Information overload. I'm confused. Do I really need four channels? - Page 1
Forum section: electronics / testgear

author: Artikbot
author_rank: Contributor
timestamp: December 03, 2016, 09:58:17 pm
content: Evening chaps,First of all, my apologies if this sounds likeyet another'What scope do I buy' thread. I'll try to not make it sound like it.Here's the deal: I've never had an oscilloscope.I've borrowed the odd single and dual channel scope from school, from the odd friend, but I've never actuallyownedone, so this is from where most of my confusion comes from.Bit of background. I've been doing electronics work for the past 5 or 6 years. I started with basic discrete digital electronics, moved into developing and building e-bike speed controllers, DC burshed motor management... More recently I've been doing most of my work in LED power management, data acquisition and handling on 8-bit PICs and 16-bit dsPICs. I'm also developing my studies and career into the analog side of life (specifically high power PSUs for large stuffandlow noise PSUs for minute instrumentation, but mostly the first half), for whatever that's worth.And I've made the decision that I can no longer do with borrowing equipment here and there, especially as my projects grow larger, more expensive and start to turn a profit (and there's only as long as I'm allowed to stay at the college labs...)My budget, as you have probably guessed, isn't massive. About 500€ all inc (taxes, shipping...).I've narrowed it down to two scopes:-Rigol DS1054Z (who would've thought!)-Siglent SDS1102XHere's the reasons for the Rigol:-Community loves it-Dave loves it-Some leftover monies are always good-Four channels. And I'm bolding this out because part of the work I've taken a liking to doing is AC/BLDC motor management, and as I move from purely modifying and analysing speed controllers onto developing them from the ground up, I'm told four channels become a bit of a requirement - so there's that. Even if there's no external triggerReasons for the Siglent:-On paper, substantially more powerful and capable than the Rigol, as far as the acquisition bit is concerned (60k wf vs 30k, 500uV/div vs 1mV, twice the BW, deeper memory, all the digital analysis bits come for free... or at least all of this is pre-hacking it, which I would definitely do).-Better handling and feeling? Seems to have more screen estate dedicated to the waveforms, the variable intensity display seems much better executed than the Rigol, also dedicated controls per-channel. Critics seem to mention a generally more 'adequate' feel compared to the Rigol and being more comfortable to work with.-No need to hack anything to get the whole parade of features - vendor ships the upgrade key free of charge. Including CAN, which considering one of my current ventures is in the automotive field, could be quite handy - although I'm aware there's external USB analysers that do that no problems for a few bucks.So the real question is - Does onneedfour channels for the kind of work above, as I have been suggested? Is it more advisable to get the technically superior Siglent over the twice-as-many-channels Rigol?For the sake of simplicity, let's condense it down to 90% power management and motor control, 10% general basic digital work (discrete CMOS/TTL logic, 8/16bit basic MCUs and such - nothing fancy).Again, my apologies if this sounds like I have no idea about what I'm looking to buy, but I really don't because I've never had a scope of my own and always had to make-do with whatever I had at the time, ideal or not.Many thanks!Edit: For the sake of completeness - I have read through both respective threads quite meticulously - but if anything I am even more confused!

author: RoGeorge
author_rank: Super Contributor
timestamp: December 03, 2016, 10:50:39 pm
content: The 4 channels from DS1054Z are very useful, especially when decoding serial protocols.

author: tautech
author_rank: Super Contributor
timestamp: December 03, 2016, 11:18:17 pm
content: Welcome to the forum Artikbot.Had to Google where Andorra was so that I might give some local advice.https://www.lonelyplanet.com/andorraYour local Siglent distributors can be found here:http://www.siglenteu.com/howtobuy.aspxAnd now as a EEVblog forum member you can ask for the Siglent supplier Saelig discount code here:https://www.eevblog.com/forum/testgear/equipment-discounts-from-saelig/As you've identified Siglent DSO's have an Ext Trigger input that can be used for CS when Decoding and as a result having only 2 main channels is not so much the disadvantage you might think.

author: mk_
author_rank: Regular Contributor
timestamp: December 03, 2016, 11:25:22 pm
content: Quote from: Artikbot on December 03, 2016, 09:58:17 pmYou will find yourself searching more channels on the backside of your oscilloskop because specialy high power PSU requires constant viewing current, voltage and a lot of more details.(Ripplecurrents - primary and secondary, Voltagedrops when jumping from 10 to 90% power... you got the idea)So don`t ask if 2ch are enough, ask yourself if 4ch are enough...and - reserve some money for good probes...Michael

author: nctnico
author_rank: Super Contributor
timestamp: December 03, 2016, 11:33:36 pm
content: Go for 4 channels and never ask again if 2 channels is enough because it isn't!

author: sambran
author_rank: Contributor
timestamp: December 04, 2016, 12:24:48 am
content: I still regret getting a 2 channel scope.

author: Artikbot
author_rank: Contributor
timestamp: December 04, 2016, 12:38:00 pm
content: Quote from: RoGeorge on December 03, 2016, 10:50:39 pmThat's most helpful to know, I've not done any digital analysis on an already working setup yet, but no doubt I will.Quote from: tautech on December 03, 2016, 11:18:17 pmThanksFor all intents and purposes I'm in Spain, although I'll be buying everything from Germany (what a surprise, heh).I wasn't so sure about the disadvantage, rather, since I've never had to spec a scope for myself to own I've never really known what would it really need to have, hence throwing the question out there on whether 2Ch+trigger is enough, or 4 channels are much more desirable.Quote from: mk_ on December 03, 2016, 11:25:22 pmMichael,Now that hits close to home. PSUs are pretty much my bread and butter, so it would make sense to go for what is best for that. Just as you mentioned ripple currents I had this train of thought of everything I just realised I can't do with just two channels, even adding an external trigger.That answers my question, thank you!Quote from: nctnico on December 03, 2016, 11:33:36 pm...I think I just might hahaQuote from: sambran on December 04, 2016, 12:24:48 amConfirmed, DS1054Z it is!Thanks for the replies everyone, it all makes a lot more sense now!

