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

[AndrejaKo]

It's a miniature 16GB drive in a solid metal cast body which I use because shitty plastic ones always fall apart on me. If the scope cannot handle 16GB drives then this is truely a deal breaker to me.

It is very clear and it is not any kind of bug:

In Owon User manual: The supported format of the USB disk: FAT32 file system, cluster size cannot exceed 4K.

Then Microsoft:

http://support.microsoft.com/kb/140365

Default cluster size for NTFS, FAT, and exFAT
Article ID: 140365

Image about FAT32 part of article

They should add in drive size instead of saying 4KB cluster size in their manual. Most people won't know off the top of their heads what that correlates to.

There's no sense in setting the value in drive size since you can format the drive and set manually the cluster size. Cluster size isn't all that related to drive size (yes, I'm aware that there are performance concerns with related to number of clusters and so on).

FAT32 supports up to 268_435_445 clusters. If cluster size is the only limitation, then the highest capacity which the scope should be able to read is 1023 GiB*, which is quite a bit bigger than the sizes we're talking about here.

What's the big deal about formatting the flash drive so that it has appropriate cluster size?

*I forgot to take into account maximum FAT size during that calculation, so maximum drive could be smaller, but in any case clusters are not the limiting point here.

[TomC]

I just upgraded my SD7102 to 2.8.3 firmware and the 2.0.8.13 PC oscilloscope software. Everything seems to work properly except the Image and High Memory Depth transfer if I connect via LAN. However WaveForm transfer and Remote Control (in Waveform transfer) work fine. If I connect via USB everything works correctly. I've tried going back to earlier versions of the PC oscilloscope software and connecting the SD7102 directly to the PC via LAN, but I still get the same error for Image and High Memory Depth transfer when connected via LAN. At this point I suspect that this may be a bug in the new firmware. I wish I had tried the LAN feature with the 2.8.2 firmware, but I never got around to it until after the upgrade. Has anybody else ran into this issue? Any ideas will be appreciated!

[AndrejaKo]

With scope connected directly to the PC, try setting the duplex manually to full duplex and try to transfer image or full memory.  To me this seems like an issue that could possibly be related to duplex detection. It will look like it works fine for short transfers, but can start to act strange for longer transfers.

[TomC]

With scope connected directly to the PC, try setting the duplex manually to full duplex and try to transfer image or full memory.  To me this seems like an issue that could possibly be related to duplex detection. It will look like it works fine for short transfers, but can start to act strange for longer transfers.

Thanks for the tip. I manually changed the duplex to full but still get the same error, I also tried changing other Ethernet Controller options like flow control and receive buffer size without success. One other thing that makes me suspect a firmware bug is the content of the Get Data dialog during image transfer. When connected via USB it shows a File Type: bmp and the field used for file size shows 1406kB. However, when connected via LAN it shows File Type: bin and file size 111212kB. The progress field updates for a while and stops at 1406kB, which means to me that the image file was probably fully transferred. But it seems that the PC software is still waiting for the rest of that 111212kB file size and after a while timeouts and emits an error window.

For full memory transfer the situation is a little different. If connected via USB it shows File Type: bin, the file size field has a ?, and the progress field is about 19531kB when the transfer ends. If connected via LAN the File Type and file size fields remains blank and the progress field has 0B. At this point the SDS7102 is frozen and has to be turned Off/On before I can do anything else. In the mean time the PC software timeouts and emits the error window. It seems to me that when the PC software sends the full memory transfer command to the DSO via LAN it causes it to freeze and of course nothing is received by the PC software so it times out.

I'm really curious if anybody else has this problem or if it's just me.

[rf-loop]

Yes I have tested it shortly. It looks like there is added bug in new (2.8.3.) FW.
(I hope they do not start "hantek process" where one fix generate two new problem.)

After I have documented problem I will also send note to Owon.

It is good if also some others do same.

