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.
