Mitsubishi Electric MR-J5D User Manual page 175

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 based on 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.
[Pr. PE04]
The number of load-side encoder pulses per servo motor revolution
=
[Pr. PE05]
The number of servo motor encoder pulses per servo motor revolution
Select a load-side encoder of which the number of load-side encoder pulses per servo motor revolution is within the following
range.
12
4096 (2 ) ≤ Number of load-side encoder pulses per servo motor revolution ≤ 67108864 (2
■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 μm
Geared servo motor
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 μm = 400000 pulses
[Pr. PE04] 400000 1
= × =
[Pr. PE05] 67108864 11
Linear encoder
Linear encoder head
Table
3125 1
×
524288 11
26
)
10 USING A FULLY CLOSED LOOP SYSTEM
10
173
10.4 Startup