author: JPortici
author_rank: Super Contributor
timestamp: December 04, 2016, 01:10:19 pm
content: Quote from: sambran on December 04, 2016, 12:24:48 ami still regret buying the 1054z.i'd rather have a 2 channel scope that works as it should (2+ext trig, 2 chan on its own is very limiting)i can't comment on the channel requirements as i don't do power electronics. My 2 cents on the 1054 itself

author: Artikbot
author_rank: Contributor
timestamp: December 04, 2016, 01:25:18 pm
content: Interesting...How is that? What kind of work do you usually do that it falls short on?

author: rstofer
author_rank: Super Contributor
timestamp: December 04, 2016, 04:26:59 pm
content: Good choice on the DS1054Z, I certainly like mine! I wanted 4 channels for serial decoding and I almost never get involved with PSUs.If you want to use the X-Y math function (differential measurement of current through a resistor?), you just used up two of the four channels and you probably want to view a voltage or two to go along with the current (phase relationships?) so that's why 4 channels is a good idea.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: December 04, 2016, 07:51:47 pm
content: In XY mode the 1054z can only use two channels. The other two are turned off automatically.QuoteOh... perhaps you mean the A minus B math function. OK, then you can have five traces showing: the two channels that are in the subtraction, the other two channels, and the math result of the subtraction.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 04, 2016, 08:19:59 pm
content: As someone who has worked with oscilloscopes since two channels was a great leap forward, there is no number of channels which is either too few or too many. You can do a great deal of work with one channel. There are many more things you can do with two. In today's world I would absolutely not go less than two, which allows you to compare phase of two signals. If you have four you will find uses for all of them, and sometimes wish you had more. I do find that for my general hobby electronic work that I seldom have all four channels of my scope active, but often have three.

author: tggzzz
author_rank: Super Contributor
timestamp: December 04, 2016, 08:57:54 pm
content: The trick is to ask the right question, because then the answer is easy.Perhaps a better question is "what instrumentsdo I need?".Consider buying an Analog Dialogue. That will give you a simple 100MS/s pattern generator & logic analyser, a waveform generator and a 10MHz digital scope.Where you need more bandwidth, e.g. for signal integrity, get an old analogue scope - but make sure it is working! 100MHz is insufficient for modern logic w.r.t. signal integrity.Look at my .sig, and relate it to electronic instrumentsAnd distrust those that say X is the only choice, especially if they don't limit the applicability of their pronouncements!

author: tggzzz
author_rank: Super Contributor
timestamp: December 04, 2016, 09:54:57 pm
content: Quote from: blueskull on December 04, 2016, 09:34:57 pmVery true, in my experience. But I would add "printf" to that toolset.When in the digital domain, use digital tools. Ditto analogue domain. But use a scope to ensure that the analogue signal will be interpreted correctly by the digital input - I.e. ensure the signal integrity.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 04, 2016, 10:17:49 pm
content: You can do almost everything you can do with a 4 channel scope with a 2 channel scope and the SDS1102X is a great two channel scope.That said, it is MUCH easier to find correlations with more channels and MUCH faster to debug issues with virtually any kind of circuit. Take a simple amplifier with a couple of stages. With a two channels scope you could measure the input and the output and see how it works, maybe switch to get the intermediate signal step or swap to measure the rails or whatnot. With a 4 channel scope, you can measure the input, the output of the first stage, the output, and a supply rail all at once, which means you'd be able to troubleshoot glitches at any one of the points and if they're intermittent or if (for example) the glitch is caused by the power supply but only when the input is doing something specific, you'll be able to trace down the issue much faster.I'd think in power supply design, it would be especially useful because you could get a couple of current probes and then measure current and voltage activity at an input and an output (or any two points, really) all at once, making it really easy to track power on/off/brownout behaviors, track down noise sources, etc.So especially if you know your application, two channels can be enough and two channels is WAY WAY WAY better than having nothing. 4 channels makes most things more convenient, gives you a few more options, and helps you correlate signals in different parts of what you're testing more quickly and reliably.

author: tggzzz
author_rank: Super Contributor
timestamp: December 04, 2016, 10:53:33 pm
content: Quote from: blueskull on December 04, 2016, 10:00:00 pmPicky, picky, picky

author: imidis
author_rank: Frequent Contributor
timestamp: December 04, 2016, 11:04:53 pm
content: When I purchase something I like to know that I won't need to go to another anytime soon. I believe if I were purchasing one I would go with the Rigol 1054Z. I believe it's decent value for a four channel scope and though I may not need the four channels, if I need them they would be really handy to have.

author: nctnico
author_rank: Super Contributor
timestamp: December 04, 2016, 11:07:06 pm
content: Quote from: tggzzz on December 04, 2016, 08:57:54 pmThe answer to that is simple: the best and most you can buy. Better tools will always allow to do a job better and quicker. If you are really serious about electronics then it may be worthwhile not to go for the cheapest but aim a couple of steps higher.

