Rigol DS1054Z Triggering Question - Page 1
Forum section: electronics / testgear

author: thebluehamster
author_rank: Newbie
timestamp: August 21, 2016, 02:37:12 pm
content: Happy with my new DS1054Z, but I'm an old dog with 50 yrs 'scope experience trying to learn new tricksI'm used to 'scopes having the trigger point be the left end of the scan. Can someone explain the Rigol concept of the trigger point defaulting to the middle of the screen? I'm working with the output of a 16 channel multiplexer and it's a pain to be always winding the horiz. position to get it to display a whole sequence from left to right.

author: Karel
author_rank: Super Contributor
timestamp: August 21, 2016, 03:02:00 pm
content: Quote from: thebluehamster on August 21, 2016, 02:37:12 pmAs fas as I know, that's the default for all digital sampling oscilloscopes, not just Rigol.

author: JPortici
author_rank: Super Contributor
timestamp: August 21, 2016, 03:10:22 pm
content: .. or an analog with delaying time base

author: electr_peter
author_rank: Unknown
timestamp: August 21, 2016, 03:43:45 pm
content: Some scopes have a setting for a default horizontal trigger location - centre of the screen (most common), left of the screen (analog default) or right of the screen. For example, Keysight 3000 series has this setting.As for Rigol DS1054Z, I do not recall such setting, so horizontal location has to changed manually. In most cases default at the centre is good enough because of pre/post trigger memory.

author: thebluehamster
author_rank: Newbie
timestamp: August 21, 2016, 04:20:52 pm
content: Quote from: Karel on August 21, 2016, 03:02:00 pmQuote from: electr_peter on August 21, 2016, 03:43:45 pmThank you both, I looked at few manuals and see this now. Great for repetitive waveforms but not great for most of what I seem to play with.For some reason the power up "last" setting wasn't working yesterday, but it seems to be OK this morning. If that keeps working it will help

author: thebluehamster
author_rank: Newbie
timestamp: August 21, 2016, 04:23:00 pm
content: Quote from: JPortici on August 21, 2016, 03:10:22 pmInteresting, none of the analogs of any level of sophistication or cost that I have used have defaulted to starting the trace/scan in the middle of the screen. Do you have a link?

author: JPortici
author_rank: Super Contributor
timestamp: August 21, 2016, 04:23:18 pm
content: but you are right, it is a pain in the ass sometimes.i.e. in a tektronix TPS when you expand/reduce the sweep speed the horizontal marker stays where it is and expands/shrings things.in the rigol however the "center" remains at the same point so you are looking at the same think, expanded or shrinked.both have their reason to be, but considered you can actually enter in delayed time base mode by presing the horizontal knob...

author: JPortici
author_rank: Super Contributor
timestamp: August 21, 2016, 04:25:25 pm
content: Quote from: thebluehamster on August 21, 2016, 04:23:00 pmnot really but that's how i'd use it, maybe "delayed trigger" is a better definition for an analog scope and the only one i've used since high school is a tek 7000, the timebase i have has this possibility

author: Muxr
author_rank: Super Contributor
timestamp: August 21, 2016, 04:37:53 pm
content: That trigger position is normal for all(?) DSO scopes. That's not the issue however. The problem is that Rigol doesn't implement any sort of encoder acceleration, so what ends up happening is you end up feeling like you're endlessly winding the knobs.These small details are never in datasheets or folks rarely ever notice or talk about it, but it's these small haptic details that make a big difference in day to day use of a tool. At least for me.Stuff like this is why I would chose an R&S HMO1202 over chinese B brand scopes, because you can be sure Rohde and Schwarz know how to implement the UI properly. Especially if you use the tool a lot.

author: thebluehamster
author_rank: Newbie
timestamp: August 21, 2016, 04:55:18 pm
content: Quote from: Muxr on August 21, 2016, 04:37:53 pmVery good point, sadly R&S is not in my retired old guy price range...

author: H.O
author_rank: Frequent Contributor
timestamp: August 21, 2016, 06:46:41 pm
content: Don't know about the DS1000Z but on my DS4000 there's three options available for the point around which the waveform expands/compresses as you change the timebase. Trigger Point, Center of screen and User defined.

author: rstofer
author_rank: Super Contributor
timestamp: August 21, 2016, 08:05:02 pm
content: Quote from: thebluehamster on August 21, 2016, 04:55:18 pmThere's a heck of a price difference between the modern equivalent of the DSO1202 and the DS1054Z. So, I just roll the knob along the length of my finger and I get there in about two strokes. And there is some kind of acceleration thing going on because I can slow scroll or cause a large jump depending on fast I twirl the knob.

