Understand frequency type shift

If a sample plan frequency is configured to generate future samples for a shift, the active QM specification using this frequency generates future samples up to the end of the shift. If a QM specification becomes effective during a shift, samples are generated based on the shift frequency definition, but no samples are generated in the past.

Shift samples are calculated based on the following:

• The shift start and end times.

• The frequency configuration options of start offset and end offset.

• The time between samples and number of samples.

The first sample is based on the shift start time and the start offset setting. No samples are generated at the end of the shift minus the end offset time.

• If the number of samples is provided and the time between samples is not provided (Null), then the available shift time is split equally among the number of samples. For example, if the number of samples is 1, then only the first sample is created. If the number of samples is 2, then only the first and final samples are created.

• If the time between samples is provided and the number of samples is not provided, the first sample is created and future samples are created adding the time interval until the end of the shift.

• If the number of samples and time interval are both provided, the first sample is generated. The following samples are generated by adding the time between samples to the previous sample time. If the number of samples is small enough that this number of samples is reached before the end of the shift, the set of samples in this shift ends early. Regardless of how large the number of samples becomes, though, no samples are generated beyond the shift end.

For more information, see the MES Client User Guide or online help.