Allen-Bradley 1785-L40E PLC-5 SRAM Controller

Allen-Bradley 1785-L40E PLC-5/40E Enhanced Processor is an Ethernet-enabled PLC-5 controller with 48K words of SRAM for user memory and ladder logic data, designed to run PLC-5 applications in backplane systems. It provides one Ethernet port for network communication, two DH+ remote I/O channels for legacy networks, and a configurable serial port (RS-232-C / RS-422-A / RS-423-A) for device interfaces and programming tools. The 48K-word SRAM supports substantial user data, with a maximum of 2048 I/O points (any mix) or 2048 inputs and 2048 outputs in a complementary arrangement. The L40E supports up to 16 I/O racks and up to 61 I/O chassis, aligning with PLC-5 scalability. As a Series E Enhanced processor, it maintains compatibility with existing DH+ networks while providing Ethernet connectivity for modernized communication needs. This model is commonly used to retrofit or expand PLC-5 installations requiring greater memory capacity and integrated Ethernet while preserving PLC-5 software compatibility.