Advanced CAN Diagnostics: Signal Decoding w/ guest Chad Bailey Pt1 

❤️❤️❤️ Productive weekend for you two!! Chad, we enjoyed having you for the weekend and hope you come back!

This was very interesting. Way more than I needed to know or will ever use, but interesting just the same. Proves that the more you know, the less you know. Keep up the great content.

Differential signaling, also called balanced audio in the audio world, isolates the signal from the ground in any module. And by splitting it to a high and a low, any noise introduced will effect both signals the same way and so will not impact the difference. As long as the CAN transceiver can subtract the two lines and get the zero to 2 volt signal referenced to the local ground, it can read it, even if there's all kinds of noise put in the signal along the way. A now defunct channel, TheOnlineEngineer, has a video 'Audio Basics: Balanced Audio' that is very good at explaining the concept. CAN just uses digital signals instead of audio.

Keep in mind break out boxes done work with security systems like newer Nissan and Hyundai….Watching now- typically I don’t run can decoding on my Pico or ATS scope if I terminate at 60 ohms I’m good if 120 I know I have a module down. If I have a break in can signal I start unplugging modules until it comes back. Looking to watching both parts… Jay

This is the true down n dirty of diagnostics. I'm loving it! Thanks Matt for digging into this!

+1 for the genomic references. People laugh when I tell them troubleshooting automotive electrical gremlins is similar to my day job as a PhD candidate in molecular biology. They really are similar: I have to learn about systems I know nothing about and spend an inordinate amount of time and effort troubleshooting them. Thanks for these very accessible CAN network videos.

This is CAN heaven! Amazing information at your finger tips. Thanks Matt and Chad!!

On scan tools the new ones have topology and they are in the can lines, or k line etc etc the scan tools pull data from the module through a signal wire not technically the can lines. The can lines take priority like he said, if a airbag goes off if need Priority on the network. So the can lines talk but the raw data comes from modules and strategies

This protocol reminds me of older technology Ethernet like tokin ring etc. I'm looking forward to learning more about can bus. Most other videos I've seen just show you to acknowledge can high and can low are present and "look" normal.

Also to save channels you can run one channel place ground on pin 6 and the signal lead on pin 14 using just one channel

Awesome video! I would recommend against using the CAN breakout box when doing any programming though, the breakout box can interfere with messages from the computer to the module; other than that, they're great!

Very interesting!

Interesting video.... I still have a lot to learn....

I fell down this rabbit hole when looking at how modules communicate with each other on a boat. The rules of communication are different compared to automotives, but the overall theme is similar. In a marine situation you need to integrate numerous devices that are manufactured by different companies, with a boat you can't afford to throw out and start again. When communication protocols are updated for faster talk, many of the older devices can't keep up. So, a minor project has a way of snowballing....

great stuff, just dont ever loose track that your viewed for being a great learner AND teacher :} just an fyi thank

My brain hurts in a good way ,thanks!

Very ineresting. Can you tell me how a ELM327 fits into this process?

You can easily check the baud rate with the scope. The baud rate is the rate at which the signal can switch from 0 to 1. Just measure on channel A and the shortest time T from where it is goes from 2.5V to 3.5V and then back to 2.5V. The baud rate will then be 1/T. You should get 2 microseconds if you have 500 kbaud.

that was roberts idea to speed up data transfer by not going through central cpu, and having the most critical information reach the cpu first. Remember what yoda told luke when you take the shot on the death star "turn off the targeting computer"

Can chad make videos on Lin bud, flexray, ect too? This would be amazing

So how do you determine which module is sending any given message. What would be useful to me, is when I see a message that looks corrupted in some way , having the ability to know who sent the errent message.

When did you get the picoscope

Ohhh! The headaches... it's your fault dude!

The openhantek domain is being auctioned off so as of 2/2024 the link is no longer valid.

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