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

1746-IH16 Allen-Bradley 16-Channel 125V DC Input Card

The 1746-IH16 module extends the SLC 500 I/O family with high-voltage DC input capability. This digital input card accepts 125VDC sinking signals from field devices like pushbuttons, selector switches, and proximity sensors. Specifically, it converts these high-level DC signals into logic-level data for the processor. Therefore, it serves as a robust interface between harsh industrial processes and the control system. Additionally, its hazardous area approval expands installation possibilities beyond standard environments.

Key Features and Input Specifications

This module provides sixteen current-sinking input channels arranged with 16 points per common. It operates with a nominal voltage of 125VDC, covering a wide range from 90 to 146VDC. However, the number of simultaneously powered points depends on the applied voltage. For instance, you can power 16 points at 125VDC, but only 6 points at 146VDC. Meanwhile, 14 points remain active at 132VDC, and 12 points work at 146VDC. The nominal input current per point measures 2.15mA at 125VDC and 2.25mA at 132VDC.

Furthermore, the 1746-IH16 offers a typical signal delay of 9 milliseconds for both OFF-to-ON and ON-to-OFF transitions. This predictable response ensures reliable timing in control sequences. The maximum off-state voltage drop reaches 20VDC, while off-state leakage current stays below 0.8mA. These specifications prevent false triggering from residual currents. The module draws 85mA from the 5VDC backplane and dissipates 5.17 watts as heat during normal operation.

Hazardous Location Certification and Safety Ratings

The Allen-Bradley 1746-IH16 carries approval for Class 1, Division 2, Groups A, B, C, or D hazardous environments. This certification allows installation in areas where flammable gases or vapors may occasionally exist. Additionally, it suits all non-hazardous industrial settings without restriction. The module provides circuit isolation between the input circuits and the control logic. It also meets NEMA standard ICS 2-230 for noise immunity, which protects against electrical interference from nearby equipment.

Mechanical and Environmental Specifications

This input module operates reliably across a broad temperature range from 0°C to 60°C (32°F to 140°F). It also handles storage temperatures between -40°C and 85°C (-40°F to 185°F). The module tolerates 5% to 95% non-condensing humidity for versatile deployment. Moreover, it withstands operational vibration of 2.5G at 57 to 200 Hertz. Its shock rating reaches 30G, making it suitable for locations with moderate mechanical stress. The module holds C-UL and CSA certifications, confirming its compliance with North American safety standards.

Installation Guidelines and Chassis Compatibility

You can install this module in any available slot of the 1746 I/O chassis. However, remember that slot 1 typically houses the SLC 500 processor. The module supports local installation alongside the controller or in expansion racks. Moreover, it works with remote I/O chassis through a communication adapter. Always disconnect power from the chassis before installation, as this module does not support RIUP. Use the included removable terminal block for convenient field wiring. The RTB also permits off-site pre-wiring, which reduces downtime during maintenance.

Packaging and Shipping Information

• One 1746-IH16 digital input module

• One removable terminal block (RTB) for wiring connections

• One quick-start installation guide

• Anti-static protective packaging

All orders ship via FedEx, UPS, or DHL with full tracking available. Inspect all items upon delivery and report any transit damage immediately.

Frequently Asked Questions

1. Can the 1746-IH16 accept 24VDC input signals?
No, this module requires high-voltage DC signals between 90 and 146VDC. For 24VDC applications, consider the 1746-IB32 or other SLC 500 DC input modules.

2. What does "16 points per common" mean for this module?
It means all sixteen input channels share a single common return terminal. This wiring arrangement simplifies field connections but requires careful attention to total current capacity.

3. Is the 1746-IH16 suitable for use in explosive atmospheres?
Yes, it holds Class 1, Division 2, Groups A, B, C, and D certification. This approval permits installation in areas with flammable gases or vapors under normal operating conditions.

4. How does temperature affect the input voltage range?
The voltage range remains constant at 90-146VDC across the full operating temperature range of 0°C to 60°C. However, derating applies to the number of simultaneously powered points at higher voltages.

5. Can I hot-swap this module while the system runs?
No, the 1746-IH16 does not support removal and insertion under power. Always power down the chassis before installing or removing this module to avoid equipment damage.