During the material availability check, the system makes sure that requirements are covered by stock or by planned receipts. You can therefore recognize at an early date, for example, when creating the sales order, whether a material will be available for the requirements date or whether you have to make extra planning arrangements to guarantee material availability. Using the material availability check contributes towards increasing the accuracy of planning and the service level for creating sales orders as well as for the internal production process.

The availability check using ATP logic is a cross-application component. It can be accessed from the business application areas listed below:

• Sales and distribution (SD-SLS)
  You can check whether the material is available on the desired delivery date when creating sales orders and also when creating delivery notes.

• Planned order processing
  You can execute the availability check for the components of a planned order. This may be necessary when converting the planned order into a production order or beforehand, if you want to make sure that the necessary material components are available for the production of the finished product.

• Production order processing (PP-SFC)
  When processing production orders, you can check whether the necessary material components are available for production of the finished product.

• Inventory management (MM-IM)
  When creating or changing reservations as well as at goods issue, you can use the availability check to ensure that a goods movement will not jeopardize the availability situation of other issue elements already created and checked in the system. A missing parts check can be run at goods receipt.

During the ATP quantity calculation, the system checks that all issues are covered by existing receipts and whether quantities are left over to cover new issues. These quantities that have not yet been assigned constitute the ATP quantity.

The calculation proceeds as follows:

• The receipts (warehouse stock, planned orders, purchase requisitions) are dynamically allocated to the issues (customer requirements, planned independent requirements, reservations), which lie directly after them on the time axis. The calculation is carried out in such a way that the issue is allocated to the receipt that lies nearest to it and that still has a positive ATP quantity.

• If the ATP quantity of this receipt does not cover the issue then the system will search for and check the next nearest receipt (always in a backwards direction) for a positive ATP quantity, which will then also be allocated to the issue.

• If receipts do not cover the issue, you must then decide whether you reduce the requirements quantity as necessary or whether you move the requirements date so that requirements coverage can be reached again.