Yaskawa Sigma-5 User Manual: Design and Maintenance - Rotary Motors - MECHATROLINK-II Communications Reference - Manual (Page 328)

9.4 Troubleshooting Malfunction Based on Operation and Conditions of the Servomotor
9-31
9
Trou
blesh
ooting
Servomotor Vi-
brates at Fre-
quency of Approx.
200 to 400 Hz.
Unbalanced servo gains
Check to see if the servo gains have
been correctly adjusted.
Execute the advanced autotuning.
Speed loop gain value (Pn100) too
high. Check the speed loop gain (Pn100).
Factory setting: Kv = 40.0 Hz Reduce the speed loop gain
(Pn100).
Position loop gain value (Pn102)
too high.
Check the position loop gain
(Pn102).
Factory setting: Kp = 40.0/s
Reduce the position loop gain
(Pn102).
Incorrect speed loop integral time
constant (Pn101)
Check the speed loop integral time
constant (Pn101).
Factory setting: Ti = 20.0 ms
Correct the speed loop integral time
constant (Pn101).
Incorrect moment of inertia ratio
(Pn103) Check the moment of inertia ratio
(Pn103). Correct the moment of inertia ratio
(Pn103).
High Motor Speed
Overshoot on
Starting and Stop-
ping
Unbalanced servo gains
Check to see if the servo gains have
been correctly adjusted.
Execute the advanced autotuning.
Speed loop gain value (Pn100) too
high
Check the speed loop gain (Pn100).
Factory setting: Kv = 40.0 Hz Reduce the speed loop gain
(Pn100).
Position loop gain value (Pn102)
too high
Check the position loop gain
(Pn102).
Factory setting: Kp = 40.0/s
Reduce the position loop gain
(Pn102).
Incorrect speed loop integral time
constant (Pn101)
Check the speed loop integral time
constant (Pn101).
Factory setting: Ti = 20.0 ms
Correct the speed loop integral time
constant (Pn101).
Incorrect moment of inertia ratio
data (Pn103) Check the moment of inertia ratio
(Pn103). Correct the moment of inertia ratio
(Pn103).
Absolute Encod-
er Position Differ-
ence Error (The
position saved in
the host controller
when the power
was turned OFF is
different from the
position when the
power was next
turned ON.)
Noise interference due to incorrect
cable specifications of encoder
cable.
The encoder cable must be tinned
annealed copper shielded twisted-
pair or screened unshielded twisted-
pair cable with a core of 0.12 mm
2
min.
Use the specified encoder cable.
Noise interference due to length of
encoder cable. Check the length of the encoder
cable.
The encoder cable must be no more
than 50 m.
Noise interference due to damaged
encoder cable. Check if the encoder cable is bent
and the sheath is damaged. Replace the encoder cable and cor-
rect the cable layout.
Excessive noise to the encoder
cable.
Check if the encoder cable is bun-
dled with a high-current line or near
a high-current line.
Correct the cable layout so that no
surge is applied.
FG potential varies because of
influence of machines such as weld-
ers at the servomotor.
Check if the machines are correctly
grounded.
Ground machines correctly, and
prevent diversion to the FG on the
encoder side.
SERVOPACK pulse counting error
due to noise interference
Check if there is noise interference
on the I/O signal line from the
encoder.
Take measures against noise in the
encoder wiring.
Excessive vibration and shock to
the encoder
Check if vibration from the machine
occurred or servomotor installation
is incorrect (mounting surface accu-
racy, fixing, alignment, etc.).
Reduce vibration from the machine,
or secure the servomotor installa-
tion.
An encoder fault occurred. − Replace the servomotor.
A SERVOPACK fault occurred.
(The pulse count does not change.)
− Replace the SERVOPACK.
Host controller multiturn data read-
ing error
Check the error detection section of
the host controller.
Correct the error detection section
of the host controller.
Check if the host controller is exe-
cuting data parity checks.
Execute a multiturn data parity
check.
Check noise in the cable between
the SERVOPACK and the host con-
troller.
Take measures against noise, and
again execute a multiturn data par-
ity check.
(cont’d)
Problem Probable Cause Investigative Actions Corrective Actions