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
- MachineryItemState(MachineryItemState_StateMachineType) to represent the machine status in terms of production and technical availability (error status).
- MachineryOperationMode(MachineryOperationModeStateMachineType) to represent the operation mode (production, order-related setup, general maintenance).
Both the above data types are defined in OPC 40001-1 (from version 1.02 onwards). Both objects each contain a CurrentStatevariable that represents the current state.
General: Determination by means of Events
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.