Working Principle of capacitive proximity sensor
Structural Category
Object-Inductive surface-RC oscillator-Switching stage-Magified
output stage
The induction surface of capacitance sensor is composed of two
coaxial mental electctrodes, which from a capacitor and connected
on RC oscillation
circuit, just like an open capacitor electrode.
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.
Outward appearance illustration
When an object approaches, the current consumption of
capactiance proximity switch will increase proportionally.
The dielectric constants foe some important materials are as below:
Features:
1) Multiplicity appearance
2) Compact volume
3) High repeat orientation precision
4) Many output form
5) Strong protection distribution
6) High on-off frequency commonly 600Hz
7) Wide voltage range
8) Dustproof, vibration-proof, waterproof and oil-proof
Model explanation of proximity switch
CM 12 30 02 N A □ / L
—— —— - —— —— —— —— —— —
1 2 3 4 5 6 7 8
1.Switch category:Lm: Inductance type
Cm: Capacitance type
Sm: Hall type
Am: Safety Explosion-proof type
Xm: Mimic Linear type
Hm: Reed type
Ru: Ultrasonic type
2.Diameter of the sensor:M12
3.Working voltage:
30: 6-36VDC 310:5-24VDC 320:12-60VDC
330: 10-30VDC 340:10-55VDC 350:10-60VDC
360: 5-36VDC 20:90-250VAC 210:24-250VAC
220: 380VAC40:12-240VDC/24-240AC
50: Special voltage
4.Detection distance:01: 1mm 05: 5mm 10: 10mm ......
5.Output form:N: Three-wire Dc NpN Output
P: Three-wire Dc PnP Output
L: Two-wire Dc Output
: Ac Two-wire Output
J: Relay Contact Output
Np: NpN+PnP Double Output
6.Output state:A: (no) normally Open (no)
B: (nc) Normally Close (nc)
C: (no-nc) normally Open-Normally Close (no+nc)
Mu: Mimic Voltage
Mi: Mimic Current
Mui: Voltage+Current
7.Subsidiart functions:T: with aviation connector
Y: water proof,oil proof
I: special requirement
H: high temp resistance
R: ring type
8.L: Long-distance
Dimension
