Continous edge counting

Forum for discussing PicoScope version 6 (non-automotive version)
tfreudi1
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Continous edge counting

Post by tfreudi1 »

Hello, i have a picoscope 2000 and want to check a shaft encoder. For that I add a measure of type "count falling edges", channel A, whole trace. When I choose a Collection time of 100ms/div I have a nice view of my edges, the Count is correct but when the "ray" reaches the right end and start again on the left side the count (Column Value) is reset to 0. But I want to have the am summary of all edges. When I change the collection time to 10s/div it takes much longer until reset but the edge count ist completly wrong.
How I can I have a summary of all edges during the whole capture time ?

Gerry
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Re: Continous edge counting

Post by Gerry »

Hi tfreudi1,

On Timebases of 100ms/div or longer PicoScope 6 switches to slow sampling mode were (where the data is streamed to the computer instead of sent in blocks). So, the end of a stream is the end of the collection of data (which is why it restarts).

The point at which the sample mode switches over to slow sampling defaults to 100ms/div, but can be changed. So, If you want continual monitoring of successive values with the use of the statistics, then you need to make sure that your selected Timebase will use fast sampling. You can do this by going to 'Tools->Preferences->Sampling->Slow Sampling Transition' and changing the value to a slower Timebase than the one you want to use.

Regards,

Gerry
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tfreudi1
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Re: Continous edge counting

Post by tfreudi1 »

Ok, in my case it is switching to slow mode at 200ms/div but still the count resets with 50ms/div.
I made a short Video, see attachment.

tfreudi1
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Re: Continous edge counting

Post by tfreudi1 »

Maybe this makes it clearer:
EdgeCntPicture
EdgeCntVideo

bennog
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Re: Continous edge counting

Post by bennog »

Please try the following option.
2019-10-30_17-06-38.png
Timebase 2 or 5 sec/div (depending on over what time you want to count the pulses)
And then increase buffer size (green arrow) until sample rate (right red arrow) is 50kS.

Stop the trace before the trace is at the ent of the screen.

Benno

tfreudi1
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Re: Continous edge counting

Post by tfreudi1 »

Thanks, I did and it works but not perfect, if I turn the shaft Encoder faster there is a kind of overflow. See Picture. This happens more often if go to 5s/div.

Overflow

Offtopic:
Somehow the img-tag is not working it always says that it can't determine the dimensions. I tried different formats and sizes and browsers.

Martyn
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Re: Continous edge counting

Post by Martyn »

Please see this Forum Topic

Your file size may have prevented the image posting, you should be able to add as an attachment
Martyn
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tfreudi1
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Re: Continous edge counting

Post by tfreudi1 »

@Martyn: Are there any known Limits ? My smallest try was 384 KB, which did'nt work

tfreudi1
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Re: Continous edge counting

Post by tfreudi1 »

Well Ok it looks like it is not really possible to have a sum of edges, maybe you can extend the picosscope software to have a checkbox for that in the measurement options for counting edges.
Meanwhile I take the SDK and try to wrote my own code to count all edges.

Problem not really solved , but I will look for a solution by myself, thanks for your answers.

Jack Davies
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Re: Continous edge counting

Post by Jack Davies »

Hello,

Is there now a solution to this? I have the same problem.

Thanks

tfreudi1
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Re: Continous edge counting

Post by tfreudi1 »

No they don't extend their software. I ended with another oszi that is able to count edges.

Gerry
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Re: Continous edge counting

Post by Gerry »

Hi Jack,

Could you either (1) post your data file to the forum or f it is too big (2) Load your data file to a cloud storage drive e.g. Google Drive and post the link here.

Contrary to what was posted by tfreudi1, you can count edges, although you may have to use a workaround to do it, until our new Software Version is available.

If you post your data and explain exactly what the problem is then we can show you how to count the edges.

Regards,

Gerry
Gerry
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tfreudi1
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Re: Continous edge counting

Post by tfreudi1 »

Sorry Gerry it wasn't precise, you can count edges, but in my case it is either counting exactly but resetting the counter so fast that I can't use it or if I change the timebase that I have enough time to see what the counter counts it will miss a lot of edges. So in my case it is unusable.
You should simple add an option to realy have a summary, but I repeat things that are sayed in this thread before.

Gerry
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Re: Continous edge counting

Post by Gerry »

Hi tfreudi1,

If the problem is that you are using a Timebase that is being reset before you can view the counted number of edges, then why don't you either (a) perform a single capture, so that you can see the counted value, or (b) perform multiple captures, and then scroll through each captured waveform using the waveform viewer to look at the edge counts for each waveform?

Regards,

Gerry
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tfreudi1
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Re: Continous edge counting

Post by tfreudi1 »

We dont have to start it all over, it is not possible for my case. My shaft encoder ist constantly, fast turning, please show me a video where you constantly, exactly count the edges for an hour.
The Rigol have a simple button "Count Edges" and it counts, and counts, and counts until I stop it, that wasn't possible with your software, but should be easy to implement.

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