That would probably solve the problem, but a simpler solution would be to take what Anders has done one stage further and bridge the gap between the two board sections using opto-isolators.
One other thing whilst I think of it, the control signals ought to be routed over the connection between the two ground planes (in order to minimise their loop areas). Robert. Greg Dyess wrote: > 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 > > > > > > > > ------------------------------------------------------------------------ > > > > No virus found in this incoming message. Checked by AVG - www.avg.com > Version: 8.5.409 / Virus Database: 270.13.66/2325 - Release Date: > 08/25/09 06:08:00 >
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