ground protection between Two independent voltage sources (power supplies).

Hello,

Hardware:
I have an Arduino uno powered by a 9V battery.
A 36V battery delivering power to my SBL1360 motor controllers.
Data sheet provided if needed in attachments

Problem:
I was told that having a common ground can produce nose back into the Arduino that can harm it and will need a filter of some sort to protect it. Now my thoughts where using a low pass filter to protect it but I am unsure if this design idea is completely wrong or if I am missing something to protect my circuit. I am sure I’ll have to use an inductive lowpass filter due to the high voltages if I am on the right track.

Thank you for your time and answers.

sbl13xx_datasheet.pdf (955 KB)

trowe96:
Hello,

Hardware:
I have an Arduino uno powered by a 9V battery.
A 36V battery delivering power to my SBL1360 motor controllers.
Data sheet provided if needed in attachments

Problem:
I was told that having a common ground can produce nose back into the Arduino that can harm it and will need a filter of some sort to protect it. Now my thoughts where using a low pass filter to protect it but I am unsure if this design idea is completely wrong or if I am missing something to protect my circuit. I am sure I'll have to use an inductive lowpass filter due to the high voltages if I am on the right track.

Thank you for your time and answers.

The ONLY common ground you need is for the signals, Keep the 36 volt ground connections as far away as possible fron the signal grounds.
Paul

Ok Thank you I thought something was odd about making the two GNDs connected for my exoskeleton. I also know that an arduino can float the 9V and be completely safe. I do think ill have to ground the 36v to the chasse of my application. I will post a wire diagram once I can find a software that can do wiring for free later if that is ok? To drive the idea home.

The problem is a ground loop.

If your motors are battery powered, only connect battery ground to Arduino ground in
one place (typically with a wire in the same cable carrying the control signals). No ground
loop, should be fine (keep Arduino away from the high current wiring always). In your
situation there shouldn't be an issue avoiding a loop.

If both Arduino and motors were driven from earthed mains supplies you'd have a ground loop,
but you still need to connect signal ground to the Arduino from the motor controller - however this
ground wire may see some voltages impressed on it from the high current ground wiring. Logic signals
can cope with a bit of noise quite happily so long as its below the logic noise threshold.

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