John, > Prior to and during homing, the soft limits are set to > "current position > +/- total length of axis" (length of axis is the difference > between the > soft limits in the ini file. That means the home sequence > should run into the physical ends of the axis before it hits > the soft limit, unless the values in the ini file are grossly wrong. > > Once an axis is homed, the soft limits are absolute, based on > the ini file values.
You mentioned below that EMC will prevent you from getting within 0.1% of either limit. My X axis length is 76" and Y is 120", thus 0.076" and 0.120" respectively. Those would seem to be about the points the soft limit is being triggered when homing. I had played with several ways of setting the soft limits, like setting the homes for X and Y at 0.2" off the limit switches, and setting that position as 0.0, hence the soft limits would go from 0 - 75.6 and 0 to 119.6 respectively, but to simplify things, I set the soft limits to the hard limits. > In all but the latest CVS, EMC will prevent you from getting > closer than 0.1% of the total axis length of either limit. > That doesn't sound like your situation, since "nowhere near > the limit" seems like a lot more than 0.1%. (0.1% of a 20" > long axis is only 0.020".) Last night after a discussion on > IRC, I recoded the soft limits. You can now go all the way > to the limits, but not beyond. Reaching the limits is not > treated as a fault, it just stops moving. Going beyond the > limits is a fault, but that is hard to do because jogs and > other motion commands are checked before they are issued. At > the moment the only way I know of to get that fault is to > issue an arc command with both endpoints inside the limit but > some part of the arc outside the limit. (Eventually we will > improve the checking, and even that arc command will be > caught before the move starts.) That makes a lot of sense, but I thought I had figured that out, in that it was happening with the Z axis. I would generally encounter this problem after issuing A G92 or similar command, so it is possible I am still getting fooled by Z, and thinking it was X or Y which was tripping the soft limit (hence, nowhere near the soft limits). I think I know what to look for on the second part, still not quite sure what is going on with homing, but I will do some more testing. Thanks, Eric ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
