YASKAWA Sigma-V Series User Manual page 281

8 Troubleshooting
Problem
Position Error
(Without Alarm)
Servomotor
Overheated
8-32
Probable Cause
Noise interference due to incorrect
encoder cable specifications
Noise interference due to length of
encoder cable.
Noise influence due to damaged
encoder cable.
Excessive noise to encoder cable.
The FG potential varies because of
influence from machines on the ser-
vomotor side such as the welder.
A multi-winding drive unit pulse
counting error occurred due to noise
interference.
Excessive vibration and shock to
the encoder
Unsecured coupling between
machine and servomotor
Noise interference due to improper
I/O signal cable specifications
Noise interference due to length of
I/O signal cable
An encoder fault occurred. (The
pulse count does not change.)
A fault occurred in the multi-wind-
ing drive unit.
Ambient operating temperature too
high
Servomotor surface dirty
Servomotor overloaded
A fault occurred in the fan.
Incorrect wiring of the fan.
The brake is not released.
Investigative Actions
Turn OFF the servo system. The
encoder cable must be tinned
annealed copper shielded twisted-
pair or screened unshielded twisted-
pair cable with a core of 0.12 mm
min.
Turn OFF the servo system. Check
the length of the encoder cable.
Turn OFF the servo system. Check
if the encoder cable is bent and the
sheath is damaged.
Turn OFF the servo system. Check
if the encoder cable is bundled with
a high-current line or near a high-
current line.
Turn OFF the servo system. Check
if the machines are correctly
grounded.
Turn OFF the servo system. Check
if the I/O signal line from the
encoder is influenced by noise.
Turn OFF the servo system. Check
if vibration from the machine
occurred or servomotor installation
is incorrect (mounting surface accu-
racy, fixing, alignment, etc.).
Turn OFF the servo system. Check
if a position error occurs at the cou-
pling between machine and servo-
motor.
Turn OFF the servo system. The I/O
signal cable must be tinned
annealed copper shielded twisted-
pair or screened unshielded twisted-
pair cable with a core of 0.12 mm
min.
Turn OFF the servo system. Check
the I/O signal cable length.
−
−
Measure the servomotor ambient
operating temperature.
Turn OFF the servo system. Visu-
ally check the surface.
Check the load status with monitor.
Check if the fan is rotating or not.
Check if the fan is rotating back-
ward.
Check the wiring.
Check the operation of the brake.
Corrective Actions
Use the specified encoder cable.
2
The encoder cable must be no more
than 50 m.
Replace the encoder cable and mod-
ify the cable layout.
• Change the cable layout so that
no surge is applied.
• Use a double-shielded encoder
cable.
Properly ground the machines
encoder FG.
Take measures against noise in the
encoder wiring.
Reduce the machine vibration or
mount the servomotor securely.
Secure the coupling between the
machine and servomotor.
Use input signal cable with the
specified specifications.
2
The I/O signal cable length must be
no more than 3 m.
Turn OFF the servo system.
Replace the servomotor.
Turn OFF the servo system.
Replace the multi-winding drive
unit.
Reduce the ambient operating tem-
perature to 40°C or less.
Clean dust and oil from the surface.
If an overload occurs, reduce the
load or replace the SERVOPACK,
converter, and servomotor with
models with higher capacities.
Replace the servomotor.
Correct the wiring.
Release the brake.
(cont'd)