The difference and selection of liquid level switch and liquid level sensor

　　Liquid level refers to the height of the liquid level in a sealed container (tank) or an open container (tank). With the development of science and technology to this day, from the ancient ruler to the modern photoelectric, ultrasonic, radar measuring instrument...human beings have invented countless methods of liquid level measurement. In daily life and industrial production and management, it is often necessary to understand the liquid level in the container. However, due to various factors such as the large tank body, inconvenient entry, and harmful substances in the tank, sensors must be used for measurement. It can be said that liquid level sensors and liquid level switches have now become "masters" in the fields of petrochemicals, metallurgy, electricity, pharmaceuticals, water supply and drainage, environmental protection, etc., and play an important role in the industrial field. So, what are the differences between liquid level switches and liquid level sensors, and how to choose them in actual applications?

1. The difference between liquid level switch and liquid level sensor

　　The working principles of liquid level switches and liquid level sensors are basically the same, so they are often used interchangeably without distinction. However, the difference between the two is very obvious:

　　1. The liquid level sensor converts the liquid level signal in the container into a switch signal or a voltage or current signal for output, and then processes the electrical signal through an external circuit, such as connecting to a PLC, a data acquisition device or a professional display to output the height of the liquid level, so that the measurer can accurately know the liquid level in the container intuitively.

　　The liquid level switch is a controller that opens the valve for draining or inletting water according to the signal output of the liquid level sensor to keep the water level constant. It can also be said that the output of the liquid level switch is a switch signal. The liquid level switch must first determine the height of the liquid level and output the switch signal based on this height.

　　2. The liquid level switch is a switch control circuit, while the liquid level sensor is equivalent to a circuit element used for voltage and current conversion. In other words, if you want to measure when the liquid reaches the liquid level, use a liquid level switch, and if you want to accurately measure the height of the liquid level, use a liquid level sensor.

2. Selection of liquid level switches and liquid level sensors

　　Technological progress has indeed changed people's lives, and various technologies have emerged one after another. But the question is, how should we choose the liquid level sensors and liquid level switches in the face of a wide variety of dazzling types?

　　1. Before selecting the model, you must first clarify the type of liquid to be measured, whether its chemical properties are toxic, highly corrosive, or polluted. If the viscosity of the liquid to be measured is too high, it will stick to the sensor or the liquid is opaque, etc., it is recommended to use non-contact measurement. If the medium is a conventional acid-base solution, water, oil, etc., contact measurement can be used.

　　2. With the development of society and the progress of science and technology, many liquid level measurement sensors with backward measurement methods have been eliminated. Sensors that use the latest measurement technology and meet certain measurement speed and accuracy requirements are sought after by people. In terms of non-contact measurement, radar level gauges and ultrasonic level sensors are mostly used; in terms of contact measurement, photoelectric level sensors, tuning fork level switches, etc. are mostly used.