Honeywell TC-IDD321 Experion LS Digital Input Module

The Honeywell TC-IDD321 is a 32-channel digital input module for the Experion LS I/O system. It accepts 24 VDC discrete input signals and uses IEC Type 1+ input compatibility to detect field-device ON and OFF states. Its 16 points per common arrangement, channel-to-channel isolation, and connection to a TC-TBNH 36-position terminal block define the main configuration requirements.

Input Configuration and Signal Detection

The TC-IDD321 provides 32 digital input channels arranged as 16 points per common. It is designed to receive discrete signals from field devices operating at a nominal 24 VDC input voltage.

The minimum ON-state current is 2 mA. For OFF-state detection, the input voltage must not exceed 5 V, while the maximum OFF-state current is 1.5 mA. These thresholds are relevant when checking field-device output characteristics and determining whether the connected signals are compatible with the module.

Electrical Isolation and Power Dissipation

The module specifies channel-to-channel isolation tested at 1500 VDC for 1 second. This isolation test rating is relevant when evaluating electrical separation between input circuits.

The maximum power dissipation is 6.1 W. This value should be considered when checking the thermal and power requirements of the installed I/O assembly.

Terminal Block Connection

The specified connection terminal block is the TC-TBNH, 36-position terminal block. The terminal block must be included in the hardware configuration check when replacing the module or preparing an installation. Confirm the terminal assignment against the applicable Honeywell wiring documentation before connecting field signals.

Technical Specifications

Frequently Asked Questions

Q: How many field input signals can the TC-IDD321 handle?

A: The module supports 32 digital input points arranged in two groups of 16 points per common. The field wiring must follow the applicable common-terminal arrangement.

Q: What input signal conditions should be checked before selecting this module?

A: Check that the field signals operate at the nominal 24 VDC level and meet the specified input thresholds: minimum 2 mA ON-state current, maximum 5 V OFF-state voltage, and maximum 1.5 mA OFF-state current.

Q: Does the TC-IDD321 provide programmable input filtering?

A: Yes. The published Experion LS technical specifications identify selectable OFF-to-ON filter settings of 0 ms, 1 ms, and 2 ms, and ON-to-OFF settings of 0 ms, 1 ms, 2 ms, 9 ms, and 18 ms. Hardware delay is specified as 1 ms maximum, in addition to the selected filter time.