Glossary · MES and ISA-95
Work calendar
Also known as: Shift calendar
German: Arbeitskalender
In ISA-95 / IEC 62264 object models, a work calendar defines time periods and their attributes, such as shifts, breaks, holidays and planned shutdowns, which can be associated with personnel, equipment and other resources for scheduling and performance calculation.
- MES
- Standards
In one sentence
In ISA-95, a work calendar defines shifts, breaks, holidays and shutdowns that are linked to resources for scheduling and performance analysis.
Example
The work calendar of packaging line 4 defines two shifts on weekdays, no production on Sundays and a planned shutdown in the first week of August.
How it applies
- Planning: Detailed scheduling uses calendars to place orders only into times when resources are available.
- Performance analysis: KPIs such as Overall equipment effectiveness (OEE) depend on planned production time, which comes from the calendar.
- Engineering: Calendars are maintained in one system and shared, so that MES, maintenance and ERP use the same time model.
- Documentation: User documentation should explain who maintains calendars, how exceptions such as extra shifts are entered and how they affect schedules and KPIs. Calendar changes can shift planned production time and therefore KPIs, so the documentation should also say whether historic figures are recalculated.
Work calendar vs. schedule
A work calendar defines when resources can work. A schedule defines what they should do in that time.