Overview
The Allen-Bradley 1746-IA4 is a compact 4-point digital AC input module for the SLC 500 family of programmable controllers. It accepts 100–120V AC nominal input signals and operates reliably across 85–132V AC at 47–63 Hz. This module is purpose-built for general industrial automation applications requiring discrete AC input sensing on a compact footprint.
Key Features
- 4 input points with 4 points per common, flexible for various control schemes
- Optical isolation and filter circuitry reduce electrical noise and enhance signal integrity in harsh environments
- Removable terminal block for fast field installation and maintenance
- Status indicator LED on front panel for real-time fault diagnosis
- Low backplane current consumption (35 mA at 5V DC, 0 mA at 24V DC)
- Industry-standard certifications: UL listed, CSA approved, CE compliant, C-Tick marked
Technical Specifications
The 1746-IA4 provides reliable signal processing with the following key parameters:
- Input voltage rating: 100–120V AC nominal; 85–132V AC operating
- Frequency: 47–63 Hz
- Nominal input current: 12 mA at 120V AC
- Maximum inrush current: 0.8 A with ≤0.5 ms duration
- OFF-state maximum voltage: 30V AC
- OFF-state maximum current: 2 mA
- Signal ON delay: ≤35 ms
- Signal OFF delay: ≤45 ms
- Thermal dissipation: 0.27 W per point (min. 0.175 W, max. 1.3 W)
- Backplane current: 0.035 A at 5V DC; 0 A at 24V DC
- Operating temperature: 0–60°C (32–140°F)
- Shock rating: 30G operating, 50G non-operating
Typical Applications
The 1746-IA4 is well-suited for:
- Machine control and sequencing with AC pushbuttons and limit switches
- Safety-critical discrete input monitoring in Class I, Division 2 environments
- Sensor interfacing in manufacturing, packaging, and material-handling systems
- Field status indication and alarm input collection
- OEM panel-mount and cabinet-integrated control systems
Compatibility & Replacements
The 1746-IA4 /A mounts directly in SLC 500 chassis and integrates seamlessly with RS-Logix 500 and Studio 5000 programming environments using ID Code 0509. This is a legacy module part of the proven 1746 series of discrete I/O modules. If additional input channels are required, Allen-Bradley offers the 1746-IA8 (8-point) and 1746-IA16 (16-point) variants for the same 120V AC voltage category. For newer installations, Rockwell Automation’s Point I/O architecture (1734 series) provides modern alternatives with enhanced diagnostics.
