Simple Oscilloscope Question - Page 1
Forum section: electronics / testgear

author: frank2644
author_rank: Contributor
timestamp: March 09, 2021, 02:22:17 am
content: After 60 years of analog scopes, I just purchased a Siglent 1104x-E and I love it.But I can't seem to do what should be a simple thing. I just want to stop the roughly 200hz signal on the display and scroll back in time looking for stuff, but I only see maybe 5ms in either direction using the play buttons (between history and Navigate button). When I use the History menu underneath the waveform display that menu shows only 3 frames available, also a very short period.I've read the manual to no avail. Seems to me this should be easy to do (even for an old guy).I've attached a JPG showing the limit using the fwd arrow button (bk arrow shows similar message)Please tell me there is a simple way to do this.Frank

author: tautech
author_rank: Super Contributor
timestamp: March 09, 2021, 03:15:08 am
content: Quote from: frank2644 on March 09, 2021, 02:22:17 amCapture long and then zoom in.If you need to see the small portion of waveform use Zoom mode (press timebase control) to enable the zoom window so you can work within the zoomed window.By using this method and setting the primary timebase for the highest memory depth you'll have a large record to inspect in the zoomed window with any of the normal controls and be able to pan completely through the captured record.

author: ataradov
author_rank: Super Contributor
timestamp: March 09, 2021, 03:58:35 am
content: There should be a manual control for the memory depth and/or sampling rate independent of the display setting. By default it would store enough to display on the screen. So yes, one possible workaround is to capture a lot and zoom in, but make sure that it also does not reduce the sample rate at long time base settings.

author: ataradov
author_rank: Super Contributor
timestamp: March 09, 2021, 05:06:52 am
content: What is so funny?

author: Fungus
author_rank: Super Contributor
timestamp: March 09, 2021, 05:07:30 am
content: This is a well known limitation of Siglents:Quote from: frank2644 on March 09, 2021, 02:22:17 amNot on a Siglent, sorry. It's an obvious thing to do but on a Siglent you have to mess around to capture more data.

author: Someone
author_rank: Super Contributor
timestamp: March 09, 2021, 07:03:14 am
content: Quote from: frank2644 on March 09, 2021, 02:22:17 amIgnore the trolls above who are trying to cause alarm. The history mode only has a certain amount of memory available to it (practical limit of the instrument) and you've set a long memory depth for each capture so they fill up the history buffer very quickly.To capture more history frames, go into the Memory Depth menu and reduce the number of points being captured in each frame.Quote from the manual:QuoteThere is detail on the specific memory depths and number of history buffers compiled here:https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg2098714/#msg2098714

author: SilverSolder
author_rank: Super Contributor
timestamp: March 09, 2021, 01:21:29 pm
content: Quote from: ataradov on March 09, 2021, 05:06:52 amNot anything specific that you said @ataradov, it was just the thought of the whole "Zoom" thread making a reappearance that made me chuckle!

author: Fungus
author_rank: Super Contributor
timestamp: March 09, 2021, 01:28:01 pm
content: Quote from: SilverSolder on March 09, 2021, 01:21:29 pmWhy wouldn't it keep reappearing?Stopping the signal and zooming in/out is one of the most basic functions of a DSO. Siglents don't do it, so...

author: frank2644
author_rank: Contributor
timestamp: March 09, 2021, 03:26:39 pm
content: Quote from: Someone on March 09, 2021, 07:03:14 amThank you Someone, following your instructions I made some progress. That is, I can now see a lot more frames are being captured, but the play buttons still only seem to shift the current window without showing any previous history. I suppose I could fiddle with the History soft menu and shuffle through the frames but that seems pretty awkward.I would think I could simply play the history using the replay hard buttons, but I cannot.Thanks, againFrank

author: masterx81
author_rank: Frequent Contributor
timestamp: March 09, 2021, 04:42:26 pm
content: What's the problem using a smaller timebase and then zooming in?

author: Fungus
author_rank: Super Contributor
timestamp: March 09, 2021, 04:59:16 pm
content: Quote from: masterx81 on March 09, 2021, 04:42:26 pmTry it and see!Normally you work zoomed in so you can see what's going on. Constantly thinking "Wait.... I have to zoom out before I can press stop then zoom in again" isn't a natural way to work. Natural is simply to press stop when you see something interesting then zoom out and see what was on either side.There's also the problem that if the event was a one-off then youcan'tzoom out and recapture it.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 09, 2021, 05:12:05 pm
content: Quote from: masterx81 on March 09, 2021, 04:42:26 pmI'm not convinced it is a "problem" per se, it seems more a matter of flexibility and convenience, "how does the car feel to drive" kind of thing.[edit:] although @Fungus' point about one-offs is a real issue if you needed to zoom out afterwards.

