Explains the cause of exception message 30.
Exception message 30 (Plan process according to schedule) appears in transactions MD04 and MD05 after running MRP but the causes are not clear.
Heare are 2 general causes with examples.
Cause 1: Today scheduling is carried out.
As showed in the screen shot above, the purchase requistion created has delivery date 06.11.2013 which is much later than the reservation's requirement date 08.10.2013, and it has exception message 30. The cause is as following.
MRP executes backward scheduling first from requirement date 08.10.2013 to calculates the release date of purchase requisition, this material has 30 days of planned delivery time only, so the release date is 08.10.2013 - 30 calendar days = 06.09.2013 which is in the past. But, the customization of MRP group assigned to this material doesn't allow past dates as below.
(Customization path: Transaction code OPPR, click button 'Start in past'.)
As the past dates are not allowed, MRP has to switch to forward scheduling from today to calculate new delivery date again as below.
Today + 30 calender days of planned delivery time = 06.11.2013 and shows exception message 30 to inform that today scheduling is carried out.
Cause 2: Firming MRP type:
If a firming MRP type is used in material master, e.g. type P1, this works with planning time fence to schedule the new proposals to the end date of time fence according to the attribute of firming type. MRP Types P1 and P3 are the ones which can make this kind of scheduling.
As showed in the screen shot above, the material has MRP type P1 and planning time fence 10 days, so the end date of planning time fence is today + 10 working days = 18.10.2013.
After running MRP, the purchase requisition created is scheduled to the end date of planning time fence and exception message 30 is raised to inform it.