Design of Mini PLC based on PIC18F452 Microcontroller using Concepts of Graceful Degradation

Abstract

Abstract— Programmable logic controllers (PLCs) which are able to interact with peripherals play a key role as a controlling unit in most of the industries now a day. Main objective of this research is to design a PIC18F452 microcontroller based low cost mini PLC which is gracefully degrading to support ladder logic programming language-one of the programming languages of standard IEC61131-3. A compiler with selected features has been designed in C# language. An operating system of the microcontroller of this mini PLC has also been designed in C language. To interface programming device and mini PLC, USB to RS232 communication protocol has been used. It is easy to envision the scheme of wiring, power supply, input & output channels, microcontroller, circuits of optical isolators etc. in the mini PLC thereby providing the students a platform to understand the internal architecture of most of the PLC systems.