synchronize two Siglent SDS1104X-E oscilloscopes to show 8 channels at same time - Page 1
Forum section: electronics / testgear

author: ptluis
author_rank: Frequent Contributor
timestamp: November 17, 2021, 10:29:59 pm
content: Hello, is it possible to synchronize two SDS1104X-E oscilloscopes so that I can view 8 channels at the same time? How should I configure the trigger in this configuration? one of the needs would be to analyze three-phase signals, view input and output voltage at two points and the rest would be for example, signals at the gate of the mosfets. Will it also be possible to log all measurements for later analysis?Thank you.

author: bdunham7
author_rank: Super Contributor
timestamp: November 17, 2021, 11:29:11 pm
content: You can only do 7 channels, because you need have at least one channel on the second scope connected to the same channel that is triggering the first scope--there is no EXT trigger. One way around that would be if you had another channel that was synchronized in a known way to the channel that is triggering the first scope, you could use that--with a horizontal offset if needed.

author: egonotto
author_rank: Super Contributor
timestamp: November 18, 2021, 12:22:12 am
content: Hello,you can try TRIG OUT. But you will have a delay. The delay is perhaps dependent from time/div placement. And perhaps the delay is not constant, than you get jitter.Place the same signal on both scopes and trigger the first scope from signal and connect the TRIG OUT from first scope to the second scope and trigger from this TRIG OUT.Activate all 4 channels an both scopes.Best regardsegonotto

author: ptluis
author_rank: Frequent Contributor
timestamp: November 18, 2021, 02:18:10 pm
content: Quote from: egonotto on November 18, 2021, 12:22:12 amIt works and your're right, a delay was observedQuote from: bdunham7 on November 17, 2021, 11:29:11 pmChecked! only 7 availableThanks for your answers. I've done the tests, it's satisfactory but I can only have 7 available channels instead of 8 as bdunham7 reported. Looks like I'm going to have to research for another 4-channel models with EXT Trig IN or 8 channel scope even if it's a USB model + laptop. I bought these two SDS1104X-E from a local seller with the condition to return them within 5 days if they don't meet my requirements, so I'm still thinking if I keep one and return the other. Meanwhile I'll run more tests while I have them. I don't know why I didn't notice that this model doesn't have Ext trig IN, I read several manuals from different brands and I ended up messing up the details

author: bdunham7
author_rank: Super Contributor
timestamp: November 18, 2021, 02:28:42 pm
content: I was looking at an older Yokogawa DL2700 8-channel DSO the other day. I didn't buy it, but it occurred to me that it just might be handy for some cases--fairly large screen, 8 real channels, 150MHz. I guess your case is an example!Are any of the signals synchronized with each other in a way that you could trigger your second scope on a different signal and still have them line up? If not, then yes you need an 8-channel scope or two 4-channels with at least one of them having an EXT trigger, like the Siglent SDS2104X.

author: Fungus
author_rank: Super Contributor
timestamp: November 18, 2021, 03:03:27 pm
content: Quote from: ptluis on November 18, 2021, 02:18:10 pmI think you should getanotherone. Three of those gives you ten channels, you'll be an oscilloscope god.Reason: 2x four channel 'scopes with external trigger in will cost a lot more money.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 18, 2021, 04:24:26 pm
content: Quote from: bdunham7 on November 18, 2021, 02:28:42 pmThat's the line of thought I'm following right now, I'm trying to see a relation between signals and how I can "split" them between scopes. Thank you for the SDS2104X sugestion. I'll check that one to.Quote from: Fungus on November 18, 2021, 03:03:27 pmfollowing your line of thought, looks like we have lots of gods in this forum as there are several here that have more than 3 oscilloscopes starting with forum founder Dave Jones and he is above godIrony aside, "three scopes" it's even a valid point, as they fit my budget right now (3500€ for Oscilloscopes and other stuff). I realize this may sound absurd but it's the nonsense things that in the end make the most sense. it is the same as connecting several monitors on a single computer, for some it is useless but for others it is very useful. in the end those who think otherwise end up realizing the practical usefulness of this "madness".It's a matter of trying to negotiate the price if I add a third oscilloscope and see if I can get a better deal. I can get the three SDS1104X-E for €1245 final price plus three TP-LINK wifi dongles

