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9) Set Pr. 285 "overspeed detection frequency" to prevent misoperation caused if an accurate signal cannot be
detected from the PLG. This shuts off the output and gives an inverter alarm (E.MB1) when;
(detection frequency) - (output frequency) > Pr.
285.
4.9. Vector control
Vector control can be performed using the standard motor with PLG.
Make sure that Pr. 80 "motor capacity", Pr. 81 "number of motor poles", Pr. 144 "number of motor poles", Pr. 369
"number of PLG pulses", Pr. 359 "PLG rotation direction" and Pr. 370 "control mode" values are set properly. (Refer
to Section 4.6 "Pre-Operation Settings and 4.7 "Control Mode Setting".) Servo lock will resist and attempts to move it
from the stop position, the limitation is the amount of torque that can be provided. Servo lock is only available in
vector control mode (when using a PLG).
(1) Zero speed control and servo lock
<Zero speed control>
When the Pr. 370 value is "1" and Pr. 80 and Pr. 81 values are not "9999", zero speed control is made valid so
that torque may be generated at zero speed.
Use Pr. 22 to set the torque limit level in the zero speed control mode. (150% torque (short duration) is possible.)
<Servo lock>
When the Pr. 370 value is "2" and Pr. 80 and Pr. 81 values are not "9999", servo lock is made valid.
Use Pr. 22 to set the torque limit level in the servo lock mode. (150% torque (short duration) is possible.)
Also, use Pr. 375 "servo lock gain" to set the servo lock gain.
A high setting will make response faster but increase the probability of instability.
When GD
2
(inertia) is large, a high servo lock gain setting will increase the probability of instability.