author: tggzzz
author_rank: Super Contributor
timestamp: December 04, 2016, 11:20:23 pm
content: Quote from: nctnico on December 04, 2016, 11:07:06 pmNo it isn't simple, because it ignores the interesting real-world dilemma: to go for a slightly better (in some respect) X, or to go for a better (in another respect) X plus a Y plus a Z.

author: nctnico
author_rank: Super Contributor
timestamp: December 04, 2016, 11:33:16 pm
content: Even though the words 'best' and 'most' where carefully choosen you overlooked them.

author: tggzzz
author_rank: Super Contributor
timestamp: December 05, 2016, 12:39:08 am
content: Quote from: nctnico on December 04, 2016, 11:33:16 pmNo, I didn't overlook them; I took them at their face value.It is better to have a balance between good enough X and good enough Y, rather than the best X and no Y.

author: Artikbot
author_rank: Contributor
timestamp: December 05, 2016, 12:43:44 am
content: Quote from: tggzzz on December 04, 2016, 09:54:57 pmPartially why I don't give much credit to the digital analysis capabilities of either scope - there are better tools out there for less than the difference between the devices. But again - digital work is a relative minority of what I do.Quote from: tggzzz on December 04, 2016, 11:20:23 pmVery good point. In this case it's the obvious benefit of two extra channels versus a technically superior device that outright lacks an important feature of the inferior model. If I had a few grand to drop it'd be much easier, alas it is what it is.Quote from: DaJMasta on December 04, 2016, 10:17:49 pmThis bit here is what has made me tip over to the Rigol in this case. I'm by no means an expert, or even remotely experienced - I can use as much help as I can get. It would appear like the help of the extra channels is substantially more desirable than the extra grunt and refinement of the Siglent in this particular scenario...Really appreciate the thoughts on this matter

author: saturation
author_rank: Super Contributor
timestamp: December 05, 2016, 01:03:48 am
content: 2 channels allowed the user to see input and output simultaneously, correlate them and thus speed your evaluation.The Z implementation exacts a speed and sampling rate penalty on every other channel you turn on. The slow down can reduce usefulness markedly. Also the small screen starts to get crowded as more traces appear but it depends on what type of waveform you are viewing before it becomes unwieldy.However, you can keep performance up by switch off channels that are hooked up but not important to see at the moment and its easier to turn on a hooked up channel than to move probes about.

author: Muxr
author_rank: Super Contributor
timestamp: December 05, 2016, 09:06:18 am
content: 2ch is fine, 4ch is better. That's how I look at it. I used a 2ch scope (and still sometimes do) for a while and never really felt handicapped by only having 2ch. Most measurements I do even on my 4ch scope are with 1 or 2 probes.

author: Fungus
author_rank: Super Contributor
timestamp: December 05, 2016, 09:22:56 am
content: Quote from: Muxr on December 05, 2016, 09:06:18 amBut not 100% of them, right?If 1% of measurements use 3 probes and only 0.01% of them use 4 probes then youstillneed a 4 channel scope.The time you should consider a 2 channel 'scope is when you can do 99% of your work with just 1 channel.(yes, Iknowmost of EE history used 1 or two channel scopes but most of human history also pooped outdoors and used horses for transport)

author: tggzzz
author_rank: Super Contributor
timestamp: December 05, 2016, 09:42:20 am
content: Quote from: Fungus on December 05, 2016, 09:22:56 am... and then you find you need a 5 channel scopeBetter to apply understanding and imagination to the problem, and find a way to use the tools at your disposal. Being able to understand and differentiate betweennecessaryandsufficientandconvenientis a valuable engineering skill.

author: tszaboo
author_rank: Super Contributor
timestamp: December 05, 2016, 09:52:28 am
content: You might need to work with a 4 channel scope, just for Analog. You debug an amplifier, looking at the input, the output, and any other node. You want to record that your power supply sequencing is good. You want to debug any differential transceiver, input 2 outputs...I dont think 4 channels is an overkill. I actually think, 4 CH MSO is something which is needed for electronics.

author: Howardlong
author_rank: Super Contributor
timestamp: December 05, 2016, 09:58:05 am
content: You can get almost always get away with 2 channels. Sure, it's less convenient, you will have to switch probes around more in the middle of a test, but you can almost always make the measurement.But if you need that extra bandwidth, you can't get away with a lower bandwidth.So I guess the question is easy, do you need the extra bandwidth?

author: Fungus
author_rank: Super Contributor
timestamp: December 05, 2016, 10:28:46 am
content: Quote from: Howardlong on December 05, 2016, 09:58:05 amSure, but what if you're still at the stage where you can stillchoose?Quote from: Howardlong on December 05, 2016, 09:58:05 amAnd the more difficult followup question is, "how much bandwidth do you need"?

