Product Overview

The 1794-OM8 belongs to the Flex I/O family for AC load control. You can insert or remove this module under power without system shutdown. This feature saves time and eliminates restart inefficiencies. The module mounts inside a terminal base for direct field wiring. It works with communication adapters like EtherNet/IP, ControlNet, and DeviceNet. An XT version is available for extreme environment applications.

Technical Specifications

The 1794-OM8 delivers robust AC switching performance for industrial loads.

• Manufacturer: Rockwell Automation / Allen-Bradley

• Part Number: 1794-OM8

• Number of Outputs: 8 non-isolated channels

• Nominal Output Voltage: 240V AC

• On-state Voltage Range: 159 to 264V AC

• Output Current Rating (Module): 4.0 Amps total

• Maximum Current per Output: 500 mA at 55°C

• Minimum Current per Output: 5 mA at 55°C

Performance Characteristics

• On-state Voltage Drop Maximum: 1.5V AC at 0.5A

• Off-state Leakage Current Maximum: 2.5 mA

• Isolation Voltage: 250 Volts continuous

• Flexbus Current: 60 mA at 5V DC

• Maximum Power Dissipation: 5 Watts at 0.5A

• Maximum Thermal Dissipation: 17.1 BTU/hr at 0.5A

Status Indicators

• Output Status LEDs: 8 yellow indicators, one per channel

• LED Function: Illuminates when corresponding output is energized

Environmental Ratings

• Operating Temperature: 0 to 55 °C (32 to 131 °F)

• Storage Temperature: -40 to 85 °C (-40 to 185 °F)

• Relative Humidity: 5 to 95% non-condensing

• Mounting: DIN rail (snap-on)

Compatible Terminal Bases

The 1794-OM8 works with these terminal base units:

• 1794-TBNF

• 1794-TBN

Compatible Communication Adapters

The 1794-OM8 supports these Flex I/O adapters:

• 1794-AENT for EtherNet/IP

• 1794-ACN for ControlNet

• 1794-ADN for DeviceNet

• 1794-APB for Profibus DP

• 1794-ASB for Remote I/O

Installation Guidance

Follow these steps to install the 1794-OM8 correctly and safely.

1. Snap the Terminal Base: Mount the 1794-TBN or 1794-TBNF onto a DIN rail.

2. Wire AC Loads: Connect contactors or valves to the base's screw terminals.

3. Verify Voltage Rating: Confirm your AC supply matches the 159-264V range.

4. Insert the Module: Press the 1794-OM8 firmly into the terminal base until latched.

5. Attach the Adapter: Connect a communication adapter like 1794-AENT on the left.

6. Apply Power: Energize the system and check for proper operation.

7. Monitor LEDs: Observe yellow indicators to confirm output switching.

The 1794-OM8 supports hot insertion under power. You can replace a faulty module without stopping the entire system. This feature reduces downtime significantly.

Package Contents

• One (1) Allen-Bradley 1794-OM8 Flex I/O AC Output Module

• Installation instructions quick reference guide

Frequently Asked Questions (FAQ)

1. What type of loads can the 1794-OM8 control?
The 1794-OM8 controls 240V AC loads such as contactors, relays, solenoids, and pilot lights. Each output handles up to 500mA continuously.

2. Can I remove the 1794-OM8 while the system is powered?
Yes, the 1794-OM8 supports hot insertion. You can remove or insert the module under power without shutting down the system.

3. Which terminal bases work with the 1794-OM8?
The 1794-OM8 is compatible with the 1794-TBN and 1794-TBNF terminal bases. These bases provide screw clamp terminations for field wiring.

4. What is the total current rating for the 1794-OM8 module?
The 1794-OM8 has a total module current rating of 4.0 Amps. This rating assumes all eight outputs operate at 500mA simultaneously.

5. Does the 1794-OM8 have channel-to-channel isolation?
No, the 1794-OM8 has eight non-isolated outputs. The isolation voltage of 250V applies between the outputs and the backplane, not between channels.