Set up condition for stopping capturing the data

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Link
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Set up condition for stopping capturing the data

Post by Link » Thu Sep 19, 2019 2:09 am

Hi there,

I'd like to set up the stop conditions. I don't know how many samples is needed to be captured, but I know what is the condition to stop it, such as there is no trigger within a specified time. For example, I would like to begin to capture the data when there is a rising edge, but stop it when there is no trigger within 5 us.

I found "Drop-out triggering" in the programmers guide, but no details about it. I haven't figure out if it can be used to set up the stop condition.
Is there any suggestion?
Thanks!

AndrewA
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Re: Set up condition for stopping capturing the data

Post by AndrewA » Fri Sep 20, 2019 2:22 pm

Hi,
Which model PicoScope do you have?
Can you post image of an example waveform you want to capture?

All the trigger types are listed on pages - 158 - 6.7.2.1 Advanced Triggers dialog -
https://www.picotech.com/download/manuals/picoscope-6-users-guide.pdf
Regards Andrew
Technical Specialist

Link
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Re: Set up condition for stopping capturing the data

Post by Link » Mon Sep 23, 2019 9:09 am

AndrewA wrote:
Fri Sep 20, 2019 2:22 pm
Hi,
Which model PicoScope do you have?
Can you post image of an example waveform you want to capture?

All the trigger types are listed on pages - 158 - 6.7.2.1 Advanced Triggers dialog -
https://www.picotech.com/download/manuals/picoscope-6-users-guide.pdf
Hi Andrew,
I'm using 5244D MSO.

Sorry I provided too little info before. Let me explain it.
I'd like to develop a program to capture the input signal based on the PicoSDK.
The length of input signal varies so I cannot set a fixed number of samples. For example, the length of CAN messages varies which depends on its size of payload. I would like to run the program for a long time. To save space and time, I only wan to capture the valid data.
I'd like to capture the signal when there is a rising edge but stop it when there is no trigger within 5 us. So, my question is, how can I set the stop condition for capturing the data based on the PicoSDK?
Setting a maximum number of samples is not an option for me in order to save time and space.
Could you please give me some suggestions?

Thanks!

bennog
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Re: Set up condition for stopping capturing the data

Post by bennog » Mon Sep 23, 2019 12:31 pm

Are you searching for a missing can message on the change of a input io signal ?
Or are you searching for a missing IRQ signal at the end of a can message ?

Benno

AndrewA
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Re: Set up condition for stopping capturing the data

Post by AndrewA » Wed Sep 25, 2019 10:21 am

Hi Link,
From what you describe you want to configure the scope to run in streaming mode, but this only allows for one trigger event and cannot be reset!
So it may not be worth trying to configure a trigger. You could look at writing your own code to detect multiple trigger events.

FYI- To setup a trigger, you will need call these three functions and setup there related structures-
ps5000aSetTriggerChannelPropertiesV2
ps5000aSetTriggerChannelConditionsV2
ps5000aSetTriggerChannelDirectionsV2

The pulse width, delay and drop-out triggering methods additionally require the use of the pulse width
qualifier functions:
ps5000aSetPulseWidthQualifierProperties
ps5000aSetPulseWidthQualifierConditions
ps5000aSetPulseWidthQualifierDirections

Please see the PG for more details.
https://www.picotech.com/download/manuals/picoscope-5000-series-a-api-programmers-guide.pdf
Regards Andrew
Technical Specialist

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