The Allen-Bradley 1794-OW8 is a Relay output module that is part of the Flex I/O product family. This module primarily features Eight (8) isolated Normally Open (N.O.) electromechanical relay that are rated 250V AC, 2 A, 50/60Hz for resistive load; 120/240V AC, 50/60Hz,1800V A Make, 180V A Break; 5…30V DC, 2 A, Resistive;

The 1794-OW8 is used with 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TBN and 1794-TBNF terminal base units. If 1794-TBNF is used, use a 3.0 Ampere, 250VAC slow-blow fuse or the Allen-Bradley recommended fuse Littelfuse with part. number 239003. This module has a off-state leakage current of 1.0 mA through snubber circuit with minimum contact load rating of 100 μA @ 100 mV DC. It has a pilot duty rating of R150, 5...30V DC, 28V A not to exceed 1 A below 28V DC.

The 1794-OW8 is compatible for use any any Flex I/O communication adapters as well as with FlexBus controllers. This module has a current draw of 5V DC, 35 mA with supply voltage rating of 24V DC, 125 mA. The relay output channels has a maximum of signal delay 10 ms for both signal transitions while the initial contact resistance is 30 mΩ, switching frequency of 1 operation every 3 s or 0.3Hz at rated load and contact mean bounce time of 1.2 ms. Additionally, each output contact has an expected contact life of 100,000 operations, min @ rated loads.

The 1794-OW8 is installed with Eight (8) yellow status indicators, One for each channel and has a keyswitch position of 9 when mounting to the terminal base.

Use only +24 Volts DC power for the 1794-OW8’s power terminals because variations in relay switching time of the outputs may cause one of the relays to momentarily switch the total load current. The entire module measures 1.8 x 3.7 x 2.1 inches. It is compatible with several terminal base units, namely the 1794-TB3, 1794-TB2, 1794-TBN, 1794-TB3S, 1794-TB3K, 1794-TBNF, 1794-TBNKF, and the 1794-TB3SK. It also has a mechanical life of 100,000 operations at rated loads. The resistive relay output current ratings of the 1794-OW8 are 2 Amps at 5 to 30 Volts DC, 0.22 Amps at 125 Volts DC, and 2 Amps for 125 Volts DC and 250 Volts DC. The module also has a continuous isolation voltage of 250 Volts for relay to another relay, to the backplane, and to the power, and 50 Volts for power to the backplane. The external DC supply voltage range of this module is 19.2 to 31.2 Volts DC and it includes the 5% AC ripple and a nominal external DC supply current of 125 mA. It has a maximum off-state leakage current of 1 mA at 240 Volts AC through a snubber. The 1794-OW8’s initial contact resistance is 30 M Ω and its minimum contact load is 100 µA at 100 mV DC. It also has a maximum power dissipation of 5.5 Watts and a maximum thermal dissipation of 18.8 BTU/hour, both at 31.2 Volts DC. The maximum output delay time for both the OFF to ON and the ON to OFF states are 10 milliseconds.