servodriver

A servodriver, also called a servo drive, is a power amplifier and control device used to drive servo motors. It translates high-level commands from a motion controller or PLC into motor currents, providing the necessary power, torque, and speed while enforcing closed-loop control through feedback from an encoder, resolver, or similar sensor.

In operation, a servodriver receives commands for position, velocity, or torque and regulates the motor currents to achieve the desired motion. It uses feedback from the motor’s encoder or other feedback devices to continuously correct errors, typically implementing a PID or model-based control algorithm. The driver modulates current with techniques such as PWM to produce smooth torque while protecting the motor and power electronics from faults like overcurrent or overheating.

Servodrivers can be stand-alone units or built into servo amplifiers mounted on the motor. They interface with control systems via analog, digital, or fieldbus networks, supporting a range of communication protocols such as EtherCAT, ProfiNet, Modbus, CANOpen, or simple 0-10 V/PNP/NPN command signals. Key specifications include rated and peak torque, supply voltage, maximum current, encoder type and resolution, control bandwidth, and available protection features (short-circuit, overtemp, safe torque off).

Applications span robotics, CNC machines, packaging, printing, and automation systems requiring precise, repeatable motion with closed-loop accuracy. Servodrivers differ from open-loop stepper drivers by using encoder feedback to maintain accuracy at higher speeds and loads. Proper setup involves matching motor, encoder, and feedback type, and tuning gains and motion profiles to achieve desired performance and safety.