PicoScope Beta 6.9 Beta Duty Cycle graphing

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Steve Smith
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PicoScope Beta 6.9 Beta Duty Cycle graphing

Post by Steve Smith »

Beta releases have NOT been fully tested by us. If you choose to install and use the beta software you should expect to run into bugs. These bugs may range in severity from minor features that don’t work to problems that may cause your PC to crash.

This forum post is intended to provide a brief introduction to a new feature prior to full instructions being added to the manual. If you have any questions/comments about its use (including just wanting to thank the developers for adding the feature :D ) then please post below.

PicoScope has for many years had Duty Cycle available as a measurement, now through maths channels you can also plot the change of Duty Cycle over time (something we have longed for). To use the new feature follow the steps below.

1. From the TOOLS drop down menu, select MATHS CHANNELS then click on the CREATE button.

2. From the "Equation Editor" select ADVANCED and then click on the DUTY button followed by the letter of the channel you want to use (in the example below we have used channel A)

3. Remember to place the negative symbol before the channel letter of your choice to graph the negative duty cycle E.g. duty(-A) for the negative duty cycle on channel A Click NEXT
Creating Negative duty math channel
Creating Negative duty math channel
If you are happy with the default colours and name click NEXT

If you are happy with the default range (0 to 100%) then click NEXT

4. You have now added Duty Cycle as a measurement and it will be available in the “Library” for future use. Click on the check box adjacent to “duty” to enable the feature.
Duty Check Box
Duty Check Box
DUTY CHECK BOX.jpg (47.23 KiB) Viewed 49972 times
5. The example below shows the negative duty control of a CR Diesel fuel pump "Volume Control Valve"
Volume control valve duty cycle
Volume control valve duty cycle
PicoScope 6 Automotive Beta version 6.9.5 can be downloaded at https://www.picoauto.com/download-software.html
Last edited by Steve Smith on Wed Jun 04, 2014 3:14 pm, edited 1 time in total.

volrem
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Re: PicoScope 6.9.5 Duty Cycle graphing

Post by volrem »

Great info. Is there anything else new in 6.9.5 version?

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Re: PicoScope 6.9.5 Duty Cycle graphing

Post by PicoMike »

We have added some additional filter functions when using Math Channels. These include: lowpass, highpass, bandpass and bandstop :)

See Steve's otehr thread: http://www.picoauto.com/support/viewtop ... 24&t=10053
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Robski
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Re: PicoScope 6.9.5 Duty Cycle graphing

Post by Robski »

Well I've just tried this after installing & being prompted to install net framework 4.0, and when I open a file with a duty cycle control & deploy the math channel the scale comes up but no trace, what's going on ??

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Re: PicoScope 6.9.5 Duty Cycle graphing

Post by Martyn »

Can you post the data file so that we can check the settings and scaling of the Duty Cycle channel.
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Re: PicoScope 6.9.5 Duty Cycle graphing

Post by Robski »

Martyn wrote:Can you post the data file so that we can check the settings and scaling of the Duty Cycle channel.
Martyn,

It was set up as per the post here, I selected several PSD files to open with duty cycle control & run the math channel with the same result every time ????

Also the screenshot above, was this from a waveform generator or an actual vehicle, if vehicle was it pull up PWM (+) ?

EDIT: right I have tried this again & appears I had to be zoomed in on the duty cycle square wave to draw a trace, is this right ??

Also it does exactly the same as the 'duty' measurement does & measure high all the time, which is great for + PWM , it appears to me that more is needed to the formula to differentiate high & low :?

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Re: PicoScope 6.9.5 Duty Cycle graphing

Post by Martyn »

The waveform we used was not from a vehicle, but it was a real signal, so it would help to see one of your data files to understand what is going on.
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Re: PicoScope Beta 6.9.5 Duty Cycle graphing

Post by Robski »

Martyn,

As you can see in the screen shot it is (-) PWM control as the current increases when PWM is low, but the duty math channel is measuring the high as i mentioned in an earlier reply along with the measurement for duty cycle.Do you see what I mean now ??

The formula needs something extra to tell the math channel to measure the low pulse surely ?
Duty cycle example_1.JPG

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Re: PicoScope Beta 6.9.5 Duty Cycle graphing

Post by Fat Freddy »

Great work guys. :D

I think it's going to answer so many questions for a lot of people. Got a few files I'd like to check out from way back. A few bugs are to be expected in a Beta like this, but it's a Beta.

For what it's worth your hard work is much appreciated. :) A big tick on my wish list.

FF

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Re: PicoScope Beta 6.9.5 Duty Cycle graphing

Post by Fat Freddy »

The formula needs something extra to tell the math channel to measure the low pulse surely ?
AFAIK easy. "100 - "

Works on the demo turns 47% to 53%. Treat the same as frequency.
Else post data files.

HTH
FF

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