Continous edge counting

Forum for discussing PicoScope version 6 (non-automotive version)
Post Reply
tfreudi1
Newbie
Posts: 0
Joined: Tue Oct 29, 2019 10:19 pm

Continous edge counting

Post by tfreudi1 » Wed Oct 30, 2019 8:52 am

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
PICO STAFF
PICO STAFF
Posts: 509
Joined: Mon Aug 11, 2014 11:14 am

Re: Continous edge counting

Post by Gerry » Wed Oct 30, 2019 11:19 am

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
Gerry
Technical Specialist

tfreudi1
Newbie
Posts: 0
Joined: Tue Oct 29, 2019 10:19 pm

Re: Continous edge counting

Post by tfreudi1 » Wed Oct 30, 2019 11:49 am

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
Newbie
Posts: 0
Joined: Tue Oct 29, 2019 10:19 pm

Re: Continous edge counting

Post by tfreudi1 » Wed Oct 30, 2019 12:04 pm

Maybe this makes it clearer:
EdgeCntPicture
EdgeCntVideo

bennog
Advanced User
Advanced User
Posts: 59
Joined: Mon Nov 26, 2012 9:16 am
Location: Netherlands

Re: Continous edge counting

Post by bennog » Wed Oct 30, 2019 4:11 pm

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
Newbie
Posts: 0
Joined: Tue Oct 29, 2019 10:19 pm

Re: Continous edge counting

Post by tfreudi1 » Thu Oct 31, 2019 10:45 am

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
Site Admin
Site Admin
Posts: 3724
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

Re: Continous edge counting

Post by Martyn » Thu Oct 31, 2019 2:03 pm

Please see this Forum Topic

Your file size may have prevented the image posting, you should be able to add as an attachment
Martyn
Technical Support Manager

tfreudi1
Newbie
Posts: 0
Joined: Tue Oct 29, 2019 10:19 pm

Re: Continous edge counting

Post by tfreudi1 » Thu Oct 31, 2019 2:14 pm

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

tfreudi1
Newbie
Posts: 0
Joined: Tue Oct 29, 2019 10:19 pm

Re: Continous edge counting

Post by tfreudi1 » Fri Nov 01, 2019 2:50 pm

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.

Post Reply