3 MOST IMPORTANT CONTROL MODES OF SERVO MOTOR :
Position control mode is used where the application demands greater accuracy. The position accuracy is achieved through the feedback signal, from the integrated encoder in the motor which in turns Position control is achieved through High Speed Pulses from the PLC or Motion/CNC Controller. High Speed Pulse is basically a PWM Signal produced to achieve a defined target position at some speed.
Velocity control mode is used where the application requires a constant speed even under varying loads. In this mode Speed determined from the encoder used to calculate the error by the controller to produce determined torque to achieve & maintain the target speed. Polishing, Conveying applications used velocity control modes.
Torque control mode is also known as current control mode. Current and torque have proportional relationship and the drive will regulate current flow to achieve the desired target torque. Moulding, winding applications require constant torque control.
Speed & Torque mode uses -10V to +10V Analog voltage to control. Most Modern Drives are equipped with Combination of control modes Position, Speed & Torque that is S-P, T-P, S-T. Advanced Drives have functions to switch modes on the fly. Fly means while the process, in between the process without any intervention.