Allen-Bradley 1785-L40B PLC-5/40 Standard Processor Module

2026-04-17T02:06:08-07:00

Type: Processor Module
Price: 66.00

Product Overview

The Allen-Bradley 1785-L40B serves as a high-performance central processing unit within the legendary PLC-5 platform. This PLC-5/40 standard processor manages complex automation tasks by coordinating extensive I/O networks through its integrated communication interfaces. It supports up to 48 Kilowords of user memory and handles massive I/O densities, making it a cornerstone for large-scale industrial manufacturing and process control. We supply this unit as 100% Brand New and Original, ensuring your legacy infrastructure maintains peak execution speeds and data integrity without the risks of refurbished hardware.

Technical Specifications

The 1785-L40B combines high-speed logic execution with versatile networking capabilities to manage distributed control systems.

Manufacturer: Allen-Bradley / Rockwell Automation

Product Line: PLC-5

Processor Type: PLC-5/40 Standard Processor

User Memory: 48 Kilowords (Battery-Backed Static RAM)

Total I/O Capacity: 2048 (Any mix) or 2048 Input + 2048 Output (Complementary)

Embedded Communication: 4 DH+/Remote I/O ports; 1 Serial port (RS-232, RS-423, RS-422A)

I/O Scan Time: 3 ms at 230.4 kbits/s; 7 ms at 115.2 kbits/s; 10 ms at 57.6 kbits/s

Backplane Current Load: 3.3A @ 5V DC

Power Dissipation: 17.3 Watts

Memory Backup: EEPROM Option (1785-ME16 to -M100)

Battery Type: 1770-XYC

Operating Temperature: 0 to 60 °C (32 to 140 °F)

Weight: 3.00 lbs (1.36 kg)

Engineering Advantages

High-Density I/O Management: The 1785-L40B controls up to 32 universal remote I/O chassis per link. This massive expansion capability allows engineers to consolidate control over expansive production lines into a single processor, reducing hardware overhead and simplifying data synchronization.

Deterministic Communication: Integrated Data Highway Plus (DH+) and Remote I/O (RIO) ports facilitate high-speed, deterministic data exchange. By selecting the 230.4 kbits/s transmission rate, the processor achieves a rack scan time of just 3 ms, providing the rapid response required for high-speed packaging and assembly logic.

Robust Memory Protection: The processor utilizes battery-backed Static RAM to prevent data loss during power cycles. For mission-critical permanent storage, it supports EEPROM modules (up to 100K words), allowing for instant program recovery and safeguarding against long-term battery depletion.

Multi-Standard Serial Connectivity: A single configurable serial port supports RS-232, RS-422A, and RS-423 standards. This eliminates the need for external signal converters when interfacing with legacy weigh scales, barcode readers, or non-Rockwell HMI terminals.

Environmental Compliance: The module meets IEC 60068-2-14 standards for thermal shock. It operates reliably in environments with rapid temperature fluctuations, ensuring consistent logic execution in unconditioned industrial cabinets.

FAQs

Which power supplies are compatible with the 1785-L40B?

The processor requires the 1771-P4S, 1771-P6S, 1771-P4S1, or 1771-P6S1 power supply modules. Ensure the power supply provides sufficient current for the 3.3A backplane load of the processor plus any additional I/O modules in the local chassis.

How do I backup the program without relying solely on the battery?

You can install an optional EEPROM module, such as the 1785-ME64 or 1785-M100. This non-volatile memory stores a master copy of your project, allowing the processor to reload the application automatically if the 1770-XYC battery fails.

Can the 1785-L40B function as both a scanner and an adapter?

Yes. The embedded communication ports are highly flexible. You can configure the DH+/Remote I/O ports to function as a Scanner (to control remote I/O racks) or as an Adapter (to appear as an I/O station to another master processor).

Is this a refurbished or surplus unit?

We guarantee this 1785-L40B is 100% Brand New and Original. It ships in factory-sealed packaging with the authentic UPC (612598124015), ensuring you receive a processor with zero operating hours and full hardware longevity.