REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol

[g2]

Dave's  video  is about measurement and connection to other  electrical appliances, and what can  happen.
When Rigol DS2072 is not grounded, it have 115 Volt  (or 230 Volt) on chassis and also on probe tip.
Completely without being connected to other equipment.
All my old analog oscilloscopes I have had, do not have 230 V out on  Chassis ground, and also on probe tip. And all other  electrical instruments I have do not have it.
Rigol DS2072 must be bad isolated from main power(230V).
Are other digital oscilloscope brands also poorly insulated ?
Of course, it is best to ground.

So I just did a few checks.  From measureing the mains input socket with an LCR meter, there's a common mode filter with 4.7nf caps between N-G and A-G.  There's no blead resistance across the caps and ground (I am not saying there should be.)

So under controlled conditions I removed a ground, powered it up, and got what you described.  This is as to be expected, the 4.7nf caps are forming a voltage divider to earth at the input CM filter, and so earth is now half way  between neutral and active potentials.  In Oz, with a 240V active and neutral at close enough to ground, this gives ~ 120VACrms on the jacks.

Shorting this to ground gives a current of 338uArms, which if you work out 1/(2*pi*f*C) on 4.7nf, and divide 240Vrms by it, you’ll get exactly that.

It’s got nothing at all to do with insulation, it’s designed that way to remove mains line noise (and vice versa.)  So just operate it with a ground and you’ll be fine.

Thank you for testing and your explanation  , Harvs, You are right !
I thought it was the special oscilloscope,
but it is then the switching power supply fault.
So it does not help to buy a second oscilloscope.
I returned the Rigol DS2072, maybe I should buy it again.
It seems to be a good oscilloscope.
Once again, thanks for the help!

[marmad]

When Rigol DS2072 is not grounded, it have 115 Volt  (or 230 Volt) on chassis and also on probe tip.
Completely without being connected to other equipment.
All my old analog oscilloscopes I have had, do not have 230 V out on  Chassis ground, and also on probe tip. And all other  electrical instruments I have do not have it.

Do the other instruments have:
"WARNING: MAINTAIN GROUND TO AVOID ELECTRIC SHOCK"
engraved in large letters on them?

[Harvs]

I returned the Rigol DS2072, maybe I should buy it again.

I hope it didn't cost you anything to return it!

[g2]

When Rigol DS2072 is not grounded, it have 115 Volt  (or 230 Volt) on chassis and also on probe tip.
Completely without being connected to other equipment.
All my old analog oscilloscopes I have had, do not have 230 V out on  Chassis ground, and also on probe tip. And all other  electrical instruments I have do not have it.

Do the other instruments have:
"WARNING: MAINTAIN GROUND TO AVOID ELECTRIC SHOCK"
engraved in large letters on them?

My old oscilloscope (Hitachi V-525) have it engraved, and I've never had it grounded.
And it's never been 115 or 230 V on its chassis.
Grounding was in the past for extra protection.
Now, it is obviously necessary.
As I have said before, in Denmark we were first grounding in new houses about 1995 (in wet room before). I would have been happy for a digital oscilloscope, who absolutely not have to be grounded.
Now Harvs come with the explanation why it does so.

[marmad]

Grounding was in the past for extra protection.
Now, it is obviously necessary.
As I have said before, in Denmark we were first grounding in new houses about 1995 (in wet room before). I would have been happy for a digital oscilloscope, who absolutely not have to be grounded.

Regardless of wiring in Danish houses, any electronics operated from switching power supplies need to be grounded - and always have. I noticed back in 1988 when I ran my PC without a ground connection that there was 110-120V potential on the metal case.

[g2]

I returned the Rigol DS2072, maybe I should buy it again.

I hope it didn't cost you anything to return it!

It cost me the postage. It was within the rights of return
But it's ok, except if it had been a defect on Rigol oscillosscope.

[g2]

Grounding was in the past for extra protection.
Now, it is obviously necessary.
As I have said before, in Denmark we were first grounding in new houses about 1995 (in wet room before). I would have been happy for a digital oscilloscope, who absolutely not have to be grounded.

