Allen-Bradley 1791-24A8 Block I/O Module - 24 AC Inputs

Allen-Bradley 1791-24A8: 32-Point AC Block I/O Module

Technical Specifications

• Brand: Allen-Bradley
• Model: 1791-24A8
• Product Type: AC Block I/O Module
• Input Channels: 24 AC inputs
• Output Channels: 8 AC outputs
• Input Voltage: 79-132V AC
• Output Voltage: 20-132V AC
• External Power: 85-132V AC, 150 mA
• Input On-State Current: 12.3mA @ 132V max
• Input Off-State Voltage: 35V AC max
• Power Dissipation: 18.76 Watts maximum
• Weight: 1.88 lbs (0.85 kg)
• Mounting: Vertical or Horizontal

Installation & Wiring Guidelines

• Install the module in either vertical or horizontal orientation within your control panel.
• Use Belden 9463 cable (Blue Hose wire) for Remote I/O network connections.
• This three-wire cable includes blue, clear, and shielded conductors for reliable communication.
• Connect modules in a daisy-chain topology to create your Remote I/O network.
• Install a terminating resistor (82Ω or 150Ω) at the last node of the network.
• The terminating resistor closes the communication loop and prevents intermittent connections.
• Ensure all connections are secure and follow local electrical codes for 120V AC installations.

Communication & Compatibility

• The 1791-24A8 operates in Remote I/O adapter mode, requiring an RIO scanner.
• It connects directly to PLC-2, PLC-3, and PLC-5 controller families via built-in RIO interface.
• For SLC 500 controllers, use with the 1747-SN Remote I/O scanner module.
• Supports standard baud rates: 57.6K, 115.2K, and 230.4K.
• Maximum cable distances: 10,000 ft at 57.6K, 5,000 ft at 115.2K, 2,500 ft at 230.4K.
• The module organizes inputs into 3 groups of 8 and outputs as 1 group of 8.
• This grouping simplifies addressing and configuration in your PLC program.

Frequently Asked Questions

• What is the voltage rating for the 1791-24A8 inputs and outputs?
  The 1791-24A8 supports 120V AC operation with inputs rated 79-132V AC and outputs 20-132V AC.
• Which Allen-Bradley PLCs work with this module?
  This module is compatible with PLC-2, PLC-3, PLC-5, and SLC 500 controllers (using 1747-SN scanner).
• What cable should I use for Remote I/O connections?
  Allen-Bradley recommends Belden 9463 cable, commonly called "Blue Hose" wire, for optimal performance.
• Why do I need a terminating resistor?
  A terminating resistor (82Ω or 150Ω) at the last network node ensures stable communication and prevents signal issues.
• Do you have stock and what is your shipping time?
  Yes, we stock the 1791-24A8 and ship within 3-5 business days via DHL, FedEx, or UPS.
• What is your return policy?
  We offer a 30-day return window for all products in original condition.

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