Siglent SDS1104X-E CAN Bus Decoding

[@ygglw]

To probe a differential signal such as CAN. Ignore the ground connection from your probes (I usually unclip them). Use two channels, one on each of the two CAN lines. On your scope using channels 1 and 3 will still provide the 1GS/s sample rate. Then generate a math channel of 1+3, hide channels 1 and 3, and run the decode on the math channel. This removes any ground reference from the bus and allows you to differentially probe. Your signal level will double and there will be far less noise or decoding issues on your signal. It is unwise to ever clip the ground to either CAN line, because there may well be a ground reference somewhere else in your circuit with a DC offset to the CAN lines, which may end up shorting out your transceiver to ground via your oscilloscope.

[@TheBionicbone]

Thanks for the comment. I do like the math function to eliminate grounding issues, but unless I am missing something I find a few things worth mentioning. To hide 1+3 you need to roll each channel out of visual area (not deactivate them which is obvious I guess so the math channel has the data). You cannot decode the math channel, only channels 1 to 4, so you still need to get a stable enough signal on one of the H or L lines. While I was playing I also tried the logging function, but it is far too slow to capture 500kbs CAN signals, but even if it was, again a log is not selectable for the decoder function. In conclusion, decoding is still great, but for Automotive it’s just not up to the task. For clarification, I agree with the grounding comment. However my issue was my ESP32 and Nano had a common ground to my laptop, the Leonardo was connected to my bench supply. My grounding was to ground laptop and bench supply which cleaned up the signals.

[@rul1175]

@@TheBionicbone Can you still hack to 200mhz???

[@TheBionicbone]

I know ppl were still doing the hack last October, and I've not seen anything relating to "the hack doesn't work anymore". However, for me I don't need it and still have a warranty so no point loosing that. Let me know if you do it.

[@hydromakers]

@@rul1175 I just hacked my scope with no issues.

[@GoldenChannels]

Just bought one of these scopes. Very helpful intro to using the decoders. Thanks!

[@TheBionicbone]

I am really please this was helpful, enjoy playing, this scope has so many features that are really very useful once you get used to them.

[@fastbike9845]

Very useful thx - I'm just starting to play with some CANbus home automation gear.

[@tHaH4x0r]

10:10 I suspect you got the sporadic errors due to the high bandwidth, and switching to x1 reduced the bw considerably. Almost every modern scope has a 'limit BW' feature which would help as well. Regardless, great video.

[@TheBionicbone]

Thanks, it's great getting feedback and now them errors make sense to me.

[@yassinebenryan2814]

usefull video thank you

[@bennylloyd-willner9667]

Great video, I am contemplating getting my first oscilloscope in about 35 years 😁 I have been away from electronics for far too long, and the Siglent SDS1104X-E seems to fit me well. I have peeked at a Rigol equivalent to save some money, but since I am also interested in understanding the CAN bus I think I'll go for the Siglent. Interested to see what you are up to in other videos so I subbed. The weather is getting worse here in Sweden so many long nights indoors make Electronics and Smart Home stuff tinkering very possible😁

[@TheBionicbone]

Hi, thanks for commenting. When I was researching the SDS1104X-E came out on top as it is much faster and this one has two true channels, so ch1 and ch3 can be used at the same time on full speed. Just be aware, for CAN scanning the scope can miss data, I think they all can, but is very good if you only want to see the quality of the signal or capture the errors, or other type of trigger. If you want to grab a lot of CAN data without loss I recommend one of the cheap digital logic readers like I mention at the beginning, or make your own. I have to say though, if you buy this scope for tinkering then I doubt you'd regret it, so for me I'd say, buy it today and don't waste time looking at other stuff because this wins hands down, I spent weeks researching!

[@bennylloyd-willner9667]

@@TheBionicbone Thanks for your response, I have watched a couple of videos since so your recommendation to sniff CANbus with other tools seem to be the way to go. 👍

[@TheBionicbone]

Sorry, I only just seen this comment. Yes, for automotive at least. If you have a “normal” tinkering in the shed type circuit I think the oscilloscope is just fine. But my car produces thousands of can messages, the oscilloscope will never keep up with them unless you are needing to trigger on an exact known message.

[@bennylloyd-willner9667]

@@TheBionicbone agree, I'll go for one oscilloscope for tinkering, and other tool for CAN bus. I haven't decided on how deep I want to dive into the CAN bus world yet, so an oscilloscope is the next thing on my shopping list. I recently got into home automation, so my plan is to make some stuff for that. I also want to make a headlamp with 50-100W LED and some smart 3D printed gear so it'll include a tripod and head mount in the same thingy. (Battery pack in a "back pack" style for longer runtime ) Of course that MUST be Bluetooth and/or WiFi controlled 😁

[@TheBionicbone]

@@bennylloyd-willner9667 smart home is on my list too. I found loads of CAN stuff on my Freelander2, check out some software called CanDrive and SavvyCan. One day I'll get round to releasing my CAN recorder / scanner, some of the codes are available on my GitHub but it's not polished at all. My full solution works with both of the above softwares and can decode high speed and medium speed CAN bus at the same time with capacity to spare. I'll do that this year, I'm up for retirement at the end of march so will have more time for these exciting things

[@shaad2841]

The local supplier of Siglent SDS1104X-E told me separate paid licenses key needs to activate mso. That's is very costly over 1000$ with logic analyzer probes.

[@TheBionicbone]

I’m not sure I’d go down the MSO route, I have a cheap LHT00SU1 logic analyser (see my other videos). It’s more than enough, and connects to the Laptop allowing for much more data to be collected.

[@shaad2841]

@@TheBionicbone Thanks for the suggestion, I have dropped planning buy a expensive oscilloscope with logic analyser built in feature. Going to buy a 4 channels 100Mhz with AWG.

[@TheBionicbone]

Also check out my recent video on how to find your keys for activation on your scope. It’s very easy to do

[@tanner3801]

Are the decoded CAN/Serial messages able to be saved to internal or external memory? When I logged a CAN bus to CSV on mine, it just seemed to record the raw values 🤔

[@TheBionicbone]

I dont think you can save the decoded values at all, only a waveform as a CSV file

[@tanner3801]

@TheBionicbone I was able to figure out how to save a long string of decoded CAN messages to USB. A little clunky but it worked well.

[@TheBionicbone]

@@tanner3801 you mean using the oscilloscope? Or did you use a logic analyser or something else?

[@tanner3801]

@TheBionicbone yes, using the siglent sds1104x. It does seem limited in the size of continuous log it can record, but I was able to record a few seconds of 500kbaud CAN, which was enough for my needs this time.

[@TheBionicbone]

Interesting, I'll have another play. Thank you, great info.

[@MarcioRochaLopes]

I had forgotten that part (threshold) in the i2c decoder. 6:43 thanks

[@TheBionicbone]

It feels a bit illogical to have to set two trigger points. I'm glad it caught me out as it emphasizes the point that could otherwise have been missed as just setting the normal trigger. I'm glad this helped you.