Purchase now the 1794-OA8, a high-performance 8-point discrete AC output module from the Allen-Bradley FLEX I/O series. This module is specifically engineered to interface your PLC control system with field-side AC loads, providing reliable switching for solenoids, motor starters, and small industrial actuators in a space-saving modular design.
What Is the 1794-OA8?
The 1794-OA8 is a digital output module designed for the FLEX I/O distributed system. It provides eight non-isolated AC outputs capable of handling 120V AC power. The module mounts onto a terminal base (such as the 1794-TB2 or 1794-TB3), which contains the wiring connections. This allows for rapid module replacement without disturbing the field wiring, a feature known as Removal and Insertion Under Power (RIUP), which is critical for minimizing system downtime in continuous process environments.
Key Technical Specifications
- Number of Outputs: 8 (Non-isolated)
- Operating Voltage: 120V AC Nominal (74-132V AC range)
- Output Current Rating: 1.0A maximum per module (500mA per channel at 55°C)
- Surge Current: 7A for 45ms, repeatable every 8 seconds
- Off-State Leakage: 2.25mA maximum
- Power Dissipation: 4.1W at maximum load
- On-State Voltage Drop: 1.0V AC at 0.5A
Applications and System Architecture
The 1794-OA8 is ideally suited for decentralized control architectures where I/O needs to be located close to the machinery to reduce wiring costs. It is commonly deployed in water treatment facilities, material handling, and HVAC control systems. Because it integrates with EtherNet/IP, ControlNet, or DeviceNet adapters, it offers flexible communication options for modern industrial networks.
Installation Advice
When installing the 1794-OA8, ensure the keyswitch on the terminal base is set to position 2 to prevent hardware mismatch. It is highly recommended to use the 1794-TBNF terminal base if you require individual channel fusing, as the 1794-OA8 itself does not provide per-channel internal protection. Always maintain a minimum load current of 5mA to ensure the triac stays in the conduction state.
Frequently Asked Questions
Q: Can the 1794-OA8 be used to switch DC loads?
A: No. The output circuitry uses triacs, which require an AC waveform to naturally commutate (turn off). Using this module with DC will result in the output staying permanently «ON» once triggered.
Q: What is the maximum surge current this module can handle?
A: It can handle a peak surge of 7A for a duration of 45ms. If your load exceeds this (e.g., large incandescent lamps), you must use an interposing relay.
Do you need more references from this brand? Explore our full catalog of Allen-Bradley here: https://atlantechdrives.com/manufacturers/allen-bradley/
