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Welcome to G-TV! Today, I will be showing you what a capacitive proximity sensor is.
Capacitive prox sensors can be used to sense both metallic and non-metallic material. Some
ideal applications include liquid level detection, material level control, counting, and induction
molding process such as the detection level of plastic pellets in a feed hopper. A capacitor
consists of two metal plates separated by an insulator called a dielectric. Capacitive
proximity sensors can detect any target that has a dielectric constant greater than air.
The dielectric constant is an electrostatic field generated by the oscillator circuit.
If an object enters this field and causes interference, oscillation then begins. The
detector or trigger circuit monitors the oscillator’s output. When it detects sufficient change
in the field, it switches on the output circuit. The output circuit remains active until the
target is removed from the sensing field. Sensing ranges can depend on the material
needed to be detected. There is no derating factor to be applied when sensing metal targets.
But, other materials do affect the sensing range. Sensors can be used to detect liquid
through a nonmetallic material such as glass or plastic, but they need to be mounted so
that the sensor detects just the liquid, and not the container. Generally, the sensing
distance for capacitive prox sensors is greater for larger or denser targets, but the effect
on the electrostatic field produced by non-conductive material can be quite small. Usually sensing
distances with this material is short. Material such as ungrounded conductive material can
be sensed from further away because it causes more interference on the electrostatic field.
Grounded conductive material causes even more interference and thus has the longest sensing
distance. Since the composition of the material and ambient conditions can have an impact
on the sensing field, many capacitive prox sensors are equipped with sensitivity adjustment
potentiometers. Capacitive prox switches can detect material at greater ranges from inductive
sensors and have a long operation life. Capacitive proximity sensors, along with thousands of
other products and services are available at galco.com.