Calculating KPIs
The formulas for calculating KPIs, and the KPI elements (ISO_22400) used in those formulas, are described in the following sections.
KPI Elements
The following elements are used in the KPI calculation formulas:
• GQ (good quantity)—The produced quantity that meets quality requirements.
• PQ (produced quantity)—The quantity that a work unit has produced in relation to a production order.
• APT (actual production time)—The actual time during which a work unit is producing. Calculated as the time spent in the following statuses: Warning + Running.
• PBT (planned busy time)—The planned operation time minus the planned downtime. Planned downtime can be used for planned maintenance work. The planned busy period is the time available for detailed planning of the work unit for expected production orders. Calculated as the time spent in the following statuses: Warning + Running + Unplanned Downtime + Unavailable.
• PRI (planned run time per item)—The planned time for producing one quantity unit, also known as the "ideal cycle time". Calculated as 1 divided by the ideal run rate for the item (1/ideal run rate)
The services that calculate these KPI elements are defined on the KPI element Thing Shape (PTC.SCA.SCO.KPIElementThingShape).
Availability (A)
Availability is the ratio of the actual production time to the planned busy time for a work unit, for a given period of time:
APT/PBT
This KPI indicates how much of the capacity of a work unit is used for production in relationship to its available capacity. Availability is also known as the "degree of utilization" or "capacity factor". The unit of time for this calculation is minutes. If the PBT is zero ( 0 ), then the availability is 1, or 100%.
Effectiveness (E)
Effectiveness is calculated as the planned run time per item multiplied by the produced quantity, divided by the actual production time:
PRI*PQ/APT
This KPI indicates the relationship between the planned target output and the actual output for a given period of time. The unit of time for this calculation is minutes. If the APT is zero ( 0 ), then the effectiveness value is 1, or 100%.
Quality (Q)
Quality is the ratio of the good quantity (GQ) to the produced quantity (PQ) for a work unit, for a given period of time:
GQ/PQ
This KPI can be used as a real-time indicator of the work unit’s level of quality. If the PQ is zero ( 0 ), then the quality ratio is 1, or 100%.
Overall Equipment Effectiveness (OEE)
Overall equipment effectiveness (OEE) represents the availability, effectiveness, and quality for a work unit, for a given period of time, all integrated into a single indicator:
A*E*Q
This KPI forms the basis for improvements by better production information, identification of production losses, and improvement of product quality by optimized processes.
Customizing KPI Calculation
You can customize the calculation of the provided KPIs on the Thing Templates used for equipment types, as well as on individual equipment Things. To customize the calculation of KPIs, override the KPI calculation services and KPI element calculation services on the Thing Templates or Things:
• KPI calculation services:
◦ Availability_Calculate
◦ Effectiveness_Calculate
◦ OEE_Calculate
◦ QualityRatio_Calculate
• KPI element calculation services:
◦ actualProductionTime_APT_Calculate
◦ goodQuantity_GQ_Calculate
◦ plannedBusyTime_PBT_Calculate
◦ plannedRunTimePerItem_PRI_Calculate
◦ producedQuantity_PQ_Calculate