QA-100 Quantassylm oscilloscope ? - Page 1
Forum section: electronics / general

author: jeffl
author_rank: Newbie
timestamp: March 05, 2012, 04:14:16 am
content: Anyone have this unit?I'm looking for an oscilloscope and a logic analyzer. I'm mainly working with PIC24 micro controllers and yes I'm a newbie. Looking for the tools I would use most. I know a Rigol DS1102E and Saleae Logic / Logic 16 would also be a good choice. Just wondering if this unit would be a good choice as an all in one unit.http://www.quantasylum.com/content/Products/QA100.aspx

author: T4P
author_rank: Super Contributor
timestamp: March 05, 2012, 05:49:15 am
content: Absolutely useless , check the specs .http://www.quantasylum.com/content/Portals/0/UploadedFiles/QA100%20Compete%20Summary.png100MSPS means at most 10MHz , and 1Ksps really ? And i see the screenshots , the application looks rather crappy when it comes to clarity , sorry , i'll prefer a rigol over that .I know it looks decent but really , Rigol DS1052e/DS1102e Or Atten ADS1102CAL .http://www.dealextreme.com/p/usb-oscilloscope-and-logic-analyzer-93518I am only buying this saleae LA DSO clone because it has proper logic probes compared to that wimpy 15$ LA only clone versionBut really , i am buying this instead for the 16 channel capability ( beats buying 2 8ch logic analyzers and not being sure if they will work in tandem or not )http://www.dealextreme.com/p/h301-portable-48mhz-usb-digital-oscilloscope-82005

author: amspire
author_rank: Super Contributor
timestamp: March 05, 2012, 05:58:32 am
content: A USB scope is not a replacement for a stand-alone scope. The fact you need a computer, and you have to wait for the computer to boot, and then the fact you end up with your test circuit connected to the noisy earth of a computer is not a good combination. Changing settings on a USB scope is a pain too - you want knobs!There is nothing wrong in buying the scope and logic analyzers as separate tools, and the truth is the logic analyzer will only be pulled out as a last resource measure. For most debugging, you just add debug code to toggle spare/unimportant pins when even a point in the code is reached. The DS1102E is all you need to capture the toggling pins.I think everyone who gets a USB scope ends up getting a stand-alone scope and then they just don't touch the USB scope again. USB scopes have their place - they could be perfect in production line use driven by a custom program.Richard.

author: T4P
author_rank: Super Contributor
timestamp: March 05, 2012, 06:00:54 am
content: Quote from: amspire on March 05, 2012, 05:58:32 amYep . USB scopes are no good . Logic analyzers yes , but scopes no . just no .

author: Bored@Work
author_rank: Super Contributor
timestamp: March 05, 2012, 01:41:46 pm
content: Quote from: amspire on March 05, 2012, 05:58:32 amI agree these cheap USB logic analyses are good value for money, and USB oscilloscopes should be banned by law. One thing which can be annoying when using a separate LA and oscilloscope is the ability to trigger both in sync. Not every LA provides a trigger output.QuoteI don't think it is a last resort. Which debugging tool I use first depends on the symptoms of the error. Often I neither start with the oscilloscope or the logic analyzer, but the in-circuit debugger for the MCU. I know people rather spend half an hour to plaster their code with printf()s or wiggling a pin, instead of the few seconds to attach a debugger. Something I don't get. And in a next step I probably reach for the LA in addition to the debugger.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 05, 2012, 04:43:19 pm
content: Quote from: BoredAtWork on March 05, 2012, 01:41:46 pmand then what?

author: jeffl
author_rank: Newbie
timestamp: March 06, 2012, 04:42:58 am
content: This was the kind of honest feedback I was looking for. Unfortunately marketing just adds to the confusion when your new.

