12.2  Alarm Displays
12.2.2  Troubleshooting Alarms
12-12
12.2.2
Troubleshooting Alarms
The causes of and corrections for the alarms are given in the following table. Contact your 
Yaskawa representative if you cannot solve a problem with the correction given in the table.
Alarm Number: 
Alarm Name
Possible Cause Confirmation Correction Reference
A.020: 
Parameter 
Checksum Error 
(There is an error 
in the parameter 
data in the 
SERVOPACK.)
The power supply 
voltage suddenly 
dropped.
Measure the power 
supply voltage.
Set the power supply volt-
age within the specified 
range, and initialize the 
parameter settings.
page 5-11
The power supply 
was shut OFF while 
writing parameter set-
tings.
Check the timing of 
shutting OFF the power 
supply.
Initialize the parameter 
settings and then set the 
parameters again.
The number of times 
that parameters were 
written exceeded the 
limit.
Check to see if the 
parameters were fre-
quently changed from 
the host controller.
The SERVOPACK may be 
faulty. Replace the 
SERVOPACK.
Reconsider the method 
for writing the parame-
ters.
–
A malfunction was 
caused by noise from 
the AC power supply, 
ground, static elec-
tricity, or other source.
Turn the power supply 
to the SERVOPACK 
OFF and ON again. If 
the alarm still occurs, 
noise may be the 
cause.
Implement countermea-
sures against noise.
page 4-5
Gas, water drops, or 
cutting oil entered the 
SERVOPACK and 
caused failure of the 
internal components.
Check the installation 
conditions.
The SERVOPACK may be 
faulty. Replace the 
SERVOPACK.
–
A failure occurred in 
the SERVOPACK.
Turn the power supply 
to the SERVOPACK 
OFF and ON again. If 
the alarm still occurs, 
the SERVOPACK may 
have failed.
The SERVOPACK may be 
faulty. Replace the 
SERVOPACK.
–
A.021: 
Parameter For-
mat Error 
(There is an error 
in the parameter 
data format in the 
SERVOPACK.)
The software version 
of the SERVOPACK 
that caused the alarm 
is older than the soft-
ware version of the 
parameters specified 
to write.
Read the product infor-
mation to see if the soft-
ware versions are the 
same. If they are differ-
ent, it could be the 
cause of the alarm.
Write the parameters from 
another SERVOPACK with 
the same model and the 
same software version, 
and then turn the power 
OFF and ON again.
page 9-2
A failure occurred in 
the SERVOPACK.
–
The SERVOPACK may be 
faulty. Replace the 
SERVOPACK.
–
A.022: 
System Check-
sum Error 
(There is an error 
in the parameter 
data in the 
SERVOPACK.)
The power supply 
voltage suddenly 
dropped.
Measure the power 
supply voltage.
The SERVOPACK may be 
faulty. Replace the 
SERVOPACK.
–
The power supply 
was shut OFF while 
setting a utility func-
tion.
Check the timing of 
shutting OFF the power 
supply.
The SERVOPACK may be 
faulty. Replace the 
SERVOPACK.
–
A failure occurred in 
the SERVOPACK.
Turn the power supply 
to the SERVOPACK 
OFF and ON again. If 
the alarm still occurs, 
the SERVOPACK may 
have failed.
The SERVOPACK may be 
faulty. Replace the 
SERVOPACK.
–
Continued on next page.