Allen Bradley 1794-OA8I FLEX I/O 8-Point Digital Output Module

The Allen Bradley 1794-OA8I is a digital AC output module for the FLEX I/O system. It provides eight individually isolated outputs capable of switching loads up to 2A per point at 120/240VAC. This module is ideal for controlling AC contactors, solenoid valves, pilot lights, and small motors directly from a Rockwell Automation controller over the DeviceNet or ControlNet backplane.

Output Specifications

• Number of outputs: 8 (individually isolated)

• Output type: Triac (zero-crossing switching)

• Voltage range: 85-265VAC, 47-63Hz

• Continuous current per point: 2A at 30°C, derate to 1A at 60°C

• Maximum total module current: 8A

• Inrush current: 20A for one cycle per point

• Off-state leakage: ≤ 2mA at 240VAC

• On-state voltage drop: ≤ 1.5V at rated current

Electrical Isolation and Protection

Indicators and Diagnostics

Each output has a green LED status indicator that lights when the output is commanded ON. A single red module status LED indicates backplane communication health and internal fault detection (over-temperature or loss of field power).

Field Power and Wiring

The 1794-OA8I requires a separate field power supply (L1 and N) connected via the removable terminal block. Maximum field power consumption: 100mA (plus load currents). Wiring: 0.5-2.5mm² (AWG 22-14). Recommended torque: 0.8Nm. Use 60/75°C copper wire only.

Backplane Communication

Compatible with 1794-TB3 or 1794-TB3K terminal bases. Communicates with 1794-ACN15 (ControlNet) or 1794-ADN (DeviceNet) adapters. Data format: 1 word output image (bits 0-7 correspond to outputs). Update time: 5ms typical.

Environmental Ratings

• Operating temperature: 0°C to 55°C

• Storage temperature: -40°C to 85°C

• Relative humidity: 5-95% non-condensing

• Vibration: 5g (10-500Hz) per IEC60068-2-6

• Shock: 30g operational, 50g non-operational

• Hazardous locations: Class I, Division 2, Groups A,B,C,D (certified)

Physical Dimensions and Mounting

Height: 146mm (with base), Width: 45mm, Depth: 86mm. Weight: 280g. Mounts onto 1794 terminal base (sold separately). Installation requires DIN rail (35mm EN 50022) or panel mounting using optional adapters.

Certifications

cULus listed, CE marked (EN61326-1, EN61000-6-2), KC, EAC, and ATEX for Zone 2 (gas). RoHS compliant.

Typical Applications

AC motor starters, lighting contactors, heating elements, and valve controls in material handling, packaging, and process automation systems. The individual isolation allows mixing of different AC phases or neutral references within the same module.