4 Channel scope you recommend with 500msa per channel minimum... - Page 1
Forum section: electronics / testgear

author: alank2
author_rank: Super Contributor
timestamp: April 02, 2014, 05:32:27 pm
content: Hi Everyone,Firstly I've got a DS2072 and it is a sweet scope, it is a real shame they don't make a 4 channel version of it.The DS4014 is more money than I want to spend and also has a larger noise factor than I want to deal with.The DS1074Z is certainly affordable, but I just didn't like it as much as my DS2072 for various reasons.Is there anything in between more like the DS2072 but with 4 channels from other manufacturers? What suggestions?Thanks,Alan

author: nctnico
author_rank: Super Contributor
timestamp: April 02, 2014, 05:42:01 pm
content: Did you look at the SDS2000 series from Siglent?

author: mjkuwp
author_rank: Unknown
timestamp: April 02, 2014, 06:48:43 pm
content: What do you think of the Hameg HMO1024 ?

author: Mark_O
author_rank: Frequent Contributor
timestamp: April 03, 2014, 04:22:59 am
content: Quote from: alank2 on April 02, 2014, 05:32:27 pmI agree, and I've lamented that for some time. Would an 18-channel MSO2000 meet your needs? I.e. still just the 2 analog chans, but +16 digital channels, with decode support. That should be announced sometime this summer.QuoteDitto.QuoteFour that I'm aware of (2 already mentioned):1) Agilent DSOX20n42) Hameg HMO 724, 1024...3) Siglent SDS2xx44) LeCroy WaveAve 20x4I know Tek makes some too, but I've been disappointed with their price/performance/feature balance for so long now, I don't even look anymore.If a DS4104 is more than you want to spend (was $2400, went up to $2480), then I doubt the HMO1024 will be any more attractive to you (same ballpark). The HMO724 can be found at or under $2k, depending on how it's optioned, while the Agilent is in the $1,900 neighborhood.The Siglent will be significantly more affordable than any of the competition, and may offer excellent performance/features, though it's too soon to say. But it promises to be roughly equivalent to the 4-channel DS2000 you wish was available. Unless you're in a hurry, waiting to see how that pans out may be worthwhile.[That's what I'm doing, BTW.]One other advantage it offers is MSO upgradeability later, if you find you need/want it.[EDIT: as does the Hameg.]LeCroy makes some decent performing WaveAve 2000 units, but the screen rez is low, and the memory depth is anemic (says 12k/chan in one spot, and 1M/chan elsewhere?). Nothing that really impressed me. (In anything resembling affordable, that is. They make some slick stuff [always have], with stratospheric pricing.) I'm sure they outsourced the WaveAce series to someone else, and don't even make it themselves.I assume you wouldn't be any more interested in the GW Instek GDS-2104 than I, based on it's 24k sample depth.[However, the GDS-2104Ahas up to 2M sample depth. See Dave's comment and my response, below.]But you didn't say whether Used was an option. You may find an Agilent in that category, with better performance than you could afford new.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: April 03, 2014, 04:56:54 am
content: LeCroy WaveAce series are made by Siglent.

author: EEVblog
author_rank: Unknown
timestamp: April 03, 2014, 05:39:40 am
content: GW Instek make 4 channel low-ish end one starting from $1200:http://www.gwinstek.com/en/product/productdetail.aspx?pid=3&mid=7&id=1349

author: Mark_O
author_rank: Frequent Contributor
timestamp: April 03, 2014, 06:20:51 am
content: Quote from: EEVblog on April 03, 2014, 05:39:40 amThanks very much, Dave! That's the one I was vaguely recalling, but when I did a search, I wound up at a site with info on the older GDS-2000 non-A. The spec they give there is "25k Points Record Length Maximum", which is correct for that older model. It's easy to confuse with the newer A-model, because the front panels don't look all that much different (at least in a thumbnail). But I should have realized something was amiss.The GDS-2104Ahowever has an 8" hi-rez display at 800x600 (vs. the old 5.6"), 2M points of memory depth, and best of all, Waveform Search and Marker capability. That's pretty unique, even amongst mid-priced DSOs (e.g., the DSOX3000 has full Search for any Trigger qualifier, but the DSOX2000 can only Search for protocol matches). 2M sample depth doesn't compare with what's available on many other options, but it's a heck of a lot better than 25k!And while it does support Segmented memory acquisitions, it has a max of 2048 segments. Not bad, but not spectacular either.In my opinion, they did themselves a huge disservice though, by coming out with a radically different scope, but only changing the name from 2000 to 2000A. That's almost mind-bogglingly stupid.

author: alank2
author_rank: Super Contributor
timestamp: April 04, 2014, 01:08:14 pm
content: Quote from: Mark_O on April 03, 2014, 04:22:59 amThat sounds interesting for sure. I do love the DS2072 especially when "optimized" to its full capability. I have to wonder if Rigol will be pressured to offer a DS2074 someday with some of these other 4 channel offerings with a higher sample rate. I'd like to see that. I did think hard about the DS4014, but its price, size, noise, and what I read about it running warm just didn't push me to buy although I'm sure it is quite nice.

author: darrylp
author_rank: Regular Contributor
timestamp: April 04, 2014, 01:52:14 pm
content: Have you considered adding another ds2072a to your existing ds2072 ?

author: alank2
author_rank: Super Contributor
timestamp: April 04, 2014, 02:24:21 pm
content: Quote from: darrylp on April 04, 2014, 01:52:14 pmYes, I actually did this, but I think when it comes down to it, it just isn't the same not having everything next to each other on one screen with one time reference. I was going to build a little shelf to put one ds2072 above the other. The more I think about it, perhaps I should just give up on having a 4 channel one and just use a logic analyzer instead. Much less bulky probes for many channels anyway.