author: bdunham7
author_rank: Super Contributor
timestamp: November 18, 2021, 04:51:12 pm
content: Quote from: ptluis on November 18, 2021, 04:24:26 pmIf you replaced one SDS1104X-E with an SDS2104X+, then after a bit of hacking you would have one very good scope for normal use, a second scope for those times you want two (it happens) and a pair that works for 8 channels. I have a vaguely similar pairing myself, and though it is rare that I need 8 synchronized channels, you only need one scope to have an EXT trigger for the whole thing to work.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 18, 2021, 05:03:52 pm
content: Quote from: bdunham7 on November 18, 2021, 04:51:12 pmI agree with you, but I have been talking by phone with my seller and he doesn't have that model available on stock and siglent.eu is out of stock. Batronix have the plus version for 1.473€ Welectron only the plus version also, seems like siglent discontinued that model and replace it with the plus version and it is more expensive.

author: bdunham7
author_rank: Super Contributor
timestamp: November 18, 2021, 05:10:13 pm
content: Quote from: ptluis on November 18, 2021, 05:03:52 pmI was referring to the 'plus' (there's a plus sign there) only, I wouldn't recommend you look for the earlier discontinued model. The 'plus' seems greatly improved. The price looks a bit stiff there in the EU though...it's $1399US here before discounts and tax.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 18, 2021, 06:20:25 pm
content: Quote from: bdunham7 on November 18, 2021, 05:10:13 pmsorry I miss the + sign.My local seller is going to receive the plus next week so I'll wait until there. Thank you for your help my friend.

author: tautech
author_rank: Super Contributor
timestamp: November 18, 2021, 06:52:21 pm
content: Quote from: ptluis on November 18, 2021, 06:20:25 pmYes the SDS2kX Plus range are in a different league to all Siglent 2000 models before, I've had them all.You might like to experiment with the individual channel skew adjustments to align signal edges closer to the master scope.

author: 2N3055
author_rank: Super Contributor
timestamp: November 18, 2021, 08:19:22 pm
content: What is the bandwidth needed? Picoscope 4824A has only 20MHz bandwidth, but it is 8ch/12 bit USB scope.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 19, 2021, 12:35:46 am
content: Quote from: 2N3055 on November 18, 2021, 08:19:22 pmHello I'm aware of that model but it's to expensive around 2380€ for only 20MHz. I have other equipment's to buy.Bandwidth minimum 100MHz but the more the better.I'm in the EV business and I have my own projects/investments, but right now I'm cooperating with the development of a racing car project, so my needs at this moment are a little out of the ordinary. I deal with different types of signals, voltages, amps, etc, mechanical stuff and other things. I sold all my analog equipment and right now I'm converting to digital stuff.This would be nicehttps://www.keysight.com/zz/en/cmp/2020/introducing-the-world-s-first-8-channel-rtsa-oscilloscope.html

author: mjj
author_rank: Contributor
timestamp: November 19, 2021, 09:09:47 pm
content: How about getting the SLA1016 logic analyser add on for the second scope and connecting it to the trigger out on the first to preserve all 8 analogue inputs?

author: egonotto
author_rank: Super Contributor
timestamp: November 19, 2021, 09:20:17 pm
content: Hello,if you work with TRIG OUT. Look if the delay have much jitter. Perhaps the jitter is to large.Best regardsegonotto

author: tautech
author_rank: Super Contributor
timestamp: November 19, 2021, 10:40:24 pm
content: Quote from: mjj on November 19, 2021, 09:09:47 pmWelcome to the forum.The+20V MSO input limitation could possibly be the deal breaker for that.https://siglentna.com/wp-content/uploads/2021/05/Digital-Probe-Datasheet-V20E201912.pdf

author: ptluis
author_rank: Frequent Contributor
timestamp: November 20, 2021, 12:45:03 am
content: Quote from: mjj on November 19, 2021, 09:09:47 pmThat is something I need to study a little more because I don't own a SLA1016 and need to read more about it. I don't know if I be able to use the digital channels and the 4 analog inputs at the same time. But it could be a option if I find a solid correlation between low/medium voltage signals, sensors (for ex. 3.3v, 5v, 12v, 18v) and high voltage outputs, not all controllers are the same but it's a option to analyze. Thank you.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 20, 2021, 12:49:24 am
content: Quote from: tautech on November 19, 2021, 10:40:24 pmat least 18v signals exists need to analyze and read the pdf for more info first. Thanks for the pdf.

