Async recording

During a recording I want to measure several event times of a few milliseconds up to one second with the stopwatch function. These events occur random and I would like to save the times with async timebase to limit the amount of data, because I've got a lot of time events to record. The event times have to be saved with for example the instantaneous system pressure and both will than be presented in a scattered graph (XY recorder) to see their relation.

A trigger is used for start and t the fast recording at 50 kHz.

How should I define a timebase in order to create the async recording.

I'm not exactly sure, if I understand your question correctly. You are measuring a signal, which is more or less constant, except for some events and you only want to get samples of those events? If that is more or less what you are trying to do I attached an example setup, where you only get samples, when the value of the Signal channel changes. The setup measures the time between two button presses. I used lath value math to only get a sample when there is a change in the signal. You can then set all the other channel to not Store, so the datafile you are storing only contains the signal, that you need.

I hope the setup will help you and if you have any follow up questions I will glady help.