author: Mark_O
author_rank: Frequent Contributor
timestamp: April 05, 2014, 01:19:41 am
content: Quote from: alank2 on April 04, 2014, 01:08:14 pmI've discussed that possibility with them, but they've said no.It would require a completely new board layout, for one thing. That doesn't mean though that it would never happen (e.g., a new DS3000-series). For now, they're focusing on adding 16-channel digital LA capabilities to their DS1000Z (soon), and DS2000 (a bit later).QuoteThere's a lot to like about the DS4014, but I don't feel that the performance increase justifies the price (compared to the DS2000-series). When you throw in all the owner comments here about stuff that flat-outdoesn't work properlyon the DS4000 (still!), that kills it for me.Re: adding a second DS2072A:QuoteFirst off, if what you really need those extra channels for is mostly logic, then the MSO2072 would make a lot more sense (than two DS2000's). That gives you time-correlated signals, in two domains. (And of course, the 4-channel Siglent + MSO will [some day] give you both!) If you need themonlyfor logic though, then a separate logic analyzer will be vastly more powerful and capable than whatanyMSO can offer. I'd recommend you look at something like the USBee SX for that (with it's extensive and powerful protocol analysis capabilities, up to a 25 MSa/sec rate). Or, wait a bit and see what Saleae has up their sleeve in their new/pending offering. They're hinting it will be pretty slick.In the case of the USBeeSX, not only does it support vastly more protocols, but you can add new ones as needed. (Trythaton a Rigol. Or Tek. Or Agilent!) Plus, it can decode more streams (not limited to 2 decoders, as all these scopes are). For example, I can watch a 500k CAN bus signal (1) flow from a vehicle through a bus transceiver and be forwarded via SPI (2) at 8MHz to an embedded micro, then after filtering and conversion, sent on via RS232 (3) at 115.2k to a PC. Along with an I2C control signal (4) that's time-related. NONE of these MSO's is going to give you that (4 simultaneous decoders). And it has extremely powerful Search and Mark capabilities (basically post-acquisition 'triggering' on anycombinationof any conditions) for easy navigation and fault isolation. That goeswaybeyond what even a $20k instrument will give you (because it's not real-time). Combined with almost unlimited sample depth (hundreds of megs is no problem), to capture really long "conversations".The limitations there are in sample rate (e.g., no good at all for newer 25MHz SPI on my current board!), and no time-correlated analog checks on signal integrity. (Which I definitely like to see and confirm!) And it's not set up to handle varying signal levels all by itself (you may need to front-end it, for some applications. But I see there are nifty $18 boards for thaton eBay nowthat I didn't have available back then.) But you can't have everything, for less than 200 bucks for the module with core software (just looked... $169 now), and another $200? for the elaborate Search & Mark capable software. (looked... $299 now for the Pro Suite, on sale occasionally.) There are going to besomecompromises that are inevitable.You really have to evaluate what you're going to do with your tools, to be able to select the most appropriate ones for the job.

author: alank2
author_rank: Super Contributor
timestamp: April 05, 2014, 01:37:57 am
content: I ended up with a Saleae Logic16 with their sale and have been very happy with it. I even messed around with developing a decoder for it to see if I could and it wasn't brutal to make so I love that I can make a decoder for any type of signal that I like. I love that part of their decoder is producing simulation data too.I too am looking forward to see what they are going to have.

author: Mark_O
author_rank: Frequent Contributor
timestamp: April 05, 2014, 04:51:53 am
content: Quote from: alank2 on April 05, 2014, 01:37:57 amVery cool, Alan! As long as the signals you need to examine fit within the sample-speed constraints, these are good solutions.One of their limitations though (USBee, as well as Saleae) is (was) that they were strictly batch-mode. I.e., capture a chunk, then go back and examine it in detail. Many times, that's exactly what you want to do. But sometimes you really want something more interactive than that, so you can see live signals in real time, while probing around. There are many scenarios where this mode just makes a whole lot more sense. And can save you a lot of time, by helping you hone in on a specific pin, or see certain exchanges and see if they "look right" or not.I was really glad to see that someone (you!) hadfinallycome up with a real-time viewer. That seems so obvious, yet so overlooked. I've had no time to play with it yet myself (I'm busy in a design/code phase right now), but plan to do so eventually. As I mentioned, my main USB LA is the USBeeSX, which I bought back in our days over in the RCGroups forum. And it's seen a fair amount of use, off and on.I also own a Saleae clone, which I've never used, because I didn't buy their software. And to be frank, even if I had bought their software, I still probably wouldn't use it. Without any Search and tag capabilities, it's just a time-suck to look for a needle in a haystack, manually (and I know they're finally working to rectify that!). Since I had an alternative, there was no point in it.I haven't seen anything 3rd-party before, that I'd want to use with it, so it's just been sitting in a drawer, waiting for something nifty like your RTViewLA (? not sure about the name) to come along.I hope I can find the clone again when I have time to give it a run.

author: alank2
author_rank: Super Contributor
timestamp: April 05, 2014, 12:47:04 pm
content: Hi Mark_O,Quote from: Mark_O on April 05, 2014, 04:51:53 amOne of my favorite things about it is how easy and compact the probing it. The XKM grabbers with a compact 9 wire harness just fits over a project with ease.One of the biggest problems is the bandwidth limitation, but I love that the Logic16 allows you to reappropriate the number of channels you want as a trade off for more bandwidth. I think that was a very cool idea.Quote from: Mark_O on April 05, 2014, 04:51:53 amI'm doing what I usually do with projects and let it get a bit unwieldy with ideas, I need to bring it back down and finish it.Quote from: Mark_O on April 05, 2014, 04:51:53 amYou should, so far I've found it to be pretty handle even as basic as it is.Take care!Alan