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68
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Protective Functions
Protection
* Encoder A/
B-phase
error
* Encoder
communication
error
* Encoder
connection
error
* Encoder
communication
data error
Position
error
Hybrid
error
Over-speed
Alarm
Code No.
20
21
22
23
24
25
26
Cause
No A- and B-phase pulse is detected. The
11-wire encoder failed.
Due to no communication between the
encoder and driver, the detective function
for broken encoder wires is activated.
The connection between the 11-wire en-
coder and driver is broken. The encoder
rotates higher than the specified rate
when control power is on .
The encoder sends an erroneous data
mainly due to noises. The encoder is con-
nected correctly, though the data is not
correct.
The position error pulse is larger than
Pr63 (position error limit). The motor op-
eration does not respond to the com-
mands.
When the driver of the full-closed version
is under the full-closed and hybrid con-
trol with an external encoder, the load
position detected by the external encoder
and the motor position detected by the
motor encoder are beyond the limit speci-
fied by Pr73 (hybrid error limit).
The motor velocity exceeds the specified
limit.
Countermeasures
Correct the encoder wiring per the wiring
diagram. Correct the connection of the
pins.
Make sure that the power of the encoder
is 5VDC ? 5% (4.75 to 5.25V). Especially
when the wire length is long, it is impor-
tant to meet this requirement. You should
not bundle the encoder wires and motor
wires together. Connect the shield to FG.
See the encoder wiring diagram.
Check whether the motor operates per
the position command pulse or not. See
the torque monitor to check if the out-
put torque is saturated. Readjust the
gains. Maximize the value of Pr5E (torque
limit set-up). Correct the encoder wiring
per the wiring diagram. Increase the ac-
celeration and deceleration time. Reduce
the load and velocity.
Check the connection between the mo-
tor and load. Check the connection be-
tween the external encoder and driver.
Correct the values of the external scale
numerator and denominator regarding pa-
rameters Pr74, Pr75, Pr 76 and Pr77.
Increase the value of Pr73. Increase the
value of Pr71 (hybrid switching time).
Decrease the target speed (command
values). Decrease the value of Pr50
(velocity command input gain). Adjust the
scale ratio so that the frequency of the
command pulse is 500 kpps or less. If an
overshoot occurs, readjust the gains.
Correct the encoder wiring per the wiring
diagram.。
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