On Friday 25 September 2015 13:31:03 John Kasunich wrote: > On Fri, Sep 25, 2015, at 12:00 PM, Gene Heskett wrote: > > What I was hoping for, without hacking up some hal memory, was that > > motion was aware of a switch closing and opening if it went by them > > in normal programmed motions, and was recording which direction the > > machine was moving the last time the switches opened. That could > > then be consulted when the home all command was issued, to determine > > which side of the switch it was on, and that to find it, it needed > > to move toward it, then once found, the normal 2nd & slower phase of > > fine tuning the home would then be resumed. All that would take is > > the sign of the motion, which could then be used to diddle the sign > > of the > > HOME_SEARCH_VELOCITY. > > This cannot work. Remembering where you are while running is one > thing. Starting up is another. When the machine is powered up it has > no way of knowing which side of the switch it is on. Storing the info > somewhere is not the answer - maybe the axis was moved manually (or > even completely disassembled for repairs) since the last time the > control was powered. If the control doesn't know which side of the > switch it is on, an attempt to home has a 50% chance of running the > axis into the hard stops. Maybe no big deal on a bench-top stepper > machine. Completely unacceptable on an industrial class machine. > > The proper answer is a long actuator for the switch, so that once the > switch is activated, it stays activated all the way to the end of the > axis.
Or, as I just did, move the switch so it can't go on by it. :) 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