author: tautech
author_rank: Super Contributor
timestamp: November 20, 2021, 12:56:22 am
content: Quote from: ptluis on November 20, 2021, 12:45:03 amYou can however be aware there will be some skew and more importantly the digital channel traces offer zero waveform fidelity info. If the threshold is met you get a level change and that's all.If all 16 digital channels are active the display is full and if any analogue channels are also active they overlay the digital channels however if you only need view a few digital channels no trace overlay can be achieved.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 20, 2021, 01:51:20 am
content: Quote from: tautech on November 20, 2021, 12:56:22 ambut channel skew can also occurs with different probes or cables right? in the past I "calibrate" cables adjusting their length and never swap cables between channels but I think this SDS1104X-E has a built in menu to correct this on scope side right? I think I read somewhere in the manual but haven't tested it yet. With probes I build BNC adapters with proper length to correct the differences. I'm really liking this scopes and really need to find a good way of doing what I need. In the end of the next week I'll have an SDS2104X+ unit to test the sync with EXT trig. and see how it looks.

author: tautech
author_rank: Super Contributor
timestamp: November 20, 2021, 03:05:06 am
content: Quote from: ptluis on November 20, 2021, 01:51:20 amCorrect, skew is adjustable for each analogue channel on P2 of the channel menu. Like with many of the Universal control adjustments you can press the encoder and have a virtual keypad pop up in which to enter a value and not need to turn the encoder endlessly.QuoteYou're in for a pleasant surprise with an X Plus as these are a nice scope. Don't forget to plug a USB mouse into it which makes usage faster and not needing to place fingers on the display and get it grubby.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 20, 2021, 02:29:08 pm
content: Quote from: tautech on November 20, 2021, 03:05:06 amDidn't know about that USB feature, just downloaded User Manual and I'm going to read it this weekend. thank you

author: ptluis
author_rank: Frequent Contributor
timestamp: November 20, 2021, 02:31:48 pm
content: Quote from: egonotto on November 19, 2021, 09:20:17 pmHi it is related to my BNC-BNC cables, need to build a new set.

author: egonotto
author_rank: Super Contributor
timestamp: November 20, 2021, 05:23:59 pm
content: Hello,the trigger works with software. The software analyzed the incoming data stream and decide if it is the right time to trigger.My Rigol DS2072 has lots of jitter and my RTA seems also have jitter.If you have two scopes you can test the behavior yourself.Best regardsegonotto

author: ptluis
author_rank: Frequent Contributor
timestamp: November 20, 2021, 06:52:05 pm
content: Quote from: egonotto on November 20, 2021, 05:23:59 pmHi maybe I didn't explain correctly what I mean by BNC cables.What I verified is that the length of the BNC-BNC cables has influence on the delay I notice when I connected the two scopes from TRIG OUT (1st scope) to CH4 (2nd scope) and all the remaining channels connected to various signals, so a total of 7Ch in use + the 8th used to trigger.With an 80cm cable I got an higher delay (and more unstable) than with a 48cmThe best and the most acceptable results where with the 48cm oneI tested with 80cm, 48cm, 52cm, 2mts and 62cm. with the 2mts just forget it, not good at all.With the 48cm cable the results are very acceptable, but I want to compare the results when I have the SDS2xxxx on my hands.All cables used are 50ohm RG-58Maybe I'm doing something wrong with the scopes configurations I don't know, or some king of interference going on here, but needed to advance to other tests because I have to make a decision about my purchases concerning other things.Do I need to terminate the TRIG OUT -> CH4 with a 50ohm load?Did you try to use different cables with different sizes when you made your tests and see if that has some kind of influence in your results?Regards

author: nctnico
author_rank: Super Contributor
timestamp: November 20, 2021, 06:57:28 pm
content: In order to have 2 scopes synchronised using the trigger signal, you'll need the output from an analog trigger circuit circuit. A digital trigger output is likely to have a finite time resolution due the clock period used to create the trigger output. The only way around it is to trigger both oscilloscopes from the same signal instead of cascading. OR buy an oscilloscope which supports cross-triggering but this usually involves a few more cables in order to compensate for cable delays and communicate the exact trigger point between the oscilloscopes.

