Re[2]: [CAD_CAM_EDM_DRO] Limit and Homing switches Over 2200 members today

CG> The idea of AND'ing a low-repeatability switch with the encoder
CG> index pulse sounds like a great low-cost method of finding a
CG> precise home. Is it really that simple? You just look for the
CG> AND'ed signal and set that as home? Wouldn't you have to
CG> calibrate the alignment of the index pulse to the homing/limit
CG> switch? Or, can you just have, a short ON-time of the coarse
CG> switch, which would necessarily be less than the axial travel of
CG> one revolution of the encoder? Could you elaborate? I'd like to
CG> leave room for something like this on my interface PCB, if it's
CG> simple enough.

Following is a description of the way it is done in the real world on
my AB 8400MP. The axis moves toward home until the switch closes
and then reverses at a low speed (5 ipm?) until the home switch opens
and the encoder index mark goes by. At this point, the drive
reverses again at a very low speed (.5 ipm?) until it again finds the
index mark and stops. You are now precisely at home and it is
exactly the same position every time..
Larry..