Mitsubishi Electric EZMotion-NC E60 Series, Operation Manual

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3. Adjustment of Dog-type Reference Point Return
3.3 Reference Point Return Parameters
III -10
(2) G28 rapid traverse rate (#2025 G28rap)
This parameter designates the feedrate for dog-type reference point return in manual operation
and automatic operation.
The feedrate during high-speed reference point return will be the rapid traverse rate (SETUP
PARAM. "#2001 rapid").
(3) G28 approach speed (#2026 G28crp)
This parameter sets the approach speed to the reference point after decelerating to a stop by the
near-dog detection. The G28 approach speed is accelerated and decelerated in steps
(acceleration/deceleration zero), so if the speed is fast, mechanical shock, etc., could occur. The
G28 approach speed should be set between 100 and 300 mm/min., and within 500 mm/min. at the
fastest.
(4) Reference point shift amount (#2027 G28sft)
This parameter can set the shift amount for shifting the reference point from the electrical zero
point.
The shift direction can be set only in the reference point return direction.
If the reference point shift amount is "0", the grid point (electrical zero point) will be the reference
point.
(5) Grid mask amount (#2028 grmask)
The electrical zero point is the first grid point after the dog is kicked.
If the grid point is at the position where the near-point dog is kicked, the electrical zero point will be
the grid point at the position where the dog is kicked because of the delay of the limit switch
operation. Thus, the next grid point will be applied, or in the end, the reference point position may
be deviate by the amount of the grid space.
Thus, the position that the dog is kicked must be at the approximate center of the grid space.
△ △ △
Dog
Reference point
The electrical zero point will
change depending on the
limit switch delay.
Adjustments can be made by changing the near-point dog or by setting the grid mask amount.
Setting the grid mask has the same effect as lengthening the near-point dog.
If the grid amount is near the grid space or 0, the grid point will be at the position that the
near-point dog is kicked, so set a grid mask.
The grid mask amount is set so that the grid mask is one-half of the grid space.
The grid mask amount can be set only in the reference point return direction.
The grid amount and grid space can be confirmed on the "SERVO MONITOR (2)" screen.
Refer to the grid mask amount calculation expressions on the next page for the grid mask amount
values.