Also in China, there is starting holiday time (Qing Ming Jie) 4. - 6.Apr.
So these days there may be delays in answers. (rush + holiday)

[TomC]

Yes I have tested it shortly. It looks like there is added bug in new (2.8.3.) FW.
(I hope they do not start "hantek process" where one fix generate two new problem.)

After I have documented problem I will also send note to Owon.

It is good if also some others do same.

Also in China, there is starting holiday time (Qing Ming Jie) 4. - 6.Apr.
So these days there may be delays in answers. (rush + holiday)

Thanks for confirming my suspicion. I left a message at OWON's web site explaining the situation. I also have the GND noise problem but I didn't mention that since I'm sure they are well aware of the situation. In the mean time I'm using 3" ground wire instead of the 6.5" wires that came with the probes. This makes quite a difference if you are trying to see signals under .5V. Of course I use the spring grounds when possible, but some times there is no way to get a ground this way.

[7seas]

Hello all,

I am new to this forum and this is my first post. I have been looking at purchasing a Owon SDS7102V scope and ready to order it but then I paused after reading about the "video trigger jitter" and "ground noise problem" in this scope.

I contacted my local dealer (Saelig) with the following question and received the following answer along with waveform captures. It looks to me like the GND noise problem is resolved.

What is your opinion? I am new to DSOs so I am unsure if my conclusion is justified by the screenshots provided by the dealer.

**** Begin question to dealer ****
I want to purchase the Owon SDS7102V oscilloscope but I am concerned about the following two manufacturing defects. Have these been fixed? If I get a scope tomorrow will it continue to have the same problems?

Video trigger jitter

http://owon.forumup.com/about153-0-asc-15-owon.html

Noisy GND problem
http://owon.freeforums.org/under-work-about-gnd-noise-t21.html


**** End question to dealer ****

**** Begin reply from dealer ****

I took a look at both of the links concerning the jitter associated with video trigger.  I also set up an inexpensive camera having an NTSC output for a test.

What I found as that there is jitter on the order of about 1us with the source I used.  This is what I used – the MV401TV-N unit, which sells for about $60.  http://www.saelig.com/product/VI024.htm

The next question I would ask is about the jitter associated with the source.  I don’t have a high-quality reference with which to compare.  However, the signal itself is sufficiently stable to work with, and, if a critical measurement must be made, all one has to do is depress the Run/Stop key and freeze the image.

On the other hand, perhaps this is an opportunity for improvement for Owon, and I’ll pass the issue along to my factory contact. 

While we’re discussing jitter, you should know that the timebase jitter and inter-channel skew for the Owon is very low.  I’ve attached three screen captures of a 10MHz squarewave, where the trigger is on the falling edge.  Channel 1 trace (in red) is shown with infinite persistence turned on – each minor division is 400ps.   Similarly, the inter-channel skew is <200ps.  Incidentally, the Tabor generator is specified at <2ps.

The frequency control on the Owon SDS scopes is quite good, even considering the cost, so that makes me suspect my video source.   

The second question is about baseline noise.  There is discussion on the web about noise spikes being found on the ground connection for the square wave ‘compensation’ signal on the front panel.  This may be leakage from the SMPS, but I have not confirmed this.  At any rate, this does not affect one’s measurements, even at maximum sensitivity.

By paying attention to proper cable routing, the use of high-quality cables and connectors, good grounding techniques, etc. much, if not all, of the ambient noise can be sufficiently reduced to acceptable levels.  I’ve also attached a few photos and screen captures of an SDS7102V scope to show you what can be done at millivolt levels.

The “Baseline noise – normal” is what you will se if the inputs are left open.  The -50dBm pictures are using good-quality cabling and correct impedance-matching (the -40dBm and -50dBm are the same setup, just different settings).  The -40dBm photo shows a 5mVp-p signal. 

**** End reply from dealer ****

[chromesphere]

Hey guys, i got my 6062 and wanted to check for the noise issue, but being a newb, cant work out how to get it on the screen!  I put the volts per div on 100 or 50 mv's and time on 50us.  THe depth is on 10m.  But when i scroll upward the oscilloscope will stop at - or + 10 div's, which obviously will not show the top (noise) part of the square waveform.

