The aim of the paper is to present the implementation of a PLC designed in the form of a System-on-a-Chip. The presented PLC is compatible with the IEC61131‒3 standard. More precisely, the Instruction List language is the native language of the designed CPU, so there is no need for multiple language transformations. In the proposed solution each instruction of the CPU program written in Instruction List is directly translated to machine code. The designed CPU is capable of performing logic operations up to 32-bit Boolean data types. However, the developed CPU is very flexible due to its architecture: data memory can be addressed as bit/byte/word/dword. Moreover, diverse blocks such as timers, counters, and hardware acceleration blocks, can be connected to the CPU by means of an APB AMBA bus. The designed PLC has been implemented in an FPGA device and can be used in cyber-physical systems and Industry 4.0.

Virtual machine described in the paper is a runtime program for controllers in small distributed systems. The machine executes intermediate universal code similar to an assembler, compiled in CPDev engineering environment from source programs written in control languages of IEC 61131-3 standard. The machine is implemented as a C program, so it can run on different target platforms. Data formats and commands of the machine code are presented, together with the machine’s Petri-net model, C implementation involving universal and platform-dependent modules, target hardware interface, input/output programming mechanisms, and practical applications.

Design and operation of a compiler and virtual machine, being the essential components of a multiplatform control programming environment, are presented. The compiler translates source programs written in Structured Text language of the IEC 61131-3 standard into executable code in a dedicated intermediate language. The virtual machine, i.e. a specially designed processor implemented in software, is a runtime part of the environment executing the code in real time. Due to memory-to-memory operation principle the machine is able to process various data types defined in the standard. The focus is given on overloading and extensibility of the functions, as well as on uniform invocations of Program Organization Units. By selection of addressing mode, the environment can be deployed on multiple hardware platforms, beginning from 8-bit microcontrollers up to 32/64-bit industrial PCs. Industrial applications are indicated.