Calculating Net Requirements

The planning run is carried out at plant level. Before calculating net requirements, the system determines available warehouse stock. For all storage locations which belong to this plant, which are not excluded from MRP, and which are not planned separately (see Storage Location MRP), the following list of individual stocks are grouped together to make up the total plant stock:

• stock which has been valuated and which can be used without restriction

• stock in quality inspection

• consignment warehouse stock which can be used without restriction

• consignment warehouse stock in inspection

This stock is then used in the net requirements calculation.

The system also takes all the receipts and issues for a material into account. Receipts include, for example, planned orders or purchase requisitions whereas issues, may be sales orders or reservations.

After making a note of all the receipts and issues, the system makes a check to see whether the requirement is already covered by another receipt or by several receipts. If the requirement is is not already covered, the system then calculates the shortage quantity. The quantity to be produced or procured is calculated during lot sizing (see Lot Sizing)

In the net requirements calculation, a difference is made between reorder point planning, forecast-based planning, and MRP.

Calculating Net Requirements for Reorder Point Planning

Calculating Net Requirements for Forecast-Based Planning