My recent article, “Maintenance Plans: What do all the fields mean?”, generated two very good questions from reader Nigel Wilson, who wants to further understand how a maintenance plan functions. Here are answers to those questions.
Q: What is the relationship (if any) between shift factors and tolerances? Are they used in conjunction with each other or separately?
A: Shift factors and tolerances can be used in conjunction with each other or they can be used separately. The screen shots illustrate how this is accomplished.
Tolerance defines late or early completion time period and the impact it has on the plan schedule: (+) tolerance is set for late completions and (-) tolerance is set for early completions.
The shift factor is the percentage of shift that a plan can move if not completed on time. For example, if a maintenance plan is due Sept. 1, but the work is not confirmed until Sept. 5, the shift factor will determine the next plan due date. A100% shift on a monthly plan will move the due date to the exact day in the next month that the work was confirmed in September (in this case, Oct. 5). A 0% shift will not allow the plan to move the due date. The order was completed Sept. 5, but the due date is on the first of every month, therefore, the next due date will be Oct. 1.
To use the shift factor and tolerance together, the principals are still the same. However, you are now taking the percentage of the shift factor into account with the completion from the tolerance. The images above illustrate how the plan change date changes with a 100% shift factor and doesn’t change with a 0% shift factor.
Q: How do shift factors and tolerances handle multiple cycles on a maintenance plan?
A: Tolerances and shift factors react the same in single-cycle and strategy plans. Settings should be set at the strategy level, then they will carry over to each individual maintenance plan when it is created. To avoid this situation, you may also want to maintain hierarchies in the maintenance strategy against each pack, if you haven’t already done so. MT
Kristina Gordon is SAP PM Leader, DuPont Protective Solutions Business and SAP WMP Champion, Spruance Site, Richmond, VA. If you have SAP questions, send them to email@example.com and we’ll forward them to Kristina.