Conditionsare Objectswhich have a state which changes over time. Each Conditioninstance has a ConditionIdas an identifier which uniquely identifies it within the Server.

A Conditioninstance may be an Objectthat appears in the Server Address Space. If this is the case the ConditionIdshall be the NodeIdfor the Object.

The state of a Conditioninstance at any given time is the set values for the Variables that belong to the Conditioninstance. If one or more Variablevalues change the Servergenerates an Eventwith a unique EventId.

If a Clientcalls Refreshthe Serverwill report the current state of a Conditioninstance by re-sending the last Event(i.e. the same EventIdand Timeis sent).

A ConditionBranchis a copy of the Conditioninstance state that can change independently of the current Conditioninstance state. Each Branchhas an identifier called a BranchIdwhich is unique among all active Branchesfor a Conditioninstance. Branchesare typically not visible in the Address Spaceand this standard does not define a standard way to make them visible.