国外开源plc源码， 支持IEC 61131-3 五种编程语言。This project has the goal of producing an open source compiler for the programming languages defined in the IEC 61131-3 standard. These programming languages are mostly used in the industrial automation domain, to program PLCs (Programmable Logic Controllers). This standard defines 5 programming languages: IL,ST,FBD,LD ,SFC.