A basic magnetic level sensor is a device used to determine the liquid level within a container, such as a tank or reservoir. It operates on the principle of utilizing a magnetic field to sense the position of a magnetic float inside the container. Here's how it typically works:
Components: The sensor consists of two main components: a stationary housing and a magnetic float. The housing is typically mounted on the outside of the container, and it contains the necessary electronics for sensing and output. The magnetic float is placed inside the container and is free to move up and down with the liquid level.
Magnetic Interaction: The magnetic float is equipped with a strong magnet. As the float rises or falls with the changing liquid level, the magnetic field of the float interacts with the magnetic field of the sensor, which is located within the housing.
Sensor Detection: The housing contains one or more magnetic sensors, such as reed switches or Hall-effect sensors, which are sensitive to changes in magnetic fields. When the magnetic float approaches a sensor due to the movement of the liquid, the sensor detects the change in the magnetic field strength.
Output Signal: The sensor's electronics process the signals from the magnetic sensors. Depending on the design, the sensor may have different output options, such as analog voltage or current signals, digital signals (e.g., discrete on/off signals), or even communication protocols like Modbus or HART. These output signals can be used to indicate the current liquid level.
Calibration: Before the magnetic level sensor is put into operation, it needs to be calibrated to accurately correspond the detected magnetic field strength changes to the actual liquid level in the container. Calibration ensures that the sensor provides accurate and reliable measurements.
Advantages and Limitations:
Advantages: Magnetic level sensors are relatively simple, cost-effective, and versatile for various liquid types. They are suitable for applications where the liquid is corrosive or hazardous, as the sensor components can be located outside the container.
Limitations: Magnetic level sensors might have limitations when it comes to extremely high-temperature or high-pressure environments. Additionally, they may not be as precise as some other level sensing technologies, especially in cases where the liquid surface is turbulent or prone to splashing.
In summary, a basic magnetic level sensor uses the interaction of magnetic fields between a float inside the container and sensors within a housing to detect and measure the liquid level. It provides a convenient and often reliable solution for monitoring liquid levels in various industrial and commercial applications.