The probe is on 10x, i can see the waveform at 200mv but i cant see it at 100mv or 50mv.  Is this because the oscilloscope is 60mhz / 500m/s?

Is there a setting or something i have to change to increase the amount of div's i can scroll upward?  Apologies if this is a really basic question, last time i used an oscilloscope i was 16yo

Cheers,
Paul

[TomC]

Hey guys, i got my 6062 and wanted to check for the noise issue, but being a newb, cant work out how to get it on the screen!  I put the volts per div on 100 or 50 mv's and time on 50us.  THe depth is on 10m.  But when i scroll upward the oscilloscope will stop at - or + 10 div's, which obviously will not show the top (noise) part of the square waveform.

The probe is on 10x, i can see the waveform at 200mv but i cant see it at 100mv or 50mv.  Is this because the oscilloscope is 60mhz / 500m/s?

Is there a setting or something i have to change to increase the amount of div's i can scroll upward?  Apologies if this is a really basic question, last time i used an oscilloscope i was 16yo

Cheers,
Paul

Hello all,

I am new to this forum and this is my first post. I have been looking at purchasing a Owon SDS7102V scope and ready to order it but then I paused after reading about the "video trigger jitter" and "ground noise problem" in this scope.

I contacted my local dealer (Saelig) with the following question and received the following answer along with waveform captures. It looks to me like the GND noise problem is resolved.

What is your opinion? I am new to DSOs so I am unsure if my conclusion is justified by the screenshots provided by the dealer.

**** Begin reply from dealer ****

The second question is about baseline noise.  There is discussion on the web about noise spikes being found on the ground connection for the square wave ‘compensation’ signal on the front panel.  This may be leakage from the SMPS, but I have not confirmed this.  At any rate, this does not affect one’s measurements, even at maximum sensitivity.

By paying attention to proper cable routing, the use of high-quality cables and connectors, good grounding techniques, etc. much, if not all, of the ambient noise can be sufficiently reduced to acceptable levels.  I’ve also attached a few photos and screen captures of an SDS7102V scope to show you what can be done at millivolt levels.

The “Baseline noise – normal” is what you will se if the inputs are left open.  The -50dBm pictures are using good-quality cabling and correct impedance-matching (the -40dBm and -50dBm are the same setup, just different settings).  The -40dBm photo shows a 5mVp-p signal. 

**** End reply from dealer ****

7 seas, I bought my SDS7102 from Saelig last January. At the time I didn't know there was a GND noise issue. However, my scope does exhibit the noise depicted in your video, which is also the same noise extensively described in this forum. From what I've learned, I think GND noise is not a very good name for the problem. As the dealer indicated, with good cabling and good grounding you should be able to view very small signals. This is because the scope's internal signal path is very clean and adds very little to the input signal, so basically, what you see displayed on the screen is the signal you input to the scope via the probe or other input cable without any alteration.

So what is the problem? Some of the circuitry within the scope generates EMI. More EMI than other common electronic equipment usually generates. This EMI doesn't affect the display as long as you make sure that it doesn't reach the scope's input. But this is not always easy to do. For example, if you use the ground wires provided with the probes that come with the scope, which are about 6.5" long, you'll find that they act as a very efficient antenna. So this EMI, which we've been calling GND noise, ends up being input to the scope via the ground wire(s). This makes viewing small signals in the scope's 50mV range difficult, specially if you don't limit the scope's bandwidth to 20MHz.

As I indicated in a previous post, you can reduce this EMI interference by using shorter ground wires for the probes, for example, I try to use 3" ground wires if possible. In fact, you can almost eliminate all of the interference if you use the spring clip provided with the probes for grounding. Of course, this is only possible if the signal source and a suitable ground are next to each other.

