Allen-Bradley 1771-ASB/E Remote I/O Adapter Module

Description

The Allen-Bradley 1771-ASB/E is a remote I/O adapter module that serves as an interface between remote I/O modules and Allen-Bradley programmable controllers. The module receives and sends data from and to the I/O scanner in serial form, and reads and writes data from and to input and output modules in parallel form. It transmits data up to 10,000 cable-feet at 57.6K baud and provides backplane scanning and data transmission up to 2,500 cable-feet at 230.4K baud. The adapter supports any mix of 4, 6, 8, 16, or 32-point I/O modules and accommodates 1/2-slot, 1-slot, and 2-slot I/O addressing methods. It performs I/O configuration checks on power-up to verify module placement and scans all slots in the chassis or all but the last four slots. Additionally, it can emulate Series B adapters to provide system response compatible with 1771-S4A and 1771-S4B scanners.

Features

• Transmits data up to 10,000 cable-feet at 57.6K baud and up to 2,500 cable-feet at 230.4K baud.
• Supports 1/2-slot, 1-slot, and 2-slot I/O addressing modes.
• Supports 4, 6, 8, 16, or 32-point discrete and block-transfer I/O modules.
• Emulates Series B adapter link response for compatibility with PLC-2 and PLC-3 scanners.
• Verifies I/O module placement on power-up.
• Features front-panel ACTIVE, ADAPTER FAULT, and I/O RACK FAULT LED diagnostic indicators.
• Includes backplane noise immunity retry options selectable via switch assembly.

Applications

• Remote I/O chassis interfacing in Allen-Bradley PLC-2, PLC-3, and PLC-5 programmable controller systems.
• Distributed industrial control architectures utilizing Universal I/O chassis.

Technical Specifications

Connections/Interfaces

Installation Guidelines

• Location & Keying: The 1771-ASB module must be installed in the leftmost slot of the I/O chassis. Key the backplane connectors using keying bands between pins 54–56 for the upper connector and pins 16–18 for the lower connector.
• Power Precautions: Remove system power before inserting or removing the module from the I/O chassis to prevent potential circuitry damage.
• 32-Point / Thermocouple Plug Selection: Access configuration plugs through the side access hole. Set plugs to the left position to enable 32-point I/O modules, or to the right position when using 1771-IX or 1771-IY thermocouple modules.
• Module Mounting: Place the module in the plastic guide tracks of the leftmost slot, press firmly to seat it in the backplane connectors, and secure the chassis locking bar.
• Termination: For the last adapter module on the link, connect a terminating resistor across terminals 1 (blue) and 3 (clear) on the field wiring arm (150 ohm standard, or 82 ohm for extended node capability at 230.4K baud).

Compliance and Certifications

• CE Mark (Directive 89/336/EEC EMC: EN 50081-2, EN 50082-2; Low Voltage Directive 73/23/EEC: EN 61131-2)