Purchasing is a component of SAP MM module and its process can be roughly depicted in below diagram.
MRP (material resource planning) creates procurement proposal and later gets converted into Purchase Requisition. Next step is assigning source to Purchase Requisition, and release of Purchase Requisition. The PR gets converted to Purchase Order and upon goods receipt an invoice receipt can be done to complete the purchasing process. Additionally payment is processed (in FI module).
Procurement doesn't have to start by the MRP, it can be initiated by consumption based planning or by direct creation of PR or PO.
MRP is a system function to determine the material requirements on both the material and BoM level. A BoM (Bill of Materials) is a list of components and subcomponents a single material is consisting of.
One of the mere basic documents in Purchasing in SAP is a purchase requisition.
Purchase requisitions can be created automatically by system or manually. They can be converted in purchase orders but only upon release (approval of purchase requisition).
We will cover several topic in this leson that can help understand and create the purchase requisition.
Number ranges in purchase requisitions are required just as in other document, for the purpose of assigning the document number to new created documents.
Later, these number ranges are being assigned to different document types we can define to be used in purchase requisition processing.
We will also cover requirement tracking number which is basically a number/letter combo which can be uniquely assigned to multiple documents in order to track certain important requirements.
You will se how the source determination works and why it's useful, as well as how this source can be assigned to our purchasing document.
Finally, you will find out how to process the purchase requisition, from its creation until converting it to a purchase order.
Number ranges for Purchase Requisition
Assigning of number ranges for purchase requisition works on document type. Several different number ranges can be created and afterwards assigned to a specific purchase requisition type.
This is done in customizing. Requisition document types can have two number ranges assigned. One internal and one external range are assigned to each document type. Internal number ranges are being automatically incremented by the system, and external are assigned manually.
Screen below represents a list of number ranges for purchase requisition.
From number is the first number in the range, To number is the last available number adn the current number is the last assigned number to a document.
In addition, there is a check box indicating if this is an external number range.
For example, an internal number range can be defined as a range from 20000000 to 30000000, in this case documents of the document type that is assigned this interval will be numerated starting from 20000001 and will be incremented by 1 for each new document created. The last number available for this interval will be 30000000, and if your documents fill up the entire number range it has to be extended. It will rarely happen as it would mean that you would have 10 million purchase requisition documents.