REVIEW - Owon SDS7102 - A look at the SDS series from Owon

[marmad]

Why did you make your SDS7102 reviews on youtube private?

If you've been reading this thread then you might have an idea from my previous posts, but to clarify:

1) This thread has become rather a mess - partially because of the way it developed during the making of the 3 parts of my video review (and my own shifting feelings about the scope) - and partially for other reasons mentioned earlier. This is evidenced by a comment you yourself made 5 days ago that was incorrect:

That said, most of the issues he outlined in his early posts have been edited as data came back that OWON had indeed directly addressed them in FW and HW updates.

2) As mentioned previously, my videos (the early, most positive ones) have been found embedded in commercial sites selling the Owon. As you might imagine, I didn't make the videos as advertisements for people with financial interests at stake.

3) Lastly, I get a fair amount of PMs and emails from people who are a bit confused and looking for a more definitive answer about scope recommendations.

So,  I'm trying to figure out the best way to consolidate my final thoughts/reviews in one place - and to try to suppress the usage of my efforts as commercial advertisements. To do this, I think I need to re-edit the 3 small videos into 1 or 2 longer pieces - so I made them private temporarily - but they will be made public again later.

That reminds me of the school kid who takes his ball home when things dont go his way.

Hmm... I'm not sure I understand your analogy. This isn't a game; I spent my own time and energy creating and posting the videos and review threads to help other prospective buyers. Whatever I want to do with my videos - including moving them, re-editing them, deleting them, etc - is my own prerogative - just as it will be yours if you spend some of your own time doing the same.

[EU1]

I've replaced the board but had faced with another issue: there ia a large interferences caused by backlight LED DC-DC converter. Earlier on old board I've discovered some weak interference from backlight (https://www.eevblog.com/forum/product-reviews-photos-and-discussion/review-of-owon-sds7102/645/), but it disappeared when I connected a 50 Ohm BNC terminator or probe, even when I connected a 10kOhm resistor or any signal source with any output impedance there was no interference, so it did not affected measurements because it was visible only when nothing is connected to inputs.
I've compared peak level of noise of my oscilloscope with screenshots which other people shared on the Internet and found it is about the same. Thus I've considered that it is OK, now I have reasons to gues that it is not OK .

With new mainboard interference is much larger and they are enlarged when I connect terminator to input. I've installed the old mainboard again and see the same very small interference visible only on open input. Thus it is not due to incorrect installation - because I swapped boards few times and always I get negligible interference with old board and large interference with the new one.

The problem appears when powered from battery or from AC mains. So it is definitelly not a PSU problem.


I've made screenshots with new boards. X10 probe configuration is selected for both channels. I just forgot to switch it to X1, thus V/Div readings on the screen should be divided by 10 to get the actual input sensitivity.
An interference on both channels is the same. I leave CH1 open (no probe connected) and connect 50 Ohm BNC terminator to CH2 to show that 50 Ohm terminator increases an interference.

NewBoard_1.png: CH1 is open, CH2 shorted to ground through 50 Ohm BNC terminator, brightness is 0%.
There RF noise extremely low for 2mV/Div sensitivity. Seems that it is even much lower than a noise on the old board.
But there is a terrible 30kHz interference from backlight LED driver.

NewBoard_2.png: CH1 is open, CH2 shorted to ground through 50 Ohm BNC terminator, brightness is 100%.
30kHz noise is much lower comparing to an interference with 0% brightness, but it is still present and spikes occasionally appears.

NewBoard_3.png: FFT for CH2 which is shorted to ground through 50 Ohm BNC terminator, brightness is 0%.
30kHz interference with harmonics is clearly visible.

NewBoard_4A.png, NewBoard_4B.png: Even with low sensitivity 30kHz interference is clearly visible. With 2V/Div interference is higher than with 1V/Div. Thus interference comes rather through power line than through input.


It doesnt look like a mainboard issue, because there are a lot of DC-DC converters on the adapter board and on the mainboard itself and only an LCD backlight step-up causes interference. I guess that a mainboard of new revision is just more sensetive to low-frequency ripple on supply voltages rails and a real problem is a LCD backlight step-up on the adapter board or new mainboard has some compatibility issues with old adapter board (I'm not sure that OWON changed adapter board, this is only an assumption). There are a lot of changes in analog and power management parts on the new board comparing to my old one.


