Allen-Bradley 1785-L40B PLC5 Controller 48K Words

Product Overview

The Allen-Bradley 1785-L40B is a powerful PLC5 controller from Rockwell Automation. It features 48K words of user memory. This controller supports up to 2048 I/O points in any mix or 2048 inputs plus 2048 outputs in complementary mode. It includes four combination ports for DH+ or Remote I/O (Adapter/Scanner) and one serial port configurable for RS-232, RS-423, and RS-422A. The 1785-L40B is designed for medium to large automation tasks. It mounts in a standard 1771 chassis. This unit provides reliable control for complex processes.

Application Scenarios

This controller excels in manufacturing lines, material handling, and process control. It handles up to 29 PLC5 racks, with one local and 28 remote I/O racks. The four DH+/RIO ports allow independent networks. This makes it suitable for distributed control systems. Use it for batch processing, conveyor systems, and machine automation. The serial port supports point-to-point communication. This unit also works with legacy PLC-5 systems for upgrades.

Technical Specifications

Processor: PLC-5/40
Memory: 48K Words battery-backed static RAM
Max I/O: 2048 (any mix) or 2048 in + 2048 out (complementary)
Max Analog I/O: 2048
I/O Scan Time per Rack: 10 ms at 57.6 kbps, 7 ms at 115.2 kbps, 3 ms at 230.4 kbps
Max I/O Chassis Total: 61
Max I/O Chassis Extended Local: 0
Max I/O Chassis Universal Remote: 32
Embedded Ports: 4 DH+/RIO (Adapter/Scanner), 1 serial (RS-232/423/422A)
Backplane Current Load: 3.3A
Power Dissipation: 17.3W
Power Supply: 1771-P4S, -P6S, -P4S1, -P6S1
Operating Temperature: 0 to 60°C
Non-Operating Temperature: –40 to 85°C
Battery: 1770-XYC
Memory Backup: EEPROM via 1785-ME16, -ME32, -ME64, -M100

Installation & Maintenance Guide

Install the 1785-L40B into a PLC5 chassis. Ensure the chassis has adequate power supply. Connect I/O modules per system requirements. Configure the DH+/RIO ports for the desired network role. Use the serial port for programming or point-to-point links. Replace the battery (1770-XYC) every few years to retain memory. Keep operating temperature between 0 and 60°C. For backup, install an optional EEPROM memory module. Always follow Rockwell Automation guidelines for safe installation.

Packing List

The package includes one Allen-Bradley 1785-L40B PLC5 controller. No I/O modules, cables, or power supply are included. The unit comes individually boxed. Shipping is via FedEx, UPS, or DHL. Contact us for expedited options.