Extracting Events from One Signal, applying Time to Another

[John Huxtable]

I have speed data from two fans. I use a formula to calculate the difference between them and event isolation to determine times when this difference is greater than +/- 30 rpm.

I then wish to use the associated time stamps to observe the vibration responses when the fan speed difference is greater than +/- 30 rpm.

The raw data are in separate signals but all have the same time base. I am using version 8.0.24 standard

[John Huxtable]

I have speed data from two fans. I use a formula to calculate the difference between them and event isolation to determine times when this difference is greater than +/- 30 rpm.

I then wish to use the associated time stamps to observe the vibration responses when the fan speed difference is greater than +/- 30 rpm.

The raw data are in separate signals but all have the same time base. I am using version 8.0.24 standard

[Bernhard Kantz]

For this you can use the index operator.

Example:

Dim idx = ValuesInInterval(Speed1 - Speed2, -30, 30, EVENT_INDEX + EVENT_COMPLEMENT)
Speed1.X[idx]

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[John Huxtable]

I think I see how that gets me the time stamps in “speed1” but how do I apply this to “response1”?

[Bernhard Kantz]

If you have a FPScript formula IDX which calculates the indices you can create an additional formula. This formula creates a signal with the y-values of the data set ‘response1’ and the x-values of ‘speed1’.

Signal(response1[IDX], speed1.X[IDX]

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