Oscilloscope to capture short duration, intermittent, transient and... - Page 1
Forum section: electronics / testgear

author: ptluis
author_rank: Frequent Contributor
timestamp: November 03, 2021, 08:06:22 pm
content: I need a new oscilloscope to capture short duration, intermittent, transient signals, some rare and specific events, and also three-phase signals. Right now, all signals are below 100 MHz. My old 2Ch digital GW-Instek is tired and outdated for such tasksand so am IAs I understand it, I need fast wfms/s, long memory and fast sample rates. Siglent has something called segmented memory, Rigol I don't know maybe it's the recording function ??At first I thought of a 2-channel Siglent SDS1202X-E, but since I need to make some 3-phase measurements, I realized that probably a 4-channel is better because I don't know how to measure 3-phase systems with only 2 channels. Three-Phase are up to 72V.Now I have the following options:Siglent SDS1104X-E, €450 (I won't use half of the scope's resources)Siglent SDS1104X-U, €365 (cheaper than the previous one, but not much feedback on this model or real-time testing)Rigol DS1054Z, €405 (older model, but price is higher than Siglent X-U)MicSig STO1104C, € 499 (I recently saw this model and found it quite interesting, but I don't have much information about this brand either)Between Rigol DS1054Z and SDS1104X-U, which would be the best choice with your experience?Are there other alternatives besides those indicated? My budget is around €400I also check Rigol's clearance center, but there's nothing interesting at the moment.Thank you

author: tautech
author_rank: Super Contributor
timestamp: November 03, 2021, 08:30:25 pm
content: Ideally for best captures you'd want good sampling rates where most DSO's with a single ADC divide down the sampling rate by the # of active channels whereas the 4ch X-E's halve this division by having dual ADC's.Ex rf-loop table attached with X-U vs X-E differences.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 03, 2021, 08:40:20 pm
content: Hello Tautech, this table makes everything clearer for those models, that's what I was looking forThank you

author: bdunham7
author_rank: Super Contributor
timestamp: November 03, 2021, 10:20:26 pm
content: Quote from: ptluis on November 03, 2021, 08:06:22 pmAn exact and specific description of the signals you are hunting would be helpful. Short duration and intermittent can be handled by most any DSO, but 'rare and specific' sounds like you should study the triggering options. Depending on the specifics, color grading may be a very helpful feature with certain 'rare' signal. From another thread, this is a 20MHz pulse where everymillionthpulse has some extra amplitude.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 04, 2021, 12:41:56 am
content: Quote from: bdunham7 on November 03, 2021, 10:20:26 pmHello that looks a nice screenshoot, what siglent model was used to capture that signal?One of the uses will be to test electric vehicles controllers, their phases, comunication between microcontroller and mosfets. I don't need to decode the signals but to check the integrity of communications. i'm able to view some glitches, but due to the short memory of my oscilloscope most of the times I'm unable to freeze them. The triggering parameters of my scope are all adjusted manually otherwise I can't see them. So I need a new scope that could record a certain time of samples so that I'm able to analyze them later. I've read that Siglent scopes have a feature called segmented memory, but I don't understand if it only works with repetitive signals or if it's also good for recording random glitches. maybe you can enlighten me?

author: bdunham7
author_rank: Super Contributor
timestamp: November 04, 2021, 04:12:02 am
content: Quote from: ptluis on November 04, 2021, 12:41:56 amSDS1104X-E.Siglent isn't the only one with segmented memory or advanced trigger features, but it's what I have. Segmented memory allows you to save multiple records or frames, with each frame being what you see on the scope for each trigger event. If you have an event that you can trigger on, like my pulse, you can record many frames and then review them later like a movie, looking for glitches. So if you are using the rather basic technique of staring at the scope and pressing the STOP key if you see a glitch, you would then press the HISTORY key and you will be able to scroll back through the frames and look for your glitch. The idea is that this takes less memory than recording one long record because it doesn't record the long intervals between trigger events.There are many other advanced features that will allow you to spot glitches if you take the time to learn to use them. The color grading I showed is one, the mask feature is another, then there's all the special triggers--gated, runt, etc--that just take some setup.

