Fixed Pegging and Net Requirements Calculation 

Use

In the net requirements calculation, the system can only reduce a non-fixed receipt element that is linked to a requirement via a fixed pegging relationship if the quantity of the receipt element is higher than the pegging quantity. If the receipt quantity is less than or equal to the pegging quantity, the system can neither reduce nor delete the receipt element to adjust it to the changed planning situation. The system regards the receipt element as if it were fixed.

Features

In the first step of the net requirements calculation the fixed pegging quantity is not included. Only the requirement, receipt, and stock quantities for which no fixed pegging relationships exist, are included in the net requirements calculation.

A receipt element that is not fixed and that is linked to a requirement via a fixed pegging relationships, can be reduced in planning in the net requirement calculation if the receipt quantity is greater than the fixed pegging quantity.  The pegging quantity that is assigned to a requirement via fixed pegging is regarded by planning as fixed. If the requirement increases or is not covered completely by the pegging quantity, then a new receipt element for the missing requirement quantity is created in the planning run.

Fixed pegging and periodic lot size

The use of fixed pegging for periodic lot sizes does not make sense for this lot sizing procedure. In the net requirements calculation, the result of fixed pegging is that the assigned receipt elements, such as planned orders, are regarded as fixed in the amount of the pegging quantity. If the requirement element increases, the system creates a new receipt element in the amount of the difference quantity, because the system cannot change fixed receipt elements. The result of this is that even for periodic lot sizes there may be more than one receipt element in one period. Because the assignment between the requirement and the receipt element is already specified by the period in this lot sizing procedure, an assignment by fixed pegging is not necessary.

Example

You have created a fixed pegging relationship with a pegging quantity of 50 pieces between a requirement and a receipt element.  The requirement quantity is 60 pieces, the quantity of the receipt element is 100 pieces.

You then carry out an MRP run. The net requirements calculation reduces the receipt quantity in the receipt element by 50 pieces (only the fixed pegging quantity in the amount of 50 pieces is retained). Planning then creates a new receipt element in the amount of 10 pieces with which to cover the requirement of 60 pieces.