
8. TROUBLESHOOTING
B–64115EN/01
468
This alarm is issued if the servo ready signal (VRDY) of a servo amplifier
does not turn on or if the signal turns off during operation.
There are cases in which this alarm is issued because another servo alarm
is issued. If this occurs, first take the action for the first alarm.
Check the power magnetic circuit around the amplifier. The servo
amplifier or the axis control cards on the CNC may be defective.
CNC (Main board) Servo amplifier
MCON: From the CNC to the servo amplifier
(Turn MCC on to request the activation of the servo motor)
VRDY: From the servo amplifier to the CNC
(Notifies that the servo is ready)
The exchange of this information is performed via the FSSB (optical cable).
Single–
phase
AC200V
(servo
amplifier)
CNC SVM
Servo
motor
Breaker
Breaker
(servo
amplifier)
SVM
Servo
motor
MCC
SPM
Servo
motor
AC
reactor
PSM
FSSB
Serial spindle
FSSB
3–phase
Control
power
supply
Emergency stop
circuit
ESP
MCC
8.14
ALARM 401
(V READY OFF)
Causes and actions
D VRDY
D Example of connection
around the amplifier
(Typical example)