Time KPI’s may depend on external parameters that are not available in the machine tool controls. For this reason, relevant statuses are presented rather than absolute time values. To determine the time KPI’s, the status duration must be measured. For complex time KPI’s, the value results from measuring the combined duration of multiple relevant statuses.

General: Determination with the use of status variables

This specification provides two StateMachinesin the MachineOperationMonitoringType:

Both the above data types are defined in OPC 40001-1 (from version 1.02 onwards)[2]. Both objects each contain a CurrentStatevariable that represents the current state.

General: Determination by means of Events

Production jobs are modelled as objects of the type ProductionJobType. The objects are stored as a list in the ProductionPlanvariable of the type ProductionType.

The current status of the production job is represented in the Statevariable of the ProductionJobType. Stateis of the type ProductionJobStateMachineTypeand sends an event of the type ProductionJobTransitionEventTypewith every state change. When processing these events, the variable Statecan be used to determine the current state by evaluating the respective value ToState.

In case of an interruption, an event of the type InterruptionConditionTypecan be sent. The type of interruption can be classified using the variables ConditionClassIdand ConditionClassName.