Mitsubishi Electric MELSERVO-JN Series Instruction Manual page 20

3. Troubleshooting at startup
CAUTION
The following faults may occur at startup. If any of such faults occurs, take the corresponding action.
(1) Troubleshooting
No. Step of occurrence
1 Power on
2 Switch on servo-on
(SON).
3 Input command
pulse.
(Test operation)
(In the position
control mode)
Never adjust or change the parameter values extremely as it will make operation
unstable.
POINT
You can refer to reasons for servo motor rotation failure, etc. using MR
Configurator.
Fault
The 3-digit, 7-segment
Not improved even if CN1, CN2
LED is not lit. and CN3 connectors are
The 3-digit, 7-segment disconnected.
LED blinks.
Improved when CN1 connector is
disconnected.
Improved when CN2 connector is
disconnected.
Improved when CN3 connector is
disconnected.
Alarm occurs. Remove cause.
Digital output ALM Check the ON/OFF status of the
occurs. The 3-digit, output signal on the external I/O
7-segment LED does not signal display (refer to section
display the alarm. 5.8).
Alarm occurs. Remove cause.
Servo motor shaft is Check the followings.
free. 1. Check the display to see if the
2. Check the external I/O signal
Servo motor does not Check the cumulative command
rotate. pulses on the status display or on
MR Configurator.
Check if the ready (RD) is ON.
Check the set value of parameter
No.PA13 (command input pulse
form).
Check if the electromagnetic
brake interlock (MBR) is ON.
Check the ON/OFF status of the
output signal on the external I/O
signal display (refer to section
5.8).
Investigation
servo amplifier is ready to
operate.
display (refer to section 5.8) to
see if the servo-on (SON) is ON.
- 11 -
Introduction
Possible cause
1. Power supply voltage fault
2. Servo amplifier is faulty.
Power supply of CN1 cabling is
shorted.
1. Power supply of encoder
cabling is shorted.
2. Encoder is faulty.
Power supply of CN3 cabling is
shorted.
Wiring mistake.
The polarity of the digital output
circuit diode is not correct.
1. Servo-on (SON) is not input.
(Wiring mistake)
2. The interface power supply
(24VDC) is not supplied.
1. Wiring mistake.
(a) For open collector pulse train
input, 24VDC power is not
supplied to OPC.
(b) LSP and LSN are not on.
(c) Wiring mistake.
The polarity of the digital output
circuit diode is not correct.
2. No pulses are input.
3. Electromagnetic brake operates.
Wiring mistake.
The polarity of the digital output
circuit diode is not correct.
Reference
Section
8.2
Section
3.8.2
Section
8.2
Section
5.8
Section
3.8.2
Section
3.11
Section
4.1.11
Section
5.3
Section
3.8.2