Agile Testing of Cyber-Physical Production Systems-Usage of PLC Programming Languages for Test-Case Specification

Interconnected production systems, which may be modified during operation, pose particular challenges for testing the associated control software. To hedge the modifications, it may be necessary to run tests during operation once again. In order to avoid longer stoppages, it is desirable that the corresponding test cases can be quickly adapted and executed - in other words, that agile testing becomes possible. The article presents an approach for the Hardware-in-the-Loop (HiL) testing of PLC software where the test cases and acceptance criteria are specified using slightly extended PLC languages. This avoids the change of methodology observed when using dedicated test languages and corresponding tools. Our hypothesis is that this will lead to faster and more reliably changeable test case descriptions and thus creates the desired agility.