How to specify when the Red Pitaya records data?

[Miormoo]

I am acquiring data from my Red Pitaya using PuTTY. I want to get the data from the oscilloscope trace at exactly the moment that I press enter on the acquire command and looking exactly the same as it does on the online function screen, but the RP keeps giving me data from before/after the important moment I need to record and in a completely different domain, for example, shifted completely to the left of what it is showing on the screen on the oscilloscope function... Is there something obvious I am missing?

[Nils Roos]

As far as I know, there is no reliable way to have acquire fetch exactly the same data as shown in the scope display.

When you start acquire, it sets the ADC to immediate untriggered acquisition and collects the requested number of samples.
The scope app on the other hand requests samples in two different manners, depending on the trigger mode:

• in Auto mode, it reads as much samples as it needs from the ADC stream, displays them and then reads another batch, and so on. You don't know when it will request the next batch of samples and therefore it's not possible to synchronize it with acquire.
• in Normal/Single mode, the ADC waits for a trigger event to occur and then buffers the data for retrieval from the scope app. Since acquire only reads instantaneous samples, the data that the scope app shows will already be gone.

To achieve what you want, you could modify either the back-end code on the RedPitaya or the javascript on the client side. Make a copy of the samples that are used to prepare the display and save that.