author: JPortici
author_rank: Super Contributor
timestamp: August 21, 2016, 08:05:24 pm
content: Center of screen only.And there is acceleration. 0 to intinity, in one step

author: electr_peter
author_rank: Unknown
timestamp: August 21, 2016, 08:41:28 pm
content: One thing to note - some scopes slow down significantly (in terms of waveforms per second, WPS) when horizontal position is not at default location. This not stated in clear language in manuals/specs, beware if you need better WPS performance.I am not 100% certain about this for DS1054Z, I have to test this next week.

author: David Hess
author_rank: Super Contributor
timestamp: August 22, 2016, 01:28:08 am
content: Quote from: Karel on August 21, 2016, 03:02:00 pmAll of my old DSOs allow setting the trigger position at different locations in the acquisition record. I did not even suspect that the Rigol or any other modern but real DSO does not allow this.Quote from: thebluehamster on August 21, 2016, 04:23:00 pmHe means you can use delayed sweep to move the effective trigger position toward the right of the actual trigger.

author: ez24
author_rank: Super Contributor
timestamp: August 22, 2016, 01:40:56 am
content: Quote from: Muxr on August 21, 2016, 04:37:53 pmSeems that there will always be differences between $400 and $975 ie the OP's scope and a HMO1202

author: Fungus
author_rank: Super Contributor
timestamp: August 22, 2016, 04:22:13 am
content: Quote from: ez24 on August 22, 2016, 01:40:56 amYep, that's the part people don't seem to get.Yes, your R&S responds better to the controls, but ... it wasn't a simple case of "which one should I choose". It's not Ford vs. Chevy, it's Ford vs. Lexus. That extra bit of nicenesscost you $575(or whatever).People don't buy Ford/Chevy because they're insensitive clods who don't appreciate the fine things in life like the Lexus owners do, they buy them because they're cheaper. They have enough wheels (four) and go from A to B perfectly well.If you're a professional who uses a 'scope all day long as a way of making money then sure, get the R&S. If you're rich for some reason then sure, get the R&S. If not, get the Rigol.Not one person here can put their hand on their heart and say the wiggly lines on screen are no good or that it's a plasticky piece of crap which will last 10 minutes. The wiggly lines are fine, the build quality is good. For $400 it's a complete bargain.

author: thebluehamster
author_rank: Newbie
timestamp: August 22, 2016, 11:17:18 pm
content: I think it's a fine 'scope for the money, I hope nobody thoughtIwas implying otherwise.Quote from: David Hess on August 22, 2016, 01:28:08 amI know how delayed sweep works, but both preceding posts referred to "defaulting" so it was easy to misinterpret the comment.Now my "power up last" has decided to work correctly the issue is not such a big deal for me.While we are on the subject, is there a variable control for the Timebase/Horizontal speed hidden somewhere, or are the fixed steps "it"?

author: ProBang2
author_rank: Frequent Contributor
timestamp: August 22, 2016, 11:37:49 pm
content: Quote from: thebluehamster on August 22, 2016, 11:17:18 pmYes. There is no "hidden control for Timebase/Horizontal speed", sorry.Only the quite common 1-2-5 steps.I am just curious...What you want to measure with a variable Timebase that is not anyways delivered from the DSO´s Measurements?

author: Muxr
author_rank: Super Contributor
timestamp: August 26, 2016, 05:08:21 am
content: Quote from: Fungus on August 22, 2016, 04:22:13 amMy point precisely is that specs are not everything. Too often we get hung up on specs.. but fail to recognize things which can be just as important, like the usability and the effectiveness of the tool with prolonged use.Yes you will get some of the best spec/dollar with a DS 1054z but it's not without compromise. Also Rigol doesn't just make $400 scopes. They have scopes which cost more than the HMO 1202.

author: David Hess
author_rank: Super Contributor
timestamp: August 26, 2016, 05:24:40 am
content: Speaking of variable timebases, I just acquired a Tektronix 2445B and made the startling discovery that the variable timebase control produces a continuously variable calibrated timebase. Do you want 15, 49, or 99 ms/div? That is no problem and the readout proudly displays it.It also has an amazing dual delta delayed timebase; different traces or the same traces can be displayed with the same B sweep but with two different delays. I can't even get a modern DSO to do 1/4 of that although arguably they do not need to.

