Products > Test Equipment

What to buy - Dedicated Logic Analyzer vs "The new Scopes" aka. SDS824/DHO924(S)

<< < (4/7) > >>

Traceless:
@btest
Hi welcome to the forum and thanks for reporting your experience with the DreamSource DSLogic U3pro16. Since @ebastler also brought this device up earlier I took a closer look and hardware-wise it looks really nice. However ebastler mentioned "less refined" software. Does less refined mean less features or really bad design/lots of bugs? I took a look at the DSLogic github repo, OpenSource is definitly a plus, however development does not seem to be super active. The sigrok wiki states that support for the DSLogic U3pro16 is planned (no mention of the 32 channel version). If the software is good I might as well consider to get the SDS824 without the SLA1016 and get the DSLogic U3Pro32 as a standalone logic analyzer, it does not cost much more than the SLA1016 addon from Siglent. Also is there any reason *not* to prefer the 32 channel version of the DSLogic over the 16 Channel version, e.g. missing software support?

@tggzzz: I also took a quick look at the bus pirate that you mentioned earlier, it seems to be an interesting little device. The website unfortunately seems to lack a manual so its hard to tell from the brief specs and texts to tell what it can and can't do compared to the other devices discussed here.

BTW: As far as I can tell from the specs the SDS824 has more memory than the lower SDS8XX versions. I assume using the unofficial upgrade path 804X -> 824X will unlock the 200MHz bandwidth but the additional memory is physically missing? Has anybody tried and can confirm that?




tggzzz:
The buspirate 5 is an interesting device that does more than capture and process data. It cannot easily be characterised in conventional terms, since it is in a different niche.

There is a lot of information on the website and forum https://forum.buspirate.com/ , but not a conventional manual. The principal creator is active there, and the natives seem friendly.

It is open source, so in theory you could create addons - but that wouldn't be trivial.

Overall it is useful to know the tool exists, so that you can use it when your needs fall into its niche.

btest:

--- Quote from: Traceless on November 29, 2024, 07:18:24 pm ---@btest
Hi welcome to the forum and thanks for reporting your experience with the DreamSource DSLogic U3pro16. Since @ebastler also brought this device up earlier I took a closer look and hardware-wise it looks really nice. However ebastler mentioned "less refined" software.

--- End quote ---

Traceless,

Sorry, I did not mean in any way to imply that the software was 'less refined'. I think it being based off of Sigrok is a good thing. I was just saying to not expect it to have the triggering capability of a scope, but I do not know of any PC based logic analyzers that do. The fact that it has multi-stage triggering puts it above almost all of the others, although that's a feature I have maybe used twice over the years. The strength of a PC based LA is the ability to do long captures for post analysis. You do not need fancy triggering to do that. I've only had the software crash a couple of times over the years and cannot remember the last time it did so.

Just for grins I got my Logic Pro 8 out and downloaded their latest software. It's come a long way since the last time I used it. But at over 3x the price of the DSLogic I don't see how anyone can justify it. Turning the Analog channels on puts such a limit on the sample rate that for me it becomes pointless. As tggzzz said: "My preference is to have two tools each of which is good at one job, rather than one tool that is poor at two jobs". I think we have all learned that lesson the hard way. Worst case you can always run the trigger out of the scope into an LA input to time correlate domains.

I also want to point out you need to buy for your specific needs. I write embedded control software on many different platforms but at a top level its all the same: gather data from multiple sensors, analyze it and generate a control output. My last job one of the inputs was IMU data at the rate of 4000 messages per second over a UART. My current job is primarily a combination of CAN and UART. In the digital domain the DSLogic has easily met all my needs. I am not sure what you are trying to do but take a good look at what type of signals you are trying to analyze and buy the appropriate tools. You can download the DSView app and run it in demo mode before buying the hardware. Same with the Saleae.

As much as I do in the digital domain there are times where you have to be in the analog domain. If you get noise coupled onto your signal lines the LA will show you the invalid transitions but to really see what is going on you need a scope. It's the only way to see how much your square wave has rounded off when sent over long cables. Or, like in a case I had a couple of years ago, where the EE team tried to get away with just using the RC clock internal to a STMicro instead of putting an external crystal oscillator on it. Worked great until it got warm. Then the RC clock drifted so much that it corrupted the CAN bus timing. Not obvious on the LA but clearly shown on the scope doing an eye diagram.

Hope this helps. Again, I can only relate to my needs which I am sure are not the same as yours and these are the tools that make me most efficient.

Just realized I missed your comment on 16 vs 32 channels. The issue with any PC based LA is USB bandwidth. The more channels you have active the lower the max sample rate. For me personally I rarely have more than 7 or 8 active channels and typically its 2 or 3 so 32 channels is way way overkill so I did not spend the extra $100. Again, it's what meets your needs. It's the same software for both, and with 3 channels or less they both can sample at 1GHz. For 6 channels it's 500MHz, etc. I have no experience with Siglent scopes so cannot make any comments there.



JimboJack:
My take is

1. check the min pulse width they can detect on.
2. purchase a 'High speed' USB 2.0 isolator. supporting 480Mbps , I have not got around to using a USB 3.0 isolator 'superspeed' be on my next move

Be a good EEvblog video to see how they fair :)

as mentioned check the waveform in the osciliscope  then use a PC logic analyser with opensource tools to data capture, then you can decode CPU instructions later.

 

tggzzz:

--- Quote from: btest on November 30, 2024, 02:21:38 am ---Just for grins I got my Logic Pro 8 out and downloaded their latest software. It's come a long way since the last time I used it. But at over 3x the price of the DSLogic I don't see how anyone can justify it. Turning the Analog channels on puts such a limit on the sample rate that for me it becomes pointless. As tggzzz said: "My preference is to have two tools each of which is good at one job, rather than one tool that is poor at two jobs". I think we have all learned that lesson the hard way. Worst case you can always run the trigger out of the scope into an LA input to time correlate domains.
...
Hope this helps. Again, I can only relate to my needs which I am sure are not the same as yours and these are the tools that make me most efficient.

--- End quote ---

Just so, hence my reluctance to make A Pronouncement on this topic. (Doesn't stop me on other topics, though :) )

The more difficult triggering example is where a digital signal needs to trigger the analogue capture, e.g. when writing a specific value to a specific register might be causing analogue infelicities. Naturally if you don't need that, you don't need that, and often some skill and imagination can compensate for tool deficiencies.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod