Introduction
Is your control panel struggling with unreliable discrete outputs that fail under surge conditions? The Allen-Bradley 1794-OB16P Flex I/O module solves that problem with sixteen electronically fused sourcing outputs rated for 24VDC operation. As part of the Flex I/O family, this module integrates seamlessly into distributed control architectures, giving you precise control over solenoids, relays, indicator lamps, and other field devices. Whether you are upgrading a legacy PLC-5 system or building a new CompactLogix installation, the 1794-OB16P delivers dependable output performance in a compact DIN rail form factor.
Key Specifications That Matter
Understanding the critical specs helps you match this module to your application requirements.
Output Capacity
The 1794-OB16P provides sixteen sourcing current outputs. Each channel handles a minimum of 1.0 mA and a maximum of 500 mA, with a total module rating of 8.0A. This means you can drive multiple small loads or a combination of pilot devices without adding separate output cards.
Voltage Range
ON-state voltage ranges from 10VDC minimum to 31.2VDC maximum, with 24VDC nominal. The module accepts an external DC supply of 10 to 31.2VDC with 5% AC ripple and draws 25 to 75 mA supply current. This flexibility supports standard industrial 24VDC power systems.
Protection Features
Each channel includes electronic fusing, eliminating the need for replaceable fuses. The module withstands surge current of 2A for 50 ms, repeatable every 2 seconds. Off-state leakage current stays below 0.5 mA, and ON-state voltage drop maxes out at 0.5VDC.
Environmental Ratings
Operating temperature spans 0 to 55 C (32 to 131 F), with storage from -40 to 85 C (-40 to 185 F). The module handles 5g vibration at 10 to 500 Hz and 30g operating shock, making it suitable for demanding industrial environments.
Technical Specifications
| Specification | Value |
|---|---|
| Outputs | 16 Sourcing Current |
| ON-state Voltage Nom. | 24VDC |
| ON-state Voltage Range | 10 to 31.2VDC |
| Output Current per Channel | 1.0 mA min / 500 mA max |
| Output Current Module | 8.0A |
| Flexbus Current | 60 mA @ 5V DC |
| Power Dissipation | 5.0 W @ 31.2V DC |
| Isolation Voltage | 50V Continuous |
| Operating Temperature | 0 to 55 C (32 to 131 F) |
| Mounting | DIN Rail |
| Indicators | 16 Yellow Status LEDs |
Industry Applications
Manufacturing Automation
In automotive assembly lines, the 1794-OB16P energizes solenoid valves that control pneumatic actuators. The 500 mA per-channel capacity drives standard 24VDC solenoids directly, while electronic fusing protects against coil short circuits.
Process Control
Chemical plants use this module to operate relay coils and indicator lamps on remote skids. The wide 10 to 31.2VDC range accommodates voltage fluctuations common in large facilities. With 50V continuous isolation, it separates field wiring from the control bus.
Material Handling
Conveyor systems rely on discrete outputs to trigger diverters, brakes, and sortation mechanisms. The 1794-OB16P’s 0.5 ms OFF-to-ON and 1 ms ON-to-OFF response times keep high-speed sorting accurate. Its 30g shock rating withstands vibration from nearby motors and pneumatic equipment.
Installation and Setup
Mount the 1794-OB16P on a DIN rail using a compatible terminal base. Choose from 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3K, or 1794-TB3SK bases. The terminal base provides both mechanical attachment and I/O wiring termination points.
Wire size depends on the installed terminal base. Connect your external 24VDC supply within the 10 to 31.2VDC range, observing the 5% AC ripple limit. The module draws 25 to 75 mA supply current. Verify that your power source can deliver the total load current, up to 8.0A per module.
For communication, pair the module with Flex I/O adapters supporting EtherNet/IP, ControlNet, DeviceNet, or PROFIBUS. This enables integration with ControlLogix, CompactLogix, PLC-5, and SLC 500 controllers.
Compatibility and Integration
The 1794-OB16P works within distributed I/O architectures, mixing freely with other Flex I/O modules. It communicates through Flex I/O adapters for EtherNet/IP, ControlNet, DeviceNet, and PROFIBUS networks. Configuration depends on your specific controller platform.
Legacy systems benefit from backward compatibility with PLC-5 and SLC 500 processors. Modern installations leverage seamless integration with Logix controllers. This flexibility makes the module a practical choice for both new projects and retrofit applications.
Maintenance and Reliability
Electronic fusing eliminates routine fuse replacement, reducing maintenance labor. Periodically inspect terminal base connections for tightness and check for debris accumulation. Verify that ambient temperature remains within 0 to 55 C (32 to 131 F).
Monitor the sixteen yellow status indicators during operation. A dark LED when the output should be ON may indicate a fault or overload condition. Address any tripped electronic fuse by removing the fault and cycling power.
Store spare modules between -40 and 85 C (-40 to 185 F) in non-condensing humidity. The 5g vibration and 30g shock ratings ensure reliable operation in typical industrial settings.
Selection Guide
Before purchasing the 1794-OB16P, confirm your application requires sourcing outputs and 24VDC operation. Verify that your terminal base inventory includes one of the compatible models: 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3K, or 1794-TB3SK.
Check that your Flex I/O adapter supports your network protocol. Ensure your power supply delivers 10 to 31.2VDC with adequate current capacity for your total load.
SpareTechPLC stocks the 1794-OB16P and compatible terminal bases. Contact us to verify current availability and discuss your application requirements.
Frequently Asked Questions
Q: Can I replace individual fuses on the 1794-OB16P?
A: No. The 1794-OB16P uses electronic fusing on each channel. When a fault clears, the electronic fuse resets automatically. No replaceable fuses exist.
Q: What is the maximum current per output channel?
A: Each channel handles up to 500 mA. The total module output current is 8.0A.
Q: Which terminal bases work with this module?
A: Compatible bases include 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3K, and 1794-TB3SK.
Q: Does the 1794-OB16P provide channel-to-channel isolation?
A: No. The module provides 50V continuous isolation but does not isolate individual channels from each other.
Q: What communication adapters support this module?
A: The 1794-OB16P works with Flex I/O adapters for EtherNet/IP, ControlNet, DeviceNet, and PROFIBUS networks.
