Overview
The Allen-Bradley 1746-OA8 is a digital AC output module from the SLC 500 family, designed for controlling AC loads in industrial automation systems. This module provides 8 output channels configured in two groups of 4 channels each, making it ideal for applications requiring discrete AC load switching. The module integrates seamlessly into any available I/O slot of an SLC 500 chassis and is compatible with all SLC 500 processors.
Key Features
- 8 discrete AC output channels with dual 4-point commons for flexible wiring
- LED status indicators on each output channel for quick diagnostics
- 1500V AC isolation between field and logic sides enhances safety
- 1.0 A continuous output per channel at 30°C; operates at full 8.0 A module capacity
- Compact open-style chassis mount; single-slot design reduces footprint
- UL and CSA certified for North American industrial use
Technical Specifications
- Output Voltage Range: 85–265V AC @ 47–63 Hz
- Number of Outputs: 8 channels
- Output Configuration: 2 groups of 4 channels with common reference
- Continuous Current per Channel: 1.0 A @ 30°C (86°F); 0.5 A @ 60°C (140°F)
- Maximum Module Current: 8.0 A @ 30°C; 4.0 A @ 60°C
- Output Surge Current: 10 A for 25 milliseconds
- ON-State Voltage Drop: 1.5V @ 1.0 A
- Signal Delays: 1 ms ON delay, 11 ms OFF delay (resistive load)
- Backplane Current: 185 mA @ 5V DC
- Operating Temperature: 0°C to 60°C (32°F to 140°F)
- Storage Temperature: -40°C to 85°C (-40°F to 185°F)
- Relative Humidity: 5–95% non-condensing
- Isolation: 1500V AC between backplane and outputs; 500V DC between communication circuits
- Certifications: UL, CSA; NEMA ICS 2-230 noise immunity
- Mounting: Open-style chassis, single I/O slot
- Weight: 0.40 lbs
Typical Applications
- AC motor and contactor control in discrete automation
- Solenoid valve and pump switching for fluid systems
- Lighting control and electric heater load management
- HVAC and process equipment AC load switching
- OEM machine tool and packaging line automation
- Low-current industrial relay replacement (eliminates interposing relay needs)
Compatibility & Replacements
The 1746-OA8 is designed for SLC 500 processors including the SLC 5/01, 5/02, 5/03, 5/04, and 5/05 families. It installs into any standard I/O slot of a 1746 chassis without modification. Common alternative configurations include the 1746-OA16 (16-channel) and 1746-OD8 (DC output) modules. Rockwell Automation also offers the MicroLogix series as a modern replacement for new builds, though the 1746-OA8 remains industry-standard for legacy SLC 500 system expansions and repairs. This module is discontinued by the manufacturer but widely available as used or refurbished inventory, making it a cost-effective solution for field maintenance and system upgrades.
