I am discussing here some basic understanding and configuration of Availability check for sales order.
Most of the cases of SAP sale order we need availability check except few like third party, return orders, etc..
Availability check are of three types.
1:- ATP check :- Availability to promise . The sales order will confirm on first come first serve basis. It includes current stock, inward movements and outward movements of the material. like physical stock, planned goods receipts against PR, PO, PIR, , safety stock, stock in transit etc.
2:- Product Allocation :- It works upon predefined rule based on Product allocation procedure, with parameters like customer statistics groups, material statistics groups, statistics groups of sales doc types, item categories, standard info structure S140 or a self-defined info structure etc..
3:- ATP Check against production forecast:- The availability check will perform against Planned Independent Requirement.(PIR)
For ATP check we have following basic setting .
a):- Define Requirement Class and activate Availability check and requirement check box.
b) Define requirement Type and assign Requirement class to it.
c) Determination Of Requirement Types Using Transaction :- here you can define how requirement type will determine
i.e based on i) Material master strategy, then item category and MRP type ( from material master MRP 1 view)
ii) Item Category and MRP Type ( from material master MRP 1 view) or
iii) both : as 1, with check for allowed requirement type
d) Activate Availability check and requirement in Schedule line category with tcode ;VOV6
e) Define Checking group and put the value in total sales and total delivery as A ,B,C or D, in which way you want to see the MRP in MD04 . Like the sales order will send individual sales requirement or for whole day or for whole week like that.
Then check the box "Block Qty RQ" if you want the sales order qty should block for that sales order. else it may happen over confirmation.
Please don't check "NO Check " check box. else it won't check for availability check.
And put value 1,2,3 in Accumulation as per requirement. and response column.
Define Material Block For Other Users;- so same time different users won't use the same material or edit the material master. which may conflict the availability check.
f) The checking rule for sale order is hard coded as A and for delivery is B.
g) Now assign the checking group to the material master MRP3 view, and Sales/General view.
h) Now do the setting for carry out control for availability check in OVZ9 . Like for which transactions you want to includes in availability check. it may purchase orders, Purchase requisitions, sales req, deliveries. reservations, independent req, safety stock, stock in transit, block stock, restricted stock etc.
please click on check without RLT. else sales order will get confirm on the RLT days mentioned on material master beyond material available or not.
Now when you create the sales order availability check will carry out for the material confirmation.
Hope it will help you to understand the basics of Availability check.