author: masterx81
author_rank: Frequent Contributor
timestamp: March 09, 2021, 05:30:35 pm
content: I have from few month an sds1104x-e (before had an owon 7102), and as i've noticed this limitation on the new device, i've taken the habit to keep the timebase a bit less than necessary, then zooming in. I not find it changing too much my workflow, i'm still happy with all the other advantages of the device. Every device have it's own "quirks". Maybe a direct "rival" (for example a Rigol) have the zoom out, but not have other features of the siglent.

author: 2N3055
author_rank: Super Contributor
timestamp: March 09, 2021, 06:48:09 pm
content: Quote from: Fungus on March 09, 2021, 04:59:16 pmOkay let me ask you one thing: you see something, and then stop and zoom in/out?On what signal ?On some fast repetitive signal,by the time you see something and press stop, there wasthousandsof triggerspassed by.One you saw islost forever. Zoom in or zoom out. Only way to actually catch a transient is to use Single mode and clever trigger...If you use persistence, you might be able to observe something happened, but not catch it, Flash....Try it and see!On anything that repeats faster than once per second, your statement makes no sense.Also, that Dave's video is not exactly thorough on the topic. Not his best work. In a videotalking about zoom, henever,not onceactually used Zoom mode onanyof those scopes. He uses name "zoom" for changing timebase on stopped capture. While it changes displayed magnification, it is not Zoom mode, and not called Zoom in documentation for any of the scopes he uses. He alsonever, ever, showed use of proper Zoom modeonany of those scopes as described in manuals of those scopes. So people can see how that works, and weigh in pros and cons for themselves.Oh, ijustrealized, I wasn't right, if youdo seesomething flash on the screen, youmightbe able to go back if you 're fast enough...If you have one ofthose scopesthat haveHistory, you can go back hundreds of previous triggers, and if you are fast enough, you might go back in time.... And that is why those scopes have history mode. Because it is usefull.Regards,

author: Fungus
author_rank: Super Contributor
timestamp: March 09, 2021, 07:17:15 pm
content: You might not even want to zoom out. You might simply want to go left or right a bit to see what comes before/next. Should you have to zoom out, recapture the signal, then zoom in again just to see it? That's a whole lot of extra knob fiddling for something very common.Here's a question: What happens on a Siglent if you zoom in then scroll the trigger point off the screen and press "stop". Can you scroll the trigger point back onto the screen and see what was there?

author: nctnico
author_rank: Super Contributor
timestamp: March 09, 2021, 07:25:03 pm
content: Quote from: 2N3055 on March 09, 2021, 06:48:09 pmI guess you never work on single events... Not every signal is repetitive or repeating itself quickly!To the OP: for zooming out after the fact you have choosen the wrong scope. It doesn't support that (I sincerely hope Siglent changes that soon though; I might have an application where a Siglent scope could work out well). Anyway... given the relatively low frequency of your signal the memory might not be long enough to offer more than the regular width of the screen (depending on time/div setting). If that is the case then zoom mode is the only way to force an oscilloscope to record for a longer time (forcing the samplerate down so the memory gets filled slower) than fits on the screen so there is data to scroll left/right to. In the end the amount of time a DSO can record a signal is equal to memory length / samplerate. If you have 10Mpts and 1 Gs/s samplerate then it can record 10M / 1G = 10 milliseconds of data. If you need a longer time period, then the samplerate must go down.

author: Fungus
author_rank: Super Contributor
timestamp: March 09, 2021, 07:38:56 pm
content: Quote from: 2N3055 on March 09, 2021, 06:48:09 pmYep. A signal can easily be "interesting" for a second or two then go away again, eg. a sudden burst of noise or transients on the line. Plenty of time to react and press "stop", not really enough time to go through the sequence of zooming out andthenpressing stop.Simple version: Zooming out and recapturingtakes time.

author: 2N3055
author_rank: Super Contributor
timestamp: March 09, 2021, 09:22:47 pm
content: Quote from: nctnico on March 09, 2021, 07:25:03 pmRead again. I was replying to Fungus, who is simply trolling without any examples.I know you use it and you explained how you use it, and seem to have valid reasons to do so and know how to set it up to work for you. While I many times said I disagree it is easier and that I use some other method, you can at least demonstrate what and how you're doing it.But he is touting some magical properties and keep repeating things he doesn't understand completely, and relying on references that were proven wrong and such...

author: 2N3055
author_rank: Super Contributor
timestamp: March 09, 2021, 09:27:23 pm
content: Quote from: Fungus on March 09, 2021, 07:38:56 pmNo, troll, read a manual. You don't look at something without clue, then stop and zoom out and do all kinds of things without using brain.You're looking at something that is a long infrequent burst, so you set timebase to capture whole burst, enable zoom, go and magnify portion of signal you want to monitor, and keep it running. If you see something, you then stop and look around. And you keep an eye on a magnified portion and whole signal at the same time.