Chromesphere, you don't need to display a signal to check for the "GND noise issue". Just connect the CH1 probe and it's 6.5" ground wire to the scope's Probe Comp ground terminal. Set CH1 to 50mV/Div, the sweep to 1mS/Div, and watch the display. Ideally, if there was no EMI being picked up by the ground wire, you would see a very thin line displayed. The thickness of the line basically tells you how much interference is being picked up. With the 6.5" ground wire the line displayed by my scope is between 100 and 150mV. With the 3" ground wire it's between 50 and 75mV. With the ground spring clip it's <20mV.

Also keep in mind that the OWON is not the only possible source of EMI, so if you want to make a more credible test you should turn off fluorescent lights and other electronic equipment in the vicinity.

[chromesphere]

Thanks TomC, your procedure that you described was pretty much how i was connecting it, however, once you lower the v/div to less than 200mv, the waveform goes off the screen and you cannot adjust vertical position enough to see the top of the waveform.

I dont think there is an issue though.  Even in 200mv / div i can sort of see whats going on and it looks like about 20mv of noise which i think isnt alot?  Im in the office at the moment, surrounded by all sorts of electronics (inc fluro lights).

Paul

[rf-loop]

Problem in new FW and LAN

I'm really curious if anybody else has this problem or if it's just me.

I get answer from Owon about new LAN problem.

They have regognized problem and repair is coming soon. (Estimate: inside 2 weeks.)


About "noisy GND". It is discussed also here http://owon.forumup.com/

"noisy GND" is not very good name for this issue. But in time when find this problem it was something like "work name" for this.

This "noise" is EMI noise what is produced inside oscilloscope with several SMPS circuit.
It is mainly as  common mode noise.  It may pollute signal externally (example via GND wire impedance).

Owon signal pathway inside oscilloscope is very clean.  Front end noise level is very low. (also in these "noise issue" units) Clean signal to input BNC and it is clean also on display.

Owon have also worked with this EMI issue. And example units what I get from factory to my stock after half of March there is not this bad high level noise anymore.

[TomC]

Thanks TomC, your procedure that you described was pretty much how i was connecting it, however, once you lower the v/div to less than 200mv, the waveform goes off the screen and you cannot adjust vertical position enough to see the top of the waveform.

I dont think there is an issue though.  Even in 200mv / div i can sort of see whats going on and it looks like about 20mv of noise which i think isnt alot?  Im in the office at the moment, surrounded by all sorts of electronics (inc fluro lights).

Paul

If you got the ground and the probe both connected to the ground lug (bottom lug), there is no waveform, it should be a straight line in the center of the screen.

[chromesphere]

Attenuation on 1x, probe on 1x, coupling ac, the probe connected to the ground terminal on probe comp and ground clip connected to nothing, i get about 12mv of noise approximately.  I dont think this is the right way to do it though, because the ground clip is probably acting like an antenna.  With both connected to ground its about half so 6mv.  with the probe connected to 1khz +5v's and the ground clip on ground, its difficult to measure the noise in the square wave as the top of the square wave isnt flat (its curved) but i would estimate about 24mv of noise at any given point of the curve.

So if your thinking of getting an owon 6062, you can take my noob advise for what it is, but i would say that, well, atleast MY 6062 doesnt have the noise issue.  The 7102 users were saying noise in the order of 100-200mv's!  So far there has been no case that i can replicate that sort of noise, unless im doing something seriously wrong.

Paul

[TomC]

Attenuation on 1x, probe on 1x, coupling ac, the probe connected to the ground terminal on probe comp and ground clip connected to nothing, i get about 12mv of noise approximately.  I dont think this is the right way to do it though, because the ground clip is probably acting like an antenna.  With both connected to ground its about half so 6mv.  with the probe connected to 1khz +5v's and the ground clip on ground, its difficult to measure the noise in the square wave as the top of the square wave isnt flat (its curved) but i would estimate about 24mv of noise at any given point of the curve.

So if your thinking of getting an owon 6062, you can take my noob advise for what it is, but i would say that, well, atleast MY 6062 doesnt have the noise issue.  The 7102 users were saying noise in the order of 100-200mv's!  So far there has been no case that i can replicate that sort of noise, unless im doing something seriously wrong.

