Servo Drive Control Mode

- Mar 11, 2019-

Servo drive Control Mode


There are three main control modes for servo drives.

1. Torque control: The torque control mode is to set the external output torque of the motor shaft through the external analog input or the assignment of the direct address. The specific performance is, for example, 10V corresponds to 5Nm, when the external analog quantity is set. When the motor is set to 5V, the motor shaft output is 2.5Nm: if the motor shaft load is lower than 2.5Nm, the motor will rotate forward. When the external load is equal to 2.5Nm, the motor will not rotate. When the motor is larger than 2.5Nm, the motor will reverse (usually generated under gravity load). ). The set torque can be changed by changing the analog setting in real time, or by changing the value of the corresponding address by communication. Applications are mainly used in winding and unwinding devices where the stress of materials is strictly required, such as wire-drawing devices or fiber-optic devices. The torque setting is changed according to the change of the radius of the winding to ensure the material. The force does not change as the winding radius changes.


2. Position control: The position control mode generally determines the rotation speed by the frequency of the externally input pulse. The number of pulses is used to determine the angle of rotation. Some servos can directly assign speed and displacement through communication. Since the position mode has strict control over speed and position, it is generally applied to positioning devices. Applications such as CNC machine tools, printing machinery, etc.


3. Speed mode: The rotation speed can be controlled by the analog input or the frequency of the pulse. The speed mode can also be positioned when the outer ring PID control of the upper control device is used, but the position signal or direct load of the motor must be used. The position signal is given to the upper feedback for calculation. The position mode also supports the direct load outer loop detection position signal. At this time, the encoder at the motor shaft end only detects the motor speed, and the position signal is provided by the direct final load end detecting device. This has the advantage of reducing the intermediate transmission process. The error increases the positioning accuracy of the entire system.


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