author: Howardlong
author_rank: Super Contributor
timestamp: December 05, 2016, 11:56:04 am
content: Quote from: Fungus on December 05, 2016, 10:28:46 amI don't think there's any doubt in my own mind that personally speaking, 4ch has been almost a prerequisite since I first started using a Tek 2465 CRO twenty years ago, but before then I'd been perfectly fine with 2ch for a couple of decades before that. this was a case of what you don't know, you don't miss!While the extra two channels on the 2465 had restrictions (pretty much limiting them to digital levels), I found I used those extra channels enough of the time for developing stuff that I don't like going back to 2ch, for example the rare occasions I use a 2ch handheld scope I find it tedious to use, but that's as much to do with the UI as it is to do with it only having two channels.While you can in many situations supplement your scope channels with an LA, I much prefer using the scope than messing about with setting up a PC based LA, but that's my personal preference.Putting my neck out, I'd say that two channels is a much more relevant for equipment repair, compared R&D where you're going to find four channels more useful.QuoteNever enough ;-)Bandwidth can quickly end up being an arms race, particularly when you start having to throw money at probes. Even at 200MHz, passive probes will introduce significant artefacts. However, you will still be able to see stuff on a 200MHz scope that you wouldn't with 100MHz BW. Whether you need to see that stuff or not though is open to question: W2AEW did a great video (#25) where he had a transistor amplifier circuit go into oscillation, and why you might want more bandwidth.FWIW, from what I've seen, I agree that for what the OP is doing, and at the level at which they're doing it, in their shoes unless they have bad eyesight the DS1054Z would be the one to go for: the screen on the 1054Z is pretty small. On the other hand, its diminutive size is a plus point if you have limited bench space.

author: Howardlong
author_rank: Super Contributor
timestamp: December 05, 2016, 12:00:49 pm
content: Quote from: JPortici on December 04, 2016, 01:10:19 pmWhat aspects did you find bad about the 1054z that made you regret your purchase?

author: nctnico
author_rank: Super Contributor
timestamp: December 05, 2016, 12:23:28 pm
content: Quote from: blueskull on December 05, 2016, 09:30:21 amIf you spend that wasted time working in a supermarket you'll be surprised how little time you have to work to earn enough money to make up the price difference between a 2 channel or 4 channel scope.

author: JPortici
author_rank: Super Contributor
timestamp: December 05, 2016, 12:27:42 pm
content: Mostly one, the slowness of the user interface.the scope is slow on its own.. but let's say bearable. The moment you enable one of the features it's not usable anymore, to me.So at work i finally had to interface with an SPI EEPROM because need for speed, this meant that during development i needed to actually use four channels while in 99.5% or more of the cases i need one or two to check the spi lines. Since the scopes on the work bench are a picoscope 2000 series and a tektronix tps i decided to bring my 1054z. Setting up serial decoding is frustrating to say the least and waiting 5 to 10 seconds to decode the new packets is even worse, after 10 minutes i switched off the damn thing, decoded by hand a couple of packets at the tektronix to see if timings and signals were correct then only used the picoscope, one channel at the time. it was that faster to proceed in this way.you see, even tough on paper a picoscope (for example) has shortcomings over a 1054z, like- lack of physical controls- 48kS memory (this is an older pico, new ones start at 32MS i think for fast acquisition, in slow/continous acquisition the limit is your pc memory)- very low wfm/s at timebases higher than 1 ms because USB2.0- thousands of acquisition and decoded data already there, at a click.in the real world it is a much more powerful beast.. and i can work much better with it.. beside having serial decoding that works, math that works, measurements that don't crap out, fft with some usable resolution, ETS, more decoding standards that you'll ever dream of in this price rangeinfact, now i use the tek only if i can't get around using two channels or if i need to do isolated measurementsI haven't sold my 1054z yet because i haven't used the hobby bench in quite a while but when i'll start playing at home again and when i'll go all deep with canbus and other automotive stuff at home too, 1054 will be unloaded to someone that will still want to buy it.what will i get? i'd like to try a pico 5000, or a GDS-2104. if budget will be lower one of the siglent 2 chans until i will be able to afford a lecroy/keysight (but keysight only if they will update the 3k series with more memory)no more cheap crap, that's sure.

author: Howardlong
author_rank: Super Contributor
timestamp: December 05, 2016, 01:45:07 pm
content: I agree the UI is slow and unresponsive but it's not unusable. It's not dissimilar to a Tek MDO3000 UI in this respect, although at least the rotary encoders keep up reasonably well on the Tek. The encoders on the Rigol are pretty bad but you get used to its shortcomings.I had a Pico a few years ago, but it sat in a drawer most of its life. I bought it thinking that a USB scope it would be convenient, I found I used it maybe three times over the five or six years I had it. I still have a 200MHz 4ch TDS2024B which I think is basically the same as a TPSxxxx. I keep it for sentimental reasons, and I can't remember the last time I actually used it for real work, whereas the Rigol I use pretty regularly even though it's only 100MHz.One thing I would say is that the Rigol will decode high speed SPI that the Keysight 3000 won't. The biggest frustration I have with the Rigol decoding is that it only decodes what's on the screen, and you can't decode more than a few bytes as it only subsamples what's in memory. I'd prefer it that there was some optional manual control over the decoding, but I found it's still better than doing it manually (although sometimes it gets it wrong!).Understood regarding the memory limitation of Keysight, it does seem a bit limiting nowadays. Although there is always segmented memory, even though it's straightforward, it's a bit of a pain to have to set up. Practically speaking though it's pretty rare I find the memory on the Keysights to be a real limitation. The reason my daily driver scope is a Keysight is quite simply the highly responsive and straightforward UI. But we are talking about an order of magnitude difference in price here!It'll take an awful lot more convincing to make me buy another Pico USB scope over a Rigol bench scope though.

