When an object moves at a certain speed through the sensing area of a proximity sensor, the proximity sensor’s response frequency determines if it’s able to detect that object properly.
The response frequency of s proximity sensor indicates the maximum movement speed or interval of the sensed object that the proximity sensor can react correctly to. In other words, a smaller response frequency parameter (such as 10-100 Hz) indicates a slower tolerable movement for properly sensing objects. If an object moves through the sensing area of a 100Hz proximity sensor in less than 1/100th of a second, then the sensor is not guaranteed to correctly sense the presence of that object.
This type of proximity sensor, with lower response frequency, is usually used for power devices and human body sensing.
On the other hand, a higher frequency response parameter (such as up to 5k to 10 kHz) indicates that the device can sense a fast moving objects or sudden momentary reactions, such as an industrial control or instant shut down during industrial accident events.