Regardless of wiring in Danish houses, any electronics operated from switching power supplies need to be grounded - and always have. I noticed back in 1988 when I ran my PC without a ground connection that there was 110-120V potential on the metal case.

You are right.
I did not realize it with switching power supplies.
And coincidentally, I have had my PC grounded, but it was for another reason (I thought). At the time I pulled the ground cord from the wet room to my hobby room.
Now I can use the ground wire to a new oscilloscope 

[marmad]

I thought the display is cleared after each trace in normal mode ? 

No, a DPO scope with intensity grading has what you could call a 'Z-buffer' (for lack of a common term) which combines all acquired waveforms. If you have multiple triggers happening within a given time frame (you were set to AUTO MemDepth @ 100ns - which means up to 16,790 triggers per second), they will appear simultaneously on the display with the minimum 'decay' time (or longer - if you have persistence set higher) - and WAITing for a trigger freezes the decay. This is actually advantageous - and helps spot multiple triggers and glitches.

BTW, here's an interesting document on different techniques used for intensity grading (courtesy of tinhead). 

[Teneyes]

they will appear simultaneously on the display with a minimum decay time (or longer - if you have persistence set higher) - and WAITING for a trigger freezes the 'decay'. You were set to AUTO MemDepth @ 100ns - which means up to 16,790 waveforms per second.  This is actually advantageous - and helps spot multiple triggers and glitches.

aaaaah Yes,  Thanks Marmad,

[bambam]

Hi all newbie here to the forum.

I hope its ok posting this here so late in the thread but, i just wanted to share my appreciation towards marmad for his help with upgrading my ds2072 firmware. he is super guy and its thanks to his brilliant video review and this thread i purchased the scope.

The ds2072 is my first ever scope and so far found it so easy to use and its made electronics hobby so much more enjoyable.

[Wim13]

@Marmad, Waveform update rate..

When on 20 nSec timebase:
and input of a signal of 10 Mhz i get 41.000 WFM/sec
but when change input to 60 Mhz it drops to 22.000 WFM/sec

On 1uS timbase:
and input of 1 Mhz, i get 2.900 WFM/s
but with 10 Mhz it drops to 1.900 WFM/s

On 20 nSec timebase:
and 1 Mhz i get 46.000 WFM/s but change timebase to fine and 20.05 nSec it drops to 5.000 WFM/s

How does that fit in your explanation video about WFM/s, i dont get it.

[marmad]

When on 20 nSec timebase:
and input of a signal of 10 Mhz i get 41.000 WFM/sec
but when change input to 60 Mhz it drops to 22.000 WFM/sec

On 1uS timbase:
and input of 1 Mhz, i get 2.900 WFM/s
but with 10 Mhz it drops to 1.900 WFM/s

On 20 nSec timebase:
and 1 Mhz i get 46.000 WFM/s but change timebase to fine and 20.05 nSec it drops to 5.000 WFM/s

How does that fit in your explanation video about WFM/s, i dont get it.

Well, since the waveform update rate is comprised of three distinct sections (i.e. acquisition time + fixed blind time + variable blind time), the rate could be affected by anything you do - depending on how the DSO manufacturer implements things - because they could affect the variable blind time. It's clear the DS2000 was finely tuned to be able to achieve ~50k wfrm/s in order to directly market it against the Agilent 2000X, but it only achieves that rate under very precise conditions.

I've noticed myself when testing that the wfrm/s rate can change depending on the input frequency - perhaps due to the way that the trigger circuitry is being processed (i.e. excess triggers cause a slight interruption in the process - even if they don't trigger another acquisition). But this might be common in DSOs - I've never tested it. Mostly when you see charts of wfrm/s speeds, they are specified against a particular input frequency.

[Galaxyrise]

Or if someone could post just ONE 'before/after' example of it actually 'minimizing' aliasing, I would be happy 

This seemed like it might be interesting to play with, so I fed the DSO various frequencies and looked for an example where AA looked better.