Paul

You may want to try with the probe set to x10 and CH1 set to 50mV/Div. With the probe set to x1 the bandwidth is limited to 6MHz, so you won't see the high frequency noise. Also, don't use the 20mV/Div range because it also limits the bandwidth, to 20MHz in this case. So the 50mV/Div range is the lowest range where you can use the scope's full bandwidth. You should also make sure that the Acquire Length is set to the maximum available on your scope to insure that high frequencies are not ignored due to the sampling rate.

The GND noise that's been reported on the SDS7102's is precisely the noise that is picked up by the 6.5" ground wire acting as an antenna. True this noise can come from sources other than the OWON, but careful experiments by rf-loop and others have shown that some internal circuits in the OWON produce a significant amount of EMI that is picked up by the 6.5" ground wire in the absence of other EMI sources. There have been no issue with the scope's signal path. That's why calling the problem GND noise is somewhat confusing.

[rf-loop]

Owon analog front end from BNC to ADC is very clean!
Somewhere 2012 (not remember exactly) they made 1 major change in whole analog front end and it reduce also noise there (somewhere I have these tests). Also earlier version was quite good but littlebit too much random noise. Most old version have more noise but also it was not at all bad.

This (EMI) noise now (more than before) is coming from Owon and in different cases it may connect externally to signal.
Part of noise is radiated and part of noise is conductive.   
Noise frequecy band is least over 200MHz. Noise is "peaks" but these peaks include high frequencies. It can easy look what peak is coming from what SMPS circuit if use ecternal oscilloscope or Owon itself. It need take this noise to other input and then pick-up single  SMPS circuit signal to other channel only for trig. (just capasitive connection near SMPS circuit. After trig  sync it can easy regognize what peak is coming from what SMPS.) Also there is some low amount of TFT databus noise. (oh well, look Rigol youtube where dave put cable near TFT or touch TFT (in this thing Owon is not alone I think)

These noises signals travel in scope ground (whole internal base plate. (Z-plate as owon call it)) and this is source for noise if it can connect to signal.
 
This RF signal travel through GND wire.  GND wire is roughly around 0.2uH inductor. This signal produce voltage over this inductor. Example wirh 100MHz its reactance is totally different as with DC where it nearly zero ohm.

It is just same if common mode noise source is external and if it is example in Device Under Test (DUT) ground.  Only noise "current" flow direction is different but same effect.

This is also good to read:
http://cp.literature.agilent.com/litweb/pdf/5989-7894EN.pdf

Specially hints 6, 7 and 8 in this case.

[adnewhouse]

I have the sds7102. I bought it from saelig and it came with the VGA port and software version 2.8.2. I think that firmware updates are available here: http://www.owon.com.hk/down-en.asp?bigclassname=software_upgrading. The most recent update seems to be 2013-04-03 which is very recent. After that update my scope is running 2.8.3.

[AndrejaKo]

It's interesting that the links to new firmware are actually pointing to the SDS_Upgrade3.2 package from 2013-03-29.

Also I'd like to use this opportunity to whine a little bit: My scope would sometimes hang after power on. In the end, the main board was replaced.  The original board from batch SDS71021211xxx, which could run the newest firmware, was replaced with a board from batch SDS71021209xxx for which newest firmware is 2.8.1.6, the result of which is that I don't have access to new math functions although the scope I bought should have access to them. Also based on trigger out, the waveform update rate went down from 30ish to less than 20 Hz. Bummer  .

[chromesphere]

I've had my 6062 for about a week now and its good, but its buggy...I can make mine hang by entering normal trigger mode and then cycling (not selecting) through trigger mode type (edge video slope pulse).  Does it every time.  I'm on 3.1.1 though and I have checked my serial and it looks like I CAN upgrade my scope (yay!). 

Heres another thing I noticed the other day.  I was trying to check my version number, went into utility menu.  The H menu (bottom of the screen) appears with only the LAN option.  All the other options had disappeared.  restarted the scope, same thing.  I recalled seeing the options in the usb / pc interface, hooked it up, wasn't there either, only lan options.  Unplugged the usb cable, bang, utility menu is back again....thank god I could get the menu back.  Some pretty essential options in there!