author: MrWolf
author_rank: Regular Contributor
timestamp: December 05, 2016, 04:38:06 pm
content: Quote from: Howardlong on December 05, 2016, 01:45:07 pmPico is sort of "scientific calculator" of scopes. But currently most people are ok with +-/* and want knobs to play with. I see only way Pico going mainstream - packing all the same stuff into touchscreen box like Micsig, spice that with sharp looking UI and ext video/keyb/mouse option - it'll be all the rage. Then it would just come down to attaching ext keyb/mouse for power users and all the rest would be happy just stroking that touchscreen for basic functionality.Edit: Actually they are already moving there:https://www.picotech.com/library/picoscope/picoscope-beta-release-6.12.3Latest betas indeed come with "tappable" stuff. So "early adopter" could just take random Windows (or even Linux) tablet, tape Pico to it and it'll be all the rage already today

author: Artikbot
author_rank: Contributor
timestamp: December 05, 2016, 07:48:54 pm
content: Quote from: Fungus on December 05, 2016, 10:28:46 amThat is a reasonable question. And the answer to that isI don't know.All of my work so far has been done on either an ancient Tek single channel 20MHz tube scope or the 2ch 40MHz version of that same scope. I kind of took for granted that a modern 100MHz (even if it drops to 250MSa/s on all four channels (Nyquist says it'd be acceptable up to 50MHz in that scenario IIRC?) would even provide a certain amount of headroom for the coming years.Quote from: JPortici on December 05, 2016, 12:27:42 pmI'll be completely honest, I've flat out discarded PC-based scopes without even looking at them. I like standalone equipment and don't quite fancy the idea of having a computer kicking around the bench that I rely on for measurements.Touch screens are also something I'd like to avoid for basic operation stuff, for the simple reason that I tend to get grubby fingers when sat at my bench and scratches would quickly make the display unreadable (or if I use protectors, having to replace them constantly).Responsiveness does seem to be a common criticising point for the 1054Z, and to be honest I appreciate snappy UIs a lot. I'll do a bit more research on this before ordering, just to make sure I won't kick into frustration mode.Again, really appreciate the feedback, it's been invaluable so far

author: Fungus
author_rank: Super Contributor
timestamp: December 05, 2016, 07:59:16 pm
content: Quote from: Artikbot on December 05, 2016, 07:48:54 pmIn that case a DS1054Z will seem amazing by comparison.Quote from: Artikbot on December 05, 2016, 07:48:54 pm'Fixing' it requires spending another $600 or so. Your call...A lot of the complaints seem to center around the vertical movement. Everybody seems to see something different and a lot of that seems to be in your knob twisting technique. I made a separate thread on this:https://www.eevblog.com/forum/testgear/the-ds1054z-vertical-response-discussion-thread/It's never going to feel like an analog 'scope, they're just a potentiometer connected to the vertical amplifier so response is at the speed of light.

author: rstofer
author_rank: Super Contributor
timestamp: December 05, 2016, 08:08:00 pm
content: Quote from: Artikbot on December 05, 2016, 07:48:54 pmThink about how you use the controls of your existing scope. Do you spend 1% of the time moving the display around? 5%? Whatever...Now, suppose it took twice as long for the 1054Z UI. Does saving time on something you don't do very often make any difference in the world?It's a DSO, it has a lot of memory and it's primary job function is filling the memory and putting something on the screen. You will never get a DSO to respond the same as an analog scope.

author: nctnico
author_rank: Super Contributor
timestamp: December 05, 2016, 09:15:03 pm
content: One step up from the Rigol 1054Z is the GW Instek GDS2000E series which is responsive in general unless you let it do some serious number crunching.

author: Artikbot
author_rank: Contributor
timestamp: December 05, 2016, 09:22:26 pm
content: Quote from: rstofer on December 05, 2016, 08:08:00 pmOh, so it'scontrolsresponsiveness, not a very large representation delay.That I can live with.Quote from: Fungus on December 05, 2016, 07:59:16 pmFrom looking at your video it does seem to be quite annoying, but no, I'm not one to move things about all the time. I generally find a time base/amplitude what works for what I'm looking for, then go from there as required - not necessarily shifting the screen about all the time seeking ghosts.I hope I'll be alright... If not, well, I think I'll figure it out during the period I'm allowed to return the scopeThanks again!

author: marchelh
author_rank: Newbie
timestamp: December 05, 2016, 09:27:24 pm
content: I have tried the Rigol DS1054z but was not impressed. I had it for 2 weeks and it hung up on me for 5 times in that short time. Als I found that the interface was not very responsive when having deep memory enabled and some times it took 2 minutes to recover. A hard reset was then faster. I exchanged the Rigol for the 2 channel Siglent SDS1102X and this scope is much more stable and faster. And the deep memory called History is realy nice when analyzing i2c and other protocols. And Siglent currently has an action that you get the serial decoding option free with your purchase.

author: PA4TIM
author_rank: Super Contributor
timestamp: December 05, 2016, 10:56:04 pm
content: Most of the time I use one channel for voltage (often with a HV diff probe) and a current probe for the second channel. More as two traces on a scope screen is not my thing. So my DSO is 2 channel (350 MHz Hameg) 4 traces is much to crowded. Besides that I can not remember the last time I needed more as 2 channels. (I have several scopes incl three 4 channel analog scopes so if I really need 4 channels I can use one of them.The only reason I think 4 channel is handy, is so you do not have to set up the channel when you switch probes. But in my case that is only because I use all kind of probes. (and most times 2 scopes for this reason) On the other hand most of those probes cost more as 500 so that is no valid reason in your situation/budget)If you only want one scope and think you will need 4 channels in the future then buy one. You get 4 probes and budget probes die rather fast if you use them a lot so having 4 is not bad.

