Strange behavior with VB MSO

[jperch]

I am seeing a weird behavior with the MSO on my VB-8012. 

I have captured a wavform, see initial view. You can see the waveform starts with a rising edge at the trigger point and continues off the main screen to the right. In the "zoomed out" view at the top, you can see the waveform continues for some time, then stops before the acquisition completes. 

If I want to see the portion of the waveform that is off the main screen to the right, I use a mouse to drag the image to the left. I could also grab the window in the upper display and drag it to the right to accomplish the same thing. However, as shown in data loss on the right, the waveform disappears long before the data in the upper window ends. 

If I then drag back to view the begining, see datalost to the left, you can see that the begining of the waveform has also now disappeared from the main screen. A little more than 6 divisions after the trigger have disappeared. 

The amoount of data that disappears seems random everytime I try this. But data always seems to disappear. 

One more datapoint, The pictures show the scope is operating in "Normal" trigger mode. The data is a burst of data and does not repeat unless I tell it to. In otherwords, this is a data burst and not a continuous waveform.

It seems if I repeat this test, but with the scope "Single" trigger mode, things seem to work fine.

Is this a bug or am I doing something wrong?

Joe

[DLarsen · Accepted solution]

jperch,

I believe this is expected behavior based on the way the panel works.  The instrument gathers that full buffer of data, but the panel queries for a smaller portion to display on the screen.  When you pan over, it has to query that buffer for more data.  However, once the soft front panel starts a new acquisition (see the 'waiting for trigger' status), it disables that query temporarily so the buffer can be filled without risk of corrupt data being read back.  If you want to pan around, I highly suggest clicking "Stop" first.  It should keep your data around and act just like after a 'Single' acquisition.

[jperch]

SiMylo,

Thank you for that explanation. It makes sense.

Joe