This Method (as part of the OPC UA Mapper) serves as a Diagnostic Interface and exists for each SafetyProvider. For time series observation, this interface can be polled, e.g. by a diagnostic device. For details, refer to the OPC UA Information Model described, see 6.2.2.4.

The Diagnostic Interface Method does not take any input parameters and returns both the input and output parameters of the last call of the Method ReadSafetyData.

Additionally, a 2-octet sequence number is added to the Diagnostic Interface, allowing for a detection of missed calls due to polling. The sequence number counts the number of accesses to ReadSafetyData.

A best practice recommendation is to store all input and output parameters if SComErr_diag is <> 0.