Servo motor control mode and master signal setting method
First, the three modes of the servo system
1. Position control mode: It is generally used for some angle positioning, or length fixed length control occasions, such as the length of wood sawing the electronic saw. In postion mode,servo-received pulses and servo motors angle of rotation is in a one-to-one correspondence, so as long as the host computer sends a certain number of pulses, the servo motor can be rotated by a certain number of turns or angles, and the position amount is transmitted through the transmission institution can be changed to the corresponding length. This position mode is actually realized by using the position loop function inside the servo, because the servo motor with encoder is also a closed loop function, generally only the amount of gain of P.
2. Speed control mode: The speed loop is the inner loop of the position loop, and the deviation of the position loop can be used as the given value of the speed loop. It also uses the encoder of the motor to achieve a closed loop in speed. Speed ring control target is the speed of the servo motor. From this point of view, if only the speed mode is used, the control of the servo motor and the vector inverter is not much different, and can use the master sent analog to achieve the speed regulation, and of course it can also be controlled by the frequency of the pulse.
3. Torque control mode: The torque control mode is actually controlling the current of the motor. The torque loop is the inner loop of the speed loop. Generally, this mode is adopted in some occasions where precise control of the torque is required.
For example, some winding and tension control links can saturate the speed loop and achieve torque control through the current limit mode.
Second, the signal given mode of the master
1.the analog given
This is more common. In the position mode, the position loop is placed inside the IPC board or placed inside the CNC. After the position loop deviation is amplified by the gain, the 0-10VDC analog quantity is output to the servo driver given port , in which case the servo system actually works in speed mode, but the overall system works in position mode.
In the speed mode and torque mode, master can work in the corresponding mode as long as it gives 0-10VDC to the given port of the servo drive.
2. pulse given
The upper computer emits a square wave pulse with the same duty cycle. If the servo itself works in the position mode, it can complete a certain angle of rotation according to the number of pulses. If the servo itself works at speed mode, it will rotate according to the continuous pulse sent by the host computer at a certain speed.
3, communication given
Some bus or Ethernet methods, generally in the case of multi-axis linkage, multiple servos need synchronous control, through the method of SERCOS bus, multiple servo motors can be realized synchronous control, the main advantage of communication is that the wiring is relatively small, some are done in the software, so the flexibility is in place, the modification is very convenient, and the wiring is less,so high reliable.