Instructions

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Publication 1746-IN015C-EN-P - July 2001

Installation Instructions

SLC 500 Thermocouple/mV Analog Input Module

(Catalog Number 1746-NT8)

Inside...

Hazardous Location Considerations ........................................................ 2

Environnements dangereux ..................................................................... 2

Module Overview..................................................................................... 3

Input Ranges ............................................................................................ 3

Hardware Features .................................................................................. 4

Installing And Wiring Your Module......................................................... 5

Electrostatic Damage............................................................................... 6

Required Tools and Equipment................................................................ 6

Power Requirements................................................................................ 6

Considerations for a Modular System..................................................... 7

Considerations for a Fixed Controller ...................................................... 7

Selecting A Chassis Slot.......................................................................... 7

Module Installation and Removal............................................................ 8

Terminal Block Removal........................................................................... 9

Cold Junction Compensation (CJC) ....................................................... 10

Wiring Guidelines .................................................................................. 10

Thermocouple Junctions........................................................................ 11

Preparing and Wiring the Cables........................................................... 14

Module Specifications........................................................................... 17

For More Information ............................................................................. 20

Summary of content (20 pages)

PAGE 1
Installation Instructions SLC 500 Thermocouple/mV Analog Input Module (Catalog Number 1746-NT8) Inside... Hazardous Location Considerations ........................................................ 2 Environnements dangereux ..................................................................... 2 Module Overview..................................................................................... 3 Input Ranges ............................................................................................
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SLC 500 Thermocouple/mV Analog Input Module Hazardous Location Considerations This equipment is suitable for use in Class I, Division 2, Groups A, B, C, D or non-hazardous locations only. The following WARNING statement applies to use in hazardous locations. WARNING ! EXPLOSION HAZARD • Substitution of components may impair suitability for Class I, Division 2. • Do not replace components or disconnect equipment unless power has been switched off or the area is known to be non-hazardous.
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SLC 500 Thermocouple/mV Analog Input Module 3 Module Overview 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 millivolt analog input device. You configure each channel to accept either one.
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SLC 500 Thermocouple/mV Analog Input Module Each input channel is individually configured for a specific input device. Each channel detects and indicates: • open-circuit • over-range • under-range Hardware Features The module fits into any single slot (other than slot 0) for I/O modules in either an SLC 500 modular system or an SLC 500 fixed system expansion chassis (1746-A2). It is a Class 1(1) module (uses 8 input words and 8 output words).
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SLC 500 Thermocouple/mV Analog Input Module 5 1746-NT8 Features INPUT Channel Status LEDs (Green) CHANNEL STATUS MODULE Module Status LED (Green) 0 1 2 1 4 5 2 3 Door Label THERMOCOUPLE/mV 1746-NT8 Removable Terminal Block CJC Sensors Cable Tie Slots Hardware CJC A+ CJC ACHL 0+ CHL 0SHIELD CHL 1+ CHL 1CHL 2+ CHL 2SHIELD CHL 3+ CHL 3CHL 4+ CHL 4SHIELD CHL 5+ CHL 5CHL 6+ CHL 6SHIELD CHL 7+ CHL 7CJC B+ CJC B- Function Channel Status LED Indicators Display operating and fault status of channel
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SLC 500 Thermocouple/mV Analog Input Module Electrostatic Damage 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.
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SLC 500 Thermocouple/mV Analog Input Module 7 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. Considerations for a Fixed Controller The power supply in the 2-slot SLC 500 fixed I/O chassis (1746-A2) can support only specific combinations of modules.
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SLC 500 Thermocouple/mV Analog Input Module Module Installation and Removal ATTENTION ! Before installing or removing your module, always disconnect: • power from the SLC 500 system • any other power sources to the module • any devices wired to the module Failure to observe this precaution can cause unintended equipment operation and damage. Top and Bottom Module Release(s) Card Guide To insert your module into the chassis, follow these steps: 1.
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SLC 500 Thermocouple/mV Analog Input Module 9 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.
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SLC 500 Thermocouple/mV Analog Input Module Cold Junction Compensation (CJC) 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 are integrated in the removable terminal block. They must remain installed to retain accuracy.
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SLC 500 Thermocouple/mV Analog Input Module 11 Thermocouple Junctions There are three types of thermocouple junctions: • 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. (Ungrounded Junction can also be called Insulated Junction.
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SLC 500 Thermocouple/mV Analog Input Module Grounded Junction Thermocouples 1746-NT8 Grounded junction with nonconductive protective sheath MUXES + - CH0 CH3 + - Metal sheath with electrical continuity to thermocouple signal wires. (floating ground connection) As shown in the wiring diagram above, it is recommended that grounded junction thermocouples have either protective sheaths made of electrically insulated material (e.g. ceramic), or that the metal protective sheaths be floated.
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SLC 500 Thermocouple/mV Analog Input Module 13 Exposed Junction Thermocouples 1746-NT8 Conductive Material CH 0 MUXES + - Exposed junction with shielded cable Nonconductive Material CH 3 + - Exposed junction with shielded cable Cable Wiring Considerations 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 a
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SLC 500 Thermocouple/mV Analog Input Module • 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 no more than 0.25 Nm.
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SLC 500 Thermocouple/mV Analog Input Module 15 5. Connect the drain wires to the shield inputs of the terminal block if appropriate for thermocouple used. See “Wiring Guidelines” on page 10 for more information. • Channel 0 and 1 drain wires to pin 5 • 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.
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SLC 500 Thermocouple/mV Analog Input Module Terminal Block Diagram with Input Cable CJC A+ Thermocouple or mV Cable CJC AChannel 0+ Channel 0Shield for CH0 and CH1 Channel 1+ Channel 1Channel 2+ Channel 2Shield for CH2 and CH3 Channel 3+ Channel 3Channel 4+ Channel 4Shield for CH4 and CH5 Channel 5+ Channel 5Channel 6+ Channel 6Shield for CH6 and CH7 Channel 7+ Channel 7CJC B+ CJC B- TB1 Publication 1746-IN015C-EN-P - July 2001
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SLC 500 Thermocouple/mV Analog Input Module 17 Module Specifications Electrical Specifications Backplane Current Consumption 120 mA at 5V dc, 70 mA at 24V dc Backplane Power Consumption 2.28W maximum (0.5W at 5V dc, 1.
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SLC 500 Thermocouple/mV Analog Input Module Environmental Specifications 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) Agency Certification UL and C-UL approved Hazardous Environment Classification Class I, Division 2 Hazardous Environment Groups A, B, C, D EMC CE compliant for all applicable directives C-Tick compliant for all applicable acts Input Specifications Type of Input (Se
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SLC 500 Thermocouple/mV Analog Input Module Overall Module Accuracy at 25°C (77°F) See Module Accuracy Tables, in Appendix A of the SLC 500™ Thermocouple/mV Analog Input Module manual, publication 1746-6.22. Overall Module Accuracy (0°C to 60°C, 32°F to 140°F) See Module Accuracy Tables, in Appendix A of the SLC 500™ Thermocouple/mV Analog Input Module manual, publication 1746-6.22.
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For More Information For Refer to this Document Pub. No. A more detailed description on how to install and use your SLC 500™ Thermocouple/mV Input Module SLC 500™ Thermocouple/mV 1746-6.22 Analog Input Module User Manual A more detailed description on how to install and use your SLC 500™ Modular Hardware Style Control System. SLC 500™ Modular Hardware Style Installation and Operation Manual 1747-6.2 More information on proper wiring and grounding techniques.