An exemplary test principle for this document is presented. The test is a fully automated verification based on test patterns covering all paths of the state machines in this document, with the exception of T29 of the SafetyConsumer state machine.

NOTE The reason for T29 of the SafetyConsumer state machine not being tested by the UASCTT is that this transition cannot be triggered externally by the UASCTT by sending SPDUs or inducing other error conditions. The function of T29 according to this specification is to be proven by the manufacturer and be documented by a manufacturer declaration. Details are found in the test specification.

Different types of possible correct and incorrect SPDUs, parameters, and interactions with the upper interface of the SafetyProvider / SafetyConsumer are taken into account. These test patterns together with the expected responses/stimulations are stored as an XML document and imported into the test tool software. The test tool executes the complete test patterns while connected to the OPC UA Safety layer under test, compares the nominal with the actual reactions and is recording the results that can be printed out for the test report.

Figure 25 shows the structure of the layer tester for the SafetyProvider and SafetyConsumer.

Figure 25 – Automated SafetyProvider / SafetyConsumer test