The 1747-L541 is an SLC 504 or SLC 5/04 processor manufactured by Allen Bradley/Rockwell Automation as part of the SLC 500 series, which also comprises of the 1747-L541, L542, and L543 processors. This is a high-performance processor improved with shorter program execution and faster communication time. It requires a backplane current load of 200 milliamps at 24 volts DC and 1 ampere at 5 volts DC, with a 1-millisecond selectable timed interrupt (STI) as well as discrete input interrupt (DII) of 0.5 milliseconds. This module has a flash-based memory device of 64 kilobytes for storage of programs and data table, and it comes with RS-232 channel that supports DF1 radio modem, ASCII, Modbus RTU, and DH-485 communications. It features advanced math instructions as well as different additional instructions. This module supports remote input and output, DeviceNet pass-through, as well as indirect addressing. Allen Bradley SLC 504 series, including 1747-L541 processor, has 16, 32, or 64 keywords of memory and can control up to 4096 output and input points. The 1747-L541 processor features an inbuilt DH+ channel that supports advanced messaging capabilities as well as high-speed communication. This processor has a typical program scan time of 0.9 milliseconds per keyword and a typical input and output scan time of 0.225 milliseconds. The SLC 504 series has a 3-position key switch on the front for selecting between the remote, program, or run modes. The 1747-L541 SLC 504 processor comes with BATT, RUN, FLT, RS-232 FORCE, and DH+ LED status indicators to enhance diagnostics and troubleshooting. The SLC 500 processors have a simple, cost-effective design and support installation in applications including SCADA, HVAC control, and material handling.

Part number 1747-L541 belongs to the SLC 500 series of processors that were manufactured by Allen-Bradley and there are several versions that have a maximum memory of 64 kb (kilobytes). This processor supports a modular architecture of I/O modules, in other words, the modular design and the maximum controlled I/O points is 4096. The processor supports ladder program that should be entered in its memory using RS-232 interface, usually, although the processor is supporting DH-485, DF1 and modbus communications (there is a built-in RS-232/422/423 communication port). The switch on the panel can select the run, remote, or program modes and after programming, which is a proprietary process, the programmer just put the switch in run position. After that start up, the processor can scan program instruction and the typical I/O scan time is 0.225 milliseconds. According to the modular design, all input and output modules are located next to the processor module and also there is a power supply for all of them. The processor itself has an advanced instruction set that includes file handling, sequencing, diagnostics, shift register, advanced math instructions, immediate I/O, and program control instructions. The 1747-L541 can support several types of that modules such as digital, analog, and special combination modules but it supports also the remote I/O and it has a built-in DH+ channel for high-speed communication. All voltages and signals of this device are on the backplane. Therefore, this unit requires a current load of one (1) ampere at 5 (five) volts direct current (DC).