Thus I would like to ask people who have SDS7102 - have you any signs of 30kHz noise with visible low display brightness with open input (no probes connected)?
Because I have this noise on two mainboards of different revisions - on old 1209*** it is wery weak and produces no visible impact on measurements, but it is still visible when nothing is connected to input BNC, especially on FFT. On new board (1211****) interference level raises when I connect a probe. I've recorded a video, you can see that on 2V/Div with an input is connected to probe compansation output an interference just makes any precission measurements impossible (while on 1V/Div it is much lower):



And the second strange thing - I've noted some strange behavior of external synchronization input when it is configured to trigger on falling signal edge, on old mainboard the trigger works fine, so owners of 1211**** devices, please check check is this issue appears on your devices. On the video both ext trigger input and a channel input are connected to probe compensation output and an AC coupling is selected for trigger and channel input itself:

Resolved by adding an inductor on 5.4V rail as it was proposed by OWON.

[aghp]

ZAP
Contact seller (if seller is ok with Owon they can negotiate it with Owon, it must not be end user problem if reseller is real ok) or directly Owon hk service and tell failed TFT.

my seller told me i need at least 3 dead stuck on pixels to be considered a bad lcd, so else i will pay for exchange and there is no warranty i will get one without bad pixel ...

so i think i can live with it, until i have enough money to buy a scope from a better company...

here an update with my Owon scope's problems

bad stuck on green pixel :

i got update from my ebay seller and also from Owon's service,  1 bad pixel is NORMAL thing and is not a defect...
my seller said i need a bunch of them to be considered has a defect...

so people be aware of that  you may end up with a bunch of them 

bad probe:
for my probe defect, they said they will ship me a replacement ...

Owon is reputable company.
If your reseller is just lazy or loosy it is not so nice.

If there is stuck on pixel in main area of display it is fail!

For resolve this, take GOOD picture where is whole display so that it can easy detect pixel position on the TFT and show exatly its position..

Then also take more close picture to show better this pixel.

Stuck on pixels are NOT accepted on the main area of display.
Remember tat "bad pixel" can not understand.  Example dead dark pixel is totally different case and also it is "bad pixel". Pixel or sub pixel what is always bright on is classified much more bad and also it is "bad pixel" but there need make big difference between different fails and where is fail position on the display area. Of course one sub pixel is not so severe than cluster of pixels but... bright always on pixel in main area, not accepted at all in industrial A grade TFT.
Owon use Innolux A grade display and it need meet this! If not, it is warranty issue = fail and it need repair.
(Also it is not fail what happend later in warranty period, it have been failed as it was new and arrive to you? )

Send pictures directly to Owon. Address you find Owon hk official side.

After then you can tell to whole world how Owon in real life handle this fail so that no one can think Owon is some chinese crap company. They have good after sales customer care and they want really handle rare warranty fails as reputable companies do.  It may littlebit also understand chinese cultural differencies for succesfull hadling problems.

If you have communication problem with Owon, please ask some help so that can do successful negotiation with Chinese company. 

Owon want be, and they are, real reputable company who really care also quality and they will care customers also after get just money. This they want be and this they need also show - I know they want.  I believe they want rise they brand from dark where they was before years  after they launch they first model 6-7 years ago.

All do mistakes, all brand can be warranty fails,  but who repair mistakes and care about this there are real differencies. There can separate reputable companies and crap companies.

If your display do not meet quality class it is fail and it need repair.

First people who there answer to your email maybe do not have  enough power or knowledge for solve your situation or classify this problem or he/she maybe did not understand what you are talking and what is exactly problem.




-aghp

[bobpitt]

Hi,
I just received my SDS7102 today from ebay seller. I am measuring my circuit shown in picture 1 (ch1 on pin 10, ch 2 on pin 11) which is a 12v inverter(this circuit works properly before I get OSC). I am measuring by press "Autoset" button, the result is shown in picture 2(osc_1.png) why not picture 3(osc_2.png).