author: tautech
author_rank: Super Contributor
timestamp: November 04, 2021, 04:25:53 am
content: Quote from: bdunham7 on November 04, 2021, 04:12:02 amAnd Search.Not only can we trigger on glitches but we also get a count of now many might be in the capture.Example of its usage here:https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1370717/#msg1370717

author: ptluis
author_rank: Frequent Contributor
timestamp: November 04, 2021, 03:53:42 pm
content: Quote from: bdunham7 on November 04, 2021, 04:12:02 amI see there are other brands that offer segmented memory, but siglent at the moment is the best relation between features vs price. I'm not much familiar with all the new features and options of the new modern digital scopes. I'm realizing that I will need a timeline to learn how to use them and their location on menus. I've been searching for user guides and tutorials of the mentioned above models and "how to" stuff, but definitely need an easy to use scope that I can use immediately for my needed tasks without much complicationThe SDS1104X-E is my top list, but unfortunately, it's above my budget of 400€, so I'm thinking more on the second option the SDS1104X-U or I'll have to wait a little longer to buy the X-E version.I don't know what's going on with the search function of this board but couldn't see the following link previously, I "catch it" through google searchI know it's the 200MHz model but features should be the same as 100MHz version. More readings to dohttps://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/About acquiring techniques, some of mine are pressing the STOP buttonand other times using the peak aquire mode (works most of the times but not enough).The history feature of these siglent units looks like what I was looking for and the mask feature isn't fully understood yet, but I'll get thereI also found that the Siglent SDS1104X-E could still be unlocked for the 200MHz bandwidth with some minor differences related to the true 200MHz SDS1204X-E that's a plus.Quote from: tautech on November 04, 2021, 04:25:53 amyou see? those are the small things experienced users know that I don't, I haven't reach or miss that part in the user guideWhat worries me most at the moment is about the NAND chip related issues. I have read user reports and reviews with this issue. I personally have had problems with NAND chips in other devices.Sometimes I turn the oscilloscope on / off several times in a day, is this one of the causes of these chips failing, maybe still writing to it when the power is cut-down? or am I thinking wrong?

author: bdunham7
author_rank: Super Contributor
timestamp: November 04, 2021, 04:57:21 pm
content: Quote from: ptluis on November 04, 2021, 03:53:42 pmI've come to realize that some people use their scopes differently than I do, which is probably why some people complain about boot time and UI responsiveness while others, like me, don't care so much. Staring at the screen with a finger on the stop button, rapidly twiddling knobs, that sort of thing--is just the opposite of the way I approach things. I'm not saying I'm better--it's more likely that I'm just slower--but it seems like the difference between hunter and a trapper.There are tons of features in even an entry-level scope like the SDS1104X-E that can be used to 'trap' your glitches, you just have to take the time to learn some of them. I don't know what your previous scope was, but if it was the type that only had a few kpts of memory, you may not even be familiar with zoom. This all may take some doing--I still haven't used every feature of mine, not even close. Prepare to spend a few weeks just learning.As for your other questions, the only difference between a hacked SDS1104X-E and a genuine SDS1204X-E is the type of probe that they include with the scope and while the PP215 types are preferable IMO, it's not a big deal. The NAND issue I don't know about, I've not heard that it is a problem on any of these scopes.

author: David Hess
author_rank: Super Contributor
timestamp: November 04, 2021, 05:08:17 pm
content: Quote from: bdunham7 on November 04, 2021, 04:12:02 amSegmented memory does more than that. What you are describing is how segmented memory is processed after acquisition.During acquisition, segmented memory divides the high speed acquisition record into segments, and each individual segment records a separate trigger event, which allows for very high trigger rates until the entire acquisition memory is filled. Without this, the maximum trigger rate is limited by how quickly the acquisition record can be processed.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 04, 2021, 05:16:34 pm
content: Quote from: bdunham7 on November 04, 2021, 04:57:21 pmmy scope is an old GWinstek gds1022 25mhz 2CH 250Ms/s 4k memoryI use zoom feature although is not that practical. but is capable of 1ns timebasebelieve me it's not capable anymore for the things I want to do like three-phase capture, in an easy way, apart from start to fail, so need a new one.

