Understand availability

The availability component of OEE measures a system's availability during the scheduled operation time for a given time period, based on the following equation:

Availability = Runtime / Net Operating Time

Entity Availability

In MES, a line’s availability is based on the availability of the line’s bottleneck entities during the given time period.

To support the determination of entity availability, utilization events are applied to each entity. A utilization event indicates the current operational state of the entity. Utilization events can be applied automatically based on an entity's default utilization settings (see Configure the default utilization reasons for standard events) or manually by an operator.

The component of a utilization event that is used to determine entity availability is OEE Use. Each utilization event, via its utilization reason and that reason’s assigned utilization state, is assigned an OEE Use value of Runtime, Downtime, or Neither. MES bases the calculation of an entity’s availability by summarizing the duration of its Runtime and Downtime events in the given time period for each OEE Use. Events with an OEE Use value of Neither are not included in the calculation.

So for MES, an entity’s availability is:

Entity Availability = Runtime / (Runtime + Downtime)

Line Availability

To determine a line’s availability, the system considers the Runtime and Downtime events for any entities that were designated as bottleneck entities during the given time period. This includes all entities at a bottleneck entity position in the line. Only those portions of the events that fall within the time frame in which the entities were designated as a bottleneck entity are included.

So, a line’s availability is:

Line Availability = Bottleneck Entities Runtime / (Bottleneck Entities Runtime + Bottleneck Entities Downtime)

In addition, for a fixed or moving bottleneck entity in a line, if the utilization source is obtained from another entity outside the line, then the utilization data is retrieved from the entity that is outside the line.