Sorry for my bad English.

Bob

[EV]

Maybe you have alt trigger mode on. Change it to Ch1 mode.

[rf-loop]

Trigger is in ALT mode or CH2 is inverted.

Just first, set factory default. (in utility menu)

Then use autoset.
       -  if you do not want learn how to adjust manually oscilloscope for good settings.

If tsill result is same, really look that trigger source is CH1 (or CH2)
(btw, if you have selected ALT trig mode and selected trigger frequency to display you get 2 frequency window on the right bottom corner.

Autoset do not always give best result (and important, it do not touch all settings. What settings it affect is described  user's manual (Mar 2012 edition 1.4.5) side 73.

(autoset is ok but sometimes with more complex signals it is very good to learn how oscillocope work and how to setup it manually. Specially it is important to know if you have changed some settings what autoset do not touch! And how they affect)

[bobpitt]

Hi, EV and rf-loop
Thank you very much for your comments

Maybe you have alt trigger mode on. Change it to Ch1 mode.

Before I use Autoset I set my OSC shown in the picture 1(snap1.gif) an trigger source is CH 1.
When I press Autoset button it automatically changed to ALT mode but if I only use CH 1(CH 2 disconnected) , it's not change from  Single mode to ALT mode.

Trigger is in ALT mode or CH2 is inverted.

Just first, set factory default. (in utility menu)

Then use autoset.
       -  if you do not want learn how to adjust manually oscilloscope for good settings.

If tsill result is same, really look that trigger source is CH1 (or CH2)
(btw, if you have selected ALT trig mode and selected trigger frequency to display you get 2 frequency window on the right bottom corner.

Autoset do not always give best result (and important, it do not touch all settings. What settings it affect is described  user's manual (Mar 2012 edition 1.4.5) side 73.

(autoset is ok but sometimes with more complex signals it is very good to learn how oscillocope work and how to setup it manually. Specially it is important to know if you have changed some settings what autoset do not touch! And how they affect)

I set trigger to Single but it changed to ALT mode as I mentioned above.
CH 2 is not inverted and CH 1 is trigger source.

In the manual Mar 2012 Edition 1.4.5 Page 73, the Trigger Type is current means no change? but it's changed.
http://owon.com.hk/down-en.asp?bigclassname=%CB%B5%C3%F7%CA%E9%CF%C2%D4%D8

Actually, I know how to manually adjust oscilloscope without Autoset button , but I just want to test my SDS7102 for first time.

[rf-loop]

Hi, EV and rf-loop
Thank you very much for your comments

Maybe you have alt trigger mode on. Change it to Ch1 mode.

Before I use Autoset I set my OSC shown in the picture 1(snap1.gif) an trigger source is CH 1.
When I press Autoset button it automatically changed to ALT mode but if I only use CH 1(CH 2 disconnected) , it's not change from  Single mode to ALT mode. Or better if they cancel  change.

Trigger is in ALT mode or CH2 is inverted.

Just first, set factory default. (in utility menu)

Then use autoset.
       -  if you do not want learn how to adjust manually oscilloscope for good settings.

If tsill result is same, really look that trigger source is CH1 (or CH2)
(btw, if you have selected ALT trig mode and selected trigger frequency to display you get 2 frequency window on the right bottom corner.

Autoset do not always give best result (and important, it do not touch all settings. What settings it affect is described  user's manual (Mar 2012 edition 1.4.5) side 73.

(autoset is ok but sometimes with more complex signals it is very good to learn how oscillocope work and how to setup it manually. Specially it is important to know if you have changed some settings what autoset do not touch! And how they affect)

I set trigger to Single but it changed to ALT mode as I mentioned above.
CH 2 is not inverted and CH 1 is trigger source.

In the manual Mar 2012 Edition 1.4.5 Page 73, the Trigger Type is current means no change? but it's changed.
http://owon.com.hk/down-en.asp?bigclassname=%CB%B5%C3%F7%CA%E9%CF%C2%D4%D8

Actually, I know how to manually adjust oscilloscope without Autoset button , but I just want to test my SDS7102 for first time.

