YASKAWA S-V Series User Manual page 196

9 Troubleshooting
Problem
Linear
Servomotor
Moves
Without
Reference
Input
DB (dynamic
brake) Does Not
Operate
Abnormal Noise
from Linear
Servomotor
9-26
Probable Cause
A SERVOPACK fault occurred.
Linear scale counting up direction
and motor moving coil forward
direction do not agree.
Polarity detection is not performed
correctly.
Improper setting of parameter
Pn001.0
DB resistor disconnected
DB drive circuit fault
The linear servomotor largely
vibrated during execution of tuning-
less function (factory setting).
Mounting not secured
Vibration source on the driven
machine
Noise interference due to incorrect
I/O signal cable specifications
Noise interference due to long dis-
tance of I/O signal cable
Noise interference due to incorrect
specifications of linear scale con-
nection cables.
Noise interference because the lin-
ear scale connection cables is too
long
Investigative Actions
–
Check the directions.
Check if the value of Un004 (Elec-
tric Angle 2, angle from polarity
origin) at an arbitrary position is
between ±10 degrees.
Check the setting of parameter
Pn001.0.
Check if excessive mass, motor
overspeed, or DB frequent activa-
tion has occurred.
–
Check the motor speed waveform.
Check if there are any loosen
mounting screws.
Check the machine movable section
for foreign matter, damage or defor-
mity.
The specifications of I/O signal
cables must be:
Shielded twisted-pair or shielded
multi-core twisted-pair wire with
2
core 0.12 mm min. and tinned
annealed copper twisted wire.
Check the I/O signal cable length.
The specifications of cable for con-
necting serial converter unit must
be:
Shielded twisted-pair or shielded
multi-core twisted-pair wire with
2
core 0.12 mm min. and tinned
annealed copper twisted wire.
Check the length of the linear scale
connection cables.
(cont'd)
Corrective Actions
Replace the SERVOPACK.
Change the setting of Pn080.1
(Motor Phase Selection).
Match the linear scale direction and
moving coil direction.
Correct the settings for the polarity
detection related parameter.
Correct the setting of parameter
Pn001.0.
Replace the SERVOPACK, and
reconsider the load.
DB circuit parts are faulty.
Replace the SERVOPACK.
Reduce the load so that the mass
ratio becomes within the allowable
value, or increase the load level or
lower the rigidity level for the tun-
ing-less level setting (Fn200).
Tighten the mounting screws.
Contact the machine manufacturer.
Use the specified I/O signal cables.
Shorten the I/O signal cable length
to 3 m or less.
Use the specified linear scale con-
nection cables.
The maximum length of linear scale
connection cables:
20 m for the cable for connecting a
serial converter unit
15 m for the cable for connecting a
linear scale/hall sensor