USB Oscilloscope for undergrad student

[Ronny]

Good night everyone,

I am in an exchange program in the US and I want to bring an USB oscilloscope back to my country (Brazil), one of the big boys is out of question for me, it has to fit in my bag.
It will be used for basic stuff, reading serial that is going to a PC, checking basic circuitry for undergrad level classes, etc.
To be honest I don't have a specific budged, I would like it to be around $80, but if there is something good for a little bit more I will get it. For instance, I was going to buy an Owon just short of $ 100, but I thought it is a good idea to ask the pro guys first.
I just want something that is safe enough so it does not fry my laptop, and that is precise enough for the basic undergrad stuff (I see no problem if it is a big tougher  )

Thank you very much guys.

[Gyro]

This is the VDS1022(i) teardown thread. I assume that's the one you're looking at from the price indication. The other decent option would be the Digilent Analog Discovery.

https://www.eevblog.com/forum/testgear/owon-vds1022i-quick-teardown-(versus-the-hantek-6022be)/

[Ronny]

This is the VDS1022(i) teardown thread. I assume that's the one you're looking at from the price indication. The other decent option would be the Digilent Analog Discovery.

https://www.eevblog.com/forum/testgear/owon-vds1022i-quick-teardown-(versus-the-hantek-6022be)/

Yeah, that is the one.

In you tear down you seemed quite positive in relation to it. I quite like this one and you just backed it, unless there is someone else to recommend another one I think this will be the one.

Thanks!

[TK]

If you still have student status, you should try the Analog Discovery 2 by Digilent.  2 channels scope, waveform generator, logic analyzer, bode plot.  List price is $279 but academic price I think it is less than half.

[Ronny]

You guys mean this one?

http://store.digilentinc.com/analog-discovery-2-pro-bundle/

Well, if I get 50 % discount, I am fine with the price, especially with this neat bundle.
I have never seen this one before, looks neat. Is it that much better?

Edit: Is it isolated ?

[ebastler]

You guys mean this one?
http://store.digilentinc.com/analog-discovery-2-pro-bundle/
Well, if I get 50 % discount, I am fine with the price, especially with this neat bundle.

They don't seem to offer academic pricing on that bundle. But they do on the basic device:
http://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/.
Look for the green "get academic pricing" button.

[Fungus]

Edit: Is it isolated ?

No.

It can be.

It connects to the USB port of your PC so it all comes down to if your PC is isolated or not. Many laptops are.

(especially if running on batteries)

[Fungus]

Well, if I get 50 % discount, I am fine with the price, especially with this neat bundle.
I have never seen this one before, looks neat. Is it that much better?

Quite old, but:

[Ronny]

Well, I was seeing some stuff about this thing, it is freaking cool, it is not just an oscilloscope, it has the full package.
I applied for student discount, lets see if they give it to me. Sounds really good, if someone has a better option, you have until they approve my student discount to convince me  , because I am totally buying this one 

By the way, if I use this with a laptop running on batteries I don't think not being isolated will be a problem, I can live with that. It is a shame that they did not do it tough, such a cool little product.

[rstofer]

Well, I was seeing some stuff about this thing, it is freaking cool, it is not just an oscilloscope, it has the full package.
I applied for student discount, lets see if they give it to me. Sounds really good, if someone has a better option, you have until they approve my student discount to convince me  , because I am totally buying this one 

By the way, if I use this with a laptop running on batteries I don't think not being isolated will be a problem, I can live with that. It is a shame that they did not do it tough, such a cool little product.

I would recommend the AD even at full price.  You simply can't get the assortment of gadgets at anywhere near the price and being able to dump it in a backpack is a definite plus.  I have the original version.  I also have the new Digital Discovery.  Both bought at full price...  They don't have an 'old geezer' discount.

Isolation is an interesting problem and it's the USB system that needs isolating.  There are commercial isolators around but the cheaper ones are quite slow.  I plug my AD into a powered USB hub and hope for the best.  Actually, I don't hope, I think first.

The AD is not the device to use on high voltage switching mode power supplies.  It works perfectly well on low voltages.  If you are uncertain, measure the voltage with a meter.

