PLC-5 | Allen-Bradley 1785-LT2 Processor Module

Description

The 1785-LT2 is a PLC-5/25 processor module with 13 Kwords of SRAM memory, expandable to 21 Kwords. It supports DH+, Remote I/O, and RS-232-C/422-A/423-A communication, handles up to 3,072 I/O points, and includes a coprocessor expansion port with controller redundancy support. Program scan time is 2 ms for discrete logic, and rack I/O scan varies with communication speed.

Technical Specifications

• Manufacturer: Allen-Bradley

• Model Number: 1785-LT2

• Product Line: PLC-5

• Product Type: Processor Module (PLC-5/25)

• User Memory: 13 Kwords SRAM

• Memory Expansion: Up to 21 Kwords

• Communication Ports: DH+, Remote I/O

• Serial Ports: 1 x RS-232-C/422-A/423-A

• Coprocessor Expansion Port: Supported

• Controller Redundancy: Supported

• Max Total I/O: 3,072

• Max Analog I/O: 1,024

• Max I/O Chassis: 17 slots

• Max Universal Remote I/O Chassis: 16 slots

• Program Scan Time: 2 ms discrete logic, typical 8 ms

• Weight: 3.19 lb (1.45 kg)

Application Scenarios

The 1785-LT2 is suitable for PLC-5 control systems requiring reliable medium-scale processing, redundancy support, and flexible I/O configurations. Ideal for discrete and analog process control in manufacturing and automation systems.

Comparison with Similar Models

• 1785-LT2: Standard PLC-5/25 processor, supports 13 Kwords SRAM with memory expansion.

• 1785-LT3: Higher memory capacity and faster I/O scan for larger systems.

• 1785-LT4: Optimized for maximum analog and digital I/O support with extended chassis.

FAQs

Q1: What controllers are compatible with 1785-LT2?
A1: Works with PLC-5 series systems.

Q2: How much total I/O can it support?
A2: Up to 3,072 total points (input/output complementary).

Q3: Can I expand memory?
A3: Yes, SRAM can be expanded up to 21 Kwords.