GSK 980MDc, User Manual

Page: 406 / 473

Appendix
387
Appendix
7.2 Setting of Spindle Electronic Gear Ratio
Calculation formula of CNC:
D
M
Z
Z
CMD
CMR
× =
α
δ
CMR
CMD
Z
Z
D
M
× × =
δ α
CMR: Multiplier coefficient of spindle command
CMD: Frequency division coefficient of spindle command
α
: Pulse volume, motor rotation angle for a pulse
δ : Min. input command unit of CNC (0.001°, 0.01° or 0.0001°), this value corresponds to the travel
amount of a revolution of the spindle (related parameters 5216). When 5216 is set to 1000,
δ =360/1000=0.360
°
ZM: Gear teeth of lead screw
ZD: Gear teeth of motor
Calculation formula of spindle servo drive unit:
Parameter 12, 13 of drive unit correspond to the pulse frequency division numerator of position
command respectively. The calculation formulas for pulse frequency division denominator of position
command and gear ratio of drive unit are as follows:
C N G P
× × = ×
4
And:
CMR
CMD
Z
Z
C
C N
P
C N
G
D
M
× × ×
×
= × × × =
× ×
=
δ
α
360
4
360
4
4
P: Correspondence between required pulse amounts for motor rotates 360 degrees and CNC end:
α
/ 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
In order to enhance the machining accuracy, the gear ratio of spindle servo drive is usually set to 1:1,
namely, G=1 in the above formula, and the evolving process is as follows:
1
360
4
= × × ×
×
CMR
CMD
Z
Z
C
D
M
δ
D
M
Z
Z
C
CMD
CMR
× ×
×
=
δ
360
4
In order to match with DAP03, C=1024, spindle connects to the motor, Z
M
/Z
D
=1, and it is suggested
that the data parameter 5216 of CNC is set to 1000 (Now the incremental system of the 5
th
axis is 0.001°)