EEVblog #1146 - New Low Cost Rigol MSO5000 Oscilloscope

[nerdineer]

Does anyone know of a quicker way to remotely read large waveform raw data from the scope? Right now I have managed to use USBTMC to grab the data but its painfully slow (minutes). This is with raw samples (e.g. bytes, not ASCII).
I'm assuming the protocol adds a lot of weight...

Saving binary files to memory (e.g. a memory stick or the internal memory) is much faster. However then you need to manually remove the USB stick from the scope and plug it into the PC. All possible but annoying and I dont want to wear out the one USB port.

I'm wondering (perhaps with the hacked firmware) if it would be possible to secure FTP into the scope and simply browse and download the scope captured over Ethernet? Or if there are any other ideas or solutions?

[Commodore8888]

For those with the sketchy overshoots from the wonky low freq cal on some MSO5000s and DS/MSO7000s, I've been in touch with Rigol USA over the last month.

As noted by Martin earlier when he contacted Rigol UK, Rigol as a whole appears to know there's an issue. I've been informed there's a fix coming in the form of a new firmware rev.
When, I'm not sure, but hopefully I have more info next week from Rigol USA. It's good to hear considering the group I work with has some analog work rolling up (and it'd be nice not fighting for the sole Tek MDO 3k  ), as well, some companies/groups make sending things out for RMA a completely asinine process...

[Martin72]

Yes, rigol took everything in this case seriously.
For example, they know and work around about the weak display brightness (although, of course, they couldn´t change the angle view via software).
I wrote to them, different math trace colours were a good and useful thing to have, they answered you´re right, we tell it to the R&D Department and so on.
Or bode plot function ( will come).
Or my problems with getting a pwm signal displaying stable….
They asked me about the nature of the signal, after a few days they told me to set the holdoff time for triggering to ms instead of ns...and it works.
Really good support.

[bitseeker]

It's good to hear they're responding to the reports. So, this may be like the DS1054Z where they will be fixing issues as they're found and reported. The 1kZ took a while to get sorted, but they took care of it (even "pluses" eventually got corrected ).

[Commodore8888]

Yes, rigol took everything in this case seriously.
For example, they know and work around about the weak display brightness (although, of course, they couldn´t change the angle view via software).
I wrote to them, different math trace colours were a good and useful thing to have, they answered you´re right, we tell it to the R&D Department and so on.
Or bode plot function ( will come).
Or my problems with getting a pwm signal displaying stable….
They asked me about the nature of the signal, after a few days they told me to set the holdoff time for triggering to ms instead of ns...and it works.
Really good support.

Good to know their R/D takes this stuff seriously. Seeing as this chipset is now in multiple scopes, and they're trying to be big players now with ASICs seems like, time to step up the support effort. Especially if new features are just some simple software tweaks. Quality of life stuff.

Screen brightness? In what way, is there a regulator running the backlight in there somewhere?? Or is it just a software image brightness deal. Still would be nice if they do something to bump it a tad. It's not bad in an office environment though. Side by side with our 7000s it IS a little dimmer.

Here's hoping the overshoot/bad cal thing gets sorted soon-ish though. It sort of crosses off our new scopes for serious analog work
Difference between new features vs. "cannot be used"

Auto bode function seems neat. This using the internal AWG with an internal trigger like how you might with a stand alone AWG, wide time base, and trig out?

[tautech]

................
Or my problems with getting a pwm signal displaying stable….
They asked me about the nature of the signal, after a few days they told me to set the holdoff time for triggering to ms instead of ns...and it works.

Yes of course.
User error and nothing to do with the scope at all.

All DSO's can struggle with obtaining a stable triggering with PWM unless Trigger Holdoff time is adjusted to greater than the max pulse width.
These Holdoff triggering issues also arise in some decoding work too where sometimes Holdoff needs be longer than an entire packet.
Pretty basic stuff.

[Martin72]

Yeah, but if you hadn´t the need to adjust the trigger in this way before, you think it´s a bug.
On LeCroy and Siglent models, you don´t have to adjust the trigger timeout - and we got LeCroy only and since a couple of time a Siglent.
So I was surprised using the 5000 for the first time and measure a pwm signal.

[2N3055]

Yeah, but if you hadn´t the need to adjust the trigger in this way before, you think it´s a bug.
On LeCroy and Siglent models, you don´t have to adjust the trigger timeout - and we got LeCroy only and since a couple of time a Siglent.
So I was surprised using the 5000 for the first time and measure a pwm signal.

That is because of very fast wfm/sec rate (short blind time) on new Rigols. After getting Keysight 3000T  I also had to start adding holdoff where I didn't have to use it before...
Slower scopes have "built in holdoff"   

[hhappy1]

Thanks sir.!!

One more question.

Why it is different THD. Moving the vertical offset.

https://drive.google.com/open?id=1uJyffuycF8e_rt2JvaoOCzDjRx_0lUL4

This is 1Khz Sine wave and 2nd , 3nd, more distortion.

Tek & R&S is Not different.

[luma]

Or bode plot function ( will come).

Wait, are you saying Rigol has directly stated that bode plot is coming?

[David Hess]

Why it is different THD. Moving the vertical offset.

https://drive.google.com/open?id=1uJyffuycF8e_rt2JvaoOCzDjRx_0lUL4

This is 1Khz Sine wave and 2nd , 3nd, more distortion.

Tek & R&S is Not different.

