GSK980MDc Milling CNC System User Manual
356
Ⅲ Installation
: Pulse volume, motor rotation angle for a pulse
L: Lead (mm)
δ: Min. input command unit of CNC (0.001 mm or 0.0001mm)
ZM: Gear teeth of lead screw
ZD: Gear teeth of motor
If the electronic gear ratio numerator is greater than the denominator, the allowed CNC max. speed will
decrease.
For example: the data parameter
№015
（CMRZ）=2，№016（CMDZ）=1, the allowed Z axis max.
speed is
8000mm/min.
If the electronic gear ratio numerator is not equal to the denominator, the CNC positioning precision
will decrease. For example: when the data parameter
№015
（CMRZ）=1
and
№016（CMDZ）=5, the pulse
is not output
as the input increment is 0.004, but a pulse is output if the input increment is up to 0.005.
In order to ensure the CNC positioning precision, and match with digit servo with electronic gear
ratio function, it is suggested that the CNC electronic gear ratio is set to 1:1 or the electronic gear ratio
calculated is set to the digital servo.
When machining with the step drive, choose the drive unit with the step division function as far as
possible, and properly select mechanical transmission ratio. The 1:1 electronic gear ratio should be ensured
to avoid too large difference between the numerator and the denominator of the CNC gear ratio.
Calculation formula of drive unit:
Parameter 12, 13 of drive unit correspond to the pulse frequency division numerator of position
command respectively. The calculation formular for pulse frequency division denominator of position
command and gear ratio of drive unit are as follows:
CNGP ××=× 4
And：
CMR
CMD
Z
Z
L
C
CN
P
CN
G
D
M
××
××
=×××=
××
=
δα
4
360
4
4
P: Correspondence between required pulse amount for motor rotates 360 degrees and CNC end:
/360=P
G: electronic gear ratio of drive unit, G= position command pulse frequency division numerator/
position command pulse frequency division denominator
N: Set motor rev number to 1
C：Wire number of feedback encoder
Example:
When matching GSK980MDc with DA98B, set command multiplier coefficient and command frequency
division coefficient to 1 respectively. Wire number of feedback encoder is 2500p/r, and the minimum input
command unit of GSK980MDc is 0.001mm. When the motor and the lead are connected directly, the gear
ratio of the drive unit is as follows:
LLCMR
CMD
Z
Z
L
C
G
D
M
10
1
1
1
1001.0250044
=××
××
=××
××
=
δ
4.3.2 Servo Spindle
Calculation formula of CNC:
D
M
Z
Z
CMD
CMR
×=
α
δ
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