10.3 Parameter Settings for Fully-Closed Loop Control
10.3.3 Setting the Number of External Encoder Scale Pitches
10-6
•
Phase B leads in the divided pulses for a forward reference regardless of the setting of Pn000
= n.
X.
•
Forward direction: The direction in which the pulses are counted up.
•
Reverse direction: The direction in which the pulses are counted down.
Related Parameters
Pn000 = n.
X
Refer to the following section for details.
Pn002 = n.X
When you perform fully-closed loop control, set Pn002 to n.1
or n.3
.
10.3.3
Setting the Number of External Encoder Scale Pitches
Set the number of external encoder scale pitches per Servomotor rotation in Pn20A.
Setting Example
If the external encoder is connected directly to
the Servomotor, the setting will be 1,500
(30 mm/0.02 mm = 1,500).
Note: 1. If there is a fraction, round off the digits below the decimal point.
2. If the number of external encoder scale pitches per Servomotor rotation is not an integer, there will be devi-
ation in the position loop gain (Kp), feedforward, and position reference speed monitor. This is not relevant
for the position loop and it therefore does not interfere with the position accuracy.
Parameter
Name
Meaning
When
Enabled
Classifi-
cation
Pn002
n.0
(default set-
ting)
External
Encoder Usage
Do not use an external encoder.
After restart
Setup
n.1
External encoder moves in forward
direction for CCW motor rotation.
n.2
Reserved setting (Do not use.)
n.3
External encoder moves in reverse direc-
tion for CCW motor rotation.
n.4
Reserved setting (Do not use.)
Determine the setting of Pn002 = n.X
as described below.
•
Set Pn000 to n.
0 (Use the direction in which the linear encoder counts up as the for-
ward direction) and set Pn002 to n.1
(The external encoder moves in the forward
direction for CCW motor rotation).
•
Manually rotate the motor shaft counterclockwise.
•
If the fully-closed feedback pulse counter counts up, do not change the setting of Pn002
(Pn002 = n.1
).
•
If the fully-closed feedback pulse counter counts down, set Pn002 to n.3
.
Information
Specifications
External encoder scale pitch: 20
μ
m
Ball screw lead: 30 mm
External encoder
(scale pitch: 20
m)
Workpiece position
after movement
Workpiece position
before movement
Ball screw lead: 30 mm
Number of external encoder
pitches per Servomotor rotation
