In the preunified electronic days, the "home" positions of the x,y,z axes were determined by an electrical end of stroke. Due to differences in homing speeds and distances between prox switches and tabs, the "zero" of the machine could vary a small amount. With the newer electronics, circa 1987 or so, DEA started to use the absolute zero pulses on the scales to define home. Typical homing sequence would be to move the axes in the home direction until the EOS was encountered. Then move in the opposite direction until no EOS was sensed. Then continue movement in the same direction until an absolute zero pulse was sensed. This was defined as home. This new procedure resulted in the loss of stroke length. So, software parameters were set up to define positive and negative stroke around this "home". The mechanical offsets you refer to are a reflection of these software parameters. These offsets are used by the compensation map and should not be touched. They have nothing to do with Renishaw.

omiez