Also the scope I received came with the LAN option and not the VGA option that was advertised.  It also didn't come with the owon bag that was promised. This ebay user is getting negative feedback if they don't respond soon and I will post their name on this forum to avoid. They have a couple more days.

I like the scope, but yeah, its a bit rough around the edges!

[yuyu11uu111]

i'm new here and i'm already loving this forum

so i just ordered the owon sds7102v and i saw not many people have information on the 7102v, all i see is on the 7102 (no "v")

when it will arrive, if you guys want to see if owon fixed in this revision some of the problems, just tell me what to test for and i will capture it so you can see what has changed in this one, also it will help eliminate what problems solved and what still needs to be solved.

please detail for me step by step what to test and how to test so i wont mess up the mesurements since this is my first oscilloscope.

[AndrejaKo]

There's no functional difference between the V and non-V version, except that V has VGA out. Everything else should be the same. Still, if you think that you can do a good review of a new edition of 7102, feel free to do so. To what kind of equipment do you have access? Also if you haven't already, do read the review on the first page.

[yuyu11uu111]

There's no functional difference between the V and non-V version, except that V has VGA out. Everything else should be the same. Still, if you think that you can do a good review of a new edition of 7102, feel free to do so. To what kind of equipment do you have access? Also if you haven't already, do read the review on the first page.

will do, just thought it's some sort of rev2 for the oscilloscope

i really hope i didn't do any mistake by buying this scope since it was the best in it's price that was really up to date and not like the rigol competitor with the small shitty screen, it felt to me that in these days to buy a scope with this of a small screen is like buying 1950's car
i mean come onn

well i can't specify what i have since it is too much but basically exept a function generator and hot air soldering gun i think i have all that the important stuff

i have an order with 555 chips coming, it should arrive about the same time as the scope so i guess the best thing is to set small 555 circuit and this way others with the 7102 scope can compare with the same schematic i used and i'll give as much reference so we can eliminate power supply noise and such hope it is good enough idea for comparing between the scopes

[AndrejaKo]

Actually the reason why I recommended you to do the review is because your scope is going to be several revisions newer than the one reviewed few years ago. It's just that revision numbers aren't explicit for Owon. Instead you get them from serial number. Last 3 digits are unit number and the rest are some sort of batch number. Each revision seems to be couple of batches "long" and each  usually has a little bit different capabilities and potentially different firmware support.

[yuyu11uu111]

Actually the reason why I recommended you to do the review is because your scope is going to be several revisions newer than the one reviewed few years ago. It's just that revision numbers aren't explicit for Owon. Instead you get them from serial number. Last 3 digits are unit number and the rest are some sort of batch number. Each revision seems to be couple of batches "long" and each  usually has a little bit different capabilities and potentially different firmware support.

i bought the scope in 406$, do you think i've got a good deal, and do you think i did a mistake by choosing this scope in this market?

thank you

[AndrejaKo]

Don't look at me for that kind of advice. The main reason why I got Owon was because it's the only one in it's price range I could find locally that's not crap.

Also I can't say if you made a mistake, since I haven't been able to investigate in detail purchasing options available to you and at the same time I don't know what you actually need. The price looks OK to me, but on the other hand I'm not really up to date with scope rices in general.

[kuson]

WAITING EAGERLY

Ok, its been 1 month since Chinese New Year ... Anyone have any info on progress?   Any "from-the-floor" factory updates from Owon or "new revision / model" designation coming up?  I want to get one!  IWon Won! (I want One) :>

A question to the Jedis, :>     If my main purpose is #1. To learn electronics and  #2. To use it to probe and poke around Arduinos (is that what people do with one? ) and #3. Possibly repair/fix "this" and "that" in the house,  is there any show stoppers that would hamper me in #1,#2, or #3 in the current production models?

Thanks in advance!