Visualising data collection

[PPPlllld]

Not sure if someone has asked this. But I was working on a project that hope to visualise the data collection process, i.e. seeing a waveform in real time, I am able to collect some data as long as I want it to but just hoping to see if it is possible to visualise the whole thing during the process. 

Thanks in advance.

[JColvin]

Hi @PPPlllld,

I'm not certain what you mean by visualizing the data collection process that is different than your other post here.

Are you wanting to see each individual data point get slowly populated as they are sampled? Or are you looking for something more along the lines of seeing a change on the oscilloscope view as a measured sine wave changes to a triangle wave? (or the equivalent for digital data)?

Both are feasible to achieve, though both inherently require very slow sampling rates so that the human eye (and the computer monitors refresh rate) can show this change in data.

Or by visualize data collection, are you looking for something a lot more granular, i.e. seeing the ADC measure the analog voltage and then break it down to the binary representation to then calculate what the measured value actually represents?

Thanks,
JColvin

[PPPlllld]

It's like the digilent scope version (some sort of line plot to visualise the change) where the plot appears when they got sampled, liked the repeated or shift sampling mode. Are there any samples we could take a look at? Thank you.

[attila]

Hi @PPPlllld

See WF SDK/ samples/ py/ AnalogIn_ShiftScreen.py

[PPPlllld]

Sorry, I realized in shift mode, the data recorded are not completed newly recorded, there are some overlaying, which I understand. How can we calculate which part is newly collected data, if let's say I collected 8000 sampling rate with 8000 samples each run. 

I saw on the waveform app, in the record mode, it enables draw while recording in the config button, how can we use this functionality in python to do it real time? Thanks

just one more question from me, is there any accurate time representation of each datapoint when it is collected, now I am estimating it, based on sample size and sampling rate, was just wondering if there is anything built in. Thanks.

[attila]

Hi @PPPlllld

See the AnalogIn_Record...py examples

You can use the FDwfAnalogInFrequencyGet to know the exact sample rate. The FDwfAnalogInFrequencySet may be rounded to the most appropriate supported value, integer division of system frequency, like 100MHz/N
You can use trigger IO for synchronization or with ADP3X50 FDwfAnalogInStatusTime returns the device timer at trigger point. This is probably more useful for single/repetitive captures.