Get now the 1794-OM16, a robust 16-point discrete output module designed to switch high-voltage AC loads within the Allen-Bradley FLEX I/O system. This module is the industrial workhorse for controlling 240V AC solenoids, contactors, and motor starters in a modular, distributed configuration.
What Is the 1794-OM16?
The 1794-OM16 is a high-density digital AC output module that provides sixteen non-isolated outputs capable of operating at up to 240V AC. It is engineered to provide a reliable interface between the low-voltage control logic of a PLC and high-voltage field actuators. Its design emphasizes space efficiency and ease of maintenance, mounting onto a terminal base that allows the module to be swapped without re-wiring. This makes it an essential component for heavy industrial applications, including large-scale pumping stations, HVAC systems, and conveyor networks.
Key Technical Specifications
- Number of Outputs: 16 (Non-isolated)
- Voltage Range: 159V AC to 264V AC
- Output Current Rating: 500mA per channel (4.0A max per module)
- Surge Current: 7A for 45ms, repeatable every 8 seconds
- On-State Voltage Drop: 1.0V AC @ 0.5A
- Off-State Leakage: 2.5mA maximum
- Power Dissipation: 5.6W at maximum load
Industrial Architecture and Fusing
The 1794-OM16 is designed to sit on a 1794-TBN or 1794-TBNF terminal base. In 240V AC applications, safety and protection are critical; using the 1794-TBNF (fused) terminal base is highly recommended to provide individual circuit protection for each output. This setup prevents a single field-side short circuit from damaging the entire 16-point module or the wider system backplane.
Expert Tips
When switching 240V AC inductive loads with the 1794-OM16, be mindful of the triac-based architecture. Triacs generate heat; ensure the module is installed in a well-ventilated enclosure, especially if multiple outputs are running at their maximum 500mA rating simultaneously. If you encounter «ghost» voltages on your outputs when they are off, it is likely due to the 2.5mA leakage current; adding a small resistor or «dummy load» in parallel can bleed this off if the field device is too sensitive.
Frequently Asked Questions
Q: Can the 1794-OM16 be used for 120V AC applications?
A: While the module is rated for up to 264V, the minimum operating voltage is 159V AC. For 120V AC systems, you should use the 1794-OA16 instead to ensure proper switching.
Q: What is the maximum response time for an output to turn on?
A: The 1794-OM16 has a maximum turn-on time of 1/2 cycle (approximately 8.3ms at 60Hz or 10ms at 50Hz) plus any communication delays from the network adapter.
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