Overview
The Allen-Bradley 1746-OA8 is a digital AC output module designed for the SLC 500 controller family. This Series B module delivers 8 discrete output channels organized in two groups of 4 points per common, with nominal 120/240VAC voltage support and an operating range of 85–265VAC at 47–63 Hz. The sealed housing protects the electronics from dust and environmental contaminants, making it suitable for harsh industrial settings.
Key Features
- 8 AC output points in two groups of 4 channels each
- 120/240VAC nominal output; 85–265VAC operating range
- 1.0 A continuous per channel at 30°C; 0.5 A at 60°C
- Fast signal switching: 1 ms ON delay, 11 ms OFF delay (resistive load)
- Single-slot chassis mounting; no Removal and Insertion Under Power (RIUP) support
- UL and CSA certified for industrial applications
Technical Specifications
- Output Voltage: 120/240VAC nominal; 85–265VAC operating
- Frequency: 47–63 Hz
- Output Channels: 8 points (2 groups × 4 channels)
- Continuous Current per Point: 1.0 A @ 30°C (86°F); 0.5 A @ 60°C (140°F)
- Module Continuous Current: 8 A @ 30°C; 4 A @ 60°C
- Maximum Surge Current: 10 A per point for 25 ms
- Voltage Drop (ON state): 1.5 V @ 1.0 A
- Signal Delay (Resistive Load): ON = 1 ms; OFF = 11 ms
- Backplane Current: 185 mA @ 5 VDC
- OFF-state Leakage: 2 mA maximum
- Minimum Load Current: 10 mA
- Operating Temperature: 0 to 60°C (32 to 140°F)
- Heat Dissipation: 0.925 to 9.0 W (1.0 W per point nominal)
- Certifications: UL, CSA; NEMA ICS 2-230 Noise Immunity
- Mounting: Single slot, 1746 modular chassis
Typical Applications
The 1746-OA8 is widely used in SLC 500–based control systems for energizing solenoids, contactor coils, pilot lights, heating elements, and motor-control relay circuits operating at 120 or 240 VAC. Common installations include:
- General-purpose industrial machine control and automation
- Manufacturing process control and sequencing
- HVAC and facility automation systems
- Discrete load switching in food, beverage, and packaging lines
- System upgrades and replacement installations
Compatibility & Replacements
Compatible With
- SLC 500 modular chassis (1746-P1, 1746-P2, 1746-P3, etc.)
- SLC 5/01, SLC 5/02, SLC 5/03, SLC 5/04, SLC 5/05 processors
- RSLogix 500 programming software
- DH485 communication networks (when chassis supports communication modules)
- Any available slot except the first (reserved for processor)
Replaces / Drop-In Replacement For
Verify compatibility with your system integrator before ordering. The 1746-OA8 Series B directly replaces earlier Series A versions of the same part number. Alternate part numbers for this module include 1746-OA8/A and 1746-0A8.
Works With
- RSLogix 500 ladder logic programming
- Studio 5000 (for Integrated Architecture systems)
- SLC 500 controller redundancy (via 1747-BSN scanner module)
- CompactLogix and ControlLogix via Distributed I/O architecture
- Flex I/O and PLC-5 messaging protocols
