The increasing adoption of industrial automation, advancements in liquid level sensor technology, and increased usage in the energy and power sectors will drive the growth of the global liquid level sensor market. However, insufficient accuracy and precision of liquid level sensors may hinder market growth. There are several types of liquid level sensors: photoelectric, discrete, capacitive, and piezoresistive, each with its own characteristics and advantages. Next, let's explore the differences between photoelectric liquid level switches and capacitive liquid level sensors.
Photoelectric level switches are used to detect liquids, including stable substances, interfaces between two immiscible liquids, and the presence of deposits. They operate based on changes in the transmission of infrared light emitted by infrared LEDs. Utilizing high-energy infrared diodes and pulse modulation methods reduces light interference. Alternatively, photoelectric level switches can use high-intensity lasers, which can be injected into dusty environments to detect liquid substances. They are commonly used in applications such as leak detection and tank level measurement.
Capacitive level sensors are a new type of capacitive level gauge and control technology device developed based on the principle of light refraction on the surfaces of two different materials to produce reflection and mapping. They possess numerous advantages, including simple structure, high accuracy, no mechanical parts, no need for adjustment, high sensitivity and corrosion resistance, low power consumption, and small size, which have led to their gradual acceptance in the market.
As shown above, a photoelectric level switch is a control board that opens the valve for adding or releasing water based on the data signal output of a level sensor, thereby maintaining a stable water level. It can also be said that a photoelectric level switch outputs a switching signal. The photoelectric level switch first needs to determine the height of the level gauge, and then outputs a switching signal based on this height. A level sensor, on the other hand, converts the height of the level gauge into an electronic signal for output. We can process the electronic signal, for example, by connecting it to a PLC, data acquisition terminal, or professional display to output the height of the level gauge. Furthermore, although the basic principles of photoelectric level switches and capacitive level sensors are the same, photoelectric level switches are power switching control circuits, while capacitive level sensors are equivalent to DC transformers, circuit components used for power conversion. Therefore, the differences between photoelectric level switches and capacitive level sensors are as follows:
① Because the output of the level gauge is only related to whether the optical camera touches the liquid level, and is unrelated to other characteristics of the substance, such as temperature, pressure, density, electricity and other parameters, the capacitive level sensor is accurate and repeatable with high precision; it has a fast response time, very accurate level control, and can be installed and used immediately without calibration.
②Because the capacitive level sensor camera is relatively compact, it can be separately installed in narrow spaces, making it suitable for use in unique tanks or containers. Furthermore, multiple optical cameras can be installed