User Manual
Chapter 6
GFK-1742F
Jan 2020
Non-Programmed Motion
165
Note the relationships of the home position, the negative overtravel position, and the
positive stop position. A small amount of distance is provided in the negative direction
between the home position and the negative overtravel position. This is to allow some
“working room” for adjustment and setup of these positions and for the “find home”
routine, which requires that its final move be in the negative direction.
Distance is also provided between the overtravel limit position and the positive stop.
Enough distance should be allowed here to prevent the machine slide from hitting the
positive stop. The correct distance needs to be greater than the worst-case stopping
distance required by the machine slide after it reaches the overtravel limit position.
In this example, the machine slide’s working range is on the positive side of the home
switch. If the DSM’s Home Position parameter was set to 0, this would simplify
programming absolute positioning commands since only positive numbers would be used.
Often, the home position needs to be set to an exact distance from a reference point on the
machine. To facilitate this adjustment, the home switch cam could be made with slotted
mounting holes that would allow a coarse adjustment of the cam to bring the calibration to
within one turn of the encoder. Then, the small remaining distance would be accurately
measured,
and the value obtained would be entered into the DSM’s Ho
me Offset
parameter.
Figure 67: Home Switch Example