In OPC UA we include a disable state that is designed to perform this function. I am aware that the latest version of 18.2 and IEC 62682 has removed disabled and have started to use Shelving for the same functionality . i.e. an Operator can shelve an Alarm (or group of Alarms) for an area of the plant that is shutdown. So the question is do we want to updated our model to support setting this state on a substate machine that is not available until it is in alarm state to be available always? the disabled state is a base state? this should be discussed.

the information model for alarm include statemachines that that are substate of the active state of the overall statemachine. the sub-states are not available unless the statemachine is active. we do have an enable/Disable state that is not in iSa 18.2 that allows an alarm to be disabled if an area of the plant is shutdown. It would be easier to updated the Enable/Disable to clear on some condition then to adjust the sub state machine - would this be an acceptable solution?

notes from UA meeting -oneshot is only for active alarms, timed shelving is for not currently in alarm- check to make sure description is correct - make sure appropriate error code - make sure text explains well enough.

Updated text to reflect TimeShelved can be applied to an inactive alarm and is maintained through alarm transitions.

Revised during review to include OneShotShelving.

Needs 1.03 and 1.04 Errata to close.

Agreed to 1.03 & 1.04 Errata in Virtual F2F.