Allen-Bradley 1746-IH16 SLC 500 125V DC Input Module Overview

Product Introduction

When your control system demands reliable detection of 125V DC signals in harsh or hazardous environments, the Allen-Bradley 1746-IH16 delivers a proven solution. This SLC 500 series digital DC input module provides 16 current sinking inputs engineered for general-purpose 125V DC applications. It is approved for use in Class 1, Division 2, Groups A, B, C, or D hazardous locations, making it a trusted choice for oil and gas, chemical processing, and other demanding industrial settings. The module installs into any free 1746 I/O chassis slot and uses a Removable Terminal Block for convenient wiring.

Technical Specifications Breakdown

The 1746-IH16 operates over a voltage range of 90-146 Volts DC Sink, accommodating nominal 125V DC signals with headroom for fluctuations. Each of the 16 inputs is current sinking, with 16 points per common, simplifying field wiring. The module draws 85 milliamps from the 5V DC backplane and dissipates 5.17 Watts of total energy as heat during normal operation. Signal delay is 9 milliseconds for both OFF and ON states, ensuring predictable response times. Off-state current leakage is limited to 0.8 milliamps, preventing false triggering. The module provides circuit isolation between inputs and control logic, enhancing system integrity.

Industry Applications

In a refinery environment, the 1746-IH16 monitors 125V DC valve position feedback from limit switches located in Class 1, Division 2 areas. Its 90-146V DC range accommodates voltage drops along long cable runs, while the 9 ms signal delay filters out contact bounce. For a water treatment facility, the module reads pump status signals from 125V DC relays, with the 16 points per common configuration reducing wiring complexity. The module's 5.17W dissipation allows dense packing in the chassis without excessive heat buildup.

Installation & Setup Guidance

Mount the 1746-IH16 in any available slot of a 1746 I/O chassis. Use the 1746-HT or 1746-HCA I/O connection cables to interface with field devices. Ensure the backplane power supply delivers at least 85 mA at 5V DC per module. Wire sinking inputs so that the common is connected to the DC supply return, and each input point connects to the positive side of the 125V DC source through the sensing device. The module operates within 0-60 °C (32-140 °F) and 5-95% non-condensing humidity. Store the module between -40 and 85 °C (-40 and 185 °F) when not in use.

Maintenance & Reliability

The 1746-IH16 is built for long-term reliability in industrial environments. Its NEMA ICS 2-230-rated noise immunity and 30G operational shock rating ensure stable operation in high-vibration settings. Periodic inspection of the Removable Terminal Block connections and verification of input signal levels help maintain performance. The module's 5.17W heat dissipation is low, reducing thermal stress on adjacent components. For extended service life, keep the chassis free of dust and ensure adequate airflow.

Selection Guide & Purchasing Advice

Before purchasing the 1746-IH16, verify that your application requires 125V DC sinking inputs and that your SLC 500 chassis has an available slot and sufficient backplane current. Confirm the I/O connection type (1746-HT or 1746-HCA) matches your existing wiring. BluePLC Industrial offers this module with full support and fast shipping. For complete technical specifications, please contact BluePLC Industrial. Please verify current lifecycle status and availability with BluePLC Industrial before ordering.