Just a thought here, as I am far from an expert in such areas. Could the high-current sections be physically separated into a completely different PCB and enclosure and then opto-isolated from the more sensitive electronics? I don't recall if the original posting said that the motors were controlled in an analog or digital fashion.
Greg ________________________________ From: Anders Gustafsson <[email protected]> To: [email protected] Sent: Tuesday, August 25, 2009 9:24:15 AM Subject: Sv: Re: [kicad-users] Re:Grounding strategies, zones, star ground etc > It's worth saying that if one has a problem as described in the OP, a four > layer board would be highly preferable. Absolutely, but I only intend to make three such boards :) The aim is to control a rather ancient Beaver CNC mill that now belongs to a friend of mine. We scrapped the original controller for several reasons, ie it was a punched-tape unit and it had been used as a dwelling by a rather large colony of rats.... I will make the finished design available on the web, for others to use though as there seems to be a large number of these mills floating around and they are built to last a lifetime or two. The motors are rated at 7Nm, but I found that they pulled well over 9Nm reliably even when driven at just 15A (they are rated at 20A) > If you split the ground > plane up with a view to helping you achieve this, then you should > benefit, but if you just do it blindly thinkin The ground planes on both sides are now split, with a moat that separates the low-signal part from the noisy bits and they are joined at one point, the star ground. - Anders Gustafsson Engineer, CNE6, ASE Pedago, The Aaland Islands (N60 E20) www.pedago.fi phone +358 18 12060 mobile +358 40506 7099 fax +358 18 14060 ------------------------------------ Please read the Kicad FAQ in the group files section before posting your question. Please post your bug reports here. They will be picked up by the creator of Kicad. Please visit http://www.kicadlib.org for details of how to contribute your symbols/modules to the kicad library. For building Kicad from source and other development questions visit the kicad-devel group at http://groups.yahoo.com/group/kicad-develYahoo! Groups Links
