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PLC-5/20 processor module, 24K words memory, RS-232 communication, classic 1771 chassis-compatible controller.

Allen-Bradley 1785-L20B

SKU: 1785-L20B
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$1,310.00
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Allen-Bradley 1785-L20B | PLC-5/20 Processor Module with 24K Words Memory for Legacy Automation Systems

Overview

The Allen-Bradley 1785-L20B is a PLC-5/20 processor module from the PLC-5 Classic platform, offering 24K words of user memory and a rich 57-instruction set. Designed for use in large and mid-range automation systems, it supports distributed control and I/O networks through classic Allen-Bradley communication protocols. The 1785-L20B is ideal for maintaining or upgrading legacy systems in industrial environments.

Key Features

  • Processor Type: PLC-5/20

  • User Memory: 24K words

  • Instruction Set: 57 standard instructions

  • Communication: RS-232 serial port

  • Chassis Compatibility: 1771 I/O chassis

  • Programming Software: RSLogix 5 or AI Series

  • Mounting: Installed in leftmost slot of the 1771 chassis

  • Battery-Backed Memory: Yes (battery included)

Technical Specifications

  • Catalog Number: 1785-L20B

  • Series: PLC-5 Classic

  • Input Power (Backplane): Supplied via 1771 chassis

  • Memory Type: RAM with battery backup

  • Communication Port: RS-232 (DF1 Protocol)

  • Operating Temp: 0°C to 60°C

  • Certifications: UL, CE, CSA

  • Dimensions (HxWxD): Approx. 230 x 50 x 200 mm

Applications

  • Legacy industrial automation systems

  • Process control in manufacturing and utilities

  • Plant-wide distributed I/O networks

  • Upgrading or maintaining PLC-5 installations

  • Mission-critical systems requiring long lifecycle support

Why Choose the 1785-L20B PLC-5/20?

  • Long-Term Reliability: Proven performance in legacy environments

  • Expandable: Compatible with 1771 I/O systems

  • Rockwell Software Support: Configurable with RSLogix 5

  • Low Risk Migration: Continue operations while planning upgrades

  • Industrial Standard: Widely adopted in legacy Allen-Bradley setups

Order Now

The Allen-Bradley 1785-L20B is available and ready for worldwide shipping. 

New & Genuine Products – Factory Sealed At PLCpartssolution, all our products are 100% new, genuine, and come in original factory-sealed packaging. We guarantee authentic components that meet the highest industry standards for performance and reliability.
1-Year Warranty Included All new products sold by PLCpartssolution come with a 1-year warranty. We stand behind the quality and reliability of our parts, ensuring coverage against manufacturing defects under normal operating conditions.
Disclaimer: PLCpartssolution is an independent supplier of surplus and refurbished industrial automation products. We are not an authorized distributor, reseller, or representative of the brands listed on this website. All trademarks, brand names, and logos are the property of their respective owners. PLCpartssolution is not affiliated with, endorsed by, or approved by ABB, Fanuc, B&R, Rockwell Automation, Schneider Electric, Siemens, or any other manufacturers mentioned.

Description

Allen-Bradley 1785-L20B | PLC-5/20 Processor Module with 24K Words Memory for Legacy Automation Systems

Overview

The Allen-Bradley 1785-L20B is a PLC-5/20 processor module from the PLC-5 Classic platform, offering 24K words of user memory and a rich 57-instruction set. Designed for use in large and mid-range automation systems, it supports distributed control and I/O networks through classic Allen-Bradley communication protocols. The 1785-L20B is ideal for maintaining or upgrading legacy systems in industrial environments.

Key Features

  • Processor Type: PLC-5/20

  • User Memory: 24K words

  • Instruction Set: 57 standard instructions

  • Communication: RS-232 serial port

  • Chassis Compatibility: 1771 I/O chassis

  • Programming Software: RSLogix 5 or AI Series

  • Mounting: Installed in leftmost slot of the 1771 chassis

  • Battery-Backed Memory: Yes (battery included)

Technical Specifications

  • Catalog Number: 1785-L20B

  • Series: PLC-5 Classic

  • Input Power (Backplane): Supplied via 1771 chassis

  • Memory Type: RAM with battery backup

  • Communication Port: RS-232 (DF1 Protocol)

  • Operating Temp: 0°C to 60°C

  • Certifications: UL, CE, CSA

  • Dimensions (HxWxD): Approx. 230 x 50 x 200 mm

Applications

  • Legacy industrial automation systems

  • Process control in manufacturing and utilities

  • Plant-wide distributed I/O networks

  • Upgrading or maintaining PLC-5 installations

  • Mission-critical systems requiring long lifecycle support

Why Choose the 1785-L20B PLC-5/20?

  • Long-Term Reliability: Proven performance in legacy environments

  • Expandable: Compatible with 1771 I/O systems

  • Rockwell Software Support: Configurable with RSLogix 5

  • Low Risk Migration: Continue operations while planning upgrades

  • Industrial Standard: Widely adopted in legacy Allen-Bradley setups

Order Now

The Allen-Bradley 1785-L20B is available and ready for worldwide shipping. 

Condition

New & Genuine Products – Factory Sealed At PLCpartssolution, all our products are 100% new, genuine, and come in original factory-sealed packaging. We guarantee authentic components that meet the highest industry standards for performance and reliability.

Warranty

1-Year Warranty Included All new products sold by PLCpartssolution come with a 1-year warranty. We stand behind the quality and reliability of our parts, ensuring coverage against manufacturing defects under normal operating conditions.

Disclaimer

Disclaimer: PLCpartssolution is an independent supplier of surplus and refurbished industrial automation products. We are not an authorized distributor, reseller, or representative of the brands listed on this website. All trademarks, brand names, and logos are the property of their respective owners. PLCpartssolution is not affiliated with, endorsed by, or approved by ABB, Fanuc, B&R, Rockwell Automation, Schneider Electric, Siemens, or any other manufacturers mentioned.
Allen-Bradley 1785-L20B

Allen-Bradley 1785-L20B

$1,310.00
Add to wishlist
Allen-Bradley 1785-L20B

Allen-Bradley 1785-L20B

Your Price:
$1,310.00
Item Added to Your Cart
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