Overview
The Allen-Bradley 1746-OA8 is a digital AC output module designed for the SLC 500 family of programmable logic controllers. This discrete output module provides eight channels organized as two groups of four outputs each, enabling reliable control of AC-powered equipment across industrial automation systems. Operating over a wide voltage range of 85–265 VAC at 47–63 Hz, the 1746-OA8 delivers consistent performance in harsh electrical environments.
Key Features
- 8-point discrete AC output module with 2 output groups of 4 channels each
- Supports 120 VAC and 240 VAC nominal voltages (85–265 VAC operating range)
- 1.0 A per channel at 30°C; 0.5 A per channel at 60°C continuous current ratings
- Maximum 8.0 A per module at 30°C (4.0 A at 60°C)
- Fast response: 1 ms ON delay, 11 ms maximum OFF delay for resistive loads
- UL and CSA certified with NEMA ICS 2-230 noise immunity
- Single-slot 1746 chassis mounting (open-style enclosure)
- Backward-compatible with legacy SLC 500 platforms
Technical Specifications
- Output Voltage Range: 85–265 VAC, 47–63 Hz
- Number of Outputs: 8 channels, 2 groups of 4 points per common
- Output Current (per channel): 1.0 A @ 30°C / 0.5 A @ 60°C
- Output Current (per module): 8.0 A @ 30°C / 4.0 A @ 60°C
- ON-State Voltage Drop: 1.5 V @ 1.0 A
- Signal Response: 1 ms ON delay, 11 ms maximum OFF delay (resistive load)
- Backplane Current: 185 mA @ 5 VDC
- Isolation: Communication circuits 500 V DC, backplane 1500 V AC
- Operating Temperature: 0–60°C (32–140°F)
- Heat Dissipation: 0.925–9.0 W (1.0 W per point)
- Mounting: Single slot 1746 chassis (open-style)
- Weight: 0.40 lbs
- Certifications: UL, CSA, NEMA ICS 2-230
- Shock Rating: 30 G
- Vibration: 2.5 G @ 57–2000 Hz
Typical Applications
The 1746-OA8 is ideal for controlling discrete AC loads in a wide range of industrial automation scenarios:
- Motor and pump control (120/240 V AC)
- Solenoid valve and contactor switching
- Lighting and heating element control
- Legacy SLC 500 system upgrades and repairs
- General-purpose AC output requirements in process control systems
Compatibility & Replacements
The 1746-OA8 is purpose-built for SLC 500 series controllers and mounts directly into the 1746 chassis. Alternate part designations include 1746-OA8/A and 1746-OA8/B. While no direct drop-in replacements exist for new purchases (the module is discontinued by the manufacturer), surplus and refurbished units remain available through authorized distributors. For systems migrating to newer Rockwell Automation platforms, consult CompactLogix or ControlLogix I/O module equivalents based on your voltage and channel requirements.
