Detailed Explanation; Electronic Gear - Mitsubishi Electric MELSERVO-J2 Series Instruction Manual

5. PARAMETERS

5.2 Detailed explanation

5.2.1 Electronic gear

CAUTION
(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
CMX
CDV
Parameters No. 5
The following examples are used to explain how to calculate the electronic gear value:
(a) Ballscrew setting example
Machine specifications
Ballscrew lead: Pb
Reduction ratio: n
Servo motor resolution: Pt
CMX
CDV
Hence, set 1024 to CMX and 625 to CDV.
(b) Conveyor setting example
Machine specifications
Pulley diameter: r
Reduction ratio: n
Servo motor resolution: Pt
CMX
CDV
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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False setting will result in unexpected fast rotation, causing injury.
POINT
The range of the electronic gear setting is
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.
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]
10 [mm]
1/2
8192 [pulse/rev]
p
p
t t
p 1/2 10 1000
n 1000
S
b
160 [mm]
1/3
16384 [pulse/rev]
p p
t t
S n r 1000
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CMX
CDV
Electronic gear
Parameters No. 4, 5
n=NL/NM=1/2
NL
Servo motor
8192[pulse/rev]
8192 8192 1024
5000
625
r=160[mm]
n
NL
n=NL/NM=1/3
16384 16384
1/3 160 1000 167551.61
5 - 13
1
CMX
20 . If you set any
20
CDV
Motor
+ Deviation
counter
-
Encoder feedback pulses
Encoder
n
Pb=10[mm]
NM
Servo motor
16384[pulse/rev]
NM
4096 2048
41888 20944