Product Introduction
The Allen-Bradley 1756-OA8E is a ControlLogix digital AC output module engineered for reliable switching of 120 VAC loads in industrial automation environments. As part of the ControlLogix family, this single-slot module delivers eight electronically fused output channels arranged in two groups of four, providing robust point-level protection and simplifying troubleshooting. With a nominal output voltage of 120 VAC and an operating range of 74-132 VAC at 47-63 Hz, the 1756-OA8E handles a wide variety of AC loads, from contactors to solenoid valves.
Key Features & Benefits
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8 electronically fused outputs – each channel has built-in electronic fusing, reducing the need for external fuses and minimizing downtime.
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Wide operating voltage range – 74-132 VAC supports fluctuating line conditions.
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High current capacity – 2 A per point at 60 °C, 4 A per point at 30 °C (with linear derating).
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Fast output response – 9.3 ms at 60 Hz and 11 ms at 50 Hz for both OFF-to-ON and ON-to-OFF transitions.
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Flexible installation – fits any slot in a 1756 chassis, with no limit on the number of modules per system.
Technical Specifications
| Parameter |
Value |
| Part Number |
1756-OA8E |
| Brand |
Allen-Bradley / Rockwell Automation |
| Series |
ControlLogix |
| Module Type |
Electronically Fused AC Output Module |
| Number of Outputs |
8 (two groups of four) |
| Output Voltage Range |
74-132 VAC, 47-63 Hz |
| Output Current per Point |
2 A @ 60 °C; 4 A @ 30 °C (linear derating) |
| Output Current per Module |
8 A @ 30 °C; 4 A @ 60 °C (linear derating) |
| Backplane Current (5.1 VDC) |
200 mA |
| Backplane Current (24 VDC) |
250 mA |
| Power Dissipation |
5.5 W @ 60 °C |
| Isolation Voltage |
50 V continuous (basic insulation, tested at 1200 VAC for 2 s) |
| Output Signal Delay |
9.3 ms @ 60 Hz; 11 ms @ 50 Hz |
| Removable Terminal Blocks |
1756-TBNH, 1756-TBSH |
| Enclosure Type |
None (open-style) |
Industry Applications
The 1756-OA8E is ideal for controlling AC-powered devices such as motor starters, relays, solenoids, and indicator lights. In a typical manufacturing line, this module can switch conveyor motors on and off, while its electronic fusing protects against overloads and short circuits. The module's fast response time ensures precise timing in high-speed packaging machinery. For process industries, the 1756-OA8E provides dependable control of valve actuators and alarm systems, reducing unplanned downtime.
Installation & Setup
Installing the 1756-OA8E is straightforward. Insert the module into any available slot of a 1756 chassis. Ensure the chassis backplane can supply the required 200 mA at 5.1 VDC and 250 mA at 24 VDC. Use a compatible removable terminal block (1756-TBNH or 1756-TBSH) for wiring. Connect the AC load to the appropriate output terminals, observing the group isolation boundaries. After wiring, power up the system and verify the module is recognized by the ControlLogix controller. Configure the module in RSLogix 5000 or Studio 5000 to match your application requirements.
Maintenance & Reliability
Because the 1756-OA8E uses electronic fusing, there are no fuses to replace, which simplifies maintenance. However, periodic inspection of the terminal block connections is recommended to ensure tightness and prevent arcing. Keep the module's ambient temperature within the specified operating range (0 to 60 °C) and maintain relative humidity between 5% and 95% (non-condensing). The open-style enclosure requires protection from dust and debris; install the module in a clean, ventilated cabinet. With proper care, the 1756-OA8E provides long, reliable service.
Compatibility & Integration
The 1756-OA8E is part of the ControlLogix family, so it is fully compatible with all ControlLogix controllers, chassis, and communication modules. It can be used in both local and remote I/O racks, allowing flexible system design. The module communicates with the controller via the backplane, and no additional network configuration is needed for standard operation. It works seamlessly with existing ControlLogix programs.
Selection Guide & Purchasing Advice
Before ordering, verify that the 1756-OA8E meets your voltage and current requirements. For applications requiring higher current, consider using an external relay or contactor. Ensure you have the correct removable terminal block (1756-TBNH or 1756-TBSH) for your wiring needs. When purchasing, buy from a trusted supplier to guarantee genuine Allen-Bradley parts. PLC Source PRO offers authentic 1756-OA8E modules with competitive pricing and fast shipping.