and ±3/4 percent between 277 and 760C. Limits of error are not specified for Type J thermocouples below 0C or above 760C.

  • Page 111: T Type Thermocouple

    Thermocouple Restrictions “They should not be used in sulfurous, reducing, or alternately reducing and oxidizing atmospheres unless suitably protected with protecting tubes. They should not be used in vacuum (at high temperatures) for extended times because the Chromium in the positive thermoelement vaporizes out of solution and alters the calibration.

  • Page 112: E Type Thermocouple

    Thermocouple Restrictions “Type T thermoelements are not well suited for use in nuclear environments, since both thermoelements are subject to significant changes in composition under thermal neutron irradiation. The copper in the thermoelement is converted to nickel and zinc.” “Because of the high thermal conductivity of Type TP thermoelements, special care should be exercised in the use of the thermocouples to insure that both the measuring and reference junctions assume the desired temperatures.”...

  • Page 113: S And R Type Thermocouples

    Thermocouple Restrictions “The negative thermoelement, a copper-nickel alloy, is subject to composition changes under thermal neutron irradiation since the copper is converted to nickel and zinc.” “ASTM Standard E230-72 in the Annual Book of ASTM Standards [1972] specifies that the standard limits of error for the Type E commercial thermocouples be ±1.7C between 0 and 316C and ±1/2 percent between 316 and 871C.
  • Page 114 Thermocouple Restrictions “ASTM Standard E230-72 in the Annual Book of ASTM Standards [1972] specifies that the standard limits of error for Type S {and R} commercial thermocouples be ±1.4C between 0 and 538C and ±1/4 percent between 538 and 1482C. Limits of error are not specified for Type S {or R} thermocouples below 0C.
  • Page 115 Appendix Thermocouple Types This appendix describes the three types of thermocouple junctions. They are • Grounded Junction - The measuring junction is physically connected to the protective metal sheath providing electrical continuity between junction and sheath. • Ungrounded Junction – The measuring junction is electrically isolated from the protective metal sheath.
  • Page 116 Thermocouple Types Publication 1746-UM007C-EN-P - July 2004...
  • Page 117 Appendix Configuring the 1746-NT4 Module with RSLogix 500 This appendix describes how to configure the NT4 module with RSLogix 500 v6.10 or higher. To configure your module: 1. Access the I/O Configuration menu. 2. Determine the chassis number and slot location of where the NT4 module is located.

  • Page 118: Publication 1746-Um007C-En-P - July

    Configuring the 1746-NT4 Module with RSLogix 500 3. Press the Adv Config button. The following dialog box appears. 4. Press the Configure button. This allows you to configure options for each channel. The following dialog box appears. Publication 1746-UM007C-EN-P - July 2004...
  • Page 119 Configuring the 1746-NT4 Module with RSLogix 500 The dialog box allows you to access the parameters for all channels. Each tab has an identical menu with the parameters shown. The following list provides the options for a parameter. Parameter Description Channel Enabled Controls bit 11 of the configuration file and sets whether the channel is being used.
  • Page 120 Configuring the 1746-NT4 Module with RSLogix 500 5. Press OK to set the parameters. The following dialog box appears. 6. Choose the data file for the configuration and the location for the configuration rung within your ladder logic program. 7. Press OK. The following rung is added to the ladder logic program.
  • Page 121 Glossary The following terms and abbreviations are used throughout this manual. For definitions of terms not listed here refer to Allen-Bradley’s Industrial Automation Glossary, Publication AG-7.1. A/D - Refers to the analog to digital converter inherent to the NT4 thermocouple input module. The converter produces a digital value whose magnitude is proportional to the instantaneous magnitude of an analog input signal.
  • Page 122 Glossary 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. When the channel is disabled the channel data word is cleared (0). digital filter - A low-pass noise filter incorporated into the A/D converter.
  • Page 123 Glossary remote configuration - 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.
  • Page 124 Glossary Notes: Publication 1746-UM007C-EN-P - July 2004...
  • Page 125 Index configuring NT4 module with RSLogix connection diagram definition current draw addressing cut-off frequency configuration word definition data word overview status word alarms application example basic data word supplementary definition attenuation overview definition resolution data word format 5-15 examining in status word overview bit allocation scaling ranges by input type...
  • Page 126 Index using multiple thermocouples extension wire LEDs channel status indicators location on module module status indicator filter frequency local configuration definition 5-16 examining in status word definition 5-11 setting in configuration word input signal range definition full scale error definition manuals, related full scale range module ID code...
  • Page 127 Index 5-17 overview step response definition overview system operation input type instruction pinout diagram temperature units power-up sequence 5-16 examining in status word 5-11 programming overview setting in configuration word 5-11 6-6, 6-7 alarms terminal pinout diagram configuration settings making changes terminal wiring dynamic 3-12...
  • Page 128 Index 5-16 overview update time wiring definition routing considerations terminal wiring 3-12 cold junction compensation 3-10 shield connections Verification of dynamic configuration worksheets change Publication 1746-UM007C-EN-P - July 2004...
  • Page 129 Index Publication 1746-UM007C-EN-P - July 2004...
  • Page 131 Please contact your local Rockwell Automation representative for States return procedure. Allen-Bradley is a registered trademark of Rockwell Automation. SLC and RSLogix are trademarks of Rockwell Automation. Belden is a trademark of Belden, Inc. C-UL is a registered trademark of Underwriters Laboratories.

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