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May 14, 2016 at 02:34 PM

Schedule PM order operations with relationships of type SS and negative interval


I have been dealing with a situation in which SAP order scheduling is not working properly. Here it is:

I have two PM orders that must been related to each other in such a way that the first one must begin exactly 7 days before the second one. So, if the second order is rescheduled to a couple of days after its current programming date, the first one must be postponed as well.

For Example:

Order A:

Schedule Type: Forwarding

Base start date: 05-14-2016

Operation 0010 planned date: 05-14-2016

Order B:

Schedule Type: Forwarding

Base start date: 05-21-2016

Operation 0010 planned date: 05-21-2016


Order B [0010] ------> (SS -7D) Order A [0010]

In order to this happen, I figured that I must create a SS relation between the main order (the one that leads the beginning of the other one) and the secondary one. The interval in that case is going to be 7 days in the past. If I invert the direction of the relation as well as the sign of the interval, I won't get the scenario I need, because the order A is not going to move along with the order B, just the other way around.

So, If I have a situation like this, the scheduling works fine. If I change the base start date of the order B to X days ahead, the programming dates of order A are going to be postponed by X days too.

The problem is when I start with the two orders having the same base start date. Suppose that Order B has base start date 05-14-2016, the same as Order A. In that case, the scheduling process does not postpone order B by 7 days so that the constraint provided by the relationship with the order A be accomplished. What the system tries to do is programming order A to seven days before the start of order B, but such date (05-07-2016) lays in the past, which prevents the scheduling to perform its execution with success.

What can I do to accomplish the outcome I want?