Activating Availability Control 
Use
In the budget profile, you use Activation Type to define whether, and how, availability control is to be activated.
Features
There are three different activation types:
0 = Cannot be activated
If you chose background activation, you can activate Online Availability Control for a specific project.
Activities
When availability control is activated, the system does the following:
Determination of WBS elements carrying budget ("controlling elements")
Determination of associated assigned funds.
It checks the assigned funds against the controlling element budgets. The assigned funds can be on the budget-carrying WBS element, the lower-level WBS elements and their assigned project orders.
After activation, each posting to the project is checked by the availability control.
Note
As availability control affects system performance, you should activate it in the background for projects with less detail, only when you think that the budget may be exceeded.