author: tggzzz
author_rank: Super Contributor
timestamp: December 05, 2016, 11:16:24 pm
content: Quote from: PA4TIM on December 05, 2016, 10:56:04 pmThat's a useful observation.QuoteAnd when you need decent probes you'll find you can barely afford two!

author: JPortici
author_rank: Super Contributor
timestamp: December 06, 2016, 06:49:02 am
content: Quote from: Artikbot on December 05, 2016, 09:22:26 pmnotice i didn't bring up the vertical movement (well actually i said bearable, which it is)did we ever talk about the horizontal there in that thread? another big can of worms.notice how he doesn't address moving around the fft, the serial decode parameters, the alternative trigger modesconsider those "600" more (are they even 600 more? i don't think so anymore.) to me they will be more as the 1054 will be sold at a loss. definetly return it if you can and you don't like it.

author: tautech
author_rank: Super Contributor
timestamp: December 06, 2016, 07:45:01 am
content: 2 channels, 4 channels, 2 channels, 4 channelsTruth is, real truth.......unless you've quite some reasonable experience with a scope using 4 channels can be quite challenging and complex. Gnd loops is the obvious first trap for unwary, then triggering to make sense of all you have on screen.Add to this a display that is not really appropriate for a 4 channel scope and by this time the scope novice is thoroughly confused.There's a good # of experienced members that have commented in this thread that I for one respect their views that 2 channels is most often more than enough and when more might be needed it's time to review your measurement practices. Good advice IMO.For years I had only 2 channel scopes (CRO's) and if I didn't have the chance to get 4 channels DSO's as part of my dealership I'd still only have 2 channel DSO's, even they can Decode serial protocols.If there's argument for 4 channels for PSU design.........well decent power analysis options don't exist in this entry level class of scopes. Period.

author: Artikbot
author_rank: Contributor
timestamp: December 06, 2016, 11:03:47 am
content: Just had a thought - 2ch+ext trigger at 500MSa/s would make the Siglent effectively twice as good as the Rigol in 2ch+ext trigger mode... wouldn't it?Taking what tautech just said as an example - I also do believe from looking at Dave's videos wrt. probes, high frequency analysis and such that 250MSa/s at low memory depth doesn't provide enough sampling speed to get a realistic picture of what's actually happening in the higher order harmonics and at higher switching frequencies - and that is quite important when it comes to PSU and filter design (or so I've been taught up until this point and have tried to take it into account as much as possible).So in 1ch/2ch with signal triggering both should be equal... But if an external trigger is used, the Siglent should actually be quite a fair bit better than the Rigol, kind of making the point about the extra channels a bit moot, and only really an advantage if I do use that fourth channel....or am I just overthinking stuff?Bearing in mind this scope will have to do for at least the next four or five years.

author: nctnico
author_rank: Super Contributor
timestamp: December 06, 2016, 11:24:14 am
content: Quote from: Artikbot on December 06, 2016, 11:03:47 amBugs and the decoding is just as limited as on the DS1054Z. For 100MHz bandwidth 250Ms/s (4 channels enabled on the DS1054Z) is enough so the extra samplerate doesn't give you any extra information.I really don't get why people insist on trying to make do with 2 channels. I often find myself looking at an input signal, output signal and use a probe to measure various points in the circuit. In some cases I use a current probe as well but that needs configuring the channel for showing current. If you need to swap probes all the time it will become a nuisance and you'll likely try to skip a measurement which actually could give you a good insight on a problem in your circuit.

author: Artikbot
author_rank: Contributor
timestamp: December 06, 2016, 12:14:28 pm
content: That's pretty much what I wanted to hear, if I'm honest...Enough brain-cracking is enough. I'll order the Rigol, if I don't like it I'll find something else.But it'll be hard to not like coming from a 40 year old entry-level scope.

author: rsjsouza
author_rank: Super Contributor
timestamp: December 06, 2016, 12:58:07 pm
content: Quote from: Artikbot on December 06, 2016, 12:14:28 pmExactly. Congratulations in your decision. I have asimilar walk of lifeas you (and as many others around) and couldn't be happier with the progression of my purchases.One detail: despite I have a 4ch nowadays, I find it useful only on occasion. But when I had only two it was perfectly ok as well.

author: saturation
author_rank: Super Contributor
timestamp: December 06, 2016, 02:02:38 pm
content: Give us a review on this thread when you can. I think it important to buy local so you can return it should you choose, or you need warranty work. Rigol and Siglent have their share of quality control issues. Enjoy.Quote from: Artikbot on December 06, 2016, 12:14:28 pm

author: JohnG
author_rank: Frequent Contributor
timestamp: December 06, 2016, 02:20:17 pm
content: FWIW, I do a fair amount of power supply design and debugging, and find that I frequently use 3 or 4 channels, and there are times when I wish I had more. When you have to start chasing down gate drive delays, startup, issues, etc., it is almost essential. If you are chasing failures, you can capture more stuff and look at it later, so yo don't have to keep the DUT running any longer than necessary.Also, if you are working on high density power electronics, you may find yourself probing DFN gate drives right next to a few hundred voltages and a low impedance bus. I don't know about you, but I don't like moving probes around when a false move can fry the circuit, the probe, and you. Even a slip at the signal level some distance away can still result in exploding power parts.John

author: rstofer
author_rank: Super Contributor
timestamp: December 06, 2016, 02:27:18 pm
content: As mentioned, 4 channels is only rarely required. More often than not, a single channel is sufficient. But the thing is, when 4 channels would be a help, a 2 channel scope is not. I bought the DS1054Z specifically for the 4 channels and the decoding. If I wanted a higher frequency 2 channel scope, well, I already had one."The screen is too small!". Well, yes, it's kind of small but it's twice the area of my Tek 485 and nobody ever complained about those scopes! When I'm displaying 4 channels, they will be digital traces. How tall do they need to be just to show a logic level? Then I add decoding and the trace count increases but, somehow, it all works out!Yes, I would like to buy a Keysight <something> with a huge screen, oodles of channels and bandwidth but I really can't afford it. So, I bought what is most likely to cover what I plan to do.

