Product Overview
The Allen-Bradley 1794-OW8 is a Flex I/O relay output module engineered for reliable switching in demanding industrial environments. This module provides eight isolated Normally Open (N.O.) electromechanical relays, each rated for 250V AC at 2A resistive load. With its compact design and DIN rail mounting, the 1794-OW8 integrates seamlessly into existing control systems, delivering robust performance for a wide range of automation applications.
Technical Specifications
| Parameter |
Value |
| Outputs |
8 Relay (isolated) |
| Relay Contact Rating |
250V AC, 2A, 50/60Hz, Resistive; 120/240V AC, 50/60Hz, 1800VA Make, 180VA Break; 5…30V DC, 2A, Resistive |
| Flexbus Current |
5V DC, 35 mA |
| Supply Voltage |
24V DC, 125 mA |
| Off-state Leakage Current |
1.0 mA through Snubber Circuit |
| Minimum Contact Load |
100 μA @ 100 mV DC |
| Initial Contact Resistance |
30 mΩ |
| Bounce Time |
1.2 ms |
| Switching Frequency |
1 operation/3s (0.3Hz at rated load) max |
| Power Dissipation |
5.5 Watts |
| Thermal Dissipation |
18.8 BTU/hour at maximum |
| Indicators |
8 Yellow status indicators |
| Keyswitch Position |
9 |
| Enclosure |
Open-type |
| Mounting |
DIN Rail |
| Operating Temperature |
0 to 55°C (32 to 131°F) |
| Storage Temperature |
-40 to 85°C (-40 to 185°F) |
| Vibration |
5g @ 10 to 500 Hz |
| Operating Shock |
30 g |
Key Features & Benefits
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Eight isolated relay outputs – Each channel is electrically isolated, allowing independent switching of diverse loads.
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High contact rating – Handles up to 250V AC and 2A resistive, suitable for many industrial actuators and pilot devices.
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Flex I/O compatibility – Works with 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TBN, and 1794-TBNF terminal bases.
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Visible status indicators – Eight yellow LEDs provide immediate channel state feedback.
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Robust environmental tolerance – Operating range from 0 to 55°C and vibration resistance up to 5g.
Industry Applications
The 1794-OW8 excels in applications that require reliable switching of AC or DC loads. Typical use cases include:
- Motor starters and contactor control in conveyor systems.
- Valve actuation in process control skids.
- Lighting and heating control in building automation.
- Interfacing PLC outputs with high-power field devices.
Installation & Setup
Mount the 1794-OW8 onto a compatible terminal base (e.g., 1794-TB2) and secure it on a DIN rail. Ensure the keyswitch is set to position 9. Wire field devices to the terminal base according to your control schematic. Use only +24V DC for the module's power terminals; variations in relay switching time can cause momentary load switching if voltage is not stable. The module measures 1.8 x 3.7 x 2.1 inches, and wire size is determined by the installed terminal base.
Maintenance & Reliability
Routine inspection of relay contacts is recommended, as mechanical wear can affect performance over time. The 1794-OW8 has a mechanical life of 100,000 operations at rated loads. Keep the enclosure free of dust and moisture, and ensure ambient temperature stays within the specified range to maximize service life. With proper care, this module provides dependable operation for years.
Compatibility & Integration
The 1794-OW8 is part of the Flex I/O family and works with any Flex I/O communication adapter or FlexBus controller. It supports multiple terminal base options, including 1794-TB3, 1794-TB2, 1794-TBN, 1794-TB3S, 1794-TB3K, 1794-TBNF, 1794-TBNKF, and 1794-TB3SK. When using the 1794-TBNF base, install a 3.0A, 250VAC slow-blow fuse (e.g., Littelfuse 239003) for protection.
Selection Guide
Before ordering, verify that your system requires a relay output module with 8 isolated channels and the specified contact ratings. Confirm the terminal base compatibility and available power supply (24V DC, 125 mA). For genuine Allen-Bradley parts and expert support, PLC Source PRO offers the 1794-OW8 with reliable availability and fast shipping.