SAP-Centric Projects

Overview

Resources are an area of strength and weakness of SAP. Resource planning is actually a quite mature set of functions. Work centers contain the definition of capacities with their shift calendars, deal with labor or machines, and be associated with controlling (CO) standard cost rates by assignment of a cost center and internal service (activity type).  They are set up by SAP module, which means that a work center set up to be used in production planning (PP) or plant maintenance (PM) cannot be used in project system (PS). Work centers can be set up hierarchically.  

Their weakness is that they visibly were designed for the much more static PP system. Setting up master records or dispatching, even some of the reports, can seem quite cumbersome and disjoined from other scheduling tasks. Some of SAP work center front-end aspects resemble much more configuration screens or traditional mainframes than PC-based applications. The use of formulas in an often non-intuitive manner adds to this interpretation. It is a classical case where in the judgment of many users SAP's strong functionality is rendered impractical for daily use due to a lack of intuitiveness and flexibility.

Work centers can be assigned to PS WBS elements or to activities (PS) or operations (PM). This happens by entering work center ID and a related activity type into the activity or operation screen. If now hours or days are entered into the "work" and its unit field, capacity utilization has been planned and can be compared to the available capacity defined in the work center master record. Over- or underutilization can then be used as the basis for resource leveling.  

Activities or operations only allow to enter one resource (work center). SAP resolved this limitation through objects called "activity elements" (PS) and "sub-operations" (PM). Looking just like them and sharing all functions except scheduling capabilities, these are assigned to activities and operations respectively. By assigning one or more such activity elements or sub-operations multiple resources can be assigned.  SAP confirmation transactions allow to post actual hours against activities and their work centers and activity types, therefore also charging actual costs to them.

When interfacing with external systems like Primavera or MS Project or others, SAP work centers should always be the system of record for resource master records. One of the main reasons is that work centers are of such an integrated nature in SAP that it cannot be advised to trigger their set up from an external systems. Additionally external systems typically don't know the concept of a plant, which means that their ID should be prefixed with a plant ID.