Mitsubishi Electric MELSERVO-J3 Series Instruction Manual page 248

6. PARAMETERS
(1) Concept of electronic gear
Use the electronic gear (parameters No.PA06, PA07) to make adjustment so that the servo amplifier setting
matches the moving distance of the machine. Also, by changing the electronic gear value, the machine can
be moved at any multiplication ratio to the moving distance on the servo amplifier.
CMX Parameters No.PA06
CDV Parameters No.PA07
The following examples are used to explain how to calculate the electronic gear value.
(a) Ball screw setting example
Machine specifications
Ball screw lead: P
Reduction ratio: 1/n
Z : Number of gear teeth on servo motor side
1
Z : Number of gear teeth on load side
2
Servo motor encoder resolution: P
p
CMX
t
CDV
S n
Hence, set 32768 to CMX and 625 to CDV.
POINT
The following specification symbols are needed for electronic gear calculation.
Pb : Ball screw lead [mm]
1/n : Reduction ratio
Pt : Servo motor encoder resolution [pulse/rev]
S : Travel per servo motor revolution [mm/rev]
10 [mm]
b
Z /Z 1/2
1 2
262144 [pulse/rev]
t
p
262144
t
p 1/2 10 1000
1000
b
+ Deviation
CMX
counter
CDV -
Encoder feedback pulses
Electronic gear
Parameters No.PA06,PA07
1/n
1/n = Z /Z = 1/2
1 2
Z
2
Z
1
Servo motor encoder resolution
262144[pulse/rev]
32768
262144
5000 625
6 - 7
Motor
Encoder
Pb=10[mm]