Oscilloscope features change first and then later they update manual after they collect group of changes.

In this case it looks like this manual version have obsolete information.  Mar 2012, of course it is old and obsolete.


My opinion is that autoset must not force it to ALT mode! (Why they have changed it.)
Becouse more frequantly  need  CH1 and 2 signal have time sync. There are many scopes what do not have ALT trig mode at all.

We need wait agen new updated manual.

Or better if they cancel this change so that this manual text is right.

It is better to do more important developments!

[tinhead]

try autosetup with exact the same signal on both channels (e.g. Q to both channels), just to double check that this is default
autosetup issue or just one created by asynch signals (where alt trigger make sense).

[bobpitt]

try autosetup with exact the same signal on both channels (e.g. Q to both channels), just to double check that this is default
autosetup issue or just one created by asynch signals (where alt trigger make sense).

Hi, tinhead

I tested as your recommendation. The result is same.

If this change occurred by design , I think it is very mistake.

[rf-loop]

try autosetup with exact the same signal on both channels (e.g. Q to both channels), just to double check that this is default
autosetup issue or just one created by asynch signals (where alt trigger make sense).

If this change occurred by design , I think it is very mistake.

Personally also I do not like this. I like if it do not touch ALT, if user selected it, it kep it, if not, it do not turn it on.


On the other hand if someone connect two, not sychronized signals to oscilloscope inputs and push autoset. What happend if it do not touch to autoset. Then he ask why autoset do not work. Name is autoset but it works only partially.
This is always problem. One case people like orange but sometimes he like bicycle more and sometimes orange is better.

But personally and also becouse it is terrible difficult to really regognize if ALT is better than other setting, it is better that autosetup do not touch this. It is better that user know how to use oscilloscope and what he is really doing.

How much autoset need do? What is need never do, what it need always do, what it need try if do not find settings. How fast autosetup need be.

This is my opinion that it must not change trigger mode. But it need regognize if there is only one signal and select only it to display (close unused channel) and select used channel to trig source. But then, if there is some other trigger settings than facory defaults allready by user. How much these settings autosetup need change?

But becouse it is extremely difficult to know if really need ALT, it is better to do simply. If there is one signal, it is clear what to do. If there is two signal, protocol is best be so that it try find CH1 settings and trig and adjust CH2 level so that peak levels do not overshoot.

But in final game, there is not exactly one right way. It is only collection about different opinions if look all possible situations and all waht autoset need do and what not. Possible "right" combinations for autoset protocol is "lot of".

As long as this work like this here explained and if really "need" autoset, just connect CH1 and push autoset.
Turn then CH2 on and select this known V/div for CH2.

What if user have forget to ALT mode... do it need cancel it?  It can also think that oscilloscope may have several users.

My first wish to Owon is that default is not behind menu. It need be directly front panel HW.

But there is so many different needs and opinions.
After bowing to the east - looks back on the west.

[voidptr]

@rf_loop
@aghp
thanks for your comments :-)


so here what happen since my last message, 

fast resume:
when i received my scope i found i have 1 always stuck on bad pixel.
i also had a bad noisy probe.

my ebay seller,  said to me he will send my 2 new probes, i got them Monday after trying then i also found i have another one  busted...


so i just retake better pictures and a video of my test on probes.

----
bad pixel



-----
bad probes
http://s1114.photobucket.com/albums/k539/n45w73/dev%20stuff/?action=view&current=badprobes2of4.mp4

i started with the 2 bads probes,
the first (the new bad on i got Monday) seems to be grounded, i start at 1v and connect it to square wave calibration,
and i had to go to 20mV to see a distorded signal, of course it cant be calibrated...
sometime when you move it around noise appear but not has bad noise as the second probe
 the second bad one shows buzz noise when i got to 20mV
 
then i switched to the 2 goods one ...
showing both correct 5v square wave ...
and they are not showing any noise when i move the wire around ...
so 2 bads probes of 4 ....
---------------------




SO ...

i just resent a new message to   service@owon.com.cn
telling them my concern and wondering about the quality of their product.

i also just resent a message to my ebay seller with the same concern ...



so i will wait and see what happening ...

i have so much other stuff to do than deal with that kind of problems ...

