YASKAWA SGDS Sigma III Series User Manual page 314

Table 10.5 Troubleshooting for Malfunction without Alarm Display (Cont'd)
Symptom Cause
High Rota- Speed loop gain value too high
tion Speed
Overshoot on
Starting and
Position loop gain Pn102 value too
Stopping.
big
Incorrect speed loop integral time
constant Pn101 setting
When the autotuning is used:
Incorrect machine rigidity setting
When the autotuning is not used:
Incorrect rotational moment of
inertia ratio
ABS (abso- Noise interference due to improper
encoder cable specifications
lute) Position
Difference Er-
ror (The po-
sition saved
in Host con-
Noise interference because the
troller when
encoder cable distance is too long.
the power
Noise interference due to damaged
turned OFF is
encoder cable
different from
the position
Excessive noise to the encoder cable
when the
power turned
FG affected by noise from machines
ON.)
such as welder installed on
servomotor side
SERVOPACK pulse counting error
due to noise interference
Excessive vibration and shock to the
encoder
Encoder fault
SERVOPACK fault
Inspection
: Turn OFF the servo system before executing operations.
Factory setting: Kv=40.0 Hz,
Refer to the gain adjustment in User's
Manual.
Factory setting: Kp=40.0/s
Refer to the gain adjustment in User's
Manual.
Factory setting: Ti=20.00 ms
Refer to the gain adjustment in User's
Manual.
Check the machine rigidity setting Fn001.
Check the rotational moment of inertia ratio
Pn103.
The specifications of encoder cable must
be:
Tinned annealed copper twisted-pair or
twisted-pair shielded wires with core 0.12
2 2
mm (0.0002 in ) min.
The wiring distance must be 20 m (65.6 ft)
max.
Noise interference occurred to the signal
line because the encoder cable is bent or its
sheath damaged.
Check if the encoder cable is bundled with a
high-current line or near high-current line.
Check if the grounding for the machine is
properly made.
Check if the signal line from the encoder
receives influence from noise interference.
Vibration from machine occurred or
servomotor mounting such as mounting
surface precision, fixing, and alignment is
incorrect.
An encoder fault occurred. (no change in
pulse count)
Check the multi-turn data from
SERVOPACK.
10.1 Troubleshooting
Corrective Actions
Reduce the speed loop gain Pn100 preset value.
Reduce the position loop gain Pn102 preset value.
Correct the speed loop integral time constant Pn101
setting.
Select a proper machine rigidity setting Fn001.
Correct the moment of inertia ratio Pn103.
Use the mode switch setting function.
Use encoder cable with the specified specifications.
The encoder cable distance must be within the specified
range.
Correct the encoder cable layout.
Change the encoder cable layout so that no surge is
applied.
Ground the machine separately from PG side FG.
Take measures against noise for encoder wiring.
Reduce vibration from machine or mount securely the
servomotor.
Replace the servomotor.
Replace the SERVOPACK.
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