The basic scheduling of a planned order is usually backwards. From the requirements date, the system counts back the in-house production time of the material, as defined in the material master, and thus determines the basic start date. The basic finish date is the same as the requirements date.
When the basic start date would be in the past and this is not permitted by the settings in Customizing, the system automatically switches to forward scheduling for basic scheduling and plans the order with the basic start date today. In the MRP list and the stock/requirements list, the system indicates such orders with exception message 30 Plan process according to schedule .
The subsequent lead time scheduling using the routing determines capacity requirements and production dates according to the settings in Customizing. Scheduling adapts the basic start or finish date, if necessary. Lead time scheduling usually schedules backwards from the basic finish date.
If the times in the routing are considerably shorter than those in the material master, the following situation could have arisen up to now: the calculated production start date was further in the future than necessary. The above-mentioned exception message was displayed, and the order was proposed for postprocessing even though it could have been produced on schedule by the requirements date.
The new process provides for the following:
When backward scheduling is entered as the scheduling direction in Customizing for Lead Time Scheduling, the system overrides Customizing and switches to forward scheduling. The basic finish date is adapted and the proposed basic start date remains the same.