    

[pullin-gs]

One bad pixel?
Not meaning to sound rude, but I am curious why you are even wasting you time trying to chase that down?
.....and you have two good probes now.
What more do you expect?
A new replacement scope?  If so, just come out and tell the vendor so, and pack it all back up for a refund.  Why drag it out?

[marmad]

One bad pixel?
Not meaning to sound rude, but I am curious why you are even wasting you time trying to chase that down?

Well, bad pixels on an oscilloscope screen equate to bad data - whenever a waveform crosses near the pixel, it will appear as if the bad pixel(s) are part of the waveform. Granted one pixel isn't much, but the screens are so damn tiny on these scopes to begin with - and, let's face it, the devices are kind of expensive compared to similar non-measurement equipment - I think I'd want to see if I could get an exchange myself.

[pullin-gs]

Well, bad pixels on an oscilloscope screen equate to bad data

Nonsense. 
99% of plots are waveforms (scope connects the dots), not x/y plots.  Not only will the dot not be a part of the waveform, but it will have no value in the "data" of the digital waveform

I think I'd want to see if I could get an exchange myself.

Exactly!  That is my point.  Why beat around the bush about it with post-after-post, documenting with very detailed pictures of the perpetrator-dot.   Get a new scope and be done with it.

[pullin-gs]

Back on topic.
When I run an FFT, the frequency reading (using cursors) on the scope is off.
However,  the frequency of the same waveform is spot-on when viewed using the PC software.
This is not random.  It happens everytime.
Scope is new with LAN/VGA hardware (got it 2 weeks ago), version 2.6

Test#1 setup and data:

Input is CH1, or CH2....it matters not....both behave same.
My test signal is a 27.25MHZ sine-wave (XTAL-controlled),
I take a 10db reading at 5MHZ,  giving sample resolution is about .025Mhz (50mhz/2040)
On the scope, the frequency reads 27.44 (using cursors) at leftmost part of screen.
Move the 27.25MHZ point to the center of screen, frequency now reads 27.30.
Move it to far right, frequency reads 27.30.
When I download the same waveform to the PC software, ALL readings (27.24mhz) are spot-on to within a single sample resolution of .025MHZ.
The scope-interpreted readings can be as much as 10(!) samples off!

Test#2
The same thing happens with a 72.9MHZ signal, but it is more pronounced.

Any ideas?

PS: this single thread is the best OWEN SDS hardware/software discussion on the net!....even with all that green-pixel talk!

[marmad]

Nonsense.
99% of plots are waveforms (scope connects the dots), not x/y plots.  Not only will the dot not be a part of the waveform, but it will have no value in the "data" of the digital waveform

I understand that the bad pixels have no value in the actual digital data - but the displayed waveform (the pixels illuminated on the LCD) is the 'data' which you retrieve with your eyes when measuring signals.  As I mentioned before, 1 pixel is not a big deal - but I might be worried that more pixels close by would go bad.  What if you had 5 bad pixels forming a short line? When part of the waveform being measured intersected or touched that line, and you looked over at the screen, you would see a waveform (the 'data') that was partially incorrect - with an extra segment integrated into it.

This seems an obvious point - you get most of your 'data' from the scope by looking at the screen. If the screen starts going bad - it interferes with getting good data just as a bad probe would.

[bobpitt]

A new software bug?

It is happened(random) when I use Autoset button and CH 2 floated, CH 1 connected to circuit.

[rf-loop]

A new software bug?

It is happened when I use Autoset button and CH 2 floated, CH 1 connected to circuit.

CH2 floated and picked up something as signal and you press autosetup. You try to some kids play or just fun?

How this oscilloscope can know if CH2 signal what it see is real what you want look or if signal is just something from some floating wire?  With oscilloscope perspective this is signal and autosetup  try find "guess" what it is and try find settings for this signal.

"autosetup"  other function is: "Lets look if you (oscilloscope) are more clever than me."

You can also try to connect some antenna to both inputs and try if autosetup can guess what is going on.

