Yaskawa Sigma-5 User Manual: Design and Maintenance - Linear Motors User Manual
Page 285

8 Troubleshooting
8-34
Position Error
(without alarm)
Noise interference due to improper
specifications of the cable for con-
necting serial converter unit.
The specifications of the cable for 
connecting serial converter unit 
must be:
Twisted-pair or twisted-pair 
shielded wire with core 
0.12 mm
2
min. and tinned annealed
copper twisted wire.
Use the cable for connecting serial 
converter unit with the specified 
specifications.
Noise interference because the
length of the cable for connecting 
serial converter unit is too long.
Check the length of the cable for 
connecting serial converter unit.
The length of the cable for connect-
ing serial converter unit must be 20 
m max.
Noise influence due to damaged
cable for connecting serial con-
verter unit
Check the cable for connecting
serial converter unit to see if it is 
bent or its sheath is damaged.
If the cable is damaged, replace the 
cable for connecting serial con-
verter unit, and correct the cable 
layout.
Excessive noise interference to the
cable for connecting serial con-
verter unit
Check if the cable for connecting 
serial converter unit is bundled with 
a high-current line or near high-cur-
rent line.
Change the layout of the cable for
connecting serial converter unit 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 encoder side FG.
SERVOPACK pulse count 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:
Twisted-pair or twisted-pair 
shielded 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 linear scale fault occurred.
(The pulse count does not change.)
−
Replace the linear servomotor.
A SERVOPACK fault occurred.
−
Replace the SERVOPACK.
Servomotor
Overheated
Ambient operating temperature is 
too high.
Measure the linear servomotor 
ambient operating temperature.
Reduce the ambient operating tem-
perature to 40
°C max.
Linear servomotor surface is dirty.
Check visually.
Clean dust and oil from linear ser-
vomotor surface.
Linear servomotor overloaded
Check the load status with monitor.
If overloaded, reduce load or 
replace with larger capacity SER-
VOPACK and linear servomotor.
Polarity detection is not performed 
correctly.
Check if the value of Un004 (Elec-
tric Angle 2) at an arbitrary position 
is between 
±10 degrees.
Correct the settings for the polarity 
detection related parameter.
Problem
Probable Cause
Investigative Actions
Corrective Actions
