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 Considering Relationships between Operations in an Order

Use

Two activities from different operations can be linked by a time relationship that specifies a minimum or maximum time interval between the activity dates.

The system considers cross-operation relationships within an order only if you have specified this in the strategy profile. You can also specify if the larger planning-related minimum interval should be used for infinite scheduling , instead of the process-related minimum interval .

Integration

If time relationships are not considered during scheduling or rescheduling, the minimum or maximum intervals may be violated. If you want to display alerts in the Alert Monitor, for violated minimum and maximum intervals , you must use an appropriate PP/DS alert profile .

You can also create and change minimum intervals for planning manually or have them generated automatically by the system when creating planned orders.

See Processing of Planning-Related Minimum Intervals and Planning-Related Offsets

Prerequisites

The system only considers cross-operation time relationships if the following prerequisites are fulfilled:

  • You have maintained relationships between activities with minimum and maximum intervals.

    If there is a relationship between 2 operations, for which a minimum interval has not been specified in the source of supplyfor in-house production, the system uses the minimum interval 0.

  • You have specified in the strategy profile whether/in which area the system is to consider time relationships

  • You have specified in the strategy profile that the system should consider maximum intervals

    Note Note

    It can be useful in complex planning situations not to consider the maximum intervals so that the system can (more easily) find a solution in detailed scheduling, which can be used as a starting point for further planning.

    End of the note.

Features

Do not consider relationships

The system schedules or reschedules an operation without considering relationships. This means that the minimum or maximum intervals could be violated.

Always consider relationships

The system must schedule or reschedule an operation such that the minimum and maximum intervals are retained. If the operation has a relationship to an unfixed operation, the system must schedule or reschedule this dependent operation accordingly; for an unfixed deallocated operation, the system must adjust the dates and modes. A fixed dependent operation defines a fixed reference date for the minimum or maximum interval that restricts the scheduling or rescheduling of the operation. The system does not execute scheduling or rescheduling if it is not possible to schedule or reschedule the operation and its dependent operations accordingly, for example, if the resources are occupied.

Only consider relationships in the propagation range

Operations outside the propagation rangeare generally fixed during scheduling. This can mean a severe restriction on scheduling. With the consider relationships only in the propagation range option, you can schedule more flexibly, since the system does not have to consider a relationship between an operation in the propagation range and an operation outside the propagation range (see do not consider relationships ); the system can schedule or reschedule the operation in the propagation range without time constraints. However, the system must consider relationships between operations in the propagation range (see Always consider relationships).