YASKAWA S-V Series User Manual page 199

Problem Probable Cause
Overtravel (OT)
Incorrect linear servomotor stop
method selection
(cont'd)
Improper limit switch position and
Improper Position
dog length
to Stop by
The overtravel limit switch position
Overtravel (OT)
is too short for the coasting
Signal
distance.
Noise interference due to improper
specifications of the linear scale
connection cables.
Noise interference because the
length of the linear scale connection
cables is too long.
Noise influence due to damaged lin-
ear scale connection cables
Excessive noise interference to the
linear scale connection cables
FG electrical potential varies by
influence of such machines on the
Position Error
linear servomotor side as welders.
(without alarm)
SERVOPACK pulse counting error
due to noise
Excessive vibration and shock to
the serial converter unit
Noise interference due to improper
I/O signal cable specifications
Noise interference due to length of
I/O signal cable
A serial converter unit fault
occurred.
A linear scale fault occurred.
A SERVOPACK fault occurred.
9.3 Troubleshooting Malfunction Based on Operation and Conditions
Investigative Actions
Check Pn001.0 and Pn001.1 when
the linear servomotor power is OFF.
Check Pn001.0 and Pn001.1 when
in force control.
−
−
The specifications of the linear
scale connection 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 length of the linear scale
connection cables.
Check the linear scale connection
cables to see if any of them is bent
or its sheath is damaged.
Check if the any of the linear scale
connection cables is bundled with a
high-current line or near high-cur-
rent line.
Check if the machine is correctly
grounded.
Check if the I/O signal cable from
the serial converter unit is influ-
enced by noise.
Check if machine vibration
occurred or serial converter unit
mounting such as mounting surface
precision, fixing is incorrect.
The specifications of the I/O signal
cable 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.
−
−
−
(cont'd)
Corrective Actions
Select a linear servomotor stop
method other than "coast to stop."
Select a linear servomotor stop
method other than "coast to stop."
Install the limit switch at the
appropriate position.
Install the overtravel limit switch at
the appropriate position.
Use the linear scale connection
cables with the specified specifica-
tions.
The maximum length of the linear
scale connection cables:
20 m for the cable for connecting a
serial converter unit 15 m for the
cable for connecting a linear a linear
scale/hall sensor.
If the cable is damaged, replace it
and correct the cable layout.
Change the layout of the linear scale
connection cables so that no surge
voltage is applied.
Ground the machine separately
from linear scale side FG.
Take a measure against noise for the
serial converter unit wiring.
Reduce the machine vibration or
mount the serial converter unit
securely.
Use I/O signal cable with the speci-
fied specifications.
The I/O signal cable length must be
less than 3 m.
Replace the serial converter unit
Replace the linear servomotor.
Replace the SERVOPACK.
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