Hardware Simulation for Testing IEC 61131-3

Sammanfattning: Testing of control code written in IEC 61131-3 has long been a strenuous manual process. The focus in this master's thesis is on building a simulator of an Alfa Laval separator to enable testing of control code. In this particular case, the control code being tested is written and executed in a soft PLC called TwinCAT. The simulator for testing code is written in C#. When testing code, automated tests are preferred because it enables easy regression testing. For this purpose a testing tool using a customized script language has been developed. Testing with a simulator is also beneficial because errors can be found early in the development process, thus reducing the number of errors left to be found when testing on hardware. Comparison tests show that the simulator performs sufficiently well for testing of control code.