On Sunday 27 December 2015 18:38:38 Ben Potter wrote: > > On Sunday 27 December 2015 18:03:20 Ben Potter wrote: > > > I have to admit I'm curious how industrial 4th axes are set up - I > > > presume an extended ground pin at a minimum - or do they need a > > > full power down of the machine too? > > > > A full power down of that motors driver will suffice. Its safe to > > power > > up the driver while the motor is disconnected, and when it is > connected, but the intermittent connections of unplugging it while the > driver is powered up will > > > write a ~30~ to that drivers story a very large percentage of the > > time. > > > > I killed a xylotex board twice with bad connectors. Connector name > > starts > > with an M. > > Sorry Gene, I may not have been clear enough - My (crude) 4th axis - > which is due to machine a better 4th axis this week uses this method. > The complete machine needs to power down and be left alone long enough > for the DC bus to discharge. It's not bad, and keeps me going, but I > keep thinking 'there's gotta be a better way'. > > I was wondering if the big machine builders had come up with a hotplug > solution. My brain has been saying extended ground pin plus a resistor > across two pins - the drive would need to detect the correct > resistance before powering up. The big concern for me is how fast > would the drive need to power down in a disconnect situation. > > I do hitting things with a hammer, this electronic stuff is a bit > arcane for me. > :) I hear that.
The better drivers, even the xylotex, have an enable line that if taken to the correct logic level, disables the driver, and until proven differently, I'd have to assume that also would make the connect/disconnect safe to do. The main reason its not used in most of our smaller stuff is that means 3 pins per axis are used on the breakout board. And that runs us out of pins to do other things. So generally, at my 20 anyway, the drivers are wired active when powered up. On a 4 axis machine, you would need 4 more output pins to individually control them. However, if and when I get my A axis moved to p2 on the 5i25, I'll have a spare pin, and I may just power it down between moves. But first I need some stuff from china, and a round tuit needs to be found to get my spindle PSU under software softstart control. > In the back of my brain may also be the thought of 'how do I make this > toolpost grinder into a safely switchable tool'. At least that one is > fairly low power > > Thanks > Ben > > > ---------------------------------------------------------------------- >-------- _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
