Allen-Bradley ControlLogix 1756-IT6I Temperature Measurement Module

Overview

The 1756-IT6I is a six-channel isolated analog input module from Allen-Bradley’s ControlLogix family, specifically designed for high-accuracy temperature measurement applications. It supports multiple thermocouple types and cold junction compensation (CJC) sensing, providing dependable analog signal acquisition for industrial automation and process control systems.

With its 16-bit resolution, low drift, and multiple input ranges, the 1756-IT6I ensures precise monitoring of temperature-critical operations across manufacturing, energy, and chemical industries.

Technical Specifications

• Manufacturer: Allen-Bradley

• Model / Part Number: 1756-IT6I

• Product Line: ControlLogix

• Product Type: Analog Thermocouple Input Module

• Weight: 1.38 lbs (0.62 kg)

Input Configuration

• Number of Inputs: 6 isolated thermocouple inputs + 1 cold junction compensation (CJC)

• Supported Thermocouple Types: B, C, E, J, K, N, R, S, T

• Input Range: -12…78 mV and -12…30 mV (high-resolution mode)

• Input Resolution: 16 bits

• -12…78 mV range: 1.4 μV/bit typical

• -12…30 mV range: 0.7 μV/bit typical

Performance Characteristics

• Minimum Module Scan Time:

• Floating Point (millivolt): 25 ms

• Floating Point (temperature): 50 ms

• Integer (millivolt): 10 ms

• Data Format: Integer mode (left justified, 2’s complement) and IEEE 32-bit floating point

• Accuracy: ±0.1% of range at 25°C typical

• Calibration Interval: Recommended every 6 months

Power and Backplane Requirements

• Backplane Current @ 5V DC: 250 mA

• Backplane Current @ 24V DC: 125 mA

• Power Dissipation (Max): 4.3 W

Hardware and Connectivity

• Compatible Removable Terminal Blocks (RTB): 1756-TBNH, 1756-TBSH

• Module Slot Width: 1

• Wire Category: 2 (signal level)

• Isolation: Channel-to-channel and channel-to-backplane isolation

Environmental Specifications

• Operating Temperature: 0…60°C (32…140°F)

• Storage Temperature: -40…85°C (-40…185°F)

• Enclosure Type: Open-style

Application Notes

The 1756-IT6I module is ideal for high-precision temperature monitoring in critical processes such as furnace control, chemical reaction management, and energy plant temperature profiling. Its isolated channels allow simultaneous multi-sensor operation without signal interference.

FAQ

Q: What types of thermocouples are supported by the 1756-IT6I?
A: It supports thermocouple types B, C, E, J, K, N, R, S, and T.

Q: How many channels does the module provide?
A: It includes six isolated thermocouple inputs and one CJC channel.

Q: What is the resolution of the input signals?
A: The module provides 16-bit resolution, equivalent to approximately 0.7 μV per bit in high-resolution mode.

Q: Which terminal blocks are compatible?
A: It supports 1756-TBNH and 1756-TBSH removable terminal blocks.