Method to check the synchronization of output of two devices.

[GoviRe]

Hello,

I want to check the synchronization of outputs of two different devices measuring pulse signals.

Can someone suggest me a method to check the synchronization between the outputs of two devices measuring pulse signals.

Thanks.

[muks]

What is the device? How have you connected it?

[GoviRe]

They are pulse sensor devices each has an output from photodiode.I am reading data from two devices using two different channels of DAQ at same sampling rate.

[Dennis_Knutson]

Do you mean you have two separate DAQ devices or two sensors? What sort of synchronization check? For a single DAQ device, do just wish to know the inter-channel delay?

[GoviRe]

Hello,

I want to check the synchronization between the output pulse signals of two devices.

I tired (shown in the attached image)like this 1)sampled both signals with different ,(2) DAQ channels at 500Hz and collected 5000 samples(10 secs data) then measured the frequency present in 10 secs data and 3)mtultipled the frequency obtained with 60 to get the Heart Rate(BeatsPerMinute).

Can someone exaplain me 1)if this the right of way or is there any other better method to do this.

2)I dont understand why the measured amplitude od Device2 is showing 1.23V whereas the graph shows a value of 3.5V.

3)Also can I know how to plot the (realtime)measured HR of both devices in a single figure.so that I can see how they are chaging.

Thanks.

[Dennis_Knutson]

You haven't shown the most important part - the actual acquisition. I don't understand the conversion to dbl and then waveforms when you can directly convert to waveform from dynamic data.

I never use express VIs or the evil dynamic data so I really don't know the collector VI.

Simply building an array of waveforms will allow display on a single graph.

[GoviRe]

Hello Dennis_Knutson,

I attached the vi. 

You asked : I don't understand the conversion to dbl and then waveforms when you can directly convert to waveform from dynamic data.

  But when I connected collector vi in between DAQ acquired data and build waveform vi it is automatically uses DBL .

Can someone if this is the right way to do it  or  is there any other better method to do this.     

Thanks.   

[A.E.M]

Hi GoviRe

You can change the output of the "Convert from dynamic data" by double-clicking on it. Try to change the output to "Single waveform".

I'm not sure what you are trying to achieve. If you want to compare the two signals, you can actually subtract one set of data from the other to find the amplitude difference. However, if there's a phase shift between the two, you have to make sure to account for the phase shift.

How Can I Determine Phase Mismatch Between Two Channels?

I would recommend you to try and google "LabVIEW compare signals" as we have many examples and users asking help for similar things.

We also have the NI Example Finder (Help => Find Examples). Maybe you can have a look at the VI called "Limit Testing Measurement".

[GoviRe]

Hello,

Can someone explain of how to plot the frequency values obtained from two "Extract single Tone Information.vi" in single graph after every 5seconds(sampling at 500hz, so collection of 2500 samples equals 5 secs)  so that the frequency varying of two devcies can be analysed in realtime.

Thanks.

[Dennis_Knutson]

Connect the values to a chart after bundling them together.