author: raptor1956
author_rank: Frequent Contributor
timestamp: August 26, 2016, 06:02:58 am
content: Although I'm quite happy with the middle of the screen most of the time I do wish there was a simple option to change that the resemble the analog method at the left side. This is quite definitely an option that only requires a firmware change and a pretty minor one at that. In fact you could have 9 options of: top-left, top-center, top-right, middle-left, middle-center (default), middle-right, bottom-left, bottom-center and bottom-right.Brian

author: Fungus
author_rank: Super Contributor
timestamp: August 26, 2016, 06:09:38 am
content: Quote from: Muxr on August 26, 2016, 05:08:21 amNope. At no point have we failed to recognize that.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 26, 2016, 07:48:58 am
content: Quote from: David Hess on August 26, 2016, 05:24:40 amMaybe I'm missing something but on a DSO you can get pretty much any timebase value you want through horizontal zoom.Same with the delayed timebase. On a good DSO you can easily display one or more signals at various delays, i.e. with Multi-Zoom. And not just two different delays, but (depending on the scope) up to eight or even more.

author: thebluehamster
author_rank: Newbie
timestamp: September 10, 2016, 04:04:42 pm
content: Quote from: ProBang2 on August 22, 2016, 11:37:49 pmFor instance, if I'm looking at the output of a 16 channel analog multiplexer I would like to be able to have it use most of the screen. By Murphy's law the clock speed is such that it's either just too wide, or only half the screen width.Quote from: Wuerstchenhund on August 26, 2016, 07:48:58 amHorizontal zoom would do it, where is it?

author: Fungus
author_rank: Super Contributor
timestamp: September 10, 2016, 04:46:44 pm
content: Quote from: thebluehamster on September 10, 2016, 04:04:42 pmPush the horizontal scale knob.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: September 11, 2016, 04:14:25 am
content: Or select it from the Horizontal Menu, where it is called "Delayed".No, on the DS1054z you cannot get "pretty much any timebase value you want" like you can on most analog scopes. You are limited to the same set of timebase values offered by the normal Horizontal Scale knob, and 5 ns/div is the fastest timebase available whether in "zoom" or not. And you may not even be able to zoom that far, depending on how the normal Horizontal Scale is set and what Memory Depth you are using in Acquire. For example if you are set at 1 ms/div, the fastest zoom value that is available is 10 ns/div. And at 10 ms/div the fastest zoom available is 100 ns/div. If you are using 1 channel, 12k Mem Depth and a basic timebase setting of 10 ms/div you can only zoom down to 50 microseconds per division.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 15, 2016, 06:21:35 am
content: Quote from: alsetalokin4017 on September 11, 2016, 04:14:25 amI see. That's indeed quite poor.My statement was in regards to DSOs in general and not specifically to the DS1054z. I should have made that clearer.

author: Fungus
author_rank: Super Contributor
timestamp: September 15, 2016, 06:28:19 am
content: Quote from: Wuerstchenhund on September 15, 2016, 06:21:35 amWhy?You only have 1GS/s sample rate so there's not much point in zooming further than 5ns/div. It already has more than one horizontal pixel per sample.Sure, you couldalwayszoom further but it doesn't seem worth bashing the 'scope over that tiny limitation.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: September 15, 2016, 07:15:25 am
content: That's right. The thread is about the DS1054z and the horizontal time/div settings are what they are. Sure, it might be nice to be able to set arbitrary time/div values like you can on the Tek 2445B... and I've certainly used this feature on analog scopes in order to make certain measurements easier using the graticule along with an external frequency standard... but frankly it seems to be very rare to actually need this feature and I don't miss it on the Rigol.

author: David Hess
author_rank: Super Contributor
timestamp: September 15, 2016, 08:27:14 am
content: Quote from: Fungus on September 15, 2016, 06:28:19 amIt is more of a practical limitation do to bandwidth. My 100 MHz 2232 which is old enough to drink is also limited to 5ns/div despite a 2 GS/s maximum sample rate. My 100 MHz analog oscilloscopes also only go to 5ns/div.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 15, 2016, 09:16:42 am
content: Quote from: Fungus on September 15, 2016, 06:28:19 amIt's not poor because of the 5ns/div limitation, I think it's poor that the zoom factors are stepped.QuoteNo need to freak out, no-one bashes the scope you so clearly feel fond of. It's just somthing that could have been implemented a bit better. I doubt it's a deal breaker for a $400 scope.

author: Fungus
author_rank: Super Contributor
timestamp: September 15, 2016, 09:37:36 am
content: Quote from: Wuerstchenhund on September 15, 2016, 09:16:42 amYou still talk like it's a Rigol-specific problem though, which isn't true. Plenty of much-more-expensive 'scopes can't do it either.It might even be true that themajorityof DSOs can't do it, that's you'd have trouble finding one that does. There's simply not much need for it in a DSO and it could complicate the hardware a lot (you'd need to resample the data in real time - not fun!)