author: tggzzz
author_rank: Super Contributor
timestamp: December 06, 2016, 02:58:54 pm
content: Quote from: rstofer on December 06, 2016, 02:27:18 pm... and when you need 5 channels, e.g. for logic timing, then 4 is insufficient!QuoteBut, delightful as it is, a 485's screenisvery cramped with dual channels plus ALT timebaseQuoteLogic analysersare designed for just such purposes, and aren't limited to only 4 channels

author: saturation
author_rank: Super Contributor
timestamp: December 06, 2016, 03:29:11 pm
content: A trick is feed the trigger out of the main DSO to the slave DSO ext trigger in. Final stability varies with many factors, mainly the sweep speed, the quality of the trigger out waveforms and any adjustments possible on both DSO to compensate for cable delays and skewing in multiple daisy chained DSO but in general the sync can be adequate. You can also use multiple DSO networked together and software but the prior method is fast, quick and easy for < 100 MHz, you could do better with better gear. I do this on occassion on the GDS1054B as master for the Rigol 1052e slave to have a 6 channel view, the Rigol can be jittery but I work around it.Quote from: link=topic=79306.msg1085782#msg1085782 date=1481034017

author: Artikbot
author_rank: Contributor
timestamp: December 06, 2016, 05:52:17 pm
content: Oooo!That looks so pretty. Me likey.And not something I have actually ever been able to accomplish with the old relics - always had to repeat measurements a few times, take pictures with the camera mounted on the tripod (or record the screen!!) and then go from there.Needless to say results were... let's say interesting.

author: nctnico
author_rank: Super Contributor
timestamp: December 06, 2016, 06:57:55 pm
content: Quote from: tggzzz on December 06, 2016, 02:58:54 pmBut then you'll need to reconnect channels which is tedious to do and you miss the analog information which may be crucial for the problem you try to tackle (*). On my Tektronix logic analyser I have 4 analog outputs which I can switch to any input. In some cases I just use the logic analyser as an analog mux to look at the various digital signals on an oscilloscope.(*) A couple of years ago someone had to integrate a bit of hardware I designed into a bigger system. That person spend a couple of weeks on trying to get it to work but gave up. I went over there and the first thing I did was use the analog channels instead of the digital channels of his MSO to look at the signals. The problem became appearant in less than 10 minutes and half an hour later we had it working.

author: tggzzz
author_rank: Super Contributor
timestamp: December 06, 2016, 07:22:04 pm
content: Quote from: nctnico on December 06, 2016, 06:57:55 pmNo surprises there!As I've written many times before, first use a scope to ensure signal integrity. Once you have good (analogue) signals that will be correctly interpreted as digital signals, flip to debugging in the digital domain. Use the right tool foreachpart of the job.But how many analogue inputs do you needsimultaneouslyto ensure signal integrity? In most cases only two, to measure setup and hold times.

author: nctnico
author_rank: Super Contributor
timestamp: December 06, 2016, 08:17:22 pm
content: Why bother reconnecting if a little bit more buys you a tool which can do both? When the digital suddenly starts to misbehave you have to go back to look at the analog signals again. All in all switching between a logic analyser and an oscilloscope (reconnecting the probes) is just a nuisance you can avoid by having more channels. I have a four channels Agilent DSO7104A with the MSO option but in nearly two years I have not used the digitals channels at all.

author: tggzzz
author_rank: Super Contributor
timestamp: December 06, 2016, 08:24:25 pm
content: Quote from: nctnico on December 06, 2016, 08:17:22 pmThat is a rather contrived use-case; it feels you are finding a problem for your solution.It is, of course, entirely possible to have some digital lines and some analogue problems on other lines. In that case, use a logic analyser on the digital lines and a scope on the analogue lines.

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: December 07, 2016, 12:08:43 am
content: I'd agree. We see people very happy with our two channel scopes, but those are people who generally only need two channels.Four channels is nice, but it's certainly not always a need (especially in a value vs. $ budget dilemma).Just my 2 cents (not 4 cents).

author: nctnico
author_rank: Super Contributor
timestamp: December 07, 2016, 12:20:14 am
content: Quote from: tggzzz on December 06, 2016, 08:24:25 pmWhy insist on jumping through hoops where there is an easy way offered by a 4 channels oscilloscope? If using a 2 channel oscilloscope was so easy for every situation then why would manufacturers even bother to make 4 channel oscilloscopes? AFAIK Yokogawa still makes 8 channel models!

author: tggzzz
author_rank: Super Contributor
timestamp: December 07, 2016, 09:38:03 am
content: Quote from: nctnico on December 07, 2016, 12:20:14 amThose are strawman points.Look at the topic, viz: "Do I really need four channels?". That's "need", not "could used if available"!

