Author Topic: Owon VDS1022I vs Hantek PC 6074BC  (Read 1897 times)

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Offline shobo

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Owon VDS1022I vs Hantek PC 6074BC
« on: March 27, 2019, 01:37:26 pm »
Dear EEVblog,what would you choose?
Begginer in practicing electronics,only having theoretical knowledge and some minor Arduino programming.
This would be my first scope and price is one of the top things to consider.
Regarding the tasks it would serve...i don't know yet.
As i am not very into what spec means,an opinion from you,the comunity,would be nice.
Thanks in advance.

Hantek - http://www.hantek.com/en/ProductDetail_2_9163.html
Owon - http://www.owon.com.hk/products_owon_vds_series_pc_oscilloscope
 

Offline Gyro

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #1 on: March 27, 2019, 01:51:58 pm »
« Last Edit: March 27, 2019, 04:22:38 pm by Gyro »
Chris

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Offline DDunfield

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #2 on: March 28, 2019, 01:53:09 am »
IMHO USB scopes generally fall into two categories.

(1) Mostly rubbish.

The majority of the low-cost USB scopes are not really oscilloscopes. They are data capture devices which capture a buffer of samples, then "go deaf" while shoveling it up to the PC. All triggering and capturing is done by the PC on the received data stream.
The problem is the "go deaf" which is NOT synchronized to the triggering (which is happening upstream on the PC). This means that if the trigger event happens to occur in the deaf period, you just won't see it (somewhat OK for repetitive signals, kiss of death for single-shot captures), and worse - "go deaf" may occur at any point after trigger, so chunks of your capture may be just missing.
If your PC or USB gets "busy" momentarily and is unable to process the data fast enough causing buffers to get tossed, the symptoms are exactly the same.


(2) Real oscilloscope

Some (few) of the low-cost USB scopes are actually complete scopes, which perform local triggering and capturing etc. and basically only use the PC for a display/UI. These can be pretty good.


I have a Owon VDS1022I and of several low-cost USB scopes I looked at, it was the only one which was (2) - ie: It actually works.
I don't know about the higher OWONs, but one would hope that if they bothered to include an actual scope in their low cost version, they would have done so on the higher ones as well.

I'm not familiar with the Hantek model indicated, but I evaluated a Hantek 6022BE and it was clearly (1) and pretty bad.

Looking at the 6004BC specs:

1G sample rate, 250Mhz bandwidth, 4CH, fixed capture buffer and FPGA visible in one of the photos all suggest more than a simple USB sampling device which would not be able to meet those specs.
But numbers in technical products are often bogus ("equivalent to") and you still don't know where the functionality dividing line between BOX and PC lies. I don't see enough actual user opinion/reviews to feel super confident. Whats your "risk tolerance"?

Dave




 

Offline shobo

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #3 on: March 28, 2019, 05:13:11 am »
Thanks for the input.
The Hantek one is the bottom of the range model,the 70 Mhz version one (250 mhz is the 6254BC).
The risk imo for both is somewhat higher for the hantek,but still present for the Owon too because either one will be ordered from Amazon from the UK(i live in Romania).
The reasonable choice would be the Owon,since i would use the price difference to buy a better soldering station and/or a cheap logic analizer.
 

Offline shobo

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #4 on: March 28, 2019, 06:10:58 am »
As an alternative to both,i discovered the PICOSCOPE 2205A which falls between the 2 price wise.
 

Offline Gyro

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #5 on: March 28, 2019, 10:07:03 am »
I think most people buy the Owon from ebay (not sure how that works out for Romania).

The Hantek spec looks pretty good on paper. The trouble is that Hantek seem to be universally rubbish at writing software - from the look of the 6047BC threads that still seems to be the case (it doesn't even have the 'new' product excuse now). It was so bad on the 6022be that people got fed up and wrote their own (open Hantek, I think, but it doesn't support the 6047BC).

Owon USB S/W comes in the category of 'does what it says on the tin'. It works as expected on the VDS series. They occasionally throw in a silly bug on a new release but it's a mature product and it's not obvious what new feature they're actually adding, so it's easy to drop back to the previous version. Basically it displays, triggers etc. as advertised.

Pico are very good at clever software, with all sorts of fancy features. I find the UI a bit more quirky - it looks more like a windows app in its controls. Pico have been in the USB scope business longer than anyone else, they are designed and (still?) built in the UK. You pay a premium for that but support is good. They are also sold from the UK, presumably they ship to Romania.


EDIT: You can download the software for all of them and try it - you'll either get basic UI or demo mode depending on which one.
« Last Edit: March 28, 2019, 10:13:57 am by Gyro »
Chris

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Offline gf

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #6 on: March 29, 2019, 07:53:31 am »
IMHO USB scopes generally fall into two categories.
...

The 6xx4BC/BD series are not comparable to the 6022BE at all. At 1GSPS you don't have any chance to stream the captured data to the PC and to do all processing (including real-time trigger processing) in software. I.e. the capture and (digital) trigger engine reside of course in the FPGA of the 6xx4BC/BD series, as well as the sample memory for up to 64k points.

EDIT: So according to your definition, they are "real" scopes, still they have some flaws as well. Most are likely software bugs, but some (most likely cost-driven) hardware/design limitations cannot be denied either.
« Last Edit: March 29, 2019, 08:25:37 am by gf »
 

Offline Gyro

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #7 on: March 29, 2019, 09:10:27 am »
The 6xx4BC/BD series are not comparable to the 6022BE at all. At 1GSPS you don't have any chance to stream the captured data to the PC and to do all processing (including real-time trigger processing) in software. I.e. the capture and (digital) trigger engine reside of course in the FPGA of the 6xx4BC/BD series, as well as the sample memory for up to 64k points.

