Torsional vibration offset angle

Hi everyone!

I'm doing some torsional analysis on our engine and I've encountered the following problem: in "Measurement", in the "Torsional Vibration" setup, before starting the recording, I

click on "Zero" to cancel the "offset angle". Then I check the box "use for torsion angle wrap around" and start the recording.

During "post-analysis", however, I find a residual offset as in the first image. If I reset (clicking on zero again) and recalculate in analysis, I get a new offset value as in the second image.

After each recalculation, the graph of the time-vector transform of the torsion angle changes and I don't know which graph is the right one.

I use the 2021.5 version for analysis.

Thanks to anyone who can help me.

Hi,

Option Zero should be used only before/during measurement, not during Offline math.

In the section “Angle offset” you see the angular difference between the two sensors. 

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When you click on “Zero”, you remove this static offset. The current average value of the signal will be subtracted. 

In Offline math, the offset will be calculated from data in the buffer. Therefore, you get different offset values when you recalculate.

We should lock this option in Offline because it should be used only before measurement.