Mitsubishi Electric MELSERVO-J5 - Page 137

3 BASIC FUNCTION
3.10 Electronic gear function [G]
135
3
For profile position mode
■When setting "3" (pulse) in [Pr. PT01.2 Unit for position data]
Adjust [Pr. PA06 Electronic gear numerator] and [Pr. PA07 Electronic gear denominator] so that the travel distance set in the
servo amplifier matches the travel distance on the machine. [Motor revolutions (Obj. 6091h: 01h)] and [Shaft revolutions (Obj.
6091h: 02h)] can also be used for the setting.
P
t
: Servo motor encoder resolution [pulse/rev]
ΔS: Travel distance per servo motor revolution [command unit/rev]
CMX: Electronic gear numerator
CDV: Electronic gear denominator
CMX/CDV = P
t
/ΔS
The following setting example shows how to calculate the electronic gear.
To calculate the electronic gear, the following specification symbols are required.
Pb: Ball screw lead [mm]
1/n: Reduction ratio
P
t
: Servo motor encoder resolution [pulse/rev]
ΔS: Travel distance per servo motor revolution [mm/rev]
Ex.
Setting example for a ball screw
Machine specifications
Ball screw lead Pb = 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 gear
Servo motor encoder resolution: P
t
= 67108864 [pulse/rev]
Therefore, set CMX = 8388608 and CDV = 625.
*1 When the command unit is "pulse", convert as α = 1.
+
-
M
CDV
CMX
([Pr. PA06]/[Pr. PA07])
([Obj. 6091h: 01h]/[Obj. 6091h: 02h])
Deviation counter
Servo motor
Encoder
Electronic gear
Travel distance
[command unit]
or
67108864 [pulse/rev]
Pb = 10 [mm]
Z
1
1/n = Z
1
/Z
2
= 1/2
Z
2
1/n
Servo motor encoder resolution
CMX
CDV
= =
P
t
ΔS
=
P
t
1/n • Pb • α
*1
67108864
1/2 • 10 • 1000
=
67108864
5000
=
8388608
625