EDIT: So according to your definition, they are "real" scopes, still they have some flaws as well. Most are likely software bugs, but some (most likely cost-driven) hardware/design limitations cannot be denied either.

@gf:  So are you able to provide any actual useful feedback on the performance of the 6xx4BC/BD? That's what the OP is interested in. The only threads that I've managed to turn up have been negative in terms of triggering and display stability. Your actual usage experience would be most helpful.

P.S. I agree that to be achieving triggering at the claimed sample rates then it must be doing something in the FPGA, even if it isn't working very well.
« Last Edit: March 29, 2019, 09:18:58 am by Gyro »
Chris

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Offline gf

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #8 on: March 29, 2019, 12:04:32 pm »
@gf:  So are you able to provide any actual useful feedback on the performance of the 6xx4BC/BD? That's what the OP is interested in. The only threads that I've managed to turn up have been negative in terms of triggering and display stability. Your actual usage experience would be most helpful.

P.S. I agree that to be achieving triggering at the claimed sample rates then it must be doing something in the FPGA, even if it isn't working very well.

Well, it basically does capture and display waveforms ;).
I do not know what functionality beyond this is needed by @shobo.
The specs are public anyway, so I see no need to repeat them.
But I can list a couple of points which bother me most.
I don't know the VDS1022I, so I can't compare.

* There are significant offset errors, even after running the calibration procedure. Hantek recently did admit a software bug in the calibration procedure and promised a correction - let's wait and see...

* Edge trigger basically works OK (for waveforms which permit edge-triggering) as long as the noise level is sufficiently low. With increasing noise level the edge trigger becomes indeed unstable. IMO the edge trigger should use a larger hysteresis by default, or offer an option in the GUI to adjust it. So when the noise level is too large then it is necessary to switch to pulse trigger (which provides some kind off holdoff functionality when using the ">" operator). Adjusting the parameters needs some fiddling, though , but it enables triggering of signals which cannot be triggered with the simple edge trigger any more. I also managed to trigger on glitches after some fiddling - but that's not "plug and play". There are also other trigger options (video, SPI, CAN,...) but I never needed them. The availability of these advanced trigger options suggests that the FPGA does even implement a configurable, stateful trigger engine, so trigger performance is possibly just a matter how this engine gets parametrized by the software.

* The white noise floor is about 350-400 uV RMS. BW limit does not reduce it. This is IMO caused by operating the HMCAD1511 at 50x digital gain, which enables a simpler (and therefore cheaper) anlog frontend design. There is no hi-res acquisition mode, so averaging is the only option to improve the noise floor.

* At 200ns/div, the captured waveform is sometimes truncated. I did not find out yet, which border conditions need to apply in order that the problem occurs.

* FFT is calculated from only 1024 points, although up to 64k can be captured by a single acquisition

* At <= 200ns/div FFT is calcaulated from upsampled (interpolated) data of up to 12.5GS. This is IMO useless, as the interpolation does not augment the signal with additional information, but in fact it reduces the number of "true" samples included in the FFT. If the data are sampled with 1GSPS with Nyquist at 500 MHz, what sense does it make to display the spectrum up to 6.25Ghz?

* The same applies to captured data when they aresaved to a file. When they were captured at <= 200ns/div, then the upsampled (interpolated) data are saved, and not the 1GSPS raw data.

* There are a couple of bugs in the software/GUI logic. Example: The interpolation mode can only be changed when the timebase is set to <= 20ns/div, although it also affects the waveform display at larger timebases. Some setting changes are not sent to the device before other settings are changed as well. Most issues can be worked around if you are aware of them, but they may make you wonder if you don't know them yet.

Yes, there are a couple of thing I'd like to see improved, but I also don't want to make the device bad. Given the price I paid for my 6074BD (i.e. the model with AWG), it would likely not be fair to expect much more than I got (for a Rigol DS1054Z, I would have needed to pay three times as much at that time).

EDIT:
I just did take a brief look at the Owon web page and my understanding is that Owon's 4CH/1GSPS model would be rather the VDS2064, and not the VDS1022I.

EDIT: Just noticed that I did mis-read the spec - the VDS2064 does not have 1GSPS either, but only 500MSPS (and for 1GSPS the VDS3104 were required).
« Last Edit: March 29, 2019, 01:54:29 pm by gf »
 

Offline Gyro

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #9 on: March 29, 2019, 12:55:13 pm »
Thanks gf, at last we have someone with some real user experience for the OP to start basing his decision on.  :-+
Chris

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Offline shobo

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #10 on: March 29, 2019, 02:23:44 pm »
Thank you everybody for the time.
I have decided to go the owon way since i found that ebay has even lower prices than amazon (20 pounds less) and money is a main concern and it seems that it has a more mature software.
 

Offline DDunfield

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Re: Owon VDS1022I vs Hantek PC 6074BC
« Reply #11 on: March 30, 2019, 12:10:38 pm »
Thank you everybody for the time.
I have decided to go the owon way since i found that ebay has even lower prices than amazon (20 pounds less) and money is a main concern and it seems that it has a more mature software.

One hint that may save you some grief. I had some issues installing the VDS, you can read the details in the thread Gyro linked above.

Condensed version: Don't use the "new" driver Owon has posted on their site. It didn't work well for me. Use the driver that is included in the software installation directory.
There is an option to install the driver within the software (click or right-click on the status display in the upper left corner), but it doesn't work - it can't find the driver location.
Just install the driver included with the software via "Device Manager". Once I removed all vestiges of the "new" driver and did this, everything worked perfectly.

This was under Win7-64, with other Windows versions YMMV.

Dave
 


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