Working with shift registers for finding index of threshold point.

[crossrulz]

In your FALSE case, you wired up the input tunnel.  It should be the one coming from the shift register.

[anupam2016]

Wired the ouput shift register with the input shift register for the false statement

Result:

The previous and the new values are the same. The subtraction shows 0 result.

heartbeat = infinty.

Thanks

[crossrulz · Accepted solution]

I think what is happening is your value is staying above the threshold for more than 1 sample, and therefore you are getting indexes that are right next to each other.  Since we only care about the rising edge for the sake of our calculations here, use a Boolean Crossing PtByPt to only perform the calculation when the threshold detector result goes from FALSE to TRUE.

[anupam2016]

Hi,

I tried implementing the Boolean crossing ptbypt VI. I wired the output of the threshold pt by pt into the input of booleancrossing ptbypt. I set the direction to false from true. The results were similar to previous tries. Both the shift registers gave same values, making heartbeat = infinite.

I also tried making the direction to true to false , but it gave no results. i.e: The shiftregisters seemed to not get updated.

Can you suggest me something else which I can try?

Thanks

P.S:I am uploading my modified VI.

[altenbach]

• Do you have a stretch of typical voltage data that we can use to play back and test? We don't have your instrument.
• Why the boolean crossing? Why don't you just check if the index has changed instead, that would ensure that the value differ and you don't get a division by zero.
• Your diagram comment is differs 180 degrees from the actual setting you use (true-false vs. false-true).
• How noisy is the data? Wouldn't it make more sense to analyze the threshold of the filtered data?
• Is this the established way to analyze that kind of data or did you come up with that?

[anupam2016]

Hello,

Will a TDMS file work. I am attaching it.

I was told to use boolean crossing, after number of tries.

The comment in the diagram is a mistake.

Noisy is present, but is negligible in contrast to the signal.

Similar logic is used in few videos where implementation is in MATLAB.

Thanks

[altenbach · Accepted solution]

Seems to work just fine. Did you set the threshold correctly?