YASKAWA G7 Series Technical Manual page 356

Time Chart
A time chart for the zero servo function is given in Fig 6.74 Time Chart for Zero Servo.
Application Precautions
Be sure to leave the run command input ON. If the run command is turned OFF, the output will be inter-
•
rupted and the zero-servo function will become ineffective.
The holding force of the zero-servo is adjusted in b9-01. The holding force will increase if the value of the
•
setting is increased, but oscillation and hunting will occur if the setting is too large. Adjust b9-01 after
adjusting the speed control gain.
The zero-servo detection width is set as the allowable position offset from the zero-servo start position. Set
•
4 times the number of pulses from the PG.
The Zero Servo End signal will go OFF when the zero servo command is turned OFF.
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IMPORTANT
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Run command
Zero servo command
Frequency (speed) reference
Excitation level
b2-01
Motor speed
Zero Servo End signal
Fig 6.74 Time Chart for Zero Servo
Do not lock the servo for extended periods of time at 100% when using the zero servo function. Drive errors
may result. Extended periods of servo lock can be achieved by ensuring that the current during the servolock
is 50% or less or by increasing the Drive capacity.
ON OFF
ON
Zero-servo status
OFF