Timeline for How should you pair conductors for I2C with PWM for a DC motor over CAT6 to minimize crosstalk?
Current License: CC BY-SA 4.0
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| Sep 10, 2023 at 0:43 | comment | added | KJ7LNW | @TimWilliams, thanks. We're switching to 12v differential using a PCA9600 even though it is a modification we were trying to avoid... So should I delete this question or leave it here for others who might try something as crazy, so they can at least read the comments? If you or anyone would like to write a good answer for posterity on why this is just a terrible idea, then I'll mark it as accepted. | |
| Sep 9, 2023 at 5:01 | comment | added | Tim Williams | Note that the linked answer makes no consideration of EMC, particularly immunity. Putting a source of switching noise within the cable itself is a good way to guarantee nothing ever communicates over that poor I2C bus. Pairings are irrelevant. Use differential, period. | |
| Sep 9, 2023 at 1:02 | history | edited | KJ7LNW | CC BY-SA 4.0 |
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| Sep 9, 2023 at 0:00 | comment | added | user1816847 | Doesn't directly answer the question, but if you can use two different cables. | |
| Sep 8, 2023 at 23:34 | comment | added | jsotola | have a look at PoE (Power over Ethernet) ... supply the 12 V as DC ... send the PWM as a low level control signal | |
| Sep 8, 2023 at 23:11 | comment | added | BeB00 | if you can, definitely try to get FTP, not UTP - no matter how you twist the pairs, you're going to get some coupling between the PWM and the I2C, and that's very bad - not only is it PWM, it's PWM for a motor, one of the noisiest things possible. 12V is a pretty huge voltage swing as well, so it wont take much coupling to cause problems. | |
| Sep 8, 2023 at 23:10 | history | edited | KJ7LNW | CC BY-SA 4.0 |
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| Sep 8, 2023 at 22:57 | history | asked | KJ7LNW | CC BY-SA 4.0 |