Allen-Bradley 1785-LT/B 1785-LT Series B PLC-5 Processor Module

Description

The Allen-Bradley 1785-LT/B is a programmable logic controller hardware component that functions specifically as a PLC 5/15 processor module within the classic PLC-5 hardware line. It serves as the primary control unit to execute user application ladder logic, govern localized signal scanning, and coordinate peripheral network routing. For processing physical parameters, this processor provides simultaneous architecture expansion that manages up to four local I/O chassis racks alongside up to three universal remote I/O link channels. Built-in standalone communication interfaces include a specialized Remote I/O scanner adapter combined with a Data Highway Plus (DH+) station port, facilitating direct parallel data transmission to operator workstations, supervisory automation interfaces, and third-party interface systems without interrupting primary control cycles.

Features

• Dual integrated network pathways containing an independent local or remote I/O scanning link plus a separate Data Highway Plus (DH+) industrial channel.
• Dual-option hardware configuration switches permitting user control over physical I/O output states during active communication fault conditions.
• Multi-slot physical addressing capacity supporting 2-slot, 1-slot, and 1/2-slot input/output group placement mapping.
• Slide-in backplane alignment structural base designed for installation inside the left-most slot position of standard 1771-I/O chassis enclosures.

Applications

• High-reliability automation control loop execution in factory manufacturing environments.
• Centralized multi-chassis industrial system expansion via remote and local input/output link networks.
• Distributed plant automation cell integration using Data Highway Plus architectures.

Technical Specifications

Installation Guidelines

• Chassis Slot Placement: Slot the module strictly into the left-most dedicated processor position of the 1771-I/O chassis frame, ensuring the guide keys align smoothly with backplane markers between slots 40/42 and 54/56.
• Fault Mode Switch Setup: Adjust configuration Switch 1 to the OFF position prior to startup to force the local chassis to safely strip away output energy if a fatal processing or communication error occurs.
• ESD Shielding Safety: Ensure full connection to a reliable grounding strap during manual deployment or component adjustments to block static path discharges into the internal processing logic boards.

Compliance and Certifications

• EN 50081-2 EMC - Generic Emission Standard for operation in a Part 2 - Industrial Environment