Overview
The Allen-Bradley 1794-OA8 is a FLEX I/O discrete AC digital output module designed for industrial automation control systems. This 8-point output module provides non-isolated, relay-free AC switching at 120V nominal, making it ideal for controlling solenoids, indicator lamps, motors, and other AC loads in compact automation installations.
Key Features
- 8 Non-Isolated AC Outputs – Each channel rated for 500 mA per output at 55°C, with a maximum module rating of 4A total current
- Compact DIN-Rail Form Factor – Open-style design mounts directly on FLEX I/O terminal base units for space-efficient enclosure integration
- Fast Response Time – Maximum output signal delay of one-half cycle for both ON and OFF transitions
- Integral Diagnostics – Built-in field device and wiring fault detection reduces troubleshooting downtime
- Flexible Terminal Base Mounting – Compatible with multiple 1794-series terminal bases including TBNF (fused) for enhanced circuit protection
- Safety-Certified – Meets UL, CE, CSA, and GOST standards for global industrial deployment
Technical Specifications
The 1794-OA8 operates within industry-standard voltage and current parameters:
- Output Voltage: 85–132V AC nominal 120V AC
- Output Current: 4A maximum module; 500 mA per output at 55°C
- On-State Voltage Drop: Maximum 1.0V @ 0.5A
- Off-State Leakage Current: Maximum 2.25 mA per output
- Minimum Output Current: 5 mA per output
- FLEXBus Current: 80 mA @ 5V DC
- Isolation Voltage: 120V (continuous, field to backplane)
- Operating Temperature: 0–55°C (32–131°F)
- Power Dissipation: 4.1W @ 0.5A; 6.3W @ 0.75–1.0A
- Physical Dimensions: 94 × 94 × 69 mm (3.7 × 3.7 × 2.7 in.)
- Mounting: DIN-rail / Panel mount
- Enclosure Style: Open-style (requires external enclosure)
- IP Rating: IP20
Typical Applications
- Discrete AC Load Control – Solenoid valve coils, AC relay coils, contactor control circuits
- Lighting and Indicator Control – Stack lights, status lamps, warning beacons
- Motor and Drive Control – Soft-starter enable lines, equipment alarm outputs
- HVAC and Process Equipment – Fan enable, heater relay switching, pump motor circuits
- Manufacturing and Assembly Lines – Work station equipment sequencing, part ejection solenoids
Compatibility & Replacements
Compatible With
- FLEX I/O modular I/O system (Allen-Bradley CompactLogix 5370, 5380 via 1794 gateway)
- Terminal base units: 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TBN, 1794-TBNF, 1794-TBNK, 1794-TBKD, 1794-TB3K, 1794-TBNFK
- Studio 5000 Logix Designer software (standard FLEX I/O tag configuration)
- Ethernet/IP and FLEX I/O communication protocols
Replaces / Drop-In Replacement For
- Earlier 1794-OA8 units (without the “/A” revision suffix)
- Verify specific version compatibility with your system integrator before ordering used units
Works With
- Studio 5000 Logix Designer – Full I/O module configuration and monitoring support
- FLEX I/O Gateway (CompactLogix 5370/5380) – Modular I/O integration via Ethernet/IP
- Allen-Bradley Safety Modules – Compatible in safety-rated FLEX I/O configurations
- RSLinx Classic / RSLinx Enterprise – Device discovery and diagnostics
