The PLC 1794-OA8 is a FLEX I/O AC digital output module. It comes with 8 non-isolated outputs in a group. This module can diagnose problems with I/O field devices, wiring, and the power supply. It can also reduce the start-up time and the time spent finding and fixing failures. The 1794-OA8 can be installed directly on the following terminal base units: the 1794-TBNK, 1794-TBKD, 1794-TB3K, 1794-TBNFK, 1794-TB3SK, 1794-TBNF, 1794-TB3, 1794-TB2, 1794-TB3S, and the 1794-TBN. Note that it is necessary to use auxiliary terminal strips if the 1794-TBN is the selected base unit.
This 120 Volts AC module has an output voltage range of 85 to 132 Volts AC and an output current rating of 4 Amps with the 8 outputs at 500 mA. The module has a maximum on-state voltage drop of 1 Volt at 0.5 Amps and a maximum off-state leakage current of 2.25 mA. Its minimum on-state current is 5 mA per output, while the on-state maximum current is dependent on its temperature; at 55 degrees Celsius, it is 500 mA per output, it is 750 mA at 35 degrees Celsius, which is per output, and it is 500 mA on 4 outputs and 1 Amp on 4 non-adjacent outputs at 30 degrees Celsius. The 1794-OA8’s FlexBus current is 80 mA at 5 Volts DC. The isolation voltage of the 1794-OA8 is continuous at 120 Volts. It also has a surge current of 7 Amps for 40 milliseconds, which is repeatable every 8 seconds. It has an output signal delay of a maximum of 1/2 cycle for both the ON to OFF and the OFF to ON states. The maximum power dissipation for the 1794-OA8 is 4.1 W at 0.5 Amps and 6.3 W both at 0.75 Amps and 1 Amp. The maximum thermal dissipation is 14 BTU/hour at 0.5 Amps, 21.2 BTU/hour at 0.75 Amps, and 21.4 BTU/hour at 1 Amps.