The vast majority of my projects operate at 15V or less - usually much less.  The AD is perfect for uC projects, tuned circuits, amplifiers, digital logic and so forth.  Measuring mains is out of the question.  But wait to you see your first Bode' plot!  Magnificent!

You want the Pro Bundle because you get the scope probe adapter.  You will want to buy a couple of x10 probes (Digilent has them) and this extends the voltage range quite a bit.  Be aware that if you use the adapter (and you should), the signal generator outputs are ONLY on the BNCs.  You will want to get a couple of BNC->grabber test cables

https://www.amazon.com/Oscilloscope-Probe-Test-Cable-Mini/dp/B00WZVY5JE/ref=sr_1_13

You can use the grabber cables for the scope input but it's nice to have the x10 capability of a real scope probe.  Plus, you can adjust the probe compensation on a real probe.

[Ronny]

Well, I was seeing some stuff about this thing, it is freaking cool, it is not just an oscilloscope, it has the full package.
I applied for student discount, lets see if they give it to me. Sounds really good, if someone has a better option, you have until they approve my student discount to convince me  , because I am totally buying this one 

By the way, if I use this with a laptop running on batteries I don't think not being isolated will be a problem, I can live with that. It is a shame that they did not do it tough, such a cool little product.

I would recommend the AD even at full price.  You simply can't get the assortment of gadgets at anywhere near the price and being able to dump it in a backpack is a definite plus.  I have the original version.  I also have the new Digital Discovery.  Both bought at full price...  They don't have an 'old geezer' discount.

Isolation is an interesting problem and it's the USB system that needs isolating.  There are commercial isolators around but the cheaper ones are quite slow.  I plug my AD into a powered USB hub and hope for the best.  Actually, I don't hope, I think first.

The AD is not the device to use on high voltage switching mode power supplies.  It works perfectly well on low voltages.  If you are uncertain, measure the voltage with a meter.

The vast majority of my projects operate at 15V or less - usually much less.  The AD is perfect for uC projects, tuned circuits, amplifiers, digital logic and so forth.  Measuring mains is out of the question.  But wait to you see your first Bode' plot!  Magnificent!

You want the Pro Bundle because you get the scope probe adapter.  You will want to buy a couple of x10 probes (Digilent has them) and this extends the voltage range quite a bit.  Be aware that if you use the adapter (and you should), the signal generator outputs are ONLY on the BNCs.  You will want to get a couple of BNC->grabber test cables

https://www.amazon.com/Oscilloscope-Probe-Test-Cable-Mini/dp/B00WZVY5JE/ref=sr_1_13

You can use the grabber cables for the scope input but it's nice to have the x10 capability of a real scope probe.  Plus, you can adjust the probe compensation on a real probe.

Thanks for the tip. Just ordered the BNC grabbers. Digilent has not given me student status yet, still waiting for it.
I will definitely order the BNC adapter board and some probes with it!
I am ok with it not being isolated, I will have a rule "Always use it with my laptop running o batteries". I think that is enough to avoid trouble.

[Ronny]

Turns out the discount is not as great as I thought it would be.

410- 321 Analog Discovery 2 Scope & Logic Analyzer $279.00 36% $179.00

If I add the BNC board (20) and the probes (20) it jumps to 240. 

I can afford that (in tears), you guys think it is worth it?

[MrW0lf]

If youre afraid that might burn it do not suggest maxing out your budget!

I'd go for either Owon VDS1022I (isolated version!), but simplistic software, no decoders AFAIK.
Or Pico 2204A, which is not isolated, but cheap and good for learning (advanced software w decoders, same as with high-$ models).
And as with all non-isolated USB scopes - make sure you use USB hub, it will probably go first and save PC.

If still decide to go for AD2. Make sure you learn real well how grounding works (different w and w/o BNC board), and what effect all the jumpers have on BNC board.

BTW if you go for Pico or AD2 could try this for isolation:
https://www.olimex.com/Products/USB-Modules/USB-ISO/
It may cripple USB bandwidth but add some safety margin.
I have both Pico similar to 2204A, AD2 and some Olimex USB-modules. Could check if it still works.