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 15, 2016, 11:15:07 am
content: Quote from: Fungus on September 15, 2016, 09:37:36 amNo, I don't. I actually never never said that it's Rigol-specific, this is just you being hyper-sensitive again.QuoteAnd plenty more of much-more expensive scopes can, so what?QuoteNo, not really. There are plenty around that can zoom in into a waveform outside the fixed timebase spacing, like the Agilent/Keysight Infiniium 8000A/9000A/80000A/90000A Series, or the Infiniium S/X/V/Z Series (not sure if the DSOX can do that). Or the LeCroy 9300/LC/WR LT/WR2LT/WP900/WR 6k(A)/WP 7k(A)/WM 8k(A)/WS400/WSXs(-B)/WRXi(-A)/WP7zi(-A)/WR6zi/WM8zi(-A)/WR8k/LM9zi/LM10zi/WS3k.QuoteNo, it wouldn't. There's no need to resample (which some of the scopes above can do easily). Zoom doesn't generate new data, it simply takes a segment of the sample data to create a closer look.And there is clearly some need for variable zooming, which is why most of the more advanced scopes have it.There's little reason why even cost-cutting hardware like the DS1054z could implement a fully variable zoom instead of the stepped approach. I guess the reason it's done is because people coming from analog scopes might find the concept of a 'delayed timebase' with fixed steps easier.Anyways, my original comment was aimed at David Hess and his suggestion that variable timebase is not available on a DSO.

author: 2N3055
author_rank: Super Contributor
timestamp: September 15, 2016, 04:39:38 pm
content: Quote from: Wuerstchenhund on September 15, 2016, 11:15:07 amHate to state the obvious, but I don't see the point in stating that 20000$ and up list price scopes have more bandwidth, nicer and bigger screens, more and more sophisticated features, beautiful and responsive GUI .. etc. etc. etc.. than equipment that costs 10-20 times less...They better do for that price!!I personally like that my screen graticule has calibrated meaning (that is why variable vertical sensitivity and variable time base on those analogue scopes was marked "UNCAL", once you use it what you see on the screen is no more quantifiable but just visible) so I personally don't need linear zoom... I appreciate that it could be useful and nice to have, but not necessary, at least not for me.On the other hand, trigger delay limited by sampling rate and buffer size can be a problem. But that is something that comes with the how digital triggering concept is usually implemented..I agree it could be implemented by postponing buffer acquisition by any arbitrary amount, and probably not even very hard to do, but I guess it was not important enough..Luckily, so far I could get by by using deep memory, but agree that it could be a problem..Right now I checked, on 500us/DIV I can zoom in to 5ns, so factor of 100000. That is a sweet spot, if you go faster or slower, you either get a limit by sample time or memory depth...So separate hardware based trigger delay would be nice...But as I said, didn't have a problem with it so far...Best regards,Sinisa

author: David Hess
author_rank: Super Contributor
timestamp: September 15, 2016, 06:10:34 pm
content: Quote from: 2N3055 on September 15, 2016, 04:39:38 pmIt comes about because despite what the manual implies, the 1000Z series does not implement delayed sweep/acquisition. Rigol calls it that but it is just a horizontal zoom. Marketing trumps engineering.There is *nothing* about digital triggering which prevents delayed sweep/acquisition. Detect the trigger in real time as usual, acquire as usual, and then continue to acquire overwriting the beginning of the acquisition record. If that later part seems like an obstacle, consider that the DSO *already* does that to support a pretrigger record.When I became aware of this issue with the 1000Z, I checked to see which budget DSOs support delayed sweep/acquisition but it is not always easy to tell from the user manuals; you certainly cannot tell from the deceptive Rigol 1000Z manual. DSOs with short record lengths support it because they have no other choice. DSOs which support B triggering also support it but as it ends up, there are many DSOs which do not support B triggering that still support delayed sweep/acquisition so unfortunately that is not a definitive test.

