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Todd Deckard
Mon 5th Jan 2015, 03:30
Greetings! I am building an azimuth/elevation satellite tracking system (2m/70cm). How concerned should I be about canning the Arduino/motors to limit EMI? It was not intended to be weatherproof and my current sketches have everything hanging out in the open.

Regards
Todd

WA9WVX
Fri 9th Jan 2015, 21:54
Greetings! I am building an azimuth/elevation satellite tracking system (2m/70cm). How concerned should I be about canning the Arduino/motors to limit EMI? It was not intended to be weatherproof and my current sketches have everything hanging out in the open.

Regards
Todd

In machine control systems there is two schools of thought, one is to galvanically isolate all systems OR make all system commons connected to earth ground but it has to be done in a certain manner. The preference has always been to common up supplies to a common star point together with the service ground. Even in the event of galvanic isolation, there can be inductive or capacitive coupling of EMI or other spurious signals.

Here is a an excellent source that outlines something called Equi-potential bonding. Download the PDF document to your computer.

http://www.automation.siemens.com/doconweb/pdf/840C_1101_E/emv_r.pdf?p=1

Also see ch6 which outlines the current practice for shielding. If you're working AC Voltage lines you should consider a Cor-Com Filter

http://www.te.com/en/brands/corcom.html

Todd Deckard
Sat 10th Jan 2015, 02:19
... one is to galvanically isolate all systems OR make all system commons connected to earth ground but it has to be done in a certain manner ...

excellent reference, thank you