TURCK proximity switch and capacitive proximity switch. Because these two types of proximity switches require lower environmental conditions. When the tested object is a conductive object or an object that can be fixed on a block metal object, the eddy current type proximity switch is generally selected because of its high response frequency, good anti-environmental interference performance, wide range of application and low price. If the measured object is non-metal (or metal), liquid level height, powder height, plastic, tobacco, etc. Capacitive proximity switch should be used. This switch has low response frequency but good stability. Environmental factors should be considered during installation. If the object to be measured is a magnetic material or in order to distinguish the object moving with it and bury the magnetic steel in the object to be measured, should choose the Hall proximity switch, its price is low.