author: bdunham7
author_rank: Super Contributor
timestamp: November 04, 2021, 05:32:38 pm
content: Quote from: David Hess on November 04, 2021, 05:08:17 pmOne of the features of the SDS1104X-E scope in question is that it uses the segmented memory method, space and settings permitting, irrespective of whether or not you have selected segmented recording. If you do manually select segments, it behaves as you say and records however many segments you have selected before processing or displaying anything. If you don't, and your record length is less than the available memory (14Mpts) either due to timebase setting or manual memory depth setting, it will still record as many frames as available memory permits--but with the frames all processed and displayed promptly. If you are visually glitch hunting, as the OP apparently is, this second mode can be quite handy as you get a real time display and when you press STOP, you can scroll back and see whatever frame caught your eye.

author: tautech
author_rank: Super Contributor
timestamp: November 04, 2021, 06:59:08 pm
content: Quote from: ptluis on November 04, 2021, 03:53:42 pmWrong, for Siglent scopes.The only time there are any boot issues with these is when owners go poking around inside trying to hack/change things.Yes we have had some NAND issues with other equipment however with the assistance we can give remotely they are 100% recoverable. Recent changes to SW will hopefully put these problems into history.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 04, 2021, 08:06:02 pm
content: Quote from: tautech on November 04, 2021, 06:59:08 pmAlthough it could be done, I'm not going to hack the scope, since i don't use anything above 100MHzHacking is a risk, one must be pr€pared if things go wrong. Hacking a 500€ equipment is not the same as hacking a chinese cheap device of 80-90 bucks.That's good to know that Siglent is able to remotely give assistance to buyers.I've been checking for firmware updates on Siglent websites and notice that they actively fix and update functionalities on the X-E model. The X-U only have one firmware at the moment, newer model of course. This is the kind of support I expect from a known Brand. It doesn't matter if I buy a 200€ or a 2000€ equipment.I'm careful reading what all users are writing about segmented memory and that's what I'm looking for at the moment. The rest of the scope features go with time, whenever I need, because they are available on the scope

author: nctnico
author_rank: Super Contributor
timestamp: November 04, 2021, 10:42:43 pm
content: Quote from: ptluis on November 04, 2021, 05:16:34 pmIf you already own a GW Instek then why not upgrade to the GDS1054B (and hack it to 100MHz)? IIRC this has search so you can record a long acquisition and use the search feature to look for specific glitches.

author: tautech
author_rank: Super Contributor
timestamp: November 04, 2021, 10:57:10 pm
content: Quote from: ptluis on November 04, 2021, 08:06:02 pmYet everyone does it as it's easier than you think.....just online generated license codes.QuoteMany of their outlets don't have the tools we have as a regional distributor and in a lot of cases they want the instrument in their repair queue when there's actually no need for it.QuoteX-U mostly gets it parentage from existing and proven models and with a more limited feature set it's a lot less complex design and UI. Still these are a good basic scope and surprised they're not more popular however for a few buck more many are lured to X-E for the additional bells and whistles.QuoteIt was never always this way however Siglent have always listened to quality feedback such that a good few members here are now official beta testers and they alone should be thanked for the barrage of improvements they propose to Siglent which are adopted.QuoteHistory and Segments are something I need play with more as never had a need for them. Rather than look backward at signals that have gone I'd rather use trigger settings to grab what I might want to see and let the scope do the work for me.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 04, 2021, 11:03:00 pm
content: Quote from: nctnico on November 04, 2021, 10:42:43 pmcan't find GW-Instek easily on europe and when I do GDS1054B it's more expensive then sds1104X-Ubut anyway, I think this video show the advantage of 2 ADC's

