Testing Solutions for Siemens PLCs Programs Based on PLCSIM Advanced

Testing Programmable Logic Controllers (PLCs) is challenging, partially due to the lack of tools for testing. Isolating a part of the PLC program, feeding it with test inputs and checking the test outputs often require manual work and physical hardware. The Siemens PLCSIM Advanced tool can simulate PLCs and provide a rich application programming interface (API). This paper presents a new CERN made tool based on PLCSIM Advanced and the TIA Portal Openness API. The tool takes a test case described in an intuitive, tabular format, which is then executed with the full PLC program or a selected part of it, effectively allowing unit testing. The inputs can be fed and the outputs can be captured via the PLCSIM API. This way the tests can be executed and evaluated automatically, without manual work or physical hardware. Therefore, it is possible to provide an automated and scalable continuous testing solution for PLC programs to reveal errors as early as possible.