Mitsubishi Electric Melservo-J3 Series MR-J3-B, Instruction Manual

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6 - 7
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
CDV
Parameters No.PA06
Parameters No.PA07
Encoder feedback pulses
CMX
CDV
Deviation
counter
Motor
Encoder
Mo
vi
n
g
d
ist
an
ce +
-
Electronic gear
Parameters No.PA06,PA07
The following examples are used to explain how to calculate the electronic gear value.
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]
(a) Ball screw setting example
Machine specifications
Ball screw lead: P
b
10 [mm]
Reduction ratio: 1/n Z
1
/Z
2
1/2
Z
1
: Number of gear teeth on servo motor side
Z
2
: Number of gear teeth on load side
Servo motor encoder resolution
262144[pulse/rev]
1/n = Z
1
/Z
2
= 1/2
Z
2
1/n
Pb=10[mm]
Z
1
Servo motor encoder resolution: P
t
262144 [pulse/rev]
CMX
CDV
S
p
t
5000
262144
625
32768
p
t
n 1000
p
b
262144
1/2 10 1000
Hence, set 32768 to CMX and 625 to CDV.