author: tautech
author_rank: Super Contributor
timestamp: November 04, 2021, 11:13:28 pm
content: Quote from: ptluis on November 04, 2021, 11:03:00 pmCool vid, hadn't seen that one.But no, X-Y mode is restricted to channels 1 and 2 so on a single ADC. The Xilinx processor in these scopes does all the hard work.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 04, 2021, 11:36:15 pm
content: Quote from: tautech on November 04, 2021, 10:57:10 pmI'm aware of thatQuoteFor me it's a matter of task, I don't mind pressing the stop button and analyzing what I need backwards, sometimes I discover some interesting things that make me go in another direction. I see an oscilloscope as a toolbox, with different tools to achieve different goals. It's not like just using the hammer because it's more convenientYou know when cancer appeared in my life, I stop and think about some things in life, and realized that solutions for a problem could be reached if we open our minds to different paths, even if they sound absurd to othersWe don't need to walk on the same path, as others do, just to reach a destination. Sometimes a longer path brings better results and less sufferingBut anyway, I think I'll postpone my purchase to the next month, maybe I could save a little more and buy the SDS1104X-E sounds a better option even if I don't use its full capabilities.QuoteYou're right I did read that but forgot

author: tautech
author_rank: Super Contributor
timestamp: November 05, 2021, 12:46:31 am
content: Quote from: ptluis on November 04, 2021, 11:36:15 pmCertainly the X-E is the better scope to grow into and offers better specs than the X-U however if Siglent were to have the X-U support WiFi and a webserver they would sell heaps more. For many a home scope with WiFi is very useful rather than run LAN cabling to a lab.Either are pretty capable so good luck with your final decision.

author: kcbrown
author_rank: Frequent Contributor
timestamp: November 05, 2021, 01:58:39 am
content: Quote from: nctnico on November 04, 2021, 10:42:43 pmHow can these be hacked to 100 MHz? The people that have tried with any recent one got maybe as far as 70 MHz but that's it, at least from what I remember reading.I've got one of these myself. Great scope. Even if the bandwidth can't be hacked, the remaining features available for it (e.g., segmented memory) can be added to it via a keygen.It should be noted that segmented memory is a second class citizen in this scope, whilst it's a first-class citizen in the Siglent. This makes the two scopes different in terms of their operation of that. With the Siglent youalwaysget segmented memory because it's always on, but the time window shown on the screen during acquisition is the entire time window that's captured per trigger event. The number of segments you get is, generally, the total amount of capture memory in the scope divided by the memory required for a single capture (and the amount of memory for a single capture can be capped at a user-defined maximum, thus ensuring some minimum number of segments). With the Instek, the time window shown on the screen during acquisition is a variable subset of the time window captured, since the amount of time captured is determined by the size of the capture buffer and the sample rate.You'll quickly get used to using either, but I've come to appreciate the "what you see is all you get" approach of the Siglent because it makes for absolute and intuitive predictability. But the Instek has some advantages of its own, not the least of which is responsiveness of the UI.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 05, 2021, 02:39:14 am
content: Quote from: bdunham7 on November 04, 2021, 04:57:21 pmSo how do I catch this kind of random glitches on a clock signal with a trigger? This one I was able to catch it with my "technique" <<Finger over the Stop button>>Sorry for the out of focus photo

author: tautech
author_rank: Super Contributor
timestamp: November 05, 2021, 02:53:01 am
content: Interval trigger with parameters set to a specific vertical trigger level should grab it.

