How To Set The Electronic Gear; Electronic Gear Settings In The Point Table Method - Mitsubishi Electric MR-JE-*C Instruction Manual

4. PARAMETERS

4.4 How to set the electronic gear

4.4.1 Electronic gear settings in the point table method

Adjust [Pr. PA06] and [Pr. PA07] to match the servo amplifier setting with the travel distance of the machine.
Electronic gear
([Pr. PA06] [Pr. PA07])
CMX
Travel distance
CDV
P : Servo motor encoder resolution: 131072 [pulse/rev]
t
ΔS: Travel distance per servo motor revolution [mm/rev]/[inch/rev]/[pulse/rev]
CMX/CDV = P /ΔS
t
Set the electronic gear within the following range. Setting out of the range will trigger [AL. 37 Parameter
error].
Electronic gear setting range
1/27649 < CMX/CDV < 8484
The following setting example shows how to calculate the electronic gear.
(1) Setting example of a ball screw
Machine specifications
Ball screw lead Pb = 10 [mm]
Reduction ratio: 1/n = Z
Z : Number of gear teeth on servo motor side
1
Z : Number of gear teeth on load side
2
Servo motor encoder resolution: P
CMX P
t
= =
ΔS
CDV
Note. Because the command unit is "mm", α is 1000. When the unit is "inch", α is 10000. When the unit is "pulse", α is 1.
Therefore, set CMX = 16384 and CDV = 625.
Servo motor
+
Deviation counter
-
Encoder
POINT
To calculate the electronic gear, the following specifications are required.
Pb: Ball screw lead [mm]
1/n: Reduction ratio
P : Servo motor encoder resolution [pulse/rev]
t
ΔS: Travel distance per servo motor revolution [mm/rev]
/Z = 1/2
1 2
= 131072 [pulse/rev]
t
P 131072
t
=
n Pb α (Note)
1/2 10 1000
M
1/n = Z /Z = 1/2
1 2
Servo motor encoder resolution
131072 [pulse/rev]
131072 16384
= =
5000
4 - 45
1/n
Z
2
Pb = 10 [mm]
Z
1
625