Allen-Bradley 1745-B1 Memory Module

Allen-Bradley 1745-B1 Memory Module is a lithium-battery backed memory backup unit designed for the SLC-100 family of Programmable Logic Controllers. This Bulletin 1745 memory module provides non-volatile support for the RAM-based user program memory when power is removed, enabling the program data to persist across power interruptions. The 1745-B1 is cataloged as a dedicated memory backup accessory that installs in the SLC-100 chassis to maintain the contents of RAM during outages by drawing power from its built-in lithium battery. In practical terms, it acts as a memory backup battery module rather than a standard RAM module, safeguarding the user program so that after power returns the controller can resume operation with minimal reload time. Typical applications include industrial automation setups that rely on the SLC-100 for sequence control and require the program memory to survive brief outages, such as intermittent power, generator switchover, or voltage dips. The part number 1745-B1 is widely referenced in Allen-Bradley 1745-series memory documentation and third-party listings as the lithium-battery memory module for SLC-100 systems.