Other automatic measurements also change when the vertical position is adjusted.  I think this is because the Rigol makes measurements on the display record instead of the processing record.  The same thing also explains why automatic RMS measurements are not accurate for noisy waveforms.

In the general case, there are three different waveform records but in some cases they are combined to save money or increase performance:

The acquisition record is what is actually produced by the digitizer and is often limited to the digitizer resolution like on the Rigol where high resolution mode produces an 8-bit result.  On older DSOs, it may be limited to the length of a dedicated bank of fast memory but modern DSOs tend to capture the acquisition record directly into the processing memory.  Early DPO style DSOs captured directly into display memory but I think they do it a different way now. (1)

The processing record is what the processor works with and is often the 8-bit acquisition record promoted to 16-bits like on older Tektronix DSOs.

The display record is what actually gets displayed and may or may not be stored in the processing memory.

(1) I think modern DPO designs capture a histogram into acquisition memory and then the processor transfers this to the display memory which is how I would do it now.  Peak detection is a very limited early example of this.

[2N3055]

I think this is because the Rigol makes measurements on the display record instead of the processing record.

It doesn't..New ones don't.

[David Hess]

I think this is because the Rigol makes measurements on the display record instead of the processing record.

It doesn't..New ones don't.

Then that is an even more peculiar behavior.

[Bud]

Thanks sir.!!

One more question.

Why it is different THD. Moving the vertical offset.

https://drive.google.com/open?id=1uJyffuycF8e_rt2JvaoOCzDjRx_0lUL4

This is 1Khz Sine wave and 2nd , 3nd, more distortion.

Tek & R&S is Not different.

Vertical offset is DC voltage that is mixed with the signal BEFORE the ADC digitizes it. The digital waveform produced by the ADC will include the effect of the DC offset on the pre-ADC circuit (distortion).

[Fungus]

Or bode plot function ( will come).

Wait, are you saying Rigol has directly stated that bode plot is coming?

Apparently so. See the dedicated topic:

https://www.eevblog.com/forum/testgear/rigol-oscilloscopes-with(out)-bode-plot-feature/msg2308233/#msg2308233

[Martin72]

Does anybody know which 9" Display are used on the rigol, name, model ?
Dave did it a fully teardown but I´m sure he wouldn´t notice it.

[mabl]

Ok guys,

so I've been wondering on why you think that HIRES does not work on the DS5000. To my understanding, HIRES will runn a box car averaging filter over the samples, potentially resulting in more resolution if the noise is gaussian.

On the display side, multiple acquired wave forms overlay and result in a gradient display. If the waveform differs from shot to shot, the trace will look wider, even if the ADC had perfect resoultion.

The new Rigols are special in a sense, that they have very high update rates, even in HIRES mode. So what I would expect is:

• Gain of significant digits when using HIRES
• Trace getting thinner when reducing update rate via trigger holdoff
• Potential influence on display grading depending on vector mode or point display mode. With points enabling to see the higher vertical resolution
• In the best case I'd like to be able to specify the averaging filter shape etc. Rigol does not allow this.

So what I just did is looking at a 15MHz "square" wave from the wave form generator and going through these options, see attached images. I do believe to see a vast improvement of the waveform. The grading is "better" in case of dot display mode (instead of vector), and if I reduce the wave form rate, things narrow down and get clearer.

Is this not what one would expect from the HIRES mode? Once we account for the high frame rate and the easy saturation of the gradient display.

[2N3055]

To take update rate out of equation, one should try single capture without and with HIRES.

[mabl]

To take update rate out of equation, one should try single capture without and with HIRES.

Fair enough. But I wanted to point out the effect of the high update rate and the difference between dot and vector display.

I have added single shot measurements to this post as well. Due to the high ADC sample rate, it would definitely be useful to change the box size. But in general, my laymen's sense is that the HIRES mode does work but the results look bad in case of graded display and vector display mode.   

[2N3055]

Problem is with the fact that it is not specified how HIRES is done and that you have no control over how many averages (how many bits) HIRES is doing. They might be doing it with filter of length 2 which would only give 0,5 bit enhancement which would pretty much be not visible.
It should be made like averaging so you can set how many bits of enhancement you want and it should correspondingly show effective sampling rate AND effective bandwidth with that filter setting..

[Martin72]

Yeah, like the filtering in 0.5 bit steps by lecroy or siglent.

They might be doing it with filter of length 2 which would only give 0,5 bit enhancement which would pretty much be not visible.

Exactly, see also:

https://www.eevblog.com/forum/blog/new-rigol-scope/msg2266332/#msg2266332

And:

The hi-res mode is active on the 5000, but somehow too "weak".

https://www.eevblog.com/forum/blog/new-rigol-scope/msg2233980/#msg2233980

[MegaVolt]

Maybe someone knows?

1. Can the generator produce PWM signals? Or PFM or some other modulation for a square wave?

2. Is there any possibility to use external synchronization? I know that there is no separate entrance for this. But how can it be possible to use one of 4 inputs for this?

[MegaVolt]

Digitized generator output good instrument. And I found small spikes on any generated signal. Perfectly visible on rectangular pulses. The frequency is somewhere 20 Hz. The amplitude is 0.15 mV.

This is all?

[jemangedeslolos]

Hello,
I will order a MSO5074 next week and I know that the fan is noisy.
Has anyone ever tried to replace it ?
Do you know what type of connector Rigol uses on this model ?

Thank you 

[Martin72]

Hi,

https://www.eevblog.com/forum/blog/new-rigol-scope/msg1952305/#msg1952305

at 9min50s you could have a closer look to the fan.