On Sunday 17 February 2008, Ray Henry wrote: >On Sun, 2008-02-17 at 09:12 -0500, Gene Heskett wrote: >> On Sunday 17 February 2008, Rob Jansen wrote: >> >Oh yeah, and an emergency button won't hurt - may even save your >> >machine, I was almost too late hitting the F1 button yesterday. >> >> The 'esc' key in emc serves as the e-stop if one is not otherwise rigged. >> That detail however IS on the agenda for when the driver box gains a 4th >> channel. > >My reaction here is for the newbee wiring enthusiast because I'm pretty >certain that you guys already know that silicon mediated estop is only >permitted under some very strictly controlled situations. A machine >that requires orderly shutdown would be an example. Even then there are >very rigorous requirements for the nature and number of the silicon >junctions permitted and the voting process required in the software that >handles them. > >We've had long discussions about naming what the GUI does when you press >stop on the keyboard or a mouse click but they don't qualify as estop in >the USA. (At this point some will say, "But you named it E-Stop when >you wrote the mini graphical interface.") To qualify we pretty much >need a normally closed loop of mechanical switches that pulls a relay >rated to break the current supplied to moving parts. > >HTH > >Rayh
Which means we either use the disable points in the amps, or a power relay to kill the AC power to the ps feeding the amps as its not safe to disconnect the motors or the driver power with a hard connection. Even the AC power thingy could be fun as there is about 1/4 farad in its filters, so that stop isn't going to be instant. A second perhaps & way too slow IMO. The amp disable is the fastest of the bunch I suspect. And it is what I'll use when I re-build the setup for the 4th axis. The point about safety is well taken though Ray, thanks. I wish it was safe to hard switch the amps supply line, but I don't believe it is in terms of amplifier life expectancy. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) History repeats itself -- the first time as a tragi-comedy, the second time as bedroom farce. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
