Slow sampling mode/Trigger inquiry

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Aleksey
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Slow sampling mode/Trigger inquiry

Post by Aleksey » Thu May 03, 2012 8:38 pm

Hello,

I am having issues trying to get the software to work in a specific manner.

I wish to sample, for example, a 5 Hz signal over 100 seconds. However, I wish to be able to clearly see the sine wave (aka, zoom in), while I am recording data in slow sample mode, to scan it for any unwanted disturbances. For that, I need the signal to "flow" on my screen from right to left, so that I don't need to continuously move my zoom window to follow the signal.

Currently, the signal simply plots itself from left to right, which makes it impossible to be always zoomed in to the most recent data.

Is that feasible?

Additionally, I wish to be able to set a trigger event, but I wish to also be able to see the data even when the trigger is not satisfied in case some unexpected event occurs so that I can start recording manually. Is that feasible?

Thank you!
Aleksey

Martyn
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Re: Slow sampling mode/Trigger inquiry

Post by Martyn » Thu May 10, 2012 8:45 am

If you setup the software so that it is running in streaming mode, generally 100ms/div or slower depending on the preferences setting, you will see a trace run across the screen. If you now add in a trigger condition that isn't met in normal operation you will have a trace that continually streams but doesn't go past the trigger point. Zooming in on this will give you what you are looking for.
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Autonerdz
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Re: Slow sampling mode/Trigger inquiry

Post by Autonerdz » Fri Jun 08, 2012 5:03 pm

Martyn,
Zooming in on this will give you what you are looking for.
This will not work live though. You must stop the scope before the data can be seen when zooming in streaming mode..
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Re: Slow sampling mode/Trigger inquiry

Post by Martyn » Mon Jun 11, 2012 12:50 pm

It works for me with both the release and beta versions of the software.
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Autonerdz
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Re: Slow sampling mode/Trigger inquiry

Post by Autonerdz » Mon Jun 11, 2012 4:37 pm

Martyn,

Here is an animation showing what happens when you zoom as described live. The signal is not properly represented until you stop the scope and the data is processed.
Attachments
capture-1.gif
Shows what happens when you zoom live in streaming mode
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Re: Slow sampling mode/Trigger inquiry

Post by Martyn » Tue Jun 12, 2012 3:16 pm

Which version of the Automotive software are you using in that example ?
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Autonerdz
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Re: Slow sampling mode/Trigger inquiry

Post by Autonerdz » Tue Jun 12, 2012 3:48 pm

Martyn,

I used the latest 6.6.23.2 for that example. Similar results from the 6.7.3.2 beta (unreleased)

It's not an issue for us. We don't really have a need to zoom live in streaming mode. The false trigger technique works very well as we demonstrate here:

http://www.autonerdz.com/cgi/yabb2/YaBB ... 231719/#13

But not zoomed in.
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Re: Slow sampling mode/Trigger inquiry

Post by Martyn » Thu Jun 14, 2012 7:05 am

I have now identified the reason why I wasn't seeing the issue. At a lower number of samples (30kS) it doesn't happen but it gets progressively more blocky as you increase from that point.
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Re: Slow sampling mode/Trigger inquiry

Post by Autonerdz » Thu Jun 14, 2012 5:00 pm

Thanks for the follow up, Martyn.

Mystery solved. That low of a sample rate distorts the sample 1kHz square wave I used for the animation but no more blockiness. Streaming mode number sample must always be increased to faithfully reconstruct the signals so the blocky wave would always be an issue doing this.

Still....a non issue for what we do in automotive.
Tom Roberts
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skype: autonerdz
THE PicoScope Automotive Authority
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