Allen-Bradley 1756-IT6I/A ControlLogix Isolated Thermocouple Input Module

The Allen-Bradley 1756-IT6I/A, also cataloged as the 1756-IT6I Analog Thermocouple Module, operates as a dedicated hardware component for isolated temperature signal acquisition within the ControlLogix platform. The module provides six isolated thermocouple inputs with millivolt measurement capability, cold junction compensation, and ControlLogix backplane communication.

Hardware Specifications

ControlLogix Thermocouple Signal Processing

The 1756-IT6I/A performs isolated thermocouple and millivolt signal conversion through six independent input channels. Each channel supports thermocouple types B, C, E, J, K, N, R, S, and T, with configurable filtering and update timing parameters. Channel isolation separates field input signals from each other and from the ControlLogix backplane.

The module uses 16-bit analog conversion resolution with selectable data representation modes. Temperature values can be transferred through IEEE 32-bit floating point formatting, while millivolt signals can be processed using integer mode.

Hardware Specifications for Industrial Control Integration

The module communicates through the ControlLogix chassis backplane and supports standard ControlLogix I/O configuration. The backplane current requirements are 250 mA at 5.1 VDC and 125 mA at 24 VDC. The removable terminal block interface supports field wiring termination through compatible 1756 series terminal blocks.

Frequently Asked Questions (FAQ)

Q: What thermocouple types are supported by the 1756-IT6I/A module?
A: The module supports B, C, E, J, K, N, R, S, and T thermocouple sensor types.

Q: Does the 1756-IT6I/A provide electrical isolation between input channels?
A: Yes. The module provides channel-to-channel isolation and channel-to-backplane isolation rated at 250 V.

Q: What backplane power is required for this module?
A: The module requires approximately 250 mA at 5.1 VDC and 125 mA at 24 VDC from the ControlLogix chassis backplane.

Field Installation Guidelines

Install the 1756-IT6I/A module in a compatible ControlLogix chassis slot and verify the chassis power supply capacity before operation. Use the specified removable terminal blocks for field connections.

Route thermocouple wiring separately from high-voltage power cables and switching circuits to reduce electromagnetic interference. Use appropriate thermocouple extension cable types matching the connected sensor type. Maintain proper shield termination practices according to plant grounding standards.

Verify input configuration, sensor type selection, cold junction compensation settings, and data format parameters before commissioning the module. Confirm that field wiring polarity and terminal assignments match the configured thermocouple channels.