What is the most common method for controlling a motor with a PLC?

The most common method for controlling a motor with a PLC is through the use of a motor starter. Motor starters serve the essential function of providing a safe and effective means of starting and stopping motors, as well as protecting them from overload and faults. They typically combine contactors to handle the high inrush current when a motor starts, with overload relays to prevent motor damage from running under overload conditions.

In many industrial applications, especially those involving larger motors, a motor starter allows the PLC to control motor operation based on automated logic while ensuring the motor operates within safe limits. This setup is straightforward and reliable, making it widely adopted in various applications where PLCs are utilized.

Other methods like Variable Frequency Drives (VFDs) are indeed used for more advanced control, particularly for speed modulation, but motor starters remain the prevalent choice for basic on/off control in many scenarios involving PLCs. Integrated circuits and relay switches may be parts of specific control circuits but are not first-line methods for PLC motor control in standard industrial practices.