Product Summary
The Allen-Bradley 1794-OB8 is a digital DC output module from the Flex I/O series. This unit features eight current sourcing outputs for robust industrial control. Engineers use it to switch solenoid valves, indicator lights, and motor contactors. Its design allows hot-swapping under power to reduce system restart delays. You get reliable performance with 500mA per channel and fast switching times.
Expert Technical Evaluation & Performance Review
Precision Output Control
The 1794-OB8 delivers exceptional response for discrete control tasks. Its nominal on-state voltage sits at 24V DC. The module switches from off to on in only 0.5ms. It transitions from on to off in just 1ms. This rapid switching suits high-speed sorting lines perfectly. You benefit from a maximum on-state voltage drop of only 0.5V DC. Off-state leakage current stays very low at 0.5mA. This ensures your loads remain de-energized when commanded.
Thermal and Electrical Tolerances
The module dissipates 3.3W of power at its maximum voltage of 31.2V DC. Its thermal dissipation reaches 11.2 BTU/hr under the same conditions. This low heat output reduces the burden on panel cooling systems. The FlexBus current draw is only 60mA @ 5V DC. Isolation voltage between channels is rated for 50V continuous. This configuration is non-isolated between channels, which is typical for sourcing modules.
Environmental Survivability
The 1794-OB8 operates reliably in harsh settings. Its temperature range spans from 0°C to 55°C (32°F to 131°F). It withstands non-condensing humidity from 5% to 95%. Users can also order XT versions for extreme environments. These variants reduce panel maintenance costs significantly. The module holds safety ratings for both European and North American hazardous locations. This makes it a safe choice for global installations.
Step-by-Step User & Installation Guide
Mounting and Mechanical Setup
You install the module on a standard DIN rail. First, position the module at a slight angle. Hook the top edge of the module onto the DIN rail. Then, push the bottom inward until it snaps securely into place. Ensure the 1794-OB8 mates correctly with a compatible terminal base unit. Use the 1794-TB3, 1794-TB3S, or 1794-TBKD for proper connection. The module fits inside the terminal bus to connect field devices.
Wiring and Electrical Configuration
Connect your external power supply first. The module accepts a voltage range of 10 to 31.2V DC. It draws an input current of 10 to 35mA. The power source should have a maximum of 5% AC ripple. Wire your field loads to the appropriate output channels on the terminal base. Each of the eight channels handles a maximum of 500mA. Do not exceed the total output current rating of 4A for the module.
Communication and Network Integration
This module supports several network protocols for flexible integration.
Logistics & Standard Packaging Details
Ensure express shipping via FedEx, UPS, or DHL for rapid delivery.