author: JohnG
author_rank: Frequent Contributor
timestamp: December 09, 2016, 02:36:37 pm
content: Look at the topic, viz: "Do I really need four channels?". That's "need", not "could used if available"!The OP also indicates he is planning on working on motor drives and power supplies, both high and low power. I have worked in this area for a number of years. You have high speed digital controllers, isolators both analog and digital, little bootstrap converters to supply floating drivers, often multiple analog outputs, etc. It's a mix of both high power and sensitive analog and digital stuff, with both low bandwidth and high bandwidth requirements. My read is that he is looking to gain something greater than beginner expertise in this area. If that is true, then 4 channels is a need. I have 4 channels and still find myself switching probes.If all you are doing is experimenting with a single-active-switch converters or similar with old analog controller, you could get by with 2 channels, but even there, 4 channels is better than 2 if you really want to gain a deeper understanding of what is going on.John

author: rstofer
author_rank: Super Contributor
timestamp: December 09, 2016, 08:13:22 pm
content: Quote from: tggzzz on December 06, 2016, 02:58:54 pmAbsolutely but the scope is right in front of me and the logic analyzer (32 channels/100 MHz, 16 channels/200 MHz) needs to be fetched and connected to a PC. All in all, a bother since I usually want to watch a simple SPI transaction. And I'd like to do this simple thing without a lot of fuss! If I am watching come incarnation of 'current state' in an FSM, yes, I will use a logic analyzer. The problem these days is that, on many development boards, there simply aren't enough IO pins. Thankfully, Xilinx has solved that problem with their Integrated Logic Analyzer. I'm not fully up to speed on the IP but, so far, it looks very capable.This is what I'm using:https://www.sump.org/projects/analyzer/One big advantage of the logic analyzer is the triggering. On the sump.org unit, triggering is pretty slick. Multiple levels, etc.I've gotten along with 2 channels for decades. I decided one day that I could afford a simple 4 channel scope, warts and all. It's just a hobby!Do I NEED 4 channels? No! But I want them, I can afford them and now I have them.

author: rstofer
author_rank: Super Contributor
timestamp: December 09, 2016, 08:35:14 pm
content: Real life problem (in my corner of the sandbox): You have modeled an automotive suspension system (front) and you want to display: Forcing function (from arbitrary waveform generator), suspension displacement, velocity and acceleration. No, at the moment, I don't have enough analog computer to be able to model this but I'm working on that. I'm having so much fun with analog computing that I will probably build a more capable unit early next year.I need to have it built and debugged before my grandson gets to Differential Equations! I really wish I had had that capability when I took DEs. Anybody remember the Predator-Prey problem? According to the textbook, the cross-coupled equations are probably unsolvable. But the solutions can easily be displayed with an analog computer.Besides SPI decoding, this type of thing is the primary reason I wanted 4 channels. I was considering building a 4 channel multiplexer but it was easier to just buy the scope.Here is a very sophisticated multiplexer:http://www.vaxman.de/projects/scope_multiplexer/scope_multiplexer.htmlNote that is has 4 PAIRS of X-Y inputs.

author: JanJansen
author_rank: Frequent Contributor
timestamp: December 10, 2016, 05:35:57 pm
content: If you take a look at better brands, the 4 channels cost almost double the 2 channel cost.Its not about channels, its about you want cheap or cheaper, else you would get the 2 channel without thinking.

author: rstofer
author_rank: Super Contributor
timestamp: December 10, 2016, 07:03:24 pm
content: Quote from: JanJansen on December 10, 2016, 05:35:57 pmThat's exactly right!I already had the Tek 485 scope to handle 350 MHz dual channel applications.What I wanted was a capable, 4 channel scope for hobby purposes. I'm not in the business, I can't write it off my taxes, it's just a hobby.But it's only one hobby of several so there is a limit to how much I can spend on it. Fixed income and all.For my hobby purposes, the DS1054Z meets all my needs. Unlocked, it is the best scope on the market less than $1200 or so. Why would I spend 3 times as much to get an equivalent scope? It's just a hobby!As to a signal generator, I think I'll eventually buy either the Siglent or the Rigol. At the moment, I don't need an AWG because my Digilent Analog Discovery is quite capable in the lower frequency (20 MHz) end of the game.But the question was "Do I really need four channels?" and the answer is no. Most of the time...

author: tggzzz
author_rank: Super Contributor
timestamp: December 10, 2016, 07:24:27 pm
content: ... snipping stuff I agree with...Quote from: rstofer on December 10, 2016, 07:03:24 pmThe older I get, the more I'm sure my younger instincts are correct.The answer to "do I need X?" isalways"no".The response to "I need X in order to Y", isalways"is Y the really important objective?", and (if the answer is affirmative) followed by "I have a Z1 and a Z2, can I use them to achieve Y?", and (if the answer is negative) that's followed by "I know the only way of achieving Y is with an X".

author: Artikbot
author_rank: Contributor
timestamp: December 13, 2016, 12:19:39 pm
content: I feel it is my duty to report back on this - the scope has been delivered!It unlocked all features first try (that's how I am - sorry!). I'll give it a try in the coming days with some gear that needs to be looked at (power LED lamps and some other stuff).Thanks to everyone who contributed!

author: Howardlong
author_rank: Super Contributor
timestamp: December 13, 2016, 01:18:59 pm
content: Be sure to let us know how you get on, good, bad or ugly.

author: tggzzz
author_rank: Super Contributor
timestamp: December 13, 2016, 02:07:55 pm
content: Quote from: Howardlong on December 13, 2016, 01:18:59 pmPlease do.Often the most interesting information will besurprises, both pleasant and unpleasant.