Yaskawa Sigma-5 User Manual: Design and Maintenance - Rotary Motors - MECHATROLINK-II Communications Reference User Manual
Page 315

9 Troubleshooting
9.1.2 Troubleshooting of Alarms
9-18
A.Cb0:
Encoder Echoback Er-
ror
The wiring and contact for
encoder cable are incorrect.
Check the wiring.
Correct the wiring.
Noise interference occurred due 
to incorrect cable specifications 
of encoder cable.
−
Use tinned annealed copper
shielded twisted-pair or screened 
unshielded twisted-pair cable with a 
core of at least 0.12 mm
2
.
Noise interference occurred 
because the wiring distance for 
the encoder cable is too long.
−
The wiring distance must be 50 m 
max.
The FG potential varies because 
of influence from machines on 
the servomotor side, such as the 
welder.
Check the cable layout for encoder 
cable.
Properly ground the machines to 
separate from encoder FG.
Excessive vibration and shocks 
were applied to the encoder.
Check the operating environment.
Reduce the machine vibration or 
correctly install the servomotor.
An encoder fault occurred.
−
Turn the power supply OFF and 
then ON again. If the alarm still 
occurs, the servomotor may be 
faulty. Replace the servomotor.
A SERVOPACK fault occurred.
−
Turn the power supply OFF and 
then ON again. If the alarm still 
occurs, the SERVOPACK may be 
faulty. Replace the SERVOPACK.
A.CC0:
Multiturn Limit Dis-
agreement
When using a direct drive (DD) 
servomotor, the multiturn limit 
value (Pn205) is different from 
that of the encoder.
Check the value of the Pn205.
Correct the setting of Pn205 (0 to 
65535).
The multiturn limit value of the 
encoder is different from that of 
the SERVOPACK. Or, the multi-
turn limit value of the SERVO-
PACK has been changed.
Check the value of the Pn205 of the 
SERVOPACK.
Execute Fn013 at the occurrence of 
alarm.
A SERVOPACK fault occurred.
−
Turn the power supply OFF and 
then ON again. If the alarm still 
occurs, the SERVOPACK may be 
faulty. Replace the SERVOPACK.
A.CF1:
Feedback Option 
Module Communica-
tions Error
(Reception error)
Wiring of cable between serial 
converter unit and SERVOPACK 
is incorrect or contact is faulty.
Check the external encoder wiring.
Correct the cable wiring.
The specified cable is not used 
between serial converter unit and 
SERVOPACK.
Confirm the external encoder wir-
ing specifications.
Use the specified cable.
Cable between serial converter 
unit and SERVOPACK is too 
long.
Measure the length of this cable.
Use 20-m cable max.
Sheath of cable between serial 
converter unit and SERVOPACK 
is broken.
Check the cable for damage.
Replace the cable.
A.CF2:
Feedback Option 
Module Communica-
tions Error
(Timer stop)
Noise interferes with the cable 
between serial converter unit and 
SERVOPACK.
−
Correct the wiring around serial 
converter unit, e.g., separating I/O 
signal line from main circuit cable 
or grounding.
A serial converter unit fault 
occurred.
−
Replace the serial converter unit.
A SERVOPACK fault occurred.
−
Replace the SERVOPACK.
(cont’d)
Alarm Number:
Alarm Name
(Alarm Description)
Cause
Investigative Actions
Corrective Actions