author: Someone
author_rank: Super Contributor
timestamp: March 09, 2021, 09:31:37 pm
content: Quote from: 2N3055 on March 09, 2021, 09:22:47 pmReread all that carefully. This is one of the example situations where "zoom out after stopping" wouldn't be achievable as the memory depth is already at maximum. So its all just adding noise to the OPs question.

author: Someone
author_rank: Super Contributor
timestamp: March 09, 2021, 09:35:51 pm
content: Quote from: frank2644 on March 09, 2021, 03:26:39 pmThere are many many options and it can be a bit hard to find them all, the navigate controls can be set to do different things (user manual section pictured below).

author: Fungus
author_rank: Super Contributor
timestamp: March 09, 2021, 10:25:18 pm
content: Quote from: Fungus on March 09, 2021, 07:17:15 pmI notice you're all ignoring this situation, which doesn't seem at all artificial or "trolling" to me.Bottom line: It's not expected or natural behavior. Dave saw it and was surprised, the person who started this thread was surprised, there are quite a few threads on this now. Other 'scopes just do it without thinking, Siglent needs to pull their finger out and fix this problem.

author: Martin72
author_rank: Super Contributor
timestamp: March 09, 2021, 10:34:19 pm
content: There is no problem.

author: frank2644
author_rank: Contributor
timestamp: March 09, 2021, 10:44:11 pm
content: To all,I'm managing to get what I want mostly using Someone's suggestions, but sometimes I'm not sure how I got there. I'm pretty sure I'll eventually get fluent, but it will take me some time.I'm working on the suggestions about zooming, but so-far it's eluding me. I think a lot of things will begin to make sense as I get more familiar with the scope.Yes, so-far with my low knowledge the replay is not as convenient as I would like, but some of the other capabilities still make me think I bought the right scope for my budget. The ability to access the scope via a PC browser on my 27 inch screen is really nice for old eyes. Not to mention the ease of capturing screen prints and annotating them for my electronic project notebook. As Fungus mentioned, hopefully Siglent will update their software some day to improve the replay capability, or maybe I get savvy enough to minimize the apparent inconvenience.Thanks to all for the comments and suggestions. Keep them coming, I read them all, but sometimes if I don't respond quickly it's because I'm overwhelmed and I'm not sure I can comment coherently.FrankP.S. I read hundreds of reviews and viewed many videos before I purchased this scope, but I don't think anyone mentioned this particular "well known" replay drawback. Although I might not have purchased this scope had I known, and at this moment I think that might have been a mistake (for me).

author: tautech
author_rank: Super Contributor
timestamp: March 10, 2021, 01:05:00 am
content: Let's have a little deeper look.....SDS1104X-EWe know when History is correctly used a little over 50 Mpts of waveform record is available however the memory depth selected by the user has an impact on how many frames of history are available for viewing in a History capture.In this series of screenshots from a single History capture with the scopes mem depth set to 1.4 Mpts we have some 500 frames available.What to do with them ?Navigate is the best where we can select either a time or history frame to migrate to and play the whole record in any of 3 different speeds.A selection of captured screenshots for study............

author: frank2644
author_rank: Contributor
timestamp: March 10, 2021, 07:07:18 pm
content: tautech, Thanks for the images,Basically, I think you are saying to set display at a slow sweep rate, use History to find your frame of interest, then change to a higher sweep rate and use Navigate to play the frame as needed.Okay, that is what I've been doing and I can get what I want eventually.The key is to record at very slow sweep rate relative to the signal. Which is not normally how I like to use my scope. So a recapture is usually required.For what it's worth (I'm a newbie to digital scopes), it seems to me the people here who say this is a problem have a point. The ability to zoom out, as Dave said in the video, seems like a good fix.Thanks to all for the comments.FrankP.S. I managed to use zooming, but I'm not sure it's any better.

author: nctnico
author_rank: Super Contributor
timestamp: March 10, 2021, 07:47:40 pm
content: Your signal might be too fast but in some cases I use 'roll mode' and stop the oscilloscope manually at the point where the signal changes. From there you can zoom in on the part of the signal that is misbehaving. But again, a 200Hz signal might be too fast for this method unless the change you want to inspect is very obvious (like the signal dropping out).

author: tautech
author_rank: Super Contributor
timestamp: March 10, 2021, 07:56:10 pm
content: Quote from: frank2644 on March 10, 2021, 07:07:18 pmThe power of a DSO is capture and inspection however even more powerful is the trigger suite.This takes longer to master than basic DSO use.....after some years using them I learn more about it.Simple single shot captures like those above were only done on that single burst so to demonstrate how we might navigate through it using History and a wee peek of the features available.We could of course use Search to find particular waveform points of interest within the burst for deeper inspection.I have a play with Search here:https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1370717/#msg1370717