author: metalphreak
author_rank: Frequent Contributor
timestamp: March 06, 2012, 04:50:43 am
content: For not much more money, you could get a Rigol scope, and something like the Open Workbench Logic Sniffer which uses the SUMP program.http://www.seeedstudio.com/depot/open-workbench-logic-sniffer-p-612.html

author: amspire
author_rank: Super Contributor
timestamp: March 06, 2012, 06:19:15 am
content: Quote from: jeffl on March 06, 2012, 04:42:58 amI forgot to mention above one of the biggest negatives of any USB instruments. The moment you can no longer get drivers, the box is useless. Companies often stop updating drivers very soon after they stop producing a device. So say you updated your PC to a new Windows 8 PC in 12 months. If this model of USB scope is no longer in production then, there may be no drivers that will run under Windows 8. The only way you could keep using it is to set up another dedicated PC running an old operating system.Well built standalone scopes however often keep working for 20 years+.Richard.

author: JuKu
author_rank: Frequent Contributor
timestamp: March 06, 2012, 09:13:00 am
content: Quote from: amspire on March 06, 2012, 06:19:15 amI don't like USB scopes either, but for a logic analyzer or some other instrument, you might still very ok with the above scenario. I have a couple of instruments I would be happy to dedicate a small PC for, if I have to. One is the XeroPlus logic analyzer - if I have to pay a couple hundred for a used laptop or something like that, it would double the price of the tool, but it would still be very good value for money. The other is a multichannel channel audio level meter software. That and a multichannel sound card is by far the most handy way to monitor audio amplitude over several channels.

author: Bored@Work
author_rank: Super Contributor
timestamp: March 06, 2012, 09:50:39 am
content: Quote from: amspire on March 06, 2012, 06:19:15 amThis is one of the many reasons why I indeed do not recommend USB instruments in general.My current exception are USB logic analyzers. They became so cheap compared to stand-alone LAs that you can buy a new one every three years for some time and you are still in the black compared to a stand-alone LA.

author: Bored@Work
author_rank: Super Contributor
timestamp: March 06, 2012, 09:54:38 am
content: Quote from: Mechatrommer on March 05, 2012, 04:43:19 pmAnd then you run your program under debugger control with breakpoints and all that, and - the most important - engage your brain!

author: T4P
author_rank: Super Contributor
timestamp: March 06, 2012, 10:16:03 am
content: Quote from: BoredAtWork on March 06, 2012, 09:50:39 amOr you could buy one every week , i saw many saleae clones in white nondescript project-looking boxes that have the pins written on top on aliexpress for 17$ . Yes 17$ for a 8ch LA . Want 16ch ? I saw the cheapest was about 100$ like i mentioned above .

author: T4P
author_rank: Super Contributor
timestamp: March 06, 2012, 10:16:52 am
content: Quote from: amspire on March 06, 2012, 06:19:15 amBut ... How long do you want to keep your LA ? Windows 8 is rubbish and i ain't upgrading to that .If i buy a new laptop i will kindly decline W8 .

author: Unknown
author_rank: Unknown
timestamp: March 06, 2012, 10:35:50 am
content: Yeah, sure. People said the same about sticking with DOS, Windows '98, Windows NT 4 and Windows 2000. How many of them are still using it? Just because there was a very long delay between Windows XP and Windows 7, because Vista was way late and failed to gain acceptance with business customers, doesn't mean that you can expect Windows 7 to be supported for 10+ years.

author: T4P
author_rank: Super Contributor
timestamp: March 06, 2012, 06:08:35 pm
content: Quote from: alm on March 06, 2012, 10:35:50 amBy then in 5 years of course you will probably buy a new USB LA already , no ?

author: Unknown
author_rank: Unknown
timestamp: March 06, 2012, 06:32:08 pm
content: USB logic analyzers are cheap enough that having to replace them every few years isn't really an issue, as BoredAtWork mentioned, especially since stand alone logic analyzers are quite expensive. It's not so great if you buy a USB scope for $350, compared to a stand-alone scope which would cost about the same.

author: T4P
author_rank: Super Contributor
timestamp: March 07, 2012, 10:55:15 am
content: Quote from: alm on March 06, 2012, 06:32:08 pmYeah .. And those 17 dollars LA's are really great stuff , nevermind that their UI might be a little shitty , but it's still usable and at least you could see the waveforms clearly .