Rigol Scope and Slow Response

Thread Starter

fsonnichsen

Joined Jun 6, 2013
36
I have to think this is a setup issue with my scope but lots of reading and experimenting later I cannot find and answer.
I have a 1054Z which for the most part I am very pleased with. However I have lately had some long-duration work. I am dealing with pulses that are generally around 0.5 to 2 seconds.
With my old tektronix I was able to set the horz to a second and just watch the trace move to the left end then IMMEDIATLY resume to the left-hand-side.
With the 1054z no matter what the horz setting (200ms thru 5s) I find the scope stays blank for several seconds (~10). Finally the pulse arrives and scans across the screen. Then it remains for another several seconds (about 10). Needless to say shifting between pulse lengths the instrument is not fast enough to show the results.

I am guessing I am encountering some type of "screen buffer" which stores several thousand samples including those on the screen and those off. For the usual rapid work I do (Khz and up) this is not noticed.
Does anyone have a similar experience--I am trying to find a command to narrow down the screen buffer to window size-or at least to fix the problem.

Thanks all
Fritz
 

hexreader

Joined Apr 16, 2011
463
Try moving the trigger point to the left of the screen (using the horizontal "position" knob)

Another option is to select roll mode - but probably not what you want.
 

Thread Starter

fsonnichsen

Joined Jun 6, 2013
36
Thanks for the replies. At present I am indeed running the cursor all the way left. It seems to work but I think I am hanging up on the right hand side. Further this gets upset whenever I reset to another horz time value. I used the Roll mode but it only is good to 200ms and as you say is not what I want.
The AUTO button does not help.

So--I will check the Holdoff setting and also look again to see if there is a Memory Depth when I get back to the lab tomorrow

Thanks
Fritz
 

Thread Starter

fsonnichsen

Joined Jun 6, 2013
36
OK-back at it:
1) I double checked AUTO mode and that did not work
2) I changed hold-off from 16ns to 2s and that did not work
3) I set the memory-depth to 12K (lowest value) and that did not work (or seem to make a change)
Possibly the wrong scope for low-speed pulse checking unless I want to sit there diddling the horz position knob
I am a little surprised that one cannot set the memory equal to the screen width-

Thanks
Fritz
 

jpanhalt

Joined Jan 18, 2008
10,463
That delay was one of the first things I noticed with my DS1054Z. My mode is "peak detect" and 12k memory depth. Occasionally, it is a problem, so I use my much older Tek TDS210.
 

tautech

Joined Oct 8, 2019
139
Perhaps @tautech has the solution.
Not so much as it's a model I haven't used.

However with DSO timebase settings slower than 50ms/div they normally enter an Auto Roll mode where the memory buffer needs fill before the display is updated. While confusing to the DSO newbie this is normal behavior.

Some DSO's offer a dedicated Roll mode (Roll mode button), in which the display is updated in near real time albeit from the RH side of the display and all trigger functions still allow triggering on events where these events will of course intersect with the trigger position and level settings.

Memory depth and/or trigger Holdoff have no effect on Roll mode behavior.
Holdoff is most often needed in decoding where you need to disable further edge triggering until a packet of data has passed otherwise the scope will continue to trigger within a data packet instead of only at the start of it. Depending on the protocol and its baud rate Holdoff might be just a few ms.
Getting rock solid stable triggering on data packets is necessary to get reliable decodes.
 
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