Counters and performance-based plans

Time is a poor proxy for wear on a machine that runs three shifts one month and one shift the next. Performance-based maintenance ties the work to usage instead: operating hours, kilometers, cycles, liters. Contoso's winding machines wear with use, so the spindle overhaul is due every 2,000 operating hours, not every few months.

Measuring points, counters and readings

Usage is recorded on a measuring point attached to the technical object. A measuring point flagged as a counter only goes up (or rolls over), like an hour meter. Each reading is saved as a measurement document. In SAP GUI, measuring points are created with IK01 and readings entered with IK11; technicians can also record readings in the Perform Maintenance Jobs app. Contoso's winding machine 10000451 has counter OPHRS (operating hours) with an annual estimate of 6,000 hours.

How SAP turns usage into a date

Orders still need dates, so SAP converts usage into a planned date using the counter's rate. Before readings exist, it uses the annual estimate: 6,000 hours a year is about 16.4 hours a day, so 2,000 hours is roughly 122 days away. As real readings arrive, SAP recalculates from the actual usage. If the machine runs harder than estimated, the planned date moves earlier; if it stands idle, the date moves later. That is the point of performance-based maintenance, and also its weakness: without regular readings, SAP keeps projecting from stale data.

SAP's documentation recommends always setting a call horizon for performance-based plans, so the order is created with enough lead time to order parts. One rule to remember: a counter reading cannot be lower than the previous one unless the counter is replaced or rolls over, so a mistyped reading is not just wrong data, it can block later readings until it is corrected.

Combining time and usage

Some objects need both: a forklift every 250 operating hours or every 6 months, whichever comes first. That is a multiple counter plan, built from a cycle set that combines time and counter cycles with a link type ("or" means whichever comes first, "and" means both). SAP's documentation notes you cannot set a call horizon on a multiple counter plan; a preliminary buffer creates the order a set number of days before its start instead.

Where do the readings come from? At Contoso, the line 1 winding machines show operating hours on their control panels, and the shift lead records them every Friday. A future initiative may feed readings automatically from the machine controls, but the conversion keeps the manual process. Whichever way readings arrive, the test is the same: a reading must reach the right measuring point, with the right date and time, and move the plan as expected.