Overview
The Allen-Bradley 1791-OA32 is a compact, high-density 32-point AC output block I/O module from the 1791 Block I/O family. This module serves as a discrete output interface for distributed control applications, functioning as a slave device on Remote I/O (RIO) networks. It integrates a built-in power supply, programmable controller interface, removable terminal strips, and signal conditioning circuitry into a single, cost-effective unit for controlling AC loads across multiple field devices.
Key Features
- 32 discrete AC output channels organized in 4 groups of 8 for efficient I/O management
- Remote I/O (RIO) protocol support enables distributed network control without dedicated scanner wiring
- Removable terminal strips with grounding stud and status indicator lights for quick connection and troubleshooting
- Flexible mounting with vertical and horizontal orientation options to suit panel layouts
- Self-contained architecture with integrated power supply eliminates need for external power modules
- Compatible with classic PLC families including PLC-2, PLC-3, PLC-5/250, and SLC 5/02 controllers
Technical Specifications
- Output Voltage Rating: 20–132VAC
- Operating Frequency: 47–63 Hz
- Output Channels: 32 points (4 groups × 8 channels)
- Maximum Holding Current: 300 mA per output @ 60°C
- Maximum Surge Current: 10 A per output (1200 W total)
- Minimum On-State Current: 50 mA per output
- External Power Supply: 85–132VAC (internally regulated, no external fuse required)
- I/O Groups: 4 programmable groups accessible via front-cover switch assembly
- Communication Protocol: Remote I/O (RIO)
- Terminal Configuration: Removable terminal blocks for power, RIO network, and output connections
- Status Indicators: LED status lights for network, group, and per-output diagnostics
- Physical Mounting: Vertical or horizontal orientation
- Operating Temperature: 0–60°C (with current derating above 30°C)
Typical Applications
The 1791-OA32 is ideal for industrial environments requiring high-density AC output control without panel space constraints. Common uses include:
- Motor starter and contactor coil control
- Solenoid-actuated valve and actuator switching
- Signal light and alarm indicator control
- Distributed pump and fan motor switching
- Lighting control systems in manufacturing or facility automation
- Process equipment interlocking and safety circuits
Compatibility & Replacements
The Allen-Bradley 1791-OA32 is fully compatible with Remote I/O scanners from the PLC-2, PLC-3, and PLC-5 families, including modules such as 1771-SN, 1772-SD, 1772-SD2, and 1775-S5. It also works with SLC 5/02 modular controllers when using appropriate network adapters. For applications requiring higher-density output or different voltage ratings, consider the 1791-OA16 (16-point alternative) or other modern Logix-based output modules. As a discontinued product (manufacturer end-of-life June 30, 2015), this unit is supplied as surplus stock; DO NOT assume firmware or older date codes match factory specifications. Verify compatibility with your existing RIO scanner before deployment.
