The Allen Bradley 1747-L511 is an SLC 5/01 Processor and part of the SLC 500 system. It is a small, easy-to-use processor with a wide range of applications including small process control, material handling, HVAC control, etc. It contains a PLC-5 processor-based advanced instruction set and can be stand-alone or distributed throughout for SCADA applications. This module is not compatible with the 1746-BLM, 1746-BTM, 1746-MPM, 1746-HS, 1746-HSCE, 1746-QV, 1747-SN, 1747-SDN, or 1747-SCNR15 modules. It is intended for use in clean and dry industrial environments, with a 0 to 60 degree Celsius operating temperature and a 30 g operating shock. It has a battery backup for the 1747-L514 module and a capacitor backup for the 1747-L511 module, and includes red PC RUN, CPU FAULT, FORCED I/O and BATTERY LOW, LED status indicators for troubleshooting and diagnostics.

The 1747-L511 is the entry-level processor of the modular style hardware of SLC 500. This processor has the most basic features having a 1KB memory which makes it capable of handling up to 3940 I/O signals. However, this module does not support implementation of Remote I/O topology. It may only be expanded by a maximum of three (3) SLC chassis of any type or a maximum of 30 I/O slots. This processor is UL listed to US and Canadian Safety Standards, CE compliant, and C-Tick marked. This processor has the memory back-up option of Electrically Erasable Programmable Read-Only Memory (EEPROM) which is basically a non-volatile memory. This non-volatile memory may be used to permanently store the Programmable Logic Controller (PLC) program to prevent accidental deletion that is commonly caused by power surges and draining of the battery. It may also be configured to automatically load the user program each time a power cycle is initiated.