YASKAWA SGDH User Manual page 559

Table 10.8 Troubleshooting for Malfunction without Alarm Display (Cont'd)
Symptom Cause
Servomotor Speed loop gain value (Pn100) too
high.
Vibrates at
about 200 to
Position loop gain value (Pn102) too
400 Hz
high
Incorrect speed loop integral time
constant (Pn101) setting
When the autotuning is used: Incor-
rect machine rigidity setting
When the autotuning is not used:
Incorrect rotational moment of iner-
tia ratio data
High
Speed loop gain value (Pn100) too
Rotation high
Speed
Overshoot on
Position loop gain value (Pn102) too
Starting and
high
Stopping.
Incorrect speed loop integral time
constant (Pn101) setting
When the autotuning is used: Incor-
rect machine rigidity setting
When the autotuning is not used:
Incorrect rotational moment of iner-
tia ratio data
Absolute
Noise interference due to improper
Encoder encoder cable specifications
Position
Difference
Error
(The position
Noise interference because the
saved in host
encoder cable distance is too long.
controller
Noise interference due to damaged
when the
encoder cable
power turned
OFF is differ-
Excessive noise to the encoder cable
ent from the
position when
FG electrical potential varies by
the power
influence of such machines on the
turned ON.)
servomotor side as welder.
SERVOPACK pulse counting error
due to noise interference
Excessive vibration and shock to the
encoder
Encoder fault
SERVOPACK fault
Host controller multiturn data read-
ing error
Inspection
: Turn OFF the servo system before executing operations.
Factory setting: Kv=40.0 Hz
Refer to 9.3.2 Servo Gain Manual Tuning.
Factory setting: Kp=40.0/s
Refer to 9.3.2 Servo Gain Manual Tuning.
Factory setting: Ti=20.00 ms
Refer to 9.3.2 Servo Gain Manual Tuning.
Check the machine rigidity setting (Fn001).
Check the rotational moment of inertia ratio
data (Pn103).
Factory setting: Kv=40.0 Hz
Refer to the gain adjustment in User's Man-
ual.
Factory setting: Kp=40.0/s
Refer to the gain adjustment in User's Man-
ual.
Factory setting: Ti=20.00 ms
Refer to the gain adjustment in User's Man-
ual.
Check the machine rigidity setting (Fn001).
Check the rotational moment of inertia ratio
data (Pn103).
The specifications of encoder cable must
be:
Twisted-pair or twisted-pair shielded wire
2 2
with core 0.12 mm (0.0002 in ) min. and
tinned annealed copper twisted wire.
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 machine is correctly grounded.
Check if the signal line from the encoder
receives influence from noise interference.
Vibration from machine occurred or servo-
motor mounting such as mounting surface
precision, fixing, and alignment is incor-
rect.
An encoder fault occurred. (no change in
pulse count)
Check the multiturn data from SERVO-
PACK.
Check the error detection at the host con-
troller.
Check if the host controller executes data
parity check.
Check noise on the signal line between
SERVOPACK and the host controller.
10-19
10.1 Troubleshooting
Corrective Actions
Reduce speed loop gain (Pn100) preset value.
Reduce position loop gain (Pn102) preset value.
Correct the speed loop integral time constant (Pn101)
setting.
Select a proper machine rigidity setting (Fn001).
Correct the rotational moment of inertia ratio data
(Pn103).
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 rotational moment of inertia ratio data
(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.
Correct the error detection section of host controller.
Execute the multiturn data parity check.
Noise influence at no parity check (as the above.)
10