Author Topic: DS1054Z: Sometimes slow?  (Read 1282 times)

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Offline elcaron

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DS1054Z: Sometimes slow?
« on: February 25, 2017, 10:03:16 PM »
I got a new Rigol DS1054Z two month ago. I general, I am quite happy with it, and at least regarding the basic stuff, I can handle it confidently (have not checked much of the fancy stuff like protocol analysis or waveform tests). However, somehow I regularly manage to get it into a state in which it behaves pretty funky:
- sluggish screen updates kind of like a slide show
- weird behavior of vertical units: change vertical division by one step, and the curve is suddenly nowhere to be found.
I feel this happens just by using basic stuff like v/h offset/division, trigger mode. Especially nothing fancy or expensive like math.
Yesterday, when I used the pulse trigger for the first time to look for issues in a PWM signal, the trigger point ended up outside (before) the recorded range in single shot mode. I suspect this might have to do with the sluggish reactions of the screen ...
All of this is regularly resolved by pressing the AUTO button. Then I can adjust everything as I want and it is fine again.
Also I can observer that at slow timescales, like 1 second, the screen is only updated half of the time, on the right halve. when the signal reaches the right edge of the screen, it stops updating for 6 seconds until the signal is at the center, then it updates the left halve at once.

Are these features I don't understand, or are these quite obvious bugs in plain sight? I am on the 04.04.SP1 firmware that was shipped with the scope, and it is unlocked.
 

Offline Fungus

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Re: DS1054Z: Sometimes slow?
« Reply #1 on: February 25, 2017, 10:30:53 PM »
I think they're probably "features you don't understand".

eg. In the 'Auto' trigger mode with a timebase less than 50 ms/div it can take a loooong time between each screen update when there's no trigger signal. Look if it says 'Auto' at the top corner.

The result is that one moment it's working fine then you touch the timebase knob and suddenly the screen only updates once every few seconds.
« Last Edit: February 25, 2017, 10:32:24 PM by Fungus »
 

Offline ebastler

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Re: DS1054Z: Sometimes slow?
« Reply #2 on: February 25, 2017, 11:40:05 PM »
I agree with Fungus here; what you describe sounds like normal behavior (of any scope).

E.g. if your signal has a DC component to it, and you increase the vertical sensitivity by one step, the signal might well end uo outside of the display area. (The DS1054Z does give you a hint where it is -- watch for a flat trace shown at the upper or lower edge of the graticule area.) Also, if you increase horizontal resolution by one step, and had the trigger point already moved towards the left or the right of the screen, it might well end up outside of the visible area. (And this can be a perfectly useful setting, if you are interested in a signal that occurs before or after the trigger point.)

As you gain more confidence in using the scope, you will not always revert to the auto-set button to get your signal back. (That's often undesirable, since it will mess up other adjustments you had already carefully made.) The scope has a few more shortcuts to get you back in the ballpark. E.g. pushing the vertical or horizontal position knobs, or the trigger level knob, will reset the respective setting to zero.

That being said, the user interface on the DS1054Z can be a bit sluggish at times. Not sluggish as in "slide show update rate", which -- as mentioned by Fungus -- is probably simply due to a slow time base setting. But sluggish as in "jerky; no real smooth response to position adjustments". This may cause you to lose track of where the signal is on the screen if you change position adjustments rapidly. Also, the horizontal position adjustment has a software-based acceleration behavior which is not well-implemented and can cause unintended overshoots. Easy does it...
 

Offline newbrain

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Re: DS1054Z: Sometimes slow?
« Reply #3 on: February 26, 2017, 12:22:20 AM »
About the half screen update with slow timebases:
This is expected behaviour, if the trigger point is in the middle of the screen. The scope will acquire samples until it finds a valid trigger, at that moment it will immediately display the recorded samples (left of the trigger), and continue acquiring and displaying the input signal (right of the trigger)
 

Offline Fungus

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Re: DS1054Z: Sometimes slow?
« Reply #4 on: February 26, 2017, 12:30:49 AM »
 

Offline Fungus

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Re: DS1054Z: Sometimes slow?
« Reply #5 on: February 26, 2017, 12:32:08 AM »
As you gain more confidence in using the scope, you will not always revert to the auto-set button to get your signal back.

Yes. Auto is bad because it resets everything.

It's all down to practice and experience, just keep using it.
« Last Edit: February 26, 2017, 01:33:20 AM by Fungus »
 

Offline elcaron

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Re: DS1054Z: Sometimes slow?
« Reply #6 on: February 26, 2017, 01:31:18 AM »
Ok, I see the issue with the slow time base. That is given.

The other stuff not so much. It is not about a slow interface but slow signal update. But I guess that is probably also a trigger/auto issue. I'll try to investigate that further, perhaps with a screenshot and/or video.

The only thing I do not see explained is how my trigger point ended up before the recorded signal of the single shot and was fixed after pressing auto.
I totally agree that hitting auto is not what I like to do, since it sets back everything.
 

