Mitsubishi Electric MELSERVO MR-J2 C Series, Instruction Manual

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5 - 13
5. PARAMETERS
5.2 Detailed explanation
5.2.1 Electronic gear
CAUTION False setting will result in unexpected fast rotation, causing injury.
POINT
The range of the electronic gear setting is
CMX
CDV 1
20
20
. If you set any
value outside this range, a parameter error (A.37) occurs.
Always make electronic gear setting in the servo off status to prevent
runaway due to false setting.
(1) Concept of electronic gear
Use the electronic gear (parameters No.4, 5) 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.
Parameters No. 4
Parameters No. 5
CMX
CDV
Electronic gear
Parameters No. 4, 5
Encoder feedback pulses
CMX
CDV
Deviation
counter
Motor
Encoder
M
ov
ing
d
is
tanc
e
+
-
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 : Ballscrew lead [mm]
n : Reduction ratio
Pt : Servo motor resolution [pulse/rev]
S : Travel per servo motor revolution [mm/rev]
(a) Ballscrew setting example
Machine specifications
Ballscrew lead: Pb 10 [mm]
Reduction ratio: n 1/2
Servo motor resolution: Pt 8192 [pulse/rev]
Servo motor
8192[pulse/rev]
n
NM
NL
Pb=10[mm]
n=NL/NM=1/2
CMX
CDV
S
p
t
5000
8192
625
1024
p
t
n 1000
p
b
8192
1/2 10 1000
Hence, set 1024 to CMX and 625 to CDV.
(b) Conveyor setting example
Machine specifications
Pulley diameter: r 160 [mm]
Reduction ratio: n 1/3
Servo motor resolution: Pt 16384 [pulse/rev]
Servo motor
16384[pulse/rev]
r=160[mm]
n
NM
NL
n=NL/NM=1/3
CMX
CDV
p
t
S
4096
41888
2048
20944 167551.61
16384
p
t
n r 1000
16384
1/3 160 1000
Reduce CMX and CDV to the setting range or less, and round off the first decimal place.
Hence, set 2048 to CMX and 20944 to CDV.
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