author: 2N3055
author_rank: Super Contributor
timestamp: September 15, 2016, 06:18:44 pm
content: Quote from: David Hess on September 15, 2016, 06:10:34 pmThinking about it you are right, it doesn't have delayed triggering at all, but by using zoom you can simulate it to the some extent... And as I said delayed trigger could be easily implemented... But since you can use zoom for a "sort of delay trigger" I guess they figured they don't need the real one...Marketing decided it was good enough ..Cheers!!

author: David Hess
author_rank: Super Contributor
timestamp: September 15, 2016, 06:33:25 pm
content: Quote from: 2N3055 on September 15, 2016, 06:18:44 pmZoom and delayed sweep/acquisition by themselves do not replace delayed triggering. Try using the Rigol 1000Z to look at a delayed waveform which has lots of jitter to find out why.What allows them to get away with it is the large record length which hides this lack of capability but it makes sense for a budget DSO; increasing digital integration follows Moore's Law makes adding additional memory cheap. It also makes programmable logic resources cheap so adding the logic to support true delayed sweep/acquisition and even delayed triggering is cheap. What it does not do however is make design time cheap and marketing is cheaper than design. To put it in terms Dilbert and Stef (userfriendly.org) would understand, if you are not marketing, then you are overhead.I have pointed out this connection with Moore's Law and increasing integration before. The reason these oscilloscopes do not have analog triggering and equivalent time sampling has nothing to do with performance; it is because digital triggering is cheaper.

author: rstofer
author_rank: Super Contributor
timestamp: September 15, 2016, 07:18:28 pm
content: Quote from: David Hess on September 15, 2016, 06:33:25 pmOr maybe somebody realized that equivalent time sampling makes assumptions about the nature of the signal. If you get one shot at the signal, ET sampling doesn't buy much.http://www.tek.com/document/application-note/real-time-versus-equivalent-time-samplingMuch of the justification for the DSO is the 'S' part - storing a single shot waveform.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 15, 2016, 07:34:18 pm
content: Quote from: 2N3055 on September 15, 2016, 04:39:38 pmInstead of "stating the obvious" you could have just read properly what Fungus and I wrote (including the part you didn't quote), which was:Quote from: Wuerstchenhund on September 15, 2016, 11:15:07 amEmphasis mine.It shouldn't take a reading genius to figure out that I listed much more expensive scopes because the particular argument included much more expensive scopes, so it's a bit silly to complain that I listed much more expensive scopesBesides, a few of the scopes I listed are pretty old (some are from the early '90s). These days they're hardly "much more expensive", but still in many areas they're still much more capable. But it shows that variable zoom isn't exactly a novelty.QuoteVariable zoom isn't something spectacular, as I said it's been around for a while, and who knows there might even be some entry-level scopes that can do it. I just don't know because that's not exactly the type of scope I use regularly.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: September 15, 2016, 07:41:37 pm
content: For the DS1054z, look in the Trigger menu for some delayed trigger options.Trigger Menu>Type>Delay, then set up your options as required.Also you can scroll horizontally through the memory so that you can look at sections of the waveform that are far distant in time from the trigger point.

author: 2N3055
author_rank: Super Contributor
timestamp: September 15, 2016, 08:30:15 pm
content: Quote from: Wuerstchenhund on September 15, 2016, 07:34:18 pmOK my English comprehension is not so good, I missed a few valid points.. You are correct...I'm very sorry that I upset you with my comment...Have a good one!!

author: David Hess
author_rank: Super Contributor
timestamp: September 16, 2016, 09:40:19 am
content: Quote from: rstofer on September 15, 2016, 07:18:28 pmAnd what happens when you get one shot at the signal and your digital trigger is subject to aliasing?Quote from: alsetalokin4017 on September 15, 2016, 07:41:37 pmFrom the manual:In delay trigger, you need to set signal source A and signal source B. The oscilloscopetriggers when the time difference (?T) between the specified edges of source A(Edge A) and source B (Edge B) meets the preset time limit, as shown in the figurebelow.Note: Edge A and Edge B must be neighbouring edges.That is *not* a delayed trigger in the sense being discussed.QuoteBut you can only do this within the acquisition record and you cannot make a new acquisition presumably at a higher sample rate. Rigol conflates the common usage for delayed sweep with horizontal magnification. The former can be used to achieve the later but the later is not a substitute for the former.I have used many DSOs which have both and go to some effort to separate them avoiding confusion. The current trend with large acquisition records appears to be to combine these functions leading to the problem of limiting the sample rate in a predictable but obscure way.