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ENCODER FEEDBACK CONTROL—A500(L)
4.8 Vector control (Zero speed control and servo lock)
Vector control can be performed when a standard motor with encoder is used.
Make sure that Pr. 80 "motor capacity", Pr. 81 "number of motor poles", Pr. 144 "number of motor poles",
Pr. 359 "encoder rotation direction", Pr. 369 "number of encoder pulses" and Pr. 370 "control mode" values
are set properly. (Refer to page 39, 40.)
Set "100%" in Pr. 89 "speed control gain" to perform vector control. For details of Pr. 89, refer to the
inverter manual.
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 an encoder).
4.8.1
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.)
4.8.2
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. (Pr. 375 factory setting: 20)
A high setting will make response faster but increase the probability of instability.
When inertia moment is large, a high servo lock gain setting will increase the probability of instability.