The purpose of this page is to clarify the understanding of the system logic regarding activating/deactivating the availability check in R/3 documents.
The availability check can be set on/off in the requirement class and schedule line category. For system carry out the ATP check in a document, Av.Check should be ON in both requirement class and schedule line category. The requirement class is assigned to the requirement type that is determined in the document. The schedule line is determined depending on the Item Category and MRP Type. In this Wiki I will illustrate the way that system looks to determine if the availability check will or not be carried out in the document.
System checks if Material Master has Availability Check group assigned
In OVZ2 this Availability Check group should not have "No check" set
Path 1 -> determine the Requirement Type by the Strategy Group of the Material Master
System looks for the Strategy Group of the Material Master in tab MRP3
Then looks in OPPT, get the Main Strategy. In OPPS system gets the Requirement Type and Requirement Class:
In OVZG system checks if Availability Check is set:
If there is not Strategy Group in Material Master , system goes to Path 2.
Path 2 -> determine the schedule line and the Requirement Type if no Strategy Group exists for the Material Master
System takes the Item Category Group (Material Master tab Sale: Sales org 2) and the Sales Order Type to check in VOV4 the Item Catergory that will be determined:
Then in VOV5 with the Item Category and the MRP Type (Material Master tab MRP1) system determine the schedule line category.
In OVZ8 is informed if the schedule line Availability Check is set.
For the Requirement Type, system looks in OVZI using Item Category and MRP Type. If Orign = 1 (Item Category and MRP Type) system will consider the Requirement Type from OVZI. Otherwise system will first look for Path 1.
If Availability Check is ON in Requirement Class and Schedule Line Category then Availability Check will be carried out in the document.
SAP Note 207942: MRP: Problems with requirements from sales order/delivery