YASKAWA SGDV SERVOPACK - Page 336

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9.1 Alarm Displays
9-13
9
Troubleshooting
A.7AB:
Built-in Fan in SER-
VOPACK Stopped
The fan inside the SERVOPACK
stopped.
Check for foreign matter or debris
inside the
SERVOPACK.
Remove foreign matter or debris
from
the SERVOPACK. If the
alarm still occurs, the SERVO-
PACK may be faulty. Replace the
SER
VOPACK.
A.820:
Encoder Checksum
Error
(Detected on the linear
sc
ale side.)
A linear scale fault occurred. 
The linear scale may be faulty.
Rep
lace the linear scale.
A SERVOPACK fault occurred. 
The SERVOPACK may be faulty.
Replace the SERVOPACK.
A.840:
Encoder Data Error
(Detected on the linear
sc
ale side.)
A linear scale malfunctioned. 
Turn the power supply OFF and
the
n ON again. If the alarm still
occurs, the linear scale may be
faulty. Replace the linear scale.
Misreading of the linear scale
occurred.

Reinstall the linear scale, so the tol-
erance is within the allowable
ran
ge.
The speed of the linear scale
exc
eeded the allowable range.

Set the motor speed within the
ran
ge specified by the linear scale
manufacturer and restart the control
power supply.
Malfunction of linear scale
because of
noise interference, etc.

Correct the wiring around the linear
scale by separating the
linear scale
connection cable from the servomo-
tor main circuit cable or by check-
ing the grounding and other wiring.
The hall sensor wiring is incor-
rect.
Check the hall sensor wiring. Correct the hall sensor wiring.
A hall sensor fault occurred.  Replace the hall sensor.
A.850:
Encoder Overspeed
(Detected when the con-
trol power supply was
turned ON.
)
(Detected on the linear
sc
ale side.)
The servomotor speed is higher
than the specified speed when the
control power supply was turned
ON.
Check the motor moving speed
(Un000) to conf
irm the servomotor
speed when the power is turned ON.
Set the motor speed within the
ran
ge specified by the linear scale
manufacturer and restart the control
power supply.
A linear scale fault occurred. 
Turn the power supply OFF and
the
n ON again. If the alarm still
occurs, the linear scale may be
faulty. Replace the linear scale.
A SERVOPACK fault occurred. 
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the SERVOPACK may be
faulty. Replace the SERVOPACK.
A.860:
Encoder Overheated
(Only when an absolute
linear scale is con-
nected.)
(Detected on the linear
scale side.)
The ambient operating tempera-
ture around the servomotor is too
high.
Measure the ambient operating tem-
perature around the servomotor.
The ambient operating temperature
must be
40C or less.
The motor load is greater than the
rated load.
Check the accumulated load ratio
(Un009) to see the
load.
The motor load must be within the
specified range.
A linear scale fault occurred. 
Turn the power supply OFF and
the
n ON again. If the alarm still
occurs, the linear scale may be
faulty. Replace the linear scale.
A SERVOPACK fault occurred. 
Turn the power supply OFF and
the
n ON again. If the alarm still
occurs, the SERVOPACK may be
faulty. Replace the SERVOPACK.
A.890:
Encoder Scale Error
A linear scale fault occurred. 
The linear scale may be faulty.
Rep
lace the linear scale.
A.891:
Encoder Module Error
A linear scale fault occurred. 
Turn the power supply OFF and
the
n ON again. If the alarm still
occurs, the linear scale may be
faulty. Replace the linear scale.
(cont’d)
Alarm Number:
Alarm Name
(Alarm Description)
Cause Investigative Actions Corrective Actions