Logging of frequency from "Measurements" screen vs time

[Bar]

Hello,

    Is there way to record average frequency vs time of a square pulse measurement? I am reading a signal from a flow meter and can see the frequency in the "Measurements" section, but I would like to log the frequency as it changes over time. ie, I would like to record the flow meter rate over time. Also, would there be a way to count all of the pulses? (the measurement is for 10s to 15s)

Thanks

[attila]

Hi @Bar

You could use View/Logging/Script for custom export.
Perform a longer Record and use Measurement statistics, cursors... or custom Math channel similar to the Example/RPM

[Bar]

Thanks @attila,

   I got it to work using your View/Logging/Script suggestion and adding the last line below. Can you let me know how to do the following:

1. Append a time stamp to the CSV file for each measurement.

2. Change the rate at which the measurements are logged. (How often is each measurement made by default?)

 

FileAppendLine("~/Desktop/scope/measure.csv",

[Scope.Channel1.measure("Average"),

Scope.Channel1.measure("Minimum"),

Scope.Channel1.measure("Maximum"),

Scope.Channel2.measure("Average"),

Scope.Channel2.measure("Frequency")])

 

Thanks again-Bar

 

 

[attila]

Hi @Bar

1. You can use a date-time column like: FileAppendLine("~/Desktop/scope/measure.csv", [Scope.Time.taken.toISOString(), Scope.Channel1.measure("Average"), ...])
2. You can adjust the Update rate under Time/Options. Of course, the capture takes longer depending on trigger and Time/Base.

[Bar]

Hi @attila,

   I got the date time column working per your suggestion. I'm having troubling finding where/how to adjust the sample logging rate. It looks like it is currently set to 250ms based on the CSV file (image attached). I see a 10ms setting listed near the time window on the right but this does not correlate to the output CSV file sample timing. 

Thanks for all of your help with this.

-Bar

 

I

[attila]

Hi @Bar

You are capturing 32768 samples at 149925Hz which takes at least 218ms + trigger arrival.
The Update sets a high limit to capture rate only if this is higher than the time it takes to perform the capture.