Try this. take old analog "museum" TV set and 4 meter wire. Connect  other end of wire to oscilloscope input and other end only two turn over TV without any connection to TV.  Or something other same fun.

Maybe it is time to get first some real experience and skills with test equipments and after then look if equipment work wrong or if it is more clever than user... (do not take seriously)     

With old HP digital I can enable or disable what parameters autosetup can change and what it keep untouched.
Becouse Owon have not this feature it is difficult in some cases as it try scan all posibilities using some priority order.

After soon I will test also. Then I can maybe give real and more serious answer.


Personally I did not like they change it so that autosetup also change some trigger selection.
Some want, some do not want. What is ok for one people is not ok for other.

 

[0xdeadbeef]

Well, I own an SDS8102 for more than half a year now, so I might add some comments
here.

Firstly, I like the size, the silent fan, the 10M record length. The (electrical)
noise level seems to be pretty good for its class. Though some buttons feel a bit
cheap, I'm kinda happy with the hardware side.
I can live with the slow wfs/s, the missing windowed zoom (though I still miss it)
and the crappy PC GUI.

What lowers its value for me is the bad implementation of several features,
especially the automatic/manual measurement.

1) The automatic measurements are inaccurate as hell and therefore kinda useless.
With 500MS/s or even 1GS/s, a 100µs period is displayed as 100.000µs as is an period
of 100.12µs
When the period gets a bit larger, the period jumps to 0.100ms.
With 500MS/s, measurements down to 10ns should be easily possible, so this is
either a buggy or bad implementation.

2) Even worse, accurate manual measurement is also not possible. While you
could measure with the cursors, the problem is that both cursors must be visible
at the same time. If you zoom in or out, the cursors remain at their screen
position, not at the sample where you put them.
And if you try to measure completely manually by subtracting cursor positions
related to the trigger point, this also fails as the cursor positions are
displayed as 0.XXXms for anything larger than 100µs.
So all in all, it's impossible to measure with a better accuracy than 1µs in
a 100µs period.

3) There is no kind of statistics for measurements (min/max/mean/standard deviation)

4) There is no gating implemented for measurements.
Indeed you can't even see which period was measured as nothing is marked. You just
get one value displayed and can't trust it, because you don't know where it was
measured. Even if there is only one possible position, the measurement is still
inaccurate (#1).

5) Simple measurements as number of pulses/edges between cursors are missing.

There are other things that are weird or a little annoying
1) "Save / Wave" saving only one channel and "Copy" button not using the last
setting (e.g. Image). Also
2) You can't e.g. change the record length when the scope is stopped.
3) The trigger level cursor is always pink and doesn't use the channel's color
4) In cursor mode, the vertical knobs change the cursor positions, but pushing
the buttons still resets the vertical position, not the cursor position.
5) Edge triggering on "both" edges is not possible
6) Changing from "Normal" to "Auto" trigger mode is clumsy (3 key presses):
Trigger Menu -> Single&Holdoff -> Auto/Normal
There should be a button on every scope, but if not, it must be at least in the
fist menu level as you need it all the time.

All in all, it's a shame to see that the SDS scopes are so much limited by their
software. And as Owon managed to implement only a few bugfixes and even
fewer marginal improvements in over one year, I kinda lost hope that the SDS
line will ever reach a level where they really live up to their expectations.

Honestly, what's the point in having 1GSa/s and a 10MPts memory if you still
can't measure anything below 1µs accurately in a 10µs/div setting?

[rf-loop]

Well, I own an SDS8102 for more than half a year now, so I might add some comments
here.

Firstly, I like the size, the silent fan, the 10M record length. The (electrical)
noise level seems to be pretty good for its class. Though some buttons feel a bit
cheap, I'm kinda happy with the hardware side.
I can live with the slow wfs/s, the missing windowed zoom (though I still miss it)
and the crappy PC GUI.

What lowers its value for me is the bad implementation of several features,
especially the automatic/manual measurement.

1) The automatic measurements are inaccurate as hell and therefore kinda useless.
With 500MS/s or even 1GS/s, a 100µs period is displayed as 100.000µs as is an period
of 100.12µs
When the period gets a bit larger, the period jumps to 0.100ms.
With 500MS/s, measurements down to 10ns should be easily possible, so this is
either a buggy or bad implementation.

