The Allen-Bradley 1771-ASB, also cataloged as the 1771ASB Remote I/O Adapter Module, operates as a dedicated hardware component for interfacing remote 1771 I/O chassis with programmable controllers within PLC-5 Series control architectures.

System Configuration & Addressing Options

• Chassis Slot Assignment: Installed exclusively in the leftmost slot of any standard 1771 I/O chassis.
• Addressing Flexibility: Configurable via physical jumpers for 2-slot, 1-slot, or 1/2-slot I/O addressing modes to optimize data table utilization.
• Module Compatibility: Interfaces with standard 8-point, 16-point, and 32-point digital/analog modules as well as specialized intelligent modules.

Hardware Specifications

Deterministic Network & Backplane Architecture

The 1771-ASB utilizes deterministic Allen-Bradley Remote I/O (RIO) communication protocol via Belden 9463 twinaxial cabling. The adapter manages high-density backplane bus communication velocity and handles I/O density scaling efficiently without incurring CPU processing overhead. Diagnostic status LEDs provide real-time hardware status verification to minimize communication latencies during operational cycles.

Shipping Package Content

• 1 x 1771-ASB Remote I/O Adapter Module
• 1 x Field Wiring Arm
• Configuration Jumpers (pre-installed / modular)

Physical Installation Guidelines

• Power Down Warning: Always remove primary system power from the 1771 I/O chassis backplane and field wiring arms prior to insertion or removal to prevent electrical arcing and component degradation.
• Keying Band Configuration: Insert plastic keying bands on the backplane connectors between pins 54/56 (upper connector) and pins 16/18 (lower connector) to ensure proper module alignment.
• Slot Positioning: Ensure placement is strictly within the leftmost dedicated chassis slot designated for adapter and processor units.

Frequently Asked Questions

• Q: What is the backplane current draw for the 1771-ASB?

  The module draws exactly 1.0 A at 5 VDC from the backplane power supply during continuous operation.

• Q: Can the 1771-ASB be hot-swapped while the backplane is powered?

  No, power must be fully removed from the chassis backplane before inserting or removing the module to avoid equipment damage.

• Q: What cable is required for extended remote I/O runs?

  Communication over long distances up to 10,000 feet requires standard Belden 9463 twinaxial cable.

• Q: Where must the module be positioned in the 1771 chassis?

  The 1771-ASB must always occupy the leftmost slot of the chassis, reserved specifically for adapters or processors.

• Q: What addressing modes does the 1771-ASB support?

  It supports 2-slot, 1-slot, and 1/2-slot I/O addressing to match various module densities in the system image table.

• Q: What is the maximum baud rate supported at maximum cable length?

  At a distance of 10,000 feet, the module reliably sustains data communication rates at 57.6K baud.

• Q: How is physical chassis keying managed for this module?

  Keying bands are placed between pins 54 and 56 on the upper backplane connector and pins 16 and 18 on the lower connector.

• Q: What diagnostic indicators are provided on the front panel?

  Status LEDs indicate adapter communication state, active transmission, and internal fault diagnostics.