Simultaneously trigger acquisition and generator

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victorm
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Joined: Tue May 05, 2020 12:02 pm

Simultaneously trigger acquisition and generator

Post by victorm » Tue May 05, 2020 1:30 pm

Dear community,

I have to implement an application (using the API) with an oscilloscope of the 5000 series that:
1 - Triggers a signal on the built-in generator.
2 - Starts the acquisition of one oscilloscope channel exactly when the generator is triggered.
3- This simultaneous trigger must be initiated by a software command.

I found in this post the proposal of setting the AWG trigger to fire with the scope trigger and disabling the scope trigger, so with the runblock command both the acquisition and generator start. However, the author talks about a delay between generator and oscilloscope that seems to be no deterministic (27us in his case).

Do you know if there is another way to achieve the intended functionality? The problem has been previously raised (see this topic), although no information is provided.

Thank you,
Víctor

AndrewA
PICO STAFF
PICO STAFF
Posts: 268
Joined: Tue Oct 21, 2014 3:07 pm

Re: Simultaneously trigger acquisition and generator

Post by AndrewA » Thu May 07, 2020 3:13 pm

Hi,
There two possible solutions;
1. Call ps...SigGenSoftwareControl() to trigger the AWG directly.
-You would need to use a channel to also capture AWG output to trigger the scope on
+output of the AWG will align with the scope trigger
-slower if you need to do this in loop

2. Set a block or rapidblock with or without a trigger. Then set the scope capture to trigger the AWG output.
As per- https://www.picotech.com/support/viewtopic.php?t=39599#p142115
Output of the AWG triggers between pre and post trigger samples, plus small delay. The delay is always the same for the same settings.
-The small delay on the AWG changes if you need to chance the scope capture settings.
+faster if you need to do this in loop.
-You don't need to use a channel to know when the AWG triggered, as long as you have measured the delay from AWG with settings you going to use.
+You can use an external trigger signal to fire the capture and AWG (but not suited in your case)

We have produced a document that provides an outline of how to set parameters in order to the trigger the signal generator output on a PicoScope:
https://www.picotech.com/download/manuals/TriggeringAPicoScopeSignalGeneratorUsingThePicoScopeAPIFunctions.pdf
Regards Andrew
Technical Specialist

victorm
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Joined: Tue May 05, 2020 12:02 pm

Re: Simultaneously trigger acquisition and generator

Post by victorm » Thu May 07, 2020 4:24 pm

Dear Andrew,

Thank you very much for your response. With regard to your suggestions:

1. Instead of a scope channel, I think that I could connect the generator to the external trigger input, so I would not employ an extra scope channel. In any case I would be interested in triggering the acquisition in a more precise way, since noise can slightly affect the trigger shot.

2. About the introduced delay of the second solution: is it always exactly the same (for example a fixed number of sampling periods)? I have to measure very small delays (below 25ns) and any trigger uncertainty may be a problem.

Thank you again for your support,
Victor

victorm
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Posts: 0
Joined: Tue May 05, 2020 12:02 pm

Re: Simultaneously trigger acquisition and generator

Post by victorm » Wed May 20, 2020 4:29 pm

Hello again,

In addition to the 2 points of the previous message, I would like to ask about the possibility of using a digital output (for example with a NI USB 6501) to drive the external trigger of the oscilloscope. If the generator and the input channels are configured to work with the external trigger, would be they triggered at exactly the same clock period?

Thank you,
Victor

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