Mitsubishi Electric MELDAS 600M Series Instruction Manual page 392

(2) G28 rapid traverse rate (150001 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 (AXIS
SPECIFICATION PARAM. 130002 Rapid).
(3) G28 approach speed (150002 G28crp)
This parameters sets the approach speed (creep speed) to the reference point after decelerating
to a stop by the near-dog detection. The creep speed is accelerated and decelerated in steps, so if
the speed is fast, mechanical shock, etc., could occur. The creep speed should be set between
100 and 300 mm/min., and within 500 mm/min. at the fastest.
(4) Reference point shift amount (150003 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 space (150004 Grspc)
This parameter sets the distance between grids.
The normal grid space is the ball screw pitch (SERVO PARAM. #160018 PIT) value or the
movement amount per motor rotation set as a mm (millimeter) unit.
To make the grid space smaller, set a divisor of the grid space.
Calculation expression for movement amount per motor rotation
• When linear feed mechanism is ball screw
• When linear feed mechanism is rack & pinion
• For rotary axis
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3. Adjusting the Dog-Type Reference Point Return
Movement amount per motor rotation =
Movement amount per motor rotation =
Movement angle per motor rotation =
PC1
∗ PIT
N =
PC2
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CHAPTER 3 MAINTENANCE
Motor side gear ratio
Machine side gear ratio
Motor side gear ratio
Machine side gear ratio
Motor side gear ratio
Machine side gear ratio
N = Movement amount per motor rotation
PC1 = Motor side gear ratio
PC2 = Machine side gear ratio
PIT = Ball screw pitch
III – 6
∗ Ball screw pitch
∗ No. of pinion gear teeth ∗ Rack pitch
∗ 360