Enforce Phase/CT Estimate Limit check box on the Info tab of the PO Company Parameters form.

Select one of the following options from the drop-down list related to limiting PO entry:

No Limit Enforcement - No restrictions will be made to PO entry when a job phase and cost type would go over budget

Warning Only - Users will only receive warnings for PO entry that would cause a job phase and cost type to go over budget

Prevent Post/Interface - Users will be prevented from posting a PO when it would push the estimate associated with the phase and cost type over budget