Expert Technical Evaluation & Performance Review
The Allen-Bradley 1794-OW8 provides eight isolated Form A relay outputs. Each channel uses a normally open electromechanical contact. This design ensures a clear break in the circuit.
Engineers trust this module for its robust contact ratings. The relay handles 250V AC at 2A for resistive loads. It also supports 120/240V AC with 1800VA make and 180VA break ratings.
The module draws only 35mA from the FlexBus at 5V DC. It requires a separate 24V DC supply at 125mA. This low power draw reduces system heat and energy costs.
Each output channel delivers a signal delay of just 10ms. The initial contact resistance stays low at 30 mΩ. Bounce time for the relay is only 1.2ms.
The switching frequency reaches 0.3Hz at a rated load. The module dissipates a maximum of 5.5W. This converts to 18.8 BTU/hour of thermal output.
Users will find the environmental tolerance very reliable. The unit operates from 0°C to 55°C. It can survive storage from -40°C to 85°C.
Vibration resistance is rated at 5g from 10 to 500Hz. The module withstands operating shock of 30g. This makes it ideal for heavy industrial applications.
The expected contact mechanical life exceeds 100,000 operations. The off-state leakage current is only 1.0mA through the snubber. This prevents unwanted activation of connected loads.
Product Procurement & Buyer Guide
Procurement teams need clarity on system compatibility. The 1794-OW8 integrates seamlessly with all Flex I/O adapters. It also works directly with FlexBus controllers.
Selecting the correct terminal base is critical. This module is compatible with the 1794-TB2, 1794-TB3, 1794-TB3S, and 1794-TBN. The 1794-TBNF base may require a special fuse.
Your power supply planning should be specific. Use only a +24V DC source for the power terminals. The module draws 35mA from the 5V FlexBus.
The module measures just 1.8 x 3.7 x 2.1 inches. It mounts easily on a standard DIN rail. The enclosure is open-type.
Each channel has its own yellow status indicator. The keyswitch position is set to 9. This prevents accidental installation on the wrong base.
For pilot duty applications, the rating is R150. This applies from 5 to 30V DC. The maximum VA is 28VA below 28V DC.
The wire size depends on the selected terminal base unit. Operating temperature stays within 0 to 55°C. Storage temperature extends from -40 to 85°C.
This module supports 74-132VAC output voltage. The minimum contact load is 100 μA at 100mV DC. This allows switching of very small signals.
Logistics & Standard Packaging Details
The standard package includes the 1794-OW8 module only.
You must order the terminal base unit separately.
Common bases include the 1794-TB2 or 1794-TB3.
The module ships in an anti-static protective foam.
A quick reference sheet is included for wiring setup.
Express delivery shipping is available via FedEx, UPS, and DHL.