author: bdunham7
author_rank: Super Contributor
timestamp: November 20, 2021, 07:30:12 pm
content: Quote from: nctnico on November 20, 2021, 06:57:28 pmThat's really the only practical solution to this at higher frequencies. I have two 4-channel DSOs, one with EXT trigger and one not, and the only way to not have the second scope jump around and blur is to use a BNC tee and equal length cables from the tee. But if he is using 10X probes, things might be tricky! I have a 10M to 50R input buffer amp that solves that issue.

author: bdunham7
author_rank: Super Contributor
timestamp: November 20, 2021, 07:35:12 pm
content: Quote from: ptluis on November 20, 2021, 06:52:05 pmYou can expect 1ns per 20cm.QuotePerhaps if you are getting ghost traces or double signals. I don't know the output impedance of TRIG OUT, but a 50R terminator is worth a try.

author: tautech
author_rank: Super Contributor
timestamp: November 20, 2021, 07:41:33 pm
content: Quote from: bdunham7 on November 20, 2021, 07:35:12 pmSDS2kX+ = Auxiliary output: TRIG OUT -- 3.3 V LVCMOS

author: nctnico
author_rank: Super Contributor
timestamp: November 20, 2021, 07:54:14 pm
content: Quote from: ptluis on November 20, 2021, 12:45:03 amWhy not simply buy an 8 channel oscilloscope? There are several Yokogawa DL708 (8 channel) and DL716 (16 channel) oscilloscopes for sale on Ebay which are in your price range. Don't expect high bandwidths but the plugin modules allow for a lot of flexibility. Don't be afraid to haggle a bit. Getting 50% or more off from the asking price is not out of the question.

author: bdunham7
author_rank: Super Contributor
timestamp: November 20, 2021, 08:01:02 pm
content: So here is mine with a 100MHz sine on CH1, the TRIG OUT connected to CH3. You can see the amount of trigger delay and the relatively clean signal, then a zoom showing the jitter and the last shot is with a 50R terminator--cleans up the signal a bit but doesn't affect the jitter. So if ~2ns jitter is important, this method isn't going to work. And the delay is so huge that I don't know why your cable would be causing an issue.

author: tautech
author_rank: Super Contributor
timestamp: November 20, 2021, 08:46:26 pm
content: 7 analogue channels and 32 digital channels all aligned to a single trigger point is 100% possible with the 4ch X-E's or 4ch 2kX+. However if using a signal bus as the trigger source care needs be taken the capacitance of 2 probes on the bus doesn't impact on bus waveform fidelity.

author: Caliaxy
author_rank: Frequent Contributor
timestamp: November 20, 2021, 10:04:41 pm
content: Quote from: nctnico on November 20, 2021, 06:57:28 pmThat doesn't sound like it's going to work either. Even if both oscilloscopes trigger at the same condition of the same (repetitive) signal, most likely they will trigger at different occurrences of it. The two sets of traces will not be necessarily synchronized, which might or might not be an issue, depending on what the signals look like.

author: bdunham7
author_rank: Super Contributor
timestamp: November 20, 2021, 10:12:50 pm
content: Quote from: Caliaxy on November 20, 2021, 10:04:41 pmA most excellent point! Choosing which signal to trigger on is critical. I have no idea what the OP's actual signals are. He referred to three-phase and gate-drive signals, so I think he might be OK here, but in general you might need a different plan, especially logic signals, etc.

author: nctnico
author_rank: Super Contributor
timestamp: November 21, 2021, 12:12:47 am
content: Quote from: Caliaxy on November 20, 2021, 10:04:41 pmTriggering both scopes from the same signal, using the same trigger condition will work. The signals will be aligned within the oscilloscope's trigger resolution / trigger jitter specs. What could be an issue is the difference in samplerate due to the clocks not running at the exact same frequency. Ideally you want to do this using oscilloscopes which support an external 10MHz reference (with 1 master and the rest slave or using a clock reference source).

author: bdunham7
author_rank: Super Contributor
timestamp: November 21, 2021, 12:18:54 am
content: Quote from: nctnico on November 21, 2021, 12:12:47 amSuppose you have a train of pulses, and on another channel you have a signal that may or may not pulse in sync with the first, either in sequence or at random. So for every A pulse there might be a B pulse or there might not be. Then you have third channel C, which we're going to put on a separate oscilloscope, which has a pulse synced with A if and only if the B channel does not. So even with identical trigger conditions, you can't control which exact A pulse the two scopes trigger on. So you might see, for example, an A pulse that coincides with a B and a C pulse on your screen even though that didn't happen in real time simply because the first scope triggered on a different instance of the pulse than the second.

