Automatic revolving doors are much more popular for the entrance area of  buildings like the hotel, shopping mall, airport etc.. And we can easily see that the door wings always start or stop at the right position, do you know how it works ?Automatic revolving door wings realized the accurate positioning by a encoder, combination of sensors, control systems, driving system and mechanical components, the details are as following. The encoder feedback–>servo control–>dynamic braking–>sensor fusion–>main control unit (PLC) .

▪  Positioning Radars/Sensors
Optical or magnetic sensors detect the exact angle and position of each door wing as it rotates.
Encoders (rotary or linear) provide real-time feedback on the door’s movement.
▪  Control System (PLC or Microcontroller)
A programmable logic controller (PLC) or embedded microcontroller processes sensor data.
It adjusts the motor’s speed and direction to ensure smooth and accurate positioning.
▪  Motor & Driving System
A servo or stepper motor (often gear-driven) allows for precise rotational control.
Some doors use a belt or chain drive system with tension adjustment to prevent slippage.
▪  Safety & Calibration
Infrared or radar sensors ensure no obstructions are present before stopping.
The system regularly self-calibrates to account for mechanical wear or environmental changes.
▪  Speed Synchronization
Multiple wings (typically 2/3/4 wings) are synchronized via the control unit to maintain even spacing.
Emergency brakes or clutches engage if misalignment is detected.
Because of the safety features which partly listed above, our automatic revolving doors like TAR300 are welcomed very much by lots of  hotels/resorts, shopping malls, office buildings, hospital and other type of projects .