Offline ebastler

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Re: DS1054Z: Sometimes slow?
« Reply #7 on: February 26, 2017, 02:25:34 AM »
The only thing I do not see explained is how my trigger point ended up before the recorded signal of the single shot and was fixed after pressing auto.

I tried to explain this here (if I understood your issue correctly):

Also, if you increase horizontal resolution by one step, and had the trigger point already moved towards the left or the right of the screen, it might well end up outside of the visible area. (And this can be a perfectly useful setting, if you are interested in a signal that occurs before or after the trigger point.)

To paraphrase, I assume you had used the "horizontal position" knob to move your trigger point away from the center of the screen. (Or move the signal section displayed on the screen away from being centered around the trigger event; that's probably the more meaningful way to look at it.) Then you switched to a faster timebase. When you do that, the scope maintains the same time offset between the trigger event and the center of the segment displayed on the screen. As the segment displayed on the screen is now shorter, the trigger event may well lie outside of the displayed segment. -- Did that make sense? 
 

Offline rstofer

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Re: DS1054Z: Sometimes slow?
« Reply #8 on: February 26, 2017, 03:28:10 AM »
The only thing I do not see explained is how my trigger point ended up before the recorded signal of the single shot and was fixed after pressing auto.
I totally agree that hitting auto is not what I like to do, since it sets back everything.

You paid good money for that Auto button!  I use mine all the time...  For one thing, it puts everything back to a known state.  It probably isn't the state I want but at least something will be on the screen.

I have my scope set to restore my last settings on startup.  That's pretty handy if I am doing the same thing as the last time but it can be pretty far from useful for my current project.  The Auto button takes care of all that.  Or, I could set the scope to restore the factory default configuration and be wrong every time...

How slow is the display if you look at the compensation signal after pushing Auto?

 

Offline ebastler

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Re: DS1054Z: Sometimes slow?
« Reply #9 on: February 27, 2017, 04:40:57 AM »
You paid good money for that Auto button!  I use mine all the time...  For one thing, it puts everything back to a known state.  It probably isn't the state I want but at least something will be on the screen.

I would argue that the auto button puts the scope into a completely unknown state (but with something on the screen). Which is exactly why I don't like using it... Or maybe that's because my previous scope of 30 years did not have one.  ;)
 

Offline rstofer

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Re: DS1054Z: Sometimes slow?
« Reply #10 on: February 27, 2017, 05:00:29 AM »
You paid good money for that Auto button!  I use mine all the time...  For one thing, it puts everything back to a known state.  It probably isn't the state I want but at least something will be on the screen.

I would argue that the auto button puts the scope into a completely unknown state (but with something on the screen). Which is exactly why I don't like using it... Or maybe that's because my previous scope of 30 years did not have one.  ;)

But it probably had a 'beam finder' button or equivalent. I didn't use that button much but when the signal if off the display, it could be handy.

And while I agree, the Auto state may be unknown to me, it is known to the scope.  Once I have the trace, I can diddle with V/div and t/div all I want.  It is regrettable that it also displays unused channels and I have to turn them back off but so be it.

I know I am in the minority but I'm not going to overlook an opportunity to make my life easier.  I have had scopes for over 60 years, ever since I built one from plans in the ARRL Handbook back in the late '50s, so I do know how to twiddle the knobs and, yes, I was "that kid".  I also know that I very likely left the scope in a mode that needs to be unwound - like XY mode - and sometimes this just isn't helpful for what I'm trying to do at the moment.  Push one button and everything is unwound!

Maybe I should set the scope to start from the factory default rather than my last settings.  Or not...

Everybody needs to decide on how they want to approach the scope.  There are certainly differences of opinion but none of them are absolutes.

I paid for that Auto button and I darn sure plan to use it!
 

Offline ebastler

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Re: DS1054Z: Sometimes slow?
« Reply #11 on: February 27, 2017, 05:27:51 AM »
I paid for that Auto button and I darn sure plan to use it!

 :)
Fair enough! I am fully aware that this is a matter of personal preference and habits; there is certainly no "right" or "wrong" here. And isn't it nice that today's scopes offer you choices how to achieve what you want! Same as e.g. using automated measurements, cursor readings, or eyeballing on the graticule, all of which have their uses...
 

Offline hgjdwx

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Re: DS1054Z: Sometimes slow?
« Reply #12 on: February 27, 2017, 12:18:17 PM »
Micsig TO1074 has a very fast auto range and response time of 1.5 seconds,
as convenient as the auto range digital multimeter,
auto set the response time of 1 second,
and it can not displays unused channels.



« Last Edit: February 27, 2017, 01:03:18 PM by hgjdwx »
 

Offline rstofer

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Re: DS1054Z: Sometimes slow?
« Reply #13 on: February 27, 2017, 03:41:37 PM »

- weird behavior of vertical units: change vertical division by one step, and the curve is suddenly nowhere to be found.


This can happen when you have the probes DC coupled.  If the signal is varying with time (AC), use AC coupling.  This will strip any DC component that might be causing an offset and leave the AC component cycling around the 0V axis, wherever that may be placed on the screen.

Remember, that pattern is 1-2-5 so each 'click' at least doubles the size of the trace.
 


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