author: nctnico
author_rank: Super Contributor
timestamp: November 21, 2021, 12:23:40 am
content: Quote from: bdunham7 on November 21, 2021, 12:18:54 amThat is only true if you only have repetitive signals to trigger on.

author: egonotto
author_rank: Super Contributor
timestamp: November 21, 2021, 01:04:25 am
content: Hello,Quote from: nctnico on November 21, 2021, 12:23:40 amno, even with a noise signal as trigger signal, you can not guarantee that both scopes trigger at the same time.If you have luck, you have a signal which is good for trigger, but in general you can have trouble.Best regardsegonotto

author: bdunham7
author_rank: Super Contributor
timestamp: November 21, 2021, 01:17:52 am
content: Quote from: nctnico on November 21, 2021, 12:23:40 amSure, there are probably many instances where it won't be an issue, like a single-shot capture of one-time event, but there are going to be situations where it might be a concern. Sometimes there may be an easy workaround, but perhaps others there won't be.

author: ptluis
author_rank: Frequent Contributor
timestamp: November 21, 2021, 01:45:08 pm
content: Hello guys, thanks so much for your answers. I already have what I need. In fact, synchronizing 2 oscilloscopes was not the best option. I will keep one Siglent SDS1104X-E and return the other. As a solution for the 8 channels I bought a used batch of material which includes a Picoscope 4824 at an amazing deal. Comes with probe attenuators, probes, cables and some extras. I had the opportunity to try it before buying and despite being only 20MHz this exceeded my expectations and is exactly what I'm looking for. Although the software requires some learning time, I think I didn't make a mistake in my choice. Only time will tell. The SDS1104X-E oscilloscope will be used as a complement.I am building a test bench for VCU´s, ebike and motorcycle controllers, LCD controllers and other stuff, to be able test the various modules/sensors offsite.I'm also dealing with VCU like the vcu200 and vcu300 which are excellent and have their own programmable software for configuration and analysis.https://www.racedom.com/en/aem-ev-vcu300-programmable-electric-vehicle-control-unitIf anyone of you is interested in knowing more about this Picoscope check this long youtube video refering to version 4823. My version is the 4824 without the "A" but they are the same.I read all the posts carefully, Life is a learning journey. Thank you again.

author: rf-loop
author_rank: Super Contributor
timestamp: November 21, 2021, 02:01:47 pm
content: Quote from: bdunham7 on November 21, 2021, 01:17:52 amTwo SDS1000X-E parallel or many other digital oscilloscope have one severe problem, more or less.Problem comes from fact that these scopes acquisition systems are not syncronized. So other may be just blind for signal when other is not and trigIn SDS1000X-E there is also two kind of blind times if acquisition is in normal defaulted fast mode depending t/div etc (if it works in burst mode or not).There is blind time after one capture before it can do new one. If signal meet trig but scope is not ready for next trig this event is lost.Then need also know that in fast mode these scopes do burst type sequential acquisitions and then they keep long pause before new burst start.wfm/s is not constant speed at all, it is average speed. In every around 40ms time it keep one over 3ms pause.Now these parallel scopes works not syncronized both have its own burst period. When other is, example in some imagined case, perhaps just trig'd other is perhaps just inside 3ms blind pause and totally loose this trig event what trig other scope.This image may explain. If there is now two SDS1000X-E running parallel and both scope one channel use same signal for trigger. Problem is that both acquisition systems are not syncronized with each others, so scopes BLIND periods may occur randomly. So other scope may trig and capture some event but other may loose it.In worst case, think if scope(s) are in single capture mode and there exist example one 1ms wide pulse or what ever below blind time.Yes both scopes may loose it in worst case if it happens that both are just in BLIND phase between bursts.If they both run just unsync but with same signal for trig then can think propability with different signals.So for many cases this is bad idea exept for playing fun or for very special cases when analyzed how these facts affect to result..Naturally if signals under test are really very slow then it can use for something. But even then these unsyncronized blind time facts need keep in mind.If use acquisition mode slow then burst mode is off, independent of t/div settings. In this case minimum capture interval is fixed to ~40ms what is same as display update interval so only single one capture can be displayed in one display frame (ancient DSO mode). With fast acq. mode (DPO mode) there can be up to over 4500 captures (wfm) overlaid in one single display frame.