2) Even worse, accurate manual measurement is also not possible. While you
could measure with the cursors, the problem is that both cursors must be visible
at the same time. If you zoom in or out, the cursors remain at their screen
position, not at the sample where you put them.
And if you try to measure completely manually by subtracting cursor positions
related to the trigger point, this also fails as the cursor positions are
displayed as 0.XXXms for anything larger than 100µs.
So all in all, it's impossible to measure with a better accuracy than 1µs in
a 100µs period.

3) There is no kind of statistics for measurements (min/max/mean/standard deviation)

4) There is no gating implemented for measurements.
Indeed you can't even see which period was measured as nothing is marked. You just
get one value displayed and can't trust it, because you don't know where it was
measured. Even if there is only one possible position, the measurement is still
inaccurate (#1).

5) Simple measurements as number of pulses/edges between cursors are missing.

There are other things that are weird or a little annoying
1) "Save / Wave" saving only one channel and "Copy" button not using the last
setting (e.g. Image). Also
2) You can't e.g. change the record length when the scope is stopped.
3) The trigger level cursor is always pink and doesn't use the channel's color
4) In cursor mode, the vertical knobs change the cursor positions, but pushing
the buttons still resets the vertical position, not the cursor position.
5) Edge triggering on "both" edges is not possible
6) Changing from "Normal" to "Auto" trigger mode is clumsy (3 key presses):
Trigger Menu -> Single&Holdoff -> Auto/Normal
There should be a button on every scope, but if not, it must be at least in the
fist menu level as you need it all the time.

All in all, it's a shame to see that the SDS scopes are so much limited by their
software. And as Owon managed to implement only a few bugfixes and even
fewer marginal improvements in over one year, I kinda lost hope that the SDS
line will ever reach a level where they really live up to their expectations.

Honestly, what's the point in having 1GSa/s and a 10MPts memory if you still

Maybe there is many errors or just simple, SDS7102 is better.

Only two examples.

a)

"3) The trigger level cursor is always pink and doesn't use the channel's color"

No, trigger level cursors are yellow to CH2 and red to CH1.


Cursors are for measurement using human eye so it also follow DISPLAY resolution, not sampling resolution.

b)

"can't measure anything below 1µs accurately in a 10µs/div setting?"

Cursors "step" resolution on the display in this case is 0.2us. and this becouse 1div is 50 pixel
How human can use cursor measurement more fine than display resolution.

Accuracy is related also to sampling timebase.

I just test.

Signal 50 000 000 Hz +- 0.01Hz

Oscilloscope warmed, and >half hour on.
Mem 10M
CH1
10us/div.

Single capture.

Zoom in to 2ns/div.
As accurate as human eye with 8x magnifier can with cursors so that can really check it is just righ in pixel level sure..

Cursors delta 20.00ns
(cursors moving resolution now of course 0.4ns (becouse 50pix/div)

captured with 10us/diV and measured better than 1ns real accuracy in this case.

Then I run scope 2ns/div with same signal. Result exatly same.
Ok, with 2ns/div automatic measurement show Period 20.00ns
Freq 50.00MHz, Cycle  RMS 15.25mV  (signal generator 15.9mV)
Of course there is now termination resistance error and oscilloscope BW flatness error. (signal is 50MHz and so littlebit attenuated).

Then just for fun.

Tektronix scope calibrator CG5001
1kHz
1V/div x8

Owon (CH1 DC, 10k mem, 100us/div):
Period 1.000ms, duty 50%
Peak-peak 8.080V
Vamp 7.920

With cursors
Period 1.000ms
Level 7.96V (Adjusted for best match possible with cursors resolution (0.04V)
It is good to remember that ADC vertical resolution is 8 bit. (not real accuracy)


Then scope calibrator to 10kHz
measure period.
With cursors there read 100.000us.
10div or less with this setting cursors reading step is 0.2us.
Over 10div cursor step continue 1pixel on display BUT reading step change to 1us.

But, honestly I can not see any kind of accuracy problem but just opposite. Owon is amazing accurate in this price class. (But I do not like it change cursors reading resolution if cursors delta is more than 10div on the display.)

