The door opening signal of an Automatic door is a contact signal. Microwave radar and infrared sensors are two commonly used signal sources. Microwave radar responds to the displacement of objects, so it has a fast response speed. It is suitable for places where people walking at normal speeds pass. The characteristic is that once the people near the door do not want to go out and stand still, the radar no longer responds, the automatic door will be closed, and the door machine has a certain protective effect. The infrared sensor responds to the presence of an object, regardless of whether the person moves or not, as long as it is within the scanning range of the sensor, it will respond and send out a contact signal.https://www.kth-automaticdoor.com/
The disadvantage is that the infrared sensor has a slower response speed, which is suitable for places where people with slow movements enter and exit. In addition, if the automatic door accepts the contact signal for too long, the controller will consider the signal input system to be obstructed. And if the automatic sliding door is kept open for too long, it will also cause damage to electrical components. Because microwave radar and infrared sensors do not know whether a person approaching the automatic door really wants to enter the door, some occasions prefer to use a key switch. The key switch can be a contact-type button, more conveniently a so-called elbow touch switch.