Measurement System / Task / Process

Let’s consider a shaft, e.g. per particular drawing and version, together with let’s say 2 diameters, their runouts and a length between two faces. That would be the Measurement Task. Choosing (usually) one measuring device whose capability we want to verify defines the Measurement System (MS).

In some cases the MS can be more than one measuring device. This happens when the operator has several instruments to choose from, or typically in an in-line measurement, where the measuring operation is parallelized to two or more measuring devices.

If the same measurement task (the shaft, for example) is measured twice - once on a shop floor with one Measurement System and then in the laboratory with another MS, two separate Validation Acts are required. 

Also, it is possible that one Measurement System is being used with the same Measurement Task, but in different Measurement Processes.

For example we can use a particular measuring device to measure a particular part immediately after it comes from the machining process. Then we let the part to be cleaned and temperature stabilized, and we measure it again with the same device as before. These are two different Measurement Processes and require separate Validation Acts as well. If that is too costly - at least validate the worst case - if that case is OK, the better cases will be OK too.