In what oscilloscope you can measure with cursors more accurate and with more resolution what is display itself?

[0xdeadbeef]

Well, I almost guessed that it doesn't use the sample memory, but the display buffer for measurement, but this is crap of course. I'm aware that even Agilent scopes in the higher price range do it the same way, but that's one reason more to dislike them.
At least the better LeCroy scopes (WaveSurfer/WaveRunner) always measure in the sample memory though. It's a mystery to me why anybody could assume that measuring in the display buffer was acceptable. IMHO this makes measurements more or less senseless, as it's more guessing than measuring.

Anyway, with any other DSO I ever worked with (even those CRT based Agilents, LeCroys and Tektronix from the late eighties), it was possible to move the cursors inside the sample buffers without the need to always show both of them. So it was always at least possible to do accurate manual measurements by setting the cursors in a zoomed view. As this isn't possible with the SDS scopes either, they make it impossible for me to do exact measurements.

All in all, the 10Mpts sampling buffer (letting aside that using 2GSa/s cripples it to 10k) is still nice to have, but its potential is not used at all. There is no convenient zoom feature, no way to search for data in the sample memory, no way to do (accurate) measurements in the sampled data.

Honestly, I'm toying with the idea of selling it an buying something else which is more usable...

[marmad]

@0xdeadbeef - Yes, I think most of us agree that the Owon has fine hardware and build quality - especially for it's price class. But unfortunately, it's been encumbered with crap firmware - on many levels.

There is the minor level - which is just annoyance. Such as not being able to change screen colors, fonts, design errors in the user interface, etc.

There is the medium level - which goes beyond annoyance - to slowing down your work due to missing or badly implemented features. In this category I would include lack of tools to mark and search easily in large records, the crappy PC GUI (and lack of SCPI commands, etc), some of what you mentioned, etc.

Lastly, there is the high level - where the firmware actually gets in the way of the quality of the data you can capture with the scope. This is also some of what you mentioned in your post, no fine control in vertical adjust, a clumsily-written sampling routine (which appears to work always the same, regardless of record depth), etc.

But it IS stable 

As of now, I think of the Owon as a good cheap learning/teaching scope - especially with the VGA and LAN outputs, but while I DO like the Owon hardware, the delivered firmware just seemed too much of a compromise for me when spending >$500 for something.

So I opted to return it while I could get a full refund and wait - either for them to revamp their firmware to take advantage of their nice hardware (which they don't appear to be doing - at least not anytime soon) - or else for a new scope which would fit my needs better - even if costing more.

Well, the Rigol DS2072 is almost here - and though it costs twice as much as the Owon - from what I've read, it seems way more than 2x better. No battery or VGA - but those features were always just 'bonus' ones for me anyway - not things I really needed. But we'll have to see what it's like when it arrives.

[saturation]

Sorry to hear, I've been following this saga since your initial posts almost 1 year ago.  In the end, a scope can be ergonomic and feature rich, but affecting its measuring fidelity is, IMHO, a fatal flaw.  That's foremost what you want a scope to do.  Since first appearing in ~ 2009??, the Rigol 1052e has not faltered seriously in its basic measuring capacity, and many folks on eevblog have been pushing it to its limits.

...But it IS stable 

As of now, I think of the Owon as a good cheap learning/teaching scope - especially with the VGA and LAN outputs, but while I DO like the Owon hardware, the delivered firmware just seemed too much of a compromise for me when spending >$500 for something.

So I opted to return it while I could get a full refund and wait - either for them to revamp their firmware to take advantage of their nice hardware (which they don't appear to be doing - at least not anytime soon) - or else for a new scope which would fit my needs better - even if costing more.

[SH@RK]

Sorry guys I do not understand everything you said  bu for the summary

Do I get it or not ?

If not , I can not get good ones like Tektronix , so do you have other options for me ?

I can not spend more than 500 $ because the shipping to my place will cost me to much (each lb = 9$) .

marmad

As you are returning it , I think I should not get it , am I wrong ?

When do you think you are reposting your review ?

Thanks