Allen-Bradley 1747-L541 SLC 500 PLC Processor Module

The Allen-Bradley 1747-L541 Series C SLC 5/04 CPU Processor Module is the central processing unit for the SLC 500 modular PLC family, delivering up to 16,000 words of user memory and nonvolatile program backup via flash memory (FRN 4). It features DH+ and RS-232 serial communications for programming and device networking and supports a large I/O footprint across the chassis—up to 4,096 inputs and 4,096 outputs, with up to 480 analog I/O points. Typical program scan time is 0.9 milliseconds per keyword, with an I/O scan time around 0.225 ms, enabling reliable performance in moderate-speed automation tasks. The module occupies a standard SLC 500 backplane and works with 1747-series I/O modules, making it compatible with existing SLC 500 installations that require a capable, memory-rich CPU. Firmware revision FRN 4 corresponds to this model’s supported software level, and the unit is commonly used in applications such as packaging lines, conveyors, and batch processing where ladder logic control and distributed I/O are essential.