Why ATP quantity for outbound delivery becomes negative?

[Former Member]

Hi,

In our case, ATP check for outbound delivery only considers deliveries and material reservations. But somehow in CO06 we found one material's ATP quantity is negative. According to our checking rule, it is only possible that we make some GI manually, for example 201 by MB1A, then the ATP quantity could become negative.

But in MB51, we can only find GI material documents with 601, then it means there is only GI by outbound deliveries.

Why the ATP quantity would become negative?

Thanks!

Wesley

[Former Member]

Hi Wesley,

In CO06, you will see the sales order also those are created in the system and they also reduce the soft committed qty from the available stock.

Negative would mean an indicator to the MRP that so much of qty. is short. SO if the available qty is 10 and i create a sales order for 15, it would show -5 as ATP.

[Former Member]

Hi, Arijeet

If we use checking rule A, then we can see sales order that will reduce committed qty as you said.

But for outbound delivery, checking rule B should be used, and we have set checking rule B not to consider sales order, but only deliveries and material reservations.

So generally, if ATP qty is not enough, then committed qty in delivery could not be entered.

So we wonder what kind of action can make ATP qty negative.

[Former Member]

Hi, all

I've found where the problem lies in.

When we are creating an outbound delivery without saving it right away, we create another outbound delivery which contains the same material as the first one. Then committed ATP qty of one delivery will not consume the total ATP qty while the other delivery taking ATP check.

So if committed qty of both deliveries is lower than total ATP qty, but the sum of qty of both deliveries exceed total ATP qty. We'll see that both deliveries pass the ATP check, but negative ATP qty occurs.

To solve this problem, we set use soft block or hard block to the material in SD documents. Then negative ATP qty will not occur in this way.

Wesley