I2C Question for Rigol DS2000 Series - Page 1
Forum section: electronics / testgear

author: Electro Fan
author_rank: Super Contributor
timestamp: August 27, 2013, 05:18:38 am
content: For any one with a Rigol DS2000 Series scope (which would seem to be about half the EEV world here) who works with I2C (which probably is a subset of all the DS2000 users): How often, if ever, when working with I2C do you find that you wish you had a 3rd or a 4th channel? Thanks, EF

author: Harvs
author_rank: Super Contributor
timestamp: August 27, 2013, 05:29:10 am
content: Quote from: Electro Fan on August 27, 2013, 05:18:38 amEvery day...

author: Electro Fan
author_rank: Super Contributor
timestamp: August 27, 2013, 05:43:52 am
content: Quote from: Harvs on August 27, 2013, 05:29:10 amBut are you still getting some useful I2C work done with just 2 channels - and you're working around it? Or, have you concluded that I2C work generally/really should have more than 2 channels? Are you using the scope just for triggering, or decoding too? Also - aside from 2 more channels - is there anything else about the I2C capabilities of the Rigol that is missing, or is it just the 2 extra channels? Please tell us more. Thx

author: Harvs
author_rank: Super Contributor
timestamp: August 27, 2013, 08:34:48 am
content: Quote from: Electro Fan on August 27, 2013, 05:43:52 amSure, I use to debug I2C on the old tek DSO with 16kp memory and it still use to work. Then I had the DS1052, and the large memory made it much easier. Now with the DS2000 we have built in decoder, huge memory, segmented memory. It's like heaven compared to 10yrs ago.QuoteWell, obviously you can see what's happening on the I2C lines, but you have little information about other signals (analog and digital.)QuoteAt the end of the day, yes there's lots of things in higher end equipment that I'd love to have. When it came down to the channel choice, it was pretty much either a DS2000 with 2 channels for $800 or a DS4000 with 4 channels for $2400. As the money would be coming directly out of my pocket, the efficiency gained did not justify the cost as most of my work is in PSUs where a 4 channel analog scope still performs beautifully.

author: Electro Fan
author_rank: Super Contributor
timestamp: August 27, 2013, 05:14:41 pm
content: Hi Harvs, I hear you about the budget. $800 to $2400 is a big swinger.Just curious, if you had a Rigol DS4000 series (other than the 2 extra channels), what features/specs would you most likely use that you don't currently have?On a related hypthothetical, any chance you would trade a DS2000 for a DS1000Z even up? In return for the 2 extra channels, could you live with:1G Sa/s Real-time Sample Rate12Mpts (Std.) and 24Mpts (Opt.) Memory DepthUp to 30,000wfms/s Waveform Capture RateUp to 60,000frames Real-time Waveform Record(Opt.)1mV/div to 10V/divLesser? Multi-Levels intensity grading waveform displayDifferent control layout/UIOr would some of the "gives" be insufficient to take the 2 extra channel "gets"?Also, don't know if you have seen the screen shot from the 1000Z for I2C? Seems a little different than on the 2000 series; see anything that stands out as a notable plus or minus?Thanks again for any thoughts you can share. EF

author: Harvs
author_rank: Super Contributor
timestamp: August 28, 2013, 12:59:14 am
content: Quote from: Electro Fan on August 27, 2013, 05:14:41 pmFor me, I can't think of any but YMMV. The DS2000 is a very feature rich scope for this end of the market, and there's nothing in the specs for the DS4000 that screams out at me. I haven't used one though. I do really like that they've retained an extra trigger in on top of the 4-channels, this may not matter to many people, but when assessing feedback loop stability using a function generator you need to be able to trigger off the func gen's trigger out. On a lot of 4-channel scopes this looses you a channel, so you're down to 3.QuoteThe DS1000Z wasn't out when I bought the DS2000 but for me the single killer is the sample rate.1GSa/s (Single-channel), 500MSa/s(Dual-channel), 250MSa/s(Fulll-channel)250MSa/s is a deal-breaker for me, I don't think it's enough for a 100MHz scope. I note it doesn't have the nice benefit of an extra trigger channel like the DS4000.Nope I would take the DS2000 2CH over the DS1000Z 4CH, but as always you'll probably be doing different things with it than I would so you need to decide what's important to you.

author: tinhead
author_rank: Super Contributor
timestamp: August 28, 2013, 01:08:33 am
content: Quote from: Harvs on August 28, 2013, 12:59:14 amwhy not? (longer than better didn't count here). It's enought to sample 100MHz signal. The DS1052 you had was not better, with 2ch enabled and long memory it does sample as well with 250MSa/s.

author: Harvs
author_rank: Super Contributor
timestamp: August 28, 2013, 01:59:18 am
content: Quote from: tinhead on August 28, 2013, 01:08:33 amThis is going to sound pretty un-scientific but, and when looking at SMPS edges the DS1052 wasn't as good as a 100Mhz analog scope, probably because there is frequency content up to 100MHz and beyond. With the analog scope it may be attenuated, but you can still tell easily if there's leading or falling edge spikes you need to be worried about. The DS2000, in my couple of months of use, is much better at revealing these problems. If the DS2000 had 4-channels I'd probably take the analog scope off the bench.But as I said, people use these tools for different ends, so someone else will be bound to have very different opinions to me. Which is completely to be expected, and hopefully they'll share there views to give a fuller picture.

author: Electro Fan
author_rank: Super Contributor
timestamp: August 28, 2013, 02:48:19 am
content: Quote from: Harvs on August 28, 2013, 01:59:18 amHi Harvs,I respect practical/observational experience as well as math and scienceThis might be goofy idea, but is there a way to cause the 2072 to sample at 250MSa/s while looking at those SMPS edges to simulate what it might look like with a 1000Z running all 4 channels at the same time?EF