YASKAWA SGMJV User Manual page 359

Problem Probable Cause
Noise interference due to improper
encoder cable specifications
Noise interference due to length of
encoder cable.
Noise interference due to damaged
encoder cable
Excessive noise interference at the
encoder cable
Absolute Encoder
FG potential varies because of
Position
influence of machines such as weld-
Difference Error
ers at the servomotor.
(The position
saved in the host
SERVOPACK pulse counting error
controller when
due to noise interference
the power was
turned OFF is
different from the
Excessive vibration and shock to
position when the
the encoder
power was next
turned ON.)
An encoder fault occurred.
A SERVOPACK fault occurred.
(The pulse count does not change.)
Host controller multi-turn data read-
ing error
Forward or reverse run prohibited
signal is input.
Forward or reverse run prohibited
signal malfunctioning.
Overtravel (OT)
Incorrect forward or reverse run
prohibited signal (P-OT/N-OT)
allocation (parameters Pn50A.3,
Pn50B.0)
Incorrect servomotor stop method
selection
10.3 Troubleshooting Malfunction Based on Operation and Conditions of the Servomotor
Investigative Actions
The encoder cable must be tinned
annealed copper twisted-pair or
shielded twisted-pair cables with a
2
core of 0.12 mm min.
Check the encoder cable length.
Check if the encoder cable is bent or
if its sheath is damaged.
Check if the encoder cable is bun-
dled with a high-current line or near
high-current line.
Check if the machines are correctly
grounded.
Check if there is noise interference
on the input/output signal line from
the encoder.
Check if vibration from the machine
occurred or servomotor installation
is incorrect (mounting surface accu-
racy, fixing, alignment, etc.).
−
−
Check the error detection at the host
controller.
Check if the host controller is exe-
cuting data parity checks.
Check noise in the input/output sig-
nal line between the SERVOPACK
and the host controller.
Check the external power supply
(+24 V) voltage for the input signal.
Check if the overtravel limit switch
operates properly.
Check if the overtravel limit switch
is wired correctly.
Check the fluctuation of the input
signal external power supply (+24
V) voltage.
Check if the overtravel limit switch
operates correctly.
Check if the overtravel limit switch
wiring is correct. (check for dam-
aged cables or loose screws.)
Check if the P-OT signal is allo-
cated in Pn50A.3.
Check if the N-OT signal is allo-
cated in Pn50B.0.
Check Pn001.0 and Pn001.1 when
the servomotor power is OFF.
Check Pn001.0 and Pn001.1 when
in torque control.
Corrective Actions
Use encoder cable with the speci-
fied specifications.
The encoder cable length must be
no more than 20 m.
Replace the encoder cable and cor-
rect the encoder cable layout.
Change the encoder cable layout so
that no surge is applied.
Ground machines correctly, and
prevent diversion to the FG at the
PG side.
Take measures against noise in the
encoder wiring.
Reduce vibration from the machine,
or secure the servomotor installa-
tion.
Replace the servomotor.
Replace the SERVOPACK.
Correct the error detection section
of the host controller.
Execute a multi-turn data parity
check.
Take measures against noise, and
again execute a multiturn data par-
ity check.
Correct the external power supply
(+24 V) voltage.
Correct the overtravel limit switch.
Correct the overtravel limit switch
wiring.
Stabilize the external power supply
(+24 V) voltage.
Stabilize the operation of the over-
travel limit switch.
Correct the overtravel limit switch
wiring.
If another signal is allocated in
Pn50A.3, select P-OT.
If another signal is allocated in
Pn50B.0, select N-OT.
Select a servo mode stop method
other than "coast to stop."
Select a servo mode stop method
other than "coast to stop."
10
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