How does a capacitive proximity sensor work?
Capacitive proximity sensors work by detecting changes in capacitance between the sensor and an object. Factors such as distance and the size of the object will affect the amount of capacitance. The sensor simply detects any changes in capacity generated between the two.
What is inductive proximity sensor?
An inductive proximity sensor is a non-contact electronic proximity sensor. It is used for positioning and detection of metal objects. The sensing range of an inductive switch is dependent on the type of metal being detected. The sensor consists of an induction loop or detector coil.
How do you sense capacitance?
The capacitance can be calculated by measuring the charging time required to reach the threshold voltage (of the relaxation oscillator), or equivalently, by measuring the oscillator’s frequency. Both of these are proportional to the RC (or LC) time constant of the oscillator circuit.
What is the principle of capacitive sensor?
Principle of operation A capacitive sensor acts like a simple capacitor. A metal plate in the sensing face of the sensor is electrically connected to an internal oscillator circuit and the target to be sensed acts as the second plate of the capacitor.
What is capacitive proximity sensor made of?
Capacitive Proximity Sensor Design Much like inductive sensors, capacitive proximity sensors are generally composed of four component groups: the sensor, the oscillator circuit, the detector circuit, and the solid-state output circuit.
Do inductive sensors sense aluminum?
These sensors have an equal range for aluminum and steel targets. In addition, these new inductive sensors have very long nonflush sensing ranges, allowing metals such as aluminum and stainless steel to be sensed at distances previously not possible.
How do you know if a circuit is inductive or capacitive?
If both inductors and capacitors are present then simply find the equivalent impedance of the load network. If the imaginary part of the equivalent impedance is positive then the load is inductive, if it is negative then it is capacitive, and if it is zero then it is resistive.
What can an inductive proximity sensor detect?
Inductive proximity sensors can only detect metal targets. They do not detect non-metal targets such as plastic, wood, paper, and ceramic. Unlike photoelectric sensors, this allows a inductive proximity sensor to detect a metal object through opaque plastic.
What are the two types of inductive sensor?
Inductive Proximity Sensors are roughly classified into the following three types according to the operating principle: the high-frequency oscillation type using electromagnetic induction, the magnetic type using a magnet, and the capacitance type using the change in capacitance.
What is a capacitance level sensor?
Capacitive level sensors are operated by two electrodes forming a capacitor, often in the form of two parallel metal plates with insulating (non-conductive or “dielectric”) material separating them. In the most basic sense, capacitors store electrostatic energy in an electric field.
Can capacitive sensor detect metal?
Capacitive sensors can detect both metal and non-conductive materials.