Principle and classification of object level sensor

Object level sensor is a sensor that can sense object level and its change and convert it into measurable electrical signal.

Level sensors can be divided into two categories according to the measurement type: one is the measurement of continuous level monitoring sensors, the other is the point measurement for the purpose of switching level sensors, such as some liquid level sensors. In real life, the switch level sensor is more widely used, because most of the time do not need to know the real-time change of the material. Such sensors are usually used in automatic control processes to keep the monitoring object level within a certain range and avoid overflow or leakage situations.

There are many measuring principles of object level sensor, and the appropriate object level sensor can be selected according to the actual situation when measuring. Level sensors mainly include: capacitive, optical, pressure and ultrasonic level sensors.

Capacitive level sensor uses the container wall as one electrode and the liquid or solid in the container as another electrode. When it changes, the component capacitance changes accordingly, so that the corresponding change of electric quantity can be detected in the circuit, and the change value of matter level can be obtained by converting these relational quantities.

Optical level sensors can be used to detect the liquid level at a certain point. The detection method is to use the total reflection principle of light at the interface between sensor and liquid. When a ray is emitted, the liquid level has reached the set point. Our common liquid level sensors follow this principle.

Pressure level sensor is a kind of level sensor for continuous measurement, mainly based on the linear relationship between the internal pressure of liquid and the depth of liquid level. Sensors can be mounted at the bottom of the container, and the higher the level, the greater the pressure.

Ultrasonic level sensor is a kind of non-contact continuous measurement level sensor, its working principle is to measure the distance between the sensor and the level plane by using the propagation time of ultrasonic echo to judge its change. Some ultrasonic level sensors, for example, can cleverly use the time-difference measurement technology common to these sensors to detect the distance between the sensor and the target object.