From BP [Mark Cotton]

In the base class of each MDIS object we have two variables, Fault Code and Warning Code that are described as vendor specific. This goes against the principle of interface standardization. I want to reuse DCS logic that I have coded for one subsea vendor interface on the next project with a different vendor. If the interface contains vendor specific data this will not be possible without modifying the DCS implementation for each vendor. We should consider removing vendor specific fault codes and look at what common types of fault we can report to the operator for each device type. The approach taken with the rest of the MDIS objects is to create a vendor specific subtypes when vendor specific information is to be provided. One solution could be to implement the Fault Code as a string with the description of the fault, if the intention is that the fault code is to be interpreted as a message to present to the operator.

It is not clear from the specification how the Warning flag and the warning codes should be used. Are there example use cases for situations in which warnings are provided? [Note: is a warning , something that does not need immediate operator action]

For an instrument object types is the intention that instrument failures such as OOR and comms fail, are to be reported in the OPC UA status for the instrument value/state? If so, in what conditions will the Fault and Fault Code be set? The fact that it is in the MDIS base object suggests that it could be set for reasons other than write failure, in the case of output devices. I think there needs to be more guidance on how the Fault and Fault Code will be used for all object types.