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Forum Index : Microcontroller and PC projects : Electronics: Zotec ZT-702S Oscilloscope

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thwill

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Joined: 16/09/2019
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Posted: 05:12pm 03 May 2023
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Hi folks,

I never did get myself a proper Oscilloscope (the management expressed their disdain but maybe I'll still wangle one for my 50th), but having seen the recent EEVblog review of the  Zotek ZT-702S Oscilloscope Multimeter I was wondering if I'd take a punt. Has anyone got any thoughts on whether it is a useful upgrade over my DSO 138 toy ? ... I guess at least it has a proper probe.

Best wishes,

Tom
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matherp
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Posted: 06:34pm 03 May 2023
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Single channel and fairly slow which may be limiting. Personally I started with a 20MHz analogue scope which you can get for around £50 on ebay if you wait for the right one to come up (I love the Hameg scopes).
e.g. That + a logic analyser did pretty much everything I wanted and still would. I have since upgraded but more out of the love of toys than necessity.

More expensive than the 20MHz scopes but this  would be my first buy today knowing what I now know
Edited 2023-05-04 04:42 by matherp
 
thwill

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Posted: 06:51pm 03 May 2023
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Thanks Peter, but space restrictions mean I'm reluctant to buy a "classic" with a tube.

TBH the DSO 138 has been ok for occasional usage (and I imagine @Volhout's PicoMite logic analyser will be fine in that area for a while) except that the origin/base-line/whatever-it's-called of the former has a tendency to jump around and require me to reconfigure it between measurements - this may be user error, but I think not in this case. Also the DSO 138 doesn't seem to have the ability to save and export a trace.

Best wishes,

Tom
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matherp
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Posted: 06:55pm 03 May 2023
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The Hameg's are comparatively compact roughly 13*28cm front panel and c 40cm deep
 
Mixtel90

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Posted: 07:03pm 03 May 2023
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The Zotek is an upgrade on your DSO138, but whether it's a worthwhile upgrade is something else. Neither is an excellent 'scope but they both work very reasonably in their own way. :) If you can find the Zotek cheap enough then it may be a good option - but watch that battery life.

I eventually went for a DSO (Hantek DSO5102P - about 250UKP) mainly because it's smaller than my analogue 'scope! They take up a serious amount of desk space and it stood on the floor for many years. Not ideal positioning.
Mick

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Andy-g0poy
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Joined: 07/03/2023
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Posted: 07:14pm 03 May 2023
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A real bench top scope is SO MUCH better than these things. Bear in mind that the 702 is getting close to half the cost of a really cheap DSO, which start at around 130 pounds.

a good branded starting point is the Hantek DSO 2C10 series which starts at 180 pounds Prices go up from there.

You will find several options between the two prices above.

At the very low end don't expect too much, but they will be much much better than the scopemeter types.


The scopemeter types do have a use, but you are talking about quick and fairly crude monitoring of simple signals out in the field usually.

Like many I made do with an old 25Mhz analogue scope at home, which was sort of good enough, but then I've always had the use of much higher end equipment at work. I treated myself to a Siglent  SDS2352X when I retired...  

Set up a few search alerts on ebay and you may well find something much better

Andy
 
stanleyella

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Posted: 10:35pm 03 May 2023
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I use a hantek 6022BE with open source software and it's ok ish for most stuff but it's usb and needs windows

 
stanleyella

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Posted: 11:53pm 03 May 2023
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In reality for £70

 
Volhout
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Posted: 07:01am 04 May 2023
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Hi Tom,

I am late in my response, and hesitate to give it since many have responded before. Each person has it's own use for an oscilloscope, and you should list yours.

I can only give one observation for myself.

I typically grab the oscilloscope when something is not right, and I want to find out what. I myself want to look at details (either timing or waveform or voltages) and for myself like a larger screen. I have difficulty working with small screens.

I am not sure if you are very budget limitted, since your frist attempt to purchase was low cost, and this proposal is also (for an oscilloscope) is low cost, but even the smallest bench scope (there are Rigol's and Hantek's starting around 250 pounds) may give you more satisfaction. And you can always remove it from the bench when pressed for space.

Volhout

P.S. I myself find a (very cheap) logic analyzer a usefull tool, that I would suggest to you regardless your choice for the scope. It will do UART and I2C decoding, ad SPI, uses a PC app (windows or linux) and PC memory for storage.
saleae
Edited 2023-05-04 17:06 by Volhout
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TassyJim

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Posted: 07:12am 04 May 2023
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A couple of years ago I pensioned of my 25 year old Tectronics CRO. 2 channel and very slow serial to transfer captures to the PC.

If you lived on this side of the world I would donate it to your cause.

I went with a Siglent.
I really appreciate the 4 channels I now have and TCPIP for talking to it from the PC. Single channel would be a handicap.
I do have the cheap DSO 138 style for testing up a pole etc.

I would save up the goodwill for a while until the boss lets you splash out.

Jim
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Mixtel90

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Posted: 07:14am 04 May 2023
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Still only 20MHz, but that's not terrible unless you are looking for little glitches. Very good price on Amazon - 65.99UKP for a dual trace 'scope.
There's a decent enough review here.
I'd definitely prefer it over the Zotec.


This one  got a good review  too. It's back to single trace. Self-contained though.
Edited 2023-05-04 17:32 by Mixtel90
Mick

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Volhout
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Posted: 10:14am 04 May 2023
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Or this one....

https://www.owontechnology.eu/product/1313239/owon-vds1022-25mhz-40v-pk-pk-series-pc-oscilloscope

Soo much better than the Hantec USB scope. Buy the one with isolated USB !!!
If your PC runs the picomite, and the PC runs the Owon scope, you are not accidentally creating short circuits when connecting the ground clip on the scope to the 3.3V on the picomite...

Review:https://www.youtube.com/watch?v=1ec1n9ScGTw

Volhout
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thwill

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Posted: 10:28am 04 May 2023
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Thanks folks, you've managed to persuade me to prevaricate on buying a better DSO for longer .

Instead I spent 4 GBP on a (hopefully) marginally better Chinesey P6100 probe for my DSO 138 - more probey and less crocodiley than what came with it.

Note that I have a preference for single-function, standalone units rather than something that plugs into the PC, YMMV.

  thwill said  TBH the DSO 138 has been ok for occasional usage <snip> except that the origin/base-line/whatever-it's-called of the former has a tendency to jump around and require me to reconfigure it between measurements - this may be user error, but I think not in this case. Also the DSO 138 doesn't seem to have the ability to save and export a trace.


Does anyone have any ideas about a "user error" explanation for this? Otherwise I might try upgrading the firmware, but IIRC @stanleyella posted in an earlier thread that he had bricked at least one DSO 138 trying that.

Best wishes,

Tom
Edited 2023-05-04 20:32 by thwill
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Mixtel90

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Posted: 01:59pm 04 May 2023
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I've been looking at reviews and I've not noticed it jumping around. I'm wondering if you have, possibly, a bad contact on a slider switch. My brother has one of these, I think. If so I'll grab it when I go to see him tonight and bring it home for a play. It doesn't seem to be too bad for such a cheap 'scope, if you only want audio frequencies.

You are using the Trigger function, aren't you?

Even a cheap probe will be better than the lead that came with it. :)
Mick

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thwill

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Posted: 02:57pm 04 May 2023
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  Mixtel90 said  I've been looking at reviews and I've not noticed it jumping around. I'm wondering if you have, possibly, a bad contact on a slider switch. My brother has one of these, I think. If so I'll grab it when I go to see him tonight and bring it home for a play.


Thanks Mick, having just powered it up to check and looked at the "manual", it's the 0V trace which is jumping around. It's never even close to the mid-line/VPos indicator on boot ... though I'm beginning to wonder if it is just that I am using RESET a lot and that reboots it - Hmm.

  Mixtel90 said  It doesn't seem to be too bad for such a cheap 'scope, if you only want audio frequencies.


That plus NES controller signals is all I've used it for so far. I'm just coming out of a period of programming and hoping to get back to those audio circuits for the Bintendo so I'll be playing with it some more in the near future.

  Mixtel90 said  You are using the Trigger function, aren't you?


On Auto ... another good reason not to spend real money until the monkey is better trained. I'd ask my father in law, but I can only take him in small doses .

  Mixtel90 said  Even a cheap probe will be better than the lead that came with it. :)


It's definitely a "cheap probe".

Best wishes,

Tom
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Mixtel90

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Posted: 03:32pm 04 May 2023
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If you switch the input to GND (or short circuit the input) you should get a stable, single line, no matter what ranges etc. you set on anything else. If that's jumping around then you have a hardware problem. There may be some slight flickering, especially at low timebase speeds, but that's fine.

Auto Trig will attempt to get it right, but it depends on the signal. It's sometimes better to run it in manual, set Trig to rising or falling edge and move the trigger level off centre. Don't be afraid to play with Trig. I found it a bit intimidating at first but it's actually very useful on bigger 'scopes - and makes a waveform visible on simpler ones. :)
Mick

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thwill

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Posted: 03:43pm 04 May 2023
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What I am attempting to describe is:

- Turn device on
- Change input to GND
- Align 0V trace to VPos to mid-line
- Pull power lead
- Plug in power lead
- The 0V trace is nowhere near the mid-line, so re-align.

And I think this movement of the 0V trace away from the mid-line was happening between measurements too, but I'm now wondering if I was pressing RESET (and thus rebooting) between some measurements (RESET is where I would have put the OK button if I had designed the HMI).

Best wishes,

Tom
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stanleyella

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Posted: 04:01pm 04 May 2023
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  Volhout said  Or this one....

https://www.owontechnology.eu/product/1313239/owon-vds1022-25mhz-40v-pk-pk-series-pc-oscilloscope

Soo much better than the Hantec USB scope. Buy the one with isolated USB !!!
If your PC runs the picomite, and the PC runs the Owon scope, you are not accidentally creating short circuits when connecting the ground clip on the scope to the 3.3V on the picomite...

Review:https://www.youtube.com/watch?v=1ec1n9ScGTw

Volhout


Vertical Resolution (A/D) 8 bits (2 channels simultaneously)

I use open hantek software... it doesn't crash which the hantek software does.

also got to install win10 driver manually

I've had mine for years but it's not used that much really but when it has been needed it's ok. It's not like a multimeter which is used daily and how often are ranges like capacitance or frequency used?
 
Mixtel90

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Posted: 04:32pm 04 May 2023
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Ah, I don't know the answer to that one, Tom. It sounds as if the firmware has an incorrect default. If it was an analogue 'scope you would expect the trace Y position to simply stay in step with the VSHIFT, but it ain't necessarily so for something controlled by buttons, especially at this price where there may not be any flash RAM available to store for such things.



EDIT:
I didn't get my brother's 'scope (it appears to be buried in a box somewhere). I told him of your problem and he seems to remember that his does exactly the same thing.
Edited 2023-05-05 18:01 by Mixtel90
Mick

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dMajo

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Posted: 01:46pm 11 May 2023
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As an entry level but fully equipped scope, I recommend these:
DS1104Z-S Plus or DS1074Z-S Plus
from Rigol. They are also very appreciated in educational environment.
Edited 2023-05-11 23:46 by dMajo
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