5-9
5-4 Full Closing Control
OMNUC G5-Series AC Servo Drives Users Manual (Built-in MECHATROLINK-II communications type)
5
BASIC CONTROL Mode
5-4 Full Closing Control
An externally provided scale is used to directly detect the position of the control target and
feedback the detected machine position to perform position control. This way, controls become
possible that is not affected by ball screw error, temperature change, etc. You can achieve
highly accurate positioning by configuring a full closing control system.
Outline of Operation
Precautions for Correct Use
If the electronic gear ratio is 1 : 1, 1 command pulse from the encoder constitutes 1 external
encoder pulse. Since the electronic gear ratio is set differently than in the POSITION CONTROL
mode, set the external encoder dividing ratio correctly.
To prevent machine damage due to an external encoder setting error, set the following
parameters to appropriate values.
• Internal/External Feedback Pulse Error Counter Overflow Level (Pn328)
• Internal/External Feedback Pulse Error Counter Reset (Pn329)
For the setting of external encoder ratio, it is recommended that 1/40
External encoder ratio
160 be satisfied.
If the external encoder ratio is set excessively small, control to the unit of 1 external encoder pulse
may be disabled.
If the external encoder ratio is increased, on the other hand, operating noise may increase.
Servo Drive
R88D-KN
Servomotor
OMNUC G5
Host Controller
(MECHATROLINK-II communications support type)
FULL CLOSING CONTROL mode
Position Control Unit
CJ1W-NCF71
CS1W-NCF71
(Absolute Movement
Command /
Relative Movement
Command)
Issue a positioning
command
Feedback the
position or speed
Electronic gear
Pn009, Pn010
Numerator
Denominator
External encoder
Position
detection
External encoder Dividing Ratio
Pn324, Pn325
Numerator
Denominator
