Video

Capactive Proximity Switch

When connecting to power supply, RC oscillator does not work. When an object is clos eto capacitor electrode, the capacitor capacity will increase, and the oscillator will vibrate. Through the treatment of behind stage circuit, both signals of stop oscillation and oscillation will be converted to switch signs for checking the existence of object. this distance can be obtained, but to nonmetal object, the action distance is d etermined by material dielectric constant, the more dielectric constant, the more action distance will be obtained.

Working principle of Capactive Proximity Switch

Structural category	Object	Inductive surface	RC oscillator	Switching stage	Magnified output stage
Outward appearance illustration

Outward appearance illustration

The dielectric constants foe some important materials are as; osted as below;

Materials	Dielectric constant	Materials	Dielectric constant	Materials	Dielectric constant	Materials	Dielectric constant
Synthectic resin adhesive	3.6	Styrene	3	Alcohol	25.8	Polyvinyl	2 9
Mica	6	Prorcelain	4.4	Glass	5	Quartz glass	3 7
Ebonite	4	Petrolin	2.2	Cardboard	4.5	Silicon	2.8
Marble	8	Quartz sand	4.5	Cable rubber compound	2.5
Paper	2.3	Soft rubber	2.5	Gasoline	2.2
Organic glass	3.2	Water	80	Wood	2.7

Application illustration

Model				CM34
Sense distance				0~20mm±10%
Non-flush type	DC10~30VDC	NPN	NO	CM34-3020NA
			NC	CM34-3020NB
			NO+NC	CM34-3020NC
		PNP	NO	CM34-3020PA
			NC	CM34-3020PB
			NO+NC	CM34-3020PC
		Two-wire system	NO	CM34-3020LA
			NC	CM34-3020LB
	AC90~250VAC		NO	CM34-2020A
			NC	CM34-2020B
			NO+NC	CM34-2020C
Output current			DC	200mA
			AC	300mA
Output voltage peak				Dc type below 3V, Ac type below 7V DC<3V, AC<7V
Consumption current				DC type 8mA at 12V, 15mA at 24V, AC below 10mA DC<15mA, AC<10mA
Standard detected object				Conductors and dielectric materials
Repeatability				0.05
Response frequency				DC50Hz/AC10Hz
Ambient temperature				-25℃-+75℃
Insulation resistance				50MΩ
Shell material				ABS Resin
Protection grade				IP54

CM34 Sensing Distance 20mm Capacitive Proximity Switch

Capactive Proximity Switch

Working principle of Capactive Proximity Switch

Outward appearance illustration

The dielectric constants foe some important materials are as; osted as below;

Application illustration