author: bdunham7
author_rank: Super Contributor
timestamp: November 05, 2021, 04:21:24 am
content: If you knew approximately what you are looking for, you might try the SLOPE trigger function, where you can specify a dV/dt that is above the maximum you would expect for the baseline signal. The glitch will have a much higher dV/dt (slope) and thus will trigger. This won't catch every glitch, just the ones in trigger range, so you still might be twiddling at least one knob.You can also use the MASK function to catch any glitch that goes outside of a boundary drawn around the baseline signal.Or, you can use the color grading feature with the appropriate amount of persistence.I set up a random, few Hz pulse on top of a 200kHz baseline signal and took these screenshots.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 05, 2021, 05:31:35 pm
content: Quote from: bdunham7 on November 05, 2021, 04:21:24 amThese are really cool features! The mask option look pretty good!unfortunately my oscilloscope has no way to set the trigger to dV/dt or anything related to that, it's a very basic one I bought about 10-12 years ago. So to see what's going on I have to do it manually, the trigger wasn't good. Glitches are random, only occur on rise and fall, never on width, and never exceed the peak signal value. So with my scope, I had to use a higher time base and then try to lower it until I could get an image where I can see something happened and capture it with the stop button. Since this oscilloscope only has 4k of memory, freezing anything on a longer time base is useless because when I zoom in there is no detail of these glitches, waste of time.The problem was a bad crystal oscillatorBut let me explain better what happened.I had a client with a defective Vectrix Electric Scooter, when cold, it drives for a few minutes, then starts to have random stutters and stops working. All of this happens at random.I had no schematics or any documentation about the electronics on this scooter.I check all cables, connections, controls, commands, everything okThen check the electric motor, Hall sensors, everything okFull and complete inspection.Then I went to the controller and this is where the fun started.This controller only fails when the following 2 conditions happen: Heat and vibrationI open the controller, check for overheating or damaged parts, etc. all OKCheck for bad/cracked solder joints, solder pads, etc. all OKThen I start looking for signals with the oscilloscope, some chips were erased, so there's less way to know what's whatCouldn't find anything wrong with the signals I have found. So I thought in a different direction, try to recreate the fault conditions, heat and vibration. I use a hot air gun set to 50 degrees Celsius and blow hot air onto the board, and start gently tapping each component while watching the signals with the oscilloscope, until bingo! I found the above fault, it was related to the clock generator, more specifically to the crystal oscillator. This crystal oscillator works well at low temperature, but when the temperature rises above a certain value it starts to become unstable and with road vibrations it completely stops oscillating!I soldered a new Crystal oscillator and the problem was definitely solved!I had a similar situation with a crystal oscillator about 20-25 years ago with a Kenwood transceiver, the crystal became unstable and stopped working due to temperature.If I had a better scope like you have, especially the mask function, catching this would have been faster and easier, so "the poor man's technique" workedAs we say in Portugal: "se não tens cão, caças com gato" translation:"if you don't have a dog, hunt with a cat " in this case, with the fingerBut I really like the practical examples you are showing me about the functionality of this oscilloscope. It looks like the equipment I want to buy.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 06, 2021, 06:20:52 pm
content: And what about the maximum frequency the SDS1104X-E can display a sinewave? anyone tested it?i saw this video about the SDS1202X-E and Tony Albus showed a 300MHz Sinewave, check it:and on this video at 4:52 the user compared the SDS1104X-E (unhacked) with The rigol the results where different:

author: bdunham7
author_rank: Super Contributor
timestamp: November 06, 2021, 06:42:20 pm
content: Quote from: ptluis on November 06, 2021, 06:20:52 pmHacked, about 400MHz fairly cleanly and without a ridiculous input level. But this is really not an important issue and the fact that it does this can be a pro or a con depending on the situation. There have been multiple threads on this, here is one discussion:https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-(lliberated-to-200mhz)-vs-rigol-ds1202z-e-bandwidth/msg3583936/#msg3583936Quote from: ptluis on November 05, 2021, 05:31:35 pmOnly if you are willing to dine on half-chewed rodents.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 10, 2021, 04:24:05 pm
content: Quote from: bdunham7 on November 05, 2021, 04:21:24 amHello , can you tell me what function generator you used to create those test waves? brand and model if possible. Thank you

author: bdunham7
author_rank: Super Contributor
timestamp: November 10, 2021, 05:27:40 pm
content: Quote from: ptluis on November 10, 2021, 04:24:05 pmSiglent SDS2042X 'improved' to SDS2122X. I used the 'Wave Combine' feature and set CH1 for the sine and CH2 for an uncorrelated (sort of--I just punched in a number) pulse. You could probably accomplish pretty much the same thing with any modern 2-channel AWG, although on some you might need to use a BNC tee to combine the signals like that.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 10, 2021, 05:42:59 pm
content: Quote from: bdunham7 on November 10, 2021, 05:27:40 pmThank you, that's the model I choose to add to my shopping list. Did you need to calibrate the unit after the "improvment" ?Edit: never mind I found the answer