Overview
The Allen-Bradley 1791-32B0 is a compact, discrete DC input block designed for remote I/O applications. This 32-channel module provides discrete DC input capacity with 4 groups of 8 input channels, making it ideal for distributed control architectures where centralized I/O is impractical. Block I/O modules are self-contained remote I/O devices complete with power supply, programmable controller interface, input/output connections and signal conditioning circuitry. The 1791-32B0 operates at nominal 24V DC, compatible with standard industrial sensors and limit switches.
Key Features
- 32 Discrete DC Input Channels – Four independently configurable groups of eight inputs for flexible signal routing
- Modular Block I/O Design – Self-contained with integrated power supply and signal conditioning, reducing wiring complexity
- Remote I/O Connectivity – Connects via high-speed Remote I/O (RIO) link for real-time data transmission
- Wide Supply Voltage Range – Operates on 19.2-30V DC supply, tolerating typical industrial power fluctuations
- Field-Replaceable – Modular construction enables quick swaps without disrupting the control system
- Sensor Compatibility – Works with standard 10-30V DC sensors like proximity switches and photoelectrics
Technical Specifications
- Input Channels: 32 (4 groups of 8)
- Nominal Input Voltage: 24V DC
- Input Voltage Range: 19.2–30V DC
- Per-Channel Input Current: 11.0 mA (nominal)
- Module Supply Current: 300 mA
- Input Response Time: Typically within a few milliseconds
- Mounting: DIN rail (vertical or horizontal)
- Communication Protocol: Remote I/O (RIO) link
- Weight: 1.81 lbs
- Condition: Used, fully functional
Typical Applications
- Assembly Lines & Packaging: Ideal for various manufacturing processes, including assembly lines, packaging, and material handling systems
- Process Control: Utilized in process industries for monitoring and controlling equipment such as pumps, valves, and sensors
- Machine Control: Perfect for machinery needing real-time data acquisition and control, enhancing productivity and precision
- Distributed I/O: When sensors and devices are located remotely from the main controller cabinet
Compatibility & Replacements
Compatible With
- Allen-Bradley ControlLogix Systems – Compatible with Allen-Bradley ControlLogix systems, facilitating straightforward installation and reducing setup time
- Remote I/O Scanner Modules – Communicates via high-speed RIO network
- Classic PLC-2, PLC-3, PLC-5 systems – Via 1747-SN I/O Scanner modules
- SLC 500 Controllers – When paired with appropriate RIO scanner hardware
Replaces / Drop-In Replacement For
- 1791-32B0 (original Series A) – Direct series replacement
- Similar 32-point discrete DC modules – Verify pinout and voltage specs before installation
- Note: This unit was discontinued by manufacturer on 2015-06-29, making tested used stock valuable for legacy system repairs
Works With
- Studio 5000 Logix Designer – Configuration and monitoring
- RSLogix 500 – Legacy SLC programming platform
- 24V DC Sensors – Proximity, photoelectric, limit switches, pressure transducers
- Discrete Signal Devices – LED indicators, solenoids, motor starters (when using corresponding output modules)
