Backward Scheduling for External Procurement
Use
For materials that are planned according to the MRP and forecast-based planning procedures , the requirement dates in the future are known. The materials must be available by these dates. The release date for the purchasing department is calculated during scheduling, that is, the date by which the materials must be ordered so that they are available for the requirements date.
Process Flow
The system starts with the requirements date and then schedules backwards to determine the release date of the purchase requisition (order start date of planned order, which is to be procured externally).
In MRP and forecast-based planning, the system always uses backward scheduling procedures to calculate the basic dates. Only if the start date that is calculated in backward scheduling happens to lie in the past, will the system automatically switch to forward scheduling .
Note
If you do not want the system to switch to forward scheduling automatically, you can specify per plant in Customizing for MRP, in the IMG activity
Parameters for determining the basic dates
that the system is to continue the backward scheduling calculation even if the resulting start date lies in the past.