User`s manual

9 Troubleshooting
9-28
Overtravel (OT)
(cont’d)
Incorrect linear servomotor stop
method selection
Check Pn001.0 and Pn001.1 when
the linear servomotor power is OFF.
Select a linear servomotor stop
method other than “coast to stop.”
Check Pn001.0 and Pn001.1 when
in force control.
Select a linear servomotor stop
method other than “coast to stop.”
Improper Position
to Stop by
Overtravel (OT)
Signal
Improper limit switch position and
dog length
−
Install the limit switch at the
appropriate position.
The overtravel limit switch position
is too short for the coasting
distance.
−
Install the overtravel limit switch at
the appropriate position.
Position Error
(without alarm)
Noise interference due to improper
specifications of the linear scale
connection cables.
The specifications of the linear
scale connection cables must be:
Shielded twisted-pair or shielded
multi-core twisted-pair wire with
core 0.12 mm
2
min. and tinned
annealed copper twisted wire.
Use the linear scale connection
cables with the specified specifica-
tions.
Noise interference because the
length of the linear scale connection
cables is too long.
Check the length of the linear scale
connection cables.
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.
Noise influence due to damaged lin-
ear scale connection cables
Check the linear scale connection
cables to see if any of them is bent
or its sheath is damaged.
If the cable is damaged, replace it
and correct the cable layout.
Excessive noise interference to the
linear scale connection cables
Check if the any of the linear scale
connection cables is bundled with a
high-current line or near high-cur-
rent line.
Change the layout of the linear scale
connection cables so that no surge
voltage is applied.
FG electrical potential varies by
influence of such machines on the
linear servomotor side as welders.
Check if the machine is correctly
grounded.
Ground the machine separately
from linear scale side FG.
SERVOPACK pulse counting error
due to noise
Check if the I/O signal cable from
the serial converter unit is influ-
enced by noise.
Take a measure against noise for the
serial converter unit wiring.
Excessive vibration and shock to
the serial converter unit
Check if machine vibration
occurred or serial converter unit
mounting such as mounting surface
precision, fixing is incorrect.
Reduce the machine vibration or
mount the serial converter unit
securely.
Noise interference due to improper
I/O signal cable specifications
The specifications of the I/O signal
cable must be:
Shielded twisted-pair or shielded
multi-core twisted-pair wire with
core 0.12 mm
2
min. and tinned
annealed copper twisted wire.
Use I/O signal cable with the speci-
fied specifications.
Noise interference due to length of
I/O signal cable
Check the I/O signal cable length.
The I/O signal cable length must be
less than 3 m.
A serial converter unit fault
occurred.
− Replace the serial converter unit
A linear scale fault occurred. − Replace the linear servomotor.
A SERVOPACK fault occurred. − Replace the SERVOPACK.
(cont’d)
Problem Probable Cause Investigative Actions Corrective Actions