The first thing I discovered is that Anti-Aliasing and High Res don't get along.  The difference is super obvious in dots.  In my tests, AA always made aliasing worse in High Res. I suspect Averaging, which was on in Xas' post is susceptible to the same problem.

I've only seen AA produce an improvement in cases where the scope was displaying low intensity.  So if you have dim traces, or a dim swath, turning on AA may add detail.  In the first normal acquisition images, you see that the vertical portions of the traces got more intense and easier to follow with the eye.  But this isn't a typical aliasing case of undersampling the waveform.  I don't know why the trace was so dim to start with.  Even at 185us with exactly 4 periods displayed, the wave (in dots) was still pretty dim and wide.  At 100us, it looks correct, and with AA turned on in 185us, it looks correct.  Is this another kind of aliasing?

The last two images were the only ones I came up with where it looked like AA actually reduced acquisition aliasing.  That's a 15.555555MHz signal.

[marmad]

I've only seen AA produce an improvement in cases where the scope was displaying low intensity.  So if you have dim traces, or a dim swath, turning on AA may add detail.  In the first normal acquisition images, you see that the vertical portions of the traces got more intense and easier to follow with the eye.  But this isn't a typical aliasing case of undersampling the waveform.  I don't know why the trace was so dim to start with.  Even at 185us with exactly 4 periods displayed, the wave (in dots) was still pretty dim and wide.  At 100us, it looks correct, and with AA turned on in 185us, it looks correct.  Is this another kind of aliasing?

The last two images were the only ones I came up with where it looked like AA actually reduced acquisition aliasing.  That's a 15.555555MHz signal.

Thanks for your efforts, GR. With all I've seen, I'm almost of the belief that someone at Rigol told a programmer that they wanted a routine for anti-aliasing - and the coder thought they meant image anti-aliasing - not waveform anti-aliasing. 

Seriously though, if you want to do any more playing around, I would strongly suggest that you don't use 14M or 56M sample lengths - since traditionally, one of the tools to battle against aliasing is to increase sample length (since that automatically increases sample rates and/or samples being decimated for the display). If anti-aliasing works at all on the Rigol, it should first and foremost be working when you have small sample lengths - so that switching it on might (in the background) automatically force the DSO to capture more samples for random decimation (or change sample speeds) in order to prevent the occurrence of the aliased waveform.

[Electro Fan]

I'm not sure if the DS6000 Demo Board has been mentioned before on EEVBlog or not (a quick search didn't turn up anything), but I found it at Batronix while searching for any possible new UltraVision products - and I hadn't seen it before and thought it was kind of interesting. It lists at €163 / $225 (excl.), and I've attached the user guide below.

"This Demo board is used to illustrate the basic functions of the oscilloscope. It is powered through USB port and can output 25 kinds of signals for the illustration of oscilloscope functions, i.e. sine, video (PAL/NTSC), AM Modulation, Sweeps, many digital signals and lots more. Delivery including Demo Board, USB Cable, CD with manual."

It's got the Instek one beat - Instek demo board only does 10 analog and 5 digital/LA functions for $205 list (so probably about $185 discounted).

I might have to get me one of these to play around with.

Hi Greg,

Just checking to see if you might have sprung for one of these demo boards (and where you think one could be purchased for $185?)

- anyone else have any demo boards you like better (new or used)?

Also, any updates on the GWI Logic Analyzer impressions?

[David_AVD]

Those test point "hoops" on that demo board look neat.  Has anyone seen those for sale?

[marmad]

Those test point "hoops" on that demo board look neat.  Has anyone seen those for sale?

Well, in the original post I made (which you can see in the quoted area above), I mentioned I found the device (and images) at Batronix(.com) in Germany.

Here's the data sheet.

[David_AVD]

Those test point "hoops" on that demo board look neat.  Has anyone seen those for sale?

Well, in the original post I made (which you can see in the quoted area above), I mentioned I found the device (and images) at Batronix(.com) in Germany.

Here's the data sheet.

Thank you.   

[Galaxyrise]

Seriously though, if you want to do any more playing around, I would strongly suggest that you don't use 14M or 56M sample lengths - since traditionally, one of the tools to battle against aliasing is to increase sample length (since that automatically increases sample rates and/or samples being decimated for the display). If anti-aliasing works at all on the Rigol, it should first and foremost be working when you have small sample lengths - so that switching it on might (in the background) automatically force the DSO to capture more samples for random decimation (or change sample speeds) in order to prevent the occurrence of the aliased waveform.

I didn't post pictures of the smaller memory depths because AA never did anything for them, not because I didn't try it.  But going back at it, I am able to get a very subtle change at 140k in some situations.  I experimented  with what happens to the sample dots themselves and could find no difference at any memory depth.

And that leads to the final nail in the coffin:  You can toggle AA while STOPped, and it does the same thing as toggling it while running.  So you're right, it's image improving, and not waveform improving. This is true for High Res, too!  Perhaps that explains why you never get 10-bit values out of the scope with RUU: it's entirely a display-time trick.

High Res troubles me in general.  For example, 1Vpp 66,666Hz sine wave at 10us/div, 200mV/div looks great in high res.  Now go to 1ms/div.  The signal shrinks to half amplitude!  Now turn on Anti-Aliasing for some real fun: it... aliases into a 8% amplitude, 5kHz wave.  Changing the vertical scale to 50mv and it halves the amplitude again!  Like I said, AA and High Res don't get along If I try to zoom all the way into the sample dots with high res active, I can't.  I always get a line.

AA does make some of my captures prettier, enhances certain glitches, and hasn't (yet) hidden any transients in my testing tonight.  The biggest drawback seems to be the wfm/s hit (which varies considerably based on the time base and memory depth.)

[Electro Fan]

Sorry for being off topic on the current thread conversations, but since this seems to be Rigol 2000 Central is it correct that the I2C and SPI decoding option for the 2000 series (which also includes the RS232 decoder) is about $220 vs on the 4000 series you need to purchase the I2C and SPI decoding options separately for about $500 each ($1k total)?   Thanks

PS, decoder pricing aside, I've tried to stay up to speed with this 80 pager on the 2000 and other Rigol threads, but if anyone can post/paste links to anything that nets out the differences between the Rigol 2000 and 4000 series that would be great - Thx again

[EV]

http://www.batronix.com/shop/oscilloscopes/Rigol-DS2202.html
Click accessories!

http://www.batronix.com/shop/oscilloscopes/Rigol-DS4022.html
Click accessories!

[Electro Fan]

http://www.batronix.com/shop/oscilloscopes/Rigol-DS2202.html
Click accessories!

http://www.batronix.com/shop/oscilloscopes/Rigol-DS4022.html
Click accessories!

The prices in your links look better than the ones shown here:

http://www.tequipment.net/RigolSD-I2C-DS4.html

http://www.tequipment.net/RigolSD-SPI-DS4.html
At Batronix it seems like the I2C and SPI decodes are packaged together for the DS4000, but at TEquipment they are packaged seperately ?

It seems there are two "issues":  1) the pricing on the 2000 accessories are less than the 4000 accessories (seems to be an industry standard trend followed by various manufacturers) and 2) for some reason in the U.S. the accessories are bundled differently which raises the pricing.

[ncross]

Thanks to everyone for the plethora of good information, bugs, comparisons, quirks... It makes purchasing one of these a much more transparent process.  Especially to a noob like me considering a first scope.

[van-c]

Thanks to everyone for the plethora of good information, bugs, comparisons, quirks... It makes purchasing one of these a much more transparent process.  Especially to a noob like me considering a first scope.

Welcome aboard.  Several noob's in your company.  I pulled the trigger on a DS2072 but still waiting for shipping in US.

--Van

[CodyShaw]

Looking to buy a 2072 either today or tomorrow. Looks like it still is a very good option!