My data set has three tacho channels how can I define the reference RPM
Selection of the tachometer used for order filtering is not possible in Audio Replay.
You must use Sound Diagnosis instead. In the playlist area, scroll to the right, and there is a column called "Tachos" where you can select the rpm trace to be used for order filtering.
In Audio replay, it just picks the "first one" in the list, which is random.
More about using Sound Diagnosis here: