Overview
The Allen-Bradley 1734-OB8 is a POINT I/O discrete digital output module from Rockwell Automation’s distributed I/O family. It features eight discrete, non-isolated sourcing output channels, making it ideal for controlling solenoids, proximity switches, alarm lamps, and other 24VDC devices. The 1734-OB8 is a POINT I/O output module designed to deliver precise output functionality, with eight outputs operating within an on-state voltage range of 10 V DC to 28.8 V DC and optimized for a nominal rating of 24 V DC. The module’s compact, open-style design fits standard DIN-rail systems and integrates seamlessly into distributed automation architectures.
Key Features
- Eight discrete, non-isolated sourcing output channels with one group of eight outputs per channel
- Electronically protected against overload and short circuits
- Maximum output signal delay of 0.1 milliseconds for responsive operation
- Maximum on-state voltage drop of 0.2 volts DC and maximum off-state leakage of 0.5 milliamps at 28.8 volts DC
- Current rating of 1.0 A per output, not to exceed 3.0 A max per module
- Compatible with DeviceNet and ProfiBus adapters; Series C modules have added compatibility with ControlNet and Ethernet adapters
Technical Specifications
- Output voltage: 24 Volts DC with a POINTBus current of 75 milliamps
- Minimum on-state current of 1.0 milliamps per channel
- Isolation voltage: 50 volts for continuous operation
- Power dissipation: approximately 2 Watts
- Mounting: DIN-rail (requires 1734-TB or 1734-TBS wiring base assembly)
- Output type: Sourcing (supplies 24VDC to devices)
- Enclosure: Open-style design
Typical Applications
The 1734-OB8 is widely used in manufacturing and process control for controlling discrete devices including solenoid valves, motor starters, indicator lamps, horn alarms, and gate drivers. Its compact design supports modular, decentralized I/O architectures where controllers and I/O modules are distributed throughout a facility, reducing panel space and wiring complexity. The electronic protection makes it suitable for harsh industrial environments where device failures must be isolated to prevent entire I/O bank shutdowns.
Compatibility & Replacements
The 1734-OB8 is part of Rockwell Automation’s POINT I/O 1734 series and mounts to standard 1734-TB or 1734-TBS terminal base assemblies. Series C modules offer expanded communication options including ControlNet and Ethernet adapters in addition to traditional DeviceNet and ProfiBus. The module is compatible with CompactLogix, ControlLogix, and MicroLogix PLC platforms when used with the appropriate communication adapters. Enhanced versions such as the 1734-OB8E add network diagnostics and open-wire detection features, while the 1734-OB8S variant provides certified safety-rated outputs for safety-critical applications.
