AnsweredAssumed Answered

Trigger issue with MSO-X 3034A

Question asked by BrianL on May 16, 2016
Latest reply on May 16, 2016 by BrianL

I've been using an MSO-X 3034A for a few years now, and for as long as I can remember, I've always had an issue getting the trigger to fire reliably.  It an inconvenience when using the scope manually, and a major problem when trying to automate it (which I'm currently doing).


Basically, in some circumstances, I can't get the scope to trigger at all.  I sometime need to wait MINUTES before it will accept/process a "force trigger" reliably.


Here's the scenario:

I'm using only the first channel on the scope, and the trigger channel is set to channel 1.

1. Set the vertical scale to a value appropriate to the input signal, and set the trigger level off scale (I don't want to auto-trigger).  FYI (not that is should matter), Trigger mode is set to Edge, Source = 1, Slope = UP, Acquire Mode = Normal

2. Set the scope's horizontal scale to 30s/division (using the fine horizontal adjust or through the software command)

3. Set the horizontal delay to 149s (moves the trigger to 1s from the left of the screen)

4. Wait at least 1 second

5. Pressing "Force Trigger" or issuing the force trigger command does not trigger the measurement (nothing appears on the screen).  I tried this repeatably, and I can say that I can reproduce this issue 100% of the time.  If I wait, the measurement WILL start, but in this case, it will start about 90s AFTER the force trigger was pressed (I measured it just now). 


Just a note:  I don't believe there's anything wrong with the procedure above.  If I adjust the horizontal scale to one of the values that is set by the coarse adjust (i.e. 50s/div, 20s/div, 10s/div,...), and set the horizontal delay so that the trigger position is 1s from the left of the screen, then the procedure outline above works 100% of the time, and the scope behaves as expected. 


I need a solution (or a workaround) to this problem fast, otherwise I will be force to use "another" scope.


BTW, before anyone asks, I did update the FW to the latest version available on the Keysight website (, and the issue persists.