What Is the 1756-IRT8IK?
How do you capture accurate temperature data across eight separate process points without signal interference dragging your readings down? The Allen-Bradley 1756-IRT8IK answers that question. It is a ControlLogix RTD thermocouple input module built by Rockwell Automation, and it packs eight isolated input channels into a single slot. Each channel handles RTD or thermocouple signals independently, so heat, noise, and ground loops on one loop stay out of the next.
Key Parameters That Matter on the Plant Floor
24-Bit Resolution
The 1756-IRT8IK resolves input at 24 bits. In practical terms, that means fine temperature steps instead of coarse jumps, which helps when a reactor or furnace runs inside a narrow band.
Eight Isolated Channels
Isolation keeps channel-to-channel interference low. A fault on one thermocouple will not corrupt the readings on the other seven.
250 Volts Continuous Isolation
The module holds 250 Volts continuous isolation, a practical barrier between field wiring and the backplane.
Power and Thermal Profile
The module draws 200 milliamps at 5.1 Volts and 150 milliamps at 24 Volts from the backplane. Maximum power dissipation is 4.6 Watts, and thermal dissipation reaches 15.7 BTU per hour. Plan panel airflow around that heat load.
Where the 1756-IRT8IK Fits
Temperature-heavy processes are the natural home for this module. Consider three common cases:
- Refinery and petrochemical loops where thermocouples monitor column, reactor, and heater temperatures.
- Oil and gas metering skids that need stable RTD readings for custody transfer calculations.
- Industrial furnaces and ovens running multi-zone control, where eight isolated channels map neatly to eight zones.
In each case, the isolation and 24-bit resolution do the real work: cleaner signals, tighter control, fewer nuisance alarms.
Installation and Integration Notes
The 1756-IRT8IK seats in a ControlLogix chassis like any 1756-series module. Confirm the slot, backplane current budget, and chassis power before you install. Because this is a temperature input module, route thermocouple and RTD wiring away from drives and high-current cables to protect the low-level signals.
This module is a ControlLogix I/O card. It is not a communication module, so do not expect it to join a network on its own. If your architecture needs a fieldbus link, plan for the appropriate ControlLogix communication module in the same chassis and confirm cabling and gateway choices with your supplier before ordering.
Maintenance and Reliability
Temperature input modules rarely fail on their own; wiring and sensors usually fail first. Inspect terminal connections periodically, watch for corrosion in humid areas, and verify sensor integrity during scheduled shutdowns. Keep the chassis clean and the panel temperature within the enclosure design range. A spare 1756-IRT8IK on the shelf shortens unplanned downtime considerably.
Before You Order
Verify the exact catalog number, channel count, and isolation rating against your existing installation. If you are matching a legacy ControlLogix rack, confirm the series and firmware compatibility with your integrator.
Please verify current lifecycle status and availability with Oil AutoTech before ordering. Oil AutoTech supplies ready-to-ship industrial automation spares for oil, gas, and process plants, with fast dispatch and worldwide delivery. Contact Oil AutoTech today for pricing and availability.
