DJI and possible EMI susceptibility

[Old Man]

Has anyone investigated how susceptible DJI controllers (or any other) are to EMI, or electro magnetic interference? I wonder about this when thinking about the power distribution boards we use to power our systems. Many of the larger multicopters use a centrally located power distribution board (PDB) with a number of large gauge wires soldered onto a flat plate. Flight controllers are then often installed on a carbon plate directly above that.

I don't have the means to measure the possibility of an EMI field surrounding a PDB but if one is generated and the flight controller is not shielded it, FC's are being taken out by their own power supply. That doesn't even consider the sharp electrical arc that can occur when connecting power leads when energizing the systems.

That arc is another item I'd like to know how to prevent or filter out before it can reach an FC.

Thoughts anyone?

 

[tahoejmfc]

I dont have the answer for all of your questions

Getting rid of Arc is easy, you need to either buy anti spark connectors or make your own connection with a resistor to slowly charge up the ESC caps instead of allowing them it have a huge inrush of voltage.
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I have a power distro setup in the main frame to my copter, its not the same as what you are talking about, it is 10 gauge wire with 4mm connectors woven in and soldered in place. The 10 gauge wires are twisted together to reduce the EMI. On top of that are my ESC's in a ring, and on top of all of that is a FC stack with the compass all the way at the top. I am flying U7 motors in a X8 configuration. 65A Maytech optos and 2 10,000 6S packs. When I hit hit gas, i have no yaw issues from EMI due to the twisting of the battery wires, and the main power distro twisted also. I did have issues with EMI on my Mikrokopter HL FC. I had to do alot more wire management with my Mikrokopter over my DJI FC. The FC and Imu have a aluminum emi shield surrounding them, the Mikrokopters have nothing.
View attachment 18588

 

[Bartman]

since electricity flows from the positive pole to the negative pole you can reduce the spark by making it happen at the negative side of the connectors. by doing so you're forcing the electricity to flow through the capacitors and other electronics before it can jump across the connectors as the contact is being established. Lean your connectors together so that the positive contact touch first and then bring the negative contact together. the spark will be much less than if you let the positive poles produce the spark.

EMI efects on DJI, don't know, sorry!

 

[Old Man]

Thanks Tahoejoe Bartman, good info, and greatly appreciated. BTW, tried a WKM LED on the A2 I've been having issues with and guess what? The light code for compass calibration illuminate....