And as always, watch the classic:

[MrW0lf]

Tested Olimex USB 1.1 isolator on 2010my Pico 2205 and AD2. Used additional 12V supply for isolator, do not recommend using standalone - will get very hot because internal converter is working hard.

Results:
Pico - normal mode quite usable, ETS and DPO modes noticeably slower. In DPO mode wfm/s dropped about 30 times.
AD2 - noticeably slower, but usable.

So if if working on something nasty, why not. Slow but safe. Would not recommend for low voltage work.

[Ronny]

Tested Olimex USB 1.1 isolator on 2010my Pico 2205 and AD2. Used additional 12V supply for isolator, do not recommend using standalone - will get very hot because internal converter is working hard.

Results:
Pico - normal mode quite usable, ETS and DPO modes noticeably slower. In DPO mode wfm/s dropped about 30 times.
AD2 - noticeably slower, but usable.

So if if working on something nasty, why not. Slow but safe. Would not recommend for low voltage work.

This is an European site, would you recommend one of the isolators they sell at Amazon?

https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=usb+isolator

[Smokey]

Sorry for being "that guy" but if you are serious about this whole EE thing, think of your gear as an investment and get stuff you aren't going to outgrow quickly. 

Analog Discovery as your only piece of equipment is a giant compromise on all fronts.  It's fine if you have have a specific requirement that you know it will meet, but you will eventually either damage it or go crazy using it as your one and only swiss army knife lab bench and then you are out that money when you could have started building a real set of gear.  I can't deal with the 0.1in header octopus monster wire connections either.

PS.. take advantage of the school labs.  That's what you are paying them for

[rstofer]

I can't deal with the 0.1in header octopus monster wire connections either.

PS.. take advantage of the school labs.  That's what you are paying them for

The octopus wires are for the logic analyzer/digital functions and seem entirely appropriate.  The scope and AWG can be brought out to BNC connections and probably should be as that opens up the use of a 10x scope probe

Even with a bench full of conventional tools, the AD is still my go-to tool for things like sending an SPI packet to the STM32F4 I am working on.  Or even receiving back the UART echo.

Sure, I can program an Arduino to send the packet but the AD offers so much more with a 27" display.

[mtdoc]

Turns out the discount is not as great as I thought it would be.

410- 321 Analog Discovery 2 Scope & Logic Analyzer $279.00 36% $179.00

If I add the BNC board (20) and the probes (20) it jumps to 240. 

I can afford that (in tears), you guys think it is worth it?

Don't by the probes from Digilent. Get a pair of p6100 probes for $10 from ebay.

It's 20 dollars for the BNC adapter which is well worth it and eliminates the need to use the small wires when using the scope.   So the total would be $209.

Yes, definitely worth it.

[ebastler]

Tested Olimex USB 1.1 isolator on 2010my Pico 2205 and AD2.
[...]
So if if working on something nasty, why not. Slow but safe. Would not recommend for low voltage work.

Thank you for pointing towards the USB isolator; I was not aware of these devices. The manufacturer's information about the speed rating is somewhat contradictory: It says "USB 2.0 compliant", but then again "Works with USB 1.1 Full Speed devices with data rate up to 12 Mbps". Given your test summary, I assume that 12 Mbps is always the maximum transfer rate, also on USB 2.0?

Have you done a teardown by any chance, to see whether the layout and components can plausibly provide the claimed 1000V isolation? If so, I'd much appreciate a photograph!  (Rather a "cut-up" than a "tear-down" for the Olimex device... )

[MrW0lf]

Don't by the probes from Digilent. Get a pair of p6100 probes for $10 from ebay.

+1 They are garbage, do not expect much over 10MHz with originals w/o distortion. Connected good 150MHz probes and much better!

Given your test summary, I assume that 12 Mbps is always the maximum transfer rate, also on USB 2.0?

Both USB 1.1 and 2.0 support 12Mbps and it's indeed maximum rate. I mostly assume USB 2.0 as 480Mbps so better refer to it as 1.1 device to avoid confusion. Did cut puppy open in isolator thread. ADUM4160 it is.

AFAIK Owon VDS1022I is also with only 12Mbit isolator so offers no speed advantage over Pico or AD2 tuned with USB-ISO or similar. However with VDS1022I isolator is hardwired, and consequently cannot get 480Mbps unlike with other two when isolation not needed.

[tszaboo]

If you are undergrad, dont buy test gear. The university will have better equipped lab, and I'm quite sure, even the dormitory will have a club. Our club had all the equipment you could ask for. You get to meet people with the same hobby, learn a lot, joint projects etc.

[Gyro]

AFAIK Owon VDS1022I is also with only 12Mbit isolator so offers no speed advantage over Pico or AD2 tuned with USB-ISO or similar.However with VDS1022I isolator is hardwired, and consequently cannot get 480Mbps unlike with other two when isolation not needed.

That one depends on how much processing is included in the USB 'head end'. There is a range of implementation choices, eg, the likes of Hantek are just basic streamers which must rely on high speed 480Mbps USB bandwidth to stream all of the ADC samples to the PC. The Owon does most of it's processing and buffering in the unit, so only needs to pass display data to the PC at whatever screen update rate is required, this is easily accomplished within USB full speed 12Mbps limits.

I have absolutely no idea which approach (or combination of approaches) the Pico, or the Diglent use in managing their data processing and USB transfer.

[Howardlong]

The Analog Discovery 1 or 2 would be my choice as well, and, as others have said, the BNC board plus a pair of probes off Amazon.

I use mine quite extensively when travelling. Despite its limitations, it is a genuinely useful tool. The UI is one of its best features, an area so many other USB scopes fail in. Its biggest downside is its bandwidth, and although the BNC board+probes improves that facet dramatically, it's can still be a limitation depending on your application.

Occasionally I use it on the bench too because of it digitial signal generation capability.

FWIW, I did a video some months ago comparing the AD 1 and 2. Practically speaking there's no difference in performance and featured other than the variable power supply on the 2 (1 has a fixed power supply). I happen to find the form factor and packaging of the 1 to be slightly more convenient when travelling.

[MrW0lf]

I have absolutely no idea which approach (or combination of approaches) the Pico, or the Diglent use in managing their data processing and USB transfer.

It seems that Digilent uses "brute force" approach, and suffers more heavily at 12Mbps (but still usable). With Pico there are about million different task-oriented modes, some seem to operate like "brute force" on Digilent, some are more clever. But wild differences even within 2000 series. SDK streaming rates range from 1MSa/s to 31MSa/s. Cannot exclude that current 1MSa/s models are 12Mbps only anyway. My old 2205 should be 480Mbps according to spec "USB 2.0 hi-speed (full-speed compatible)".

BTW - any idea what wfm/s Owon offers? From my some very random tests:

AD2 (480Mbps) all processing OFF, 200ns/div, 100MSa/s
~50wfm/s 0% misses with edge trigger
~100wfm/s no trigger

Pico 2205 (480Mbps), DPO mode, 50ns/div, 200MSa/s
1200wfm/s

Pico 2205 (12Mbps), DPO mode, 50ns/div, 200MSa/s
40wfm/s

While new Pico 2408B tops at ~110,000wfm/s in DPO/Fast mode (do not remember timebase).

Sometimes will try to investigate this in proper manner.

[Gyro]

It seems that Digilent uses "brute force" approach, and suffers more heavily at 12Mbps (but still usable).

That's a shame, I was hoping it had more brains under the hood.

With Pico there are about million different task-oriented modes, some seem to operate like "brute force" on Digilent, some are more clever. But wild differences even within 2000 series. SDK streaming rates range from 1MSa/s to 31MSa/s. Cannot exclude that current 1MSa/s models are 12Mbps only anyway. My old 2205 should be 480Mbps according to spec "USB 2.0 hi-speed (full-speed compatible)".

Well they have been in the business longer than anyone else - their first product was brute force over parallel port (100ksps).       

BTW - any idea what wfm/s Owon offers?

I'm afraid not (other than it apearing fast enough in practice), it's not a figure they specify. There's a bit of discussion in the VDS1022i teardown thread.

https://www.eevblog.com/forum/testgear/owon-vds1022i-quick-teardown-(versus-the-hantek-6022be)/

I'm not sure what speed it can manage over its SCPI interface either, although Ultrawipf looks to have been doing some experiments on it recently.