1746-IA16 | Allen-Bradley SLC 500 Digital AC Input Module 100/120V AC

Overview

The 1746-IA16 is a high-density digital input module engineered for the Allen-Bradley SLC 500 chassis system. This module serves as the primary interface between AC field devices and the SLC processor, providing 16 discrete input points. It is specifically designed to operate within a standard 120V AC voltage window, making it suitable for monitoring industrial pushbuttons, limit switches, and motor starter auxiliary contacts. The 1746-IA16 occupies a single slot in the 1746 I/O chassis and features optical isolation to protect the backplane electronics from field-side electrical surges.

Detailed Technical Specifications

• Manufacturer: Allen-Bradley / Rockwell Automation

• Product Series: SLC 500

• Model Number: 1746-IA16

• Module Function: Digital AC Input

• Number of Inputs: 16 Points (single group of 16)

• Voltage Category: 100/120V AC

• Operating Voltage Range: 85–132V AC (47–63 Hz)

• Backplane Current Draw (5V DC): 85 mA

• Backplane Current Draw (24V DC): 0 mA

• Off-State Voltage (Maximum): 50V AC

• Off-State Current (Maximum): 2 mA

• Signal Delay (ON): 35 ms

• Signal Delay (OFF): 45 ms

• Inrush Current (Maximum): 0.8 A

• I/O Connection: 1746-RT25 Removable Terminal Block (or 1746-HT/HC interface)

• Operating Temperature: 0°C to 60°C (32°F to 140°F)

• Weight: 0.28 kg (0.63 lbs)

Operational Implementation

The 1746-IA16 utilizes a robust filtering mechanism to prevent false triggering caused by contact bounce or line noise, resulting in a hardware delay of approximately 35ms to 45ms. For wiring efficiency, the module supports the use of 1746-HT and 1746-HCA connectors for pre-wired cable assemblies. It is important to ensure that the leakage current of connected solid-state sensors does not exceed the 2 mA off-state maximum to avoid "ghost" inputs where the module stays in an ON state incorrectly.

Frequently Asked Questions

Can the 1746-IA16 be used in a remote I/O rack?Yes, the 1746-IA16 is compatible with both local SLC 500 chassis and remote 1747-ASB or 1747-AENTR adapter racks, provided the power supply has sufficient 5V capacity.

What is the difference between the 1746-IA16 and the 1746-IA8?The 1746-IA16 provides double the density with 16 inputs in a single slot compared to the 8 inputs provided by the IA8, which is ideal for reducing the physical footprint of the PLC system.