Mitsubishi Electric Melservo-J5 MR-J5 Series - Page 428

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12 USING A FULLY CLOSED LOOP SYSTEM
12.4 Startup
Setting the feedback pulse electronic gear
Precautions
If an incorrect value is set for the feedback pulse electronic gear ([Pr. PE04 Fully closed loop control - Feedback pulse
electronic gear 1 - Numerator] or [Pr. PE05 Fully closed loop control - Feedback pulse electronic gear 1 - Denominator]), [AL.
037 Parameter error] may occur and prevent normal operation.
In addition, [AL. 042.8 Fully closed loop control error by position deviation] may occur during the positioning operation.
For servo motor-side encoder pulses, set the numerator [Pr. PE04] and denominator [Pr. PE05] of the electronic gear.
Set the electronic gear so that the number of servo motor encoder pulses per servo motor revolution is converted into the
number of load-side encoder pulses. The relation is as follows.
Select a load-side encoder of which the number of load-side encoder pulses per servo motor revolution is within the following
range.
4096 (2
12
)  Number of load-side encoder pulses per servo motor revolution  67108864 (2
26
)
■Example settings of a ball screw (direct connection) with a linear encoder resolution of 0.05
μm
• Conditions
Servo motor resolution: 67108864 pulses/rev
Servo motor reduction ratio: 1/11
Ball screw lead: 20 mm
Linear encoder resolution: 0.05 m
Calculate the number of linear encoder pulses per ball screw revolution.
Number of linear encoder pulses per ball screw revolution
= Ball screw lead/Linear encoder resolution
= 20 mm/0.05 m = 400000 pulses
[Pr. PE04]
[Pr. PE05]
=
The number of load-side encoder pulses per servo motor revolution
The number of servo motor encoder pulses per servo motor revolution
Geared servo motor
Table
Linear encoder
Linear encoder head
[Pr. PE04]
[Pr. PE05]
400000
67108864
3125
524288
1
11
==××
1
11