Honeywell TK-IDD321 32-Point Discrete Input Module

The Honeywell TK-IDD321 is a high-density 24 VDC discrete input module designed to interface field switch contacts, proximity sensors, and digital inputs with process control systems. It provides 32 input channels divided into two groups of 16 points per common.

Input Voltage Characteristics and Signal Thresholds

Operating with a nominal input voltage of 24 VDC, the module accepts an on-state voltage range of 10 VDC to 31.2 VDC across all channels at temperatures up to 60 deg C. It complies with IEC Type 1+ input specifications, requiring a minimum on-state current of 2 mA while defining off-state conditions at a maximum of 5 V and 1.5 mA leakage current.

Inrush Current Limits and System Interface

During signal transition or field contact closure, each input channel tolerates a peak short/inrush current of 250 mA, which decays to less than 37% of peak within 22 ms without false channel activation. The module dissipates up to 6.1 W of power under maximum load conditions and connects to field wiring using a 36-position TC-TBCH terminal block.

Technical Specifications

Frequently Asked Questions

Q: What type of field wiring terminal block is compatible with the TK-IDD321 module?

A: The module connects to field signals using a TC-TBCH 36-position terminal block.

Q: What are the voltage and current thresholds for determining an on-state signal?

A: An on-state signal requires a voltage between 10 VDC and 31.2 VDC (at up to 60 deg C) with a minimum current of 2 mA per point.

Q: How does the input circuit handle inrush current during contact closure?

A: Inputs tolerate a peak inrush current of 250 mA, decaying to less than 37% within 22 ms without triggering false signal activation.