Product Overview

The 1756-OA8E is a high-density discrete output module designed for the Rockwell Automation Allen-Bradley ControlLogix platform. This module provides eight individually fused AC outputs, configured in two isolated groups of four channels each. Engineered for high-reliability industrial environments, it serves as the primary interface between the Logix5000 controller and field-side AC devices such as motor starters, solenoid valves, and indicators.

A standout feature of this hardware is its integrated electronic fusing. Unlike standard modules that may require external fuse blocks, the 1756-OA8E provides point-level protection. This ensures that a localized short circuit or overcurrent condition on one field device does not compromise the integrity of the entire module or the remaining output channels.

Application and Functionality

The module is optimized for high-speed switching and robust power handling. It operates within a voltage range of 74V to 132V AC, accommodating standard 120V AC industrial power grids. With a turn-on/turn-off time of approximately 9.3ms at 60 Hz, it provides the deterministic response necessary for precision automation.

For high-inrush loads, the 1756-OA8E is rated to handle a 20A surge for up to 43ms. Users should note the thermal derating curve: while the module supports a total current of 8A at 30°C, the capacity is reduced to 4A when operating at the maximum temperature of 60°C. This necessitates proper ventilation and chassis placement considerations in high-temperature enclosures.

Technical Specifications

• Output Channels: 8 (2 groups of 4)

• Operating Voltage Range: 74V AC to 132V AC

• Input Frequency: 47 Hz to 63 Hz

• Backplane Current Draw: 200mA @ 5.1V DC & 250mA @ 24V DC

• Maximum Surge Current: 20A per point for 43ms

• On-State Voltage Drop: 1.5V AC @ 2.0A

• Off-State Leakage Current: 3mA per point

• Power Dissipation: 5.5 Watts (Maximum)

• Dimentions: 14.0 x 11.2 x 14.5 cm

• Thermal Dissipation: 18.76 BTU/hr

• Protection Type: Individual Electronic Fusing (Point-level)

• Compatible Chassis: 1756 ControlLogix

• Removable Terminal Block (RTB): 1756-TBNH or 1756-TBSH (Sold separately)