Allen-Bradley 1785-L20B DH+ RIO Processor Module

Availability: 20 left in stock

Product Overview The Allen-Bradley 1785-L20B acts as the central computational engine for medium-scale industrial automation and process control systems. This...

SKU: 1785-L20B

Manufacturer: Allen Bradley
Product No.: 1785-L20B
Product Type: Programmable Logic Controllers
Product Origin: USA
Payment:T/T, Western Union
Weight: 350g
Shipping port: Xiamen
Warranty: 12 months

Description Reviews

Product Overview

The Allen-Bradley 1785-L20B acts as the central computational engine for medium-scale industrial automation and process control systems. This hardware assembly executing complex control logic directly belongs to the legacy Rockwell Automation PLC-5 product platform. It drives continuous machine automation by orchestrating up to 1024 total inputs and outputs across modern industrial networks. While plant engineers widely deploy this processing unit in existing legacy panels, this specific offering delivers 100% brand new and original hardware in factory packing to secure critical system longevity and prevent unplanned facility downtime.

Technical Specifications

Parameter	Specification Details
Manufacturer	Allen-Bradley / Rockwell Automation
Model Identifier	1785-L20B
Firmware / Series	Enhanced Series (Includes Series A, B, C, D, and E revisions)
Controller Type	PLC-5/20 Processor Module
Volatile Memory Capacity	16 Kilowords SRAM
Non-Volatile Memory Expansion	Supports 1785-ME16, 1785-ME32, and 1785-ME64 cartridges
Total I/O Capacity	1024 total points (512 inputs and 512 outputs)
Local Rack Capacity	Coordinates up to 12 local I/O chassis
Dedicated Networking Ports	1 x Data Highway Plus (DH+), 1 x Remote I/O (RIO)
Local Interface Connection	1 x RS-232 / RS-422A / RS-423 Serial Port
Nominal Execution Speed	1 millisecond per Kiloword of bit instructions
Data Protection Backup	1770-XYC Lithium Battery
Operational Thermal Range	0 to 60 degrees Celsius
Module Dimensions	237.5 x 183.0 x 55.0 mm
Shipping Weight	3.00 kg

Engineering Advantages

This processor module resolves typical industrial communication bottlenecks by integrating multiple native networks directly onto the front face of the module. Plant upgrade projects utilize the concurrent Data Highway Plus and Remote I/O configurations to bridge legacy instrumentation networks with modern supervisory controls without adding complex interface converters. The high-density processing architecture allows system builders to install this unit directly into standard PLC-5 chassis slots, which speeds up component replacement during emergency maintenance windows.

To combat severe electrical noise common in heavy manufacturing environments, the module incorporates robust internal isolation barriers across its communication channels. This protective hardware design keeps high-voltage transients from degrading control loop stability or causing processor faults. Furthermore, the firmware handles expandable non-volatile memory cartridges smoothly, allowing maintenance technicians to store exact control logic backups locally on the hardware and recover quickly from localized facility power disruptions.

FAQs

Can this 1785-L20B module replace older Series A or Series B hardware revisions directly?

Yes. This processor module maintains full backward compatibility across all preceding series letters (A, B, C, and D). You can slide this card directly into the existing PLC-5 slot and download your original application file through RSLogix 5 software without needing any ladder logic alterations.
What specific procedure prevents memory loss during a backup battery replacement?

You must change the 1770-XYC lithium battery while the PLC-5 chassis remains powered ON. Removing the old battery while the chassis lacks system power interrupts the SRAM hold-voltage, which immediately erases the active user program and data tables stored on the module.
Does this unit support remote I/O scanning alongside its standard peer-to-peer data transfers?

Yes. The built-in communication ports allow you to configure one channel as a Remote I/O scanner to poll distributed field chassis while simultaneously utilizing the Data Highway Plus network to pass operational metrics back to human-machine interfaces.

What's clients say about us

Excellent Emergency Support!

Our production line was down due to a faulty Bently Nevada monitor. We found it in stock here and they shipped it via DHL immediately. Back in operation within 48 hours—truly a lifesaver for our plant.

Mark Thompson

Maintenance Manager, USA

Reliable Source for New Spares

Finding brand new, original modules is critical for our safety. This team delivers factory-fresh components with full certification. Their commitment to only selling new products makes them our most trusted partner.

Robert Hoffmann

Engineering Lead, Germany

Top-tier Service and Quality

We have sourced Honeywell and Schneider parts here for two years. Every shipment arrives well-packaged with original factory seals intact. Clear communication and the best lead times in the industry.