Overview
The Allen-Bradley 1791D-8B8P is a CompactBlock I/O DeviceNet module designed for distributed digital I/O in industrial automation systems. This versatile base module combines 8 sinking digital inputs and 8 sourcing digital outputs in a compact form factor, making it ideal for machine-level control and field device interfacing where space is limited.
Key Features
- Mixed 8-input/8-output base module in the 1791D CompactBlock series
- DeviceNet communication with automatic baud rate detection and short-circuit protection
- Expands to 32 total I/O with optional expansion modules (24 inputs/8 outputs or 8 inputs/24 outputs)
- Operates independently or as a foundation for I/O expansion
- Three selectable communication modes: polled, cyclic, and change-of-state
Technical Specifications
- Digital I/O: 8 sinking inputs, 8 sourcing outputs
- Supply Voltage: 10–30 Volt DC
- Communication Protocol: DeviceNet
- Data Rate: 500 Kbps (100 m maximum distance)
- Operating Temperature: 0–60 °C
- Storage Temperature: −40–85 °C
- Environmental Rating: IP 20
- Maximum Expansion I/O: 32 total points with expansion modules
- Mounting: DIN-rail compatible, multiple orientations supported
Typical Applications
- Distributed machine control and motor starter coordination
- Remote I/O on DeviceNet field networks
- Compact enclosure installations where space constraints limit module size
- Integration with Rockwell Automation CompactLogix or ControlLogix systems via DeviceNet
- Sensor and actuator interfacing in modular production lines
Compatibility & Replacements
Compatible With
- Rockwell Automation CompactLogix, ControlLogix, and PLC-5 controllers (via DeviceNet)
- DeviceNet communication networks and scanners
- CompactBlock I/O 1791D series expansion modules
- Studio 5000 programming software (EDS file support)
- RSLogix 5/500 industrial control software
Replaces / Drop-In Replacement For
- Verify compatibility with your system integrator before ordering. The 1791D-8B8P is a mixed base module; ensure your replacement does not require different input/output ratios (e.g., 1791D-8V8P or 1791D-16B0 are alternative configurations in the same series).
Works With
- DeviceNet protocol for distributed I/O communication
- Rockwell Automation CompactBlock expansion modules (input/output modules)
- Studio 5000 and RSLogix programming environments
- EDS (Electronic Data Sheet) files for network configuration
