extracting data at particular instants from chart

[netra]

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extracting data at particular instants from chart

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‎06-15-2013 06:07 AM

Hi,

I have a labview program that gives me real time frequency and mass values and is working fine. Now I'm trying to modify this program and get mass at particular instants. I have attached a picture that roughly shows which values from my waveform chart I want to extract.

So here, A and B are reactants and each pulse is made up of user defined dose and purge times( in sec) . 'EA' is the extra purge time after pulses of reactant A.

I want to extract data at the circled instants in the picture i.e one second before the current pulse ends in two files for reactant A and B respectively

I have tried doing this but it is getting me nowhere near the result

I don't know what to do now. I have attached my VI

and have written comments in the required part. I hope I have explained my logic clearly. ( big chance that my logic itself is wrong )

I hope I have made my question clear.

Please suggest something! I am completely lost.

Thanks in advance!

[netra]

Hi,

I have a labview program that gives me real time frequency and mass values and is working fine. Now I'm trying to modify this program and get mass at particular instants. I have attached a picture that roughly shows which values from my waveform chart I want to extract.

So here, A and B are reactants and each pulse is made up of user defined dose and purge times( in sec) . 'EA' is the extra purge time after pulses of reactant A.

I want to extract data at the circled instants in the picture i.e one second before the current pulse ends in two files for reactant A and B respectively

I have tried doing this but it is getting me nowhere near the result

I don't know what to do now. I have attached my VI

and have written comments in the required part. I hope I have explained my logic clearly. ( big chance that my logic itself is wrong )

I hope I have made my question clear.

Please suggest something! I am completely lost.

Thanks in advance!

[JKMM]

Find the delta t (time) between samples, create a lossy queue with the number of elements equal to the number of sample points in a second.  Write every data point to the queue, and detect the pulse with a slope threshold.  When you detect the next pulse, read the overflow element from the queue and that will be your sample point at pulse-1sec.  I have attached an example that shows this in real-time using programmatically generated data.