Yaskawa SGDH Linear Sigma Series - Manual (Page 372)

11 Inspection, Maintenance, and Troubleshooting
11.1.6 Troubleshooting for Malfunction without Alarm Display
11-20
Overtravel
(OT)
(Movement
over the zone
specified by
the host con-
troller) An overtravel signal is output (P-OT
(CN1-42) or N-OT (CN1-43)) is at
H. Check if the voltage of input signal external
power supply (+24 V) is correct. Connect to the external +24 V power supply.
Check if the overtravel limit switch (SW)
operates properly. Correct the overtravel limit SW.
Check if the overtravel limit switch (SW) is
connected correctly. Correct the overtravel limit SW wiring.
The overtravel signal does not oper-
ate normally (P-OT or N-OT signal
sometimes changes). Check the fluctuation of the input signal
external power supply (+24 V) voltage. Stabilize the external +24 V power supply voltage.
Check if the overtravel limit switch (SW)
activate correctly. Adjust the overtravel limit SW so that it operates cor-
rectly.
Check if the overtravel limit switch wiring
is correct. (check for damaged cables or
loosen screws.) Correct the overtravel limit SW wiring.
Incorrect P-OT/N-OT signal selec-
tion Check the P-OT signal selection (Pn50A.3). Correct the setting of P-OT signal selection (Pn50A.3).
Check the N-OT signal selection
(Pn50B.0). Correct the setting of N-OT signal selection (Pn50B.0).
Incorrect servomotor stop method
selection Check if “coast to stop” in servo OFF status
is selected. Check Pn001.0 and Pn001.1.
Check if “coast to stop” in force control
mode is selected. Check Pn001.0 and Pn001.1.
Improper overtravel position setting The distance to the position of OT (over-
travel) is too short considering the coasting
distance. Correct the OT position.
Noise interference due to improper
serial converter unit cable specifica-
tions The serial converter unit cable specifica-
tions must be:
Twisted-pair or twisted-pair shielded wire
with core 0.12 mm
2 (0.0002 in 2 ) min. and
tinned annealed copper twisted wire.
Use serial converter unit cable with the specified specifi-
cations.
Noise interference because the serial
converter unit cable distance is too
long. The wiring distance must be 20 m (65.6 ft)
max. The serial converter unit cable distance must be within
the specified range.
Noise influence due to damaged
serial converter unit cable Check if the serial converter unit cable is
bent or its sheath is damaged. Correct the serial converter unit cable layout.
Excessive noise interference to serial
converter unit cable Check if the serial converter unit cable is
bundled with a high-current line or near
high-current line. Change the serial converter unit cable layout so that no
surge is applied.
FG electrical potential varies by
influence of such machines on the
servomotor side as welders. Check if the machine is correctly grounded. Ground the machine separately from PG side FG.
SERVOPACK pulse count error due
to noise Check if the signal line from the serial con-
verter unit is influenced by noise. Take a measure against noise for the serial converter unit
wiring.
Excessive vibration and shock to the
serial converter unit Machine vibration occurred or servomotor
mounting such as mounting surface preci-
sion, fixing, alignment is incorrect. Reduce the machine vibration or mount the servomotor
securely.
Serial converter unit fault − Replace the serial converter unit.
SERVOPACK fault − Replace the SERVOPACK.
Position error
(without
alarm) Noise interference due to improper
input signal cable specifications The input signal cable specifications must
be:
Twisted-pair or twisted-pair shielded wire
with core 0.12 mm
2 (0.0002 in 2 ) min. and
tinned annealed copper twisted wire.
Use input signal cable with the specified specifications.
Noise interference because the input
signal cable distance is too long. The wiring distance must be 3 m (9.84 ft)
max. and the impedance several hundreds
ohm max. The input signal cable distance must be within the speci-
fied range.
Reference pulse frequency is too
high. Check Un00C (Reference Pulse Counter.) Reduce the reference pulse frequency to a value within
the specification.
Serial converter unit fault (pulse
count does not change) − Replace the serial converter unit.
Table 11.7 Troubleshooting for Malfunction without Alarm Display (Cont’d)
Symptom Cause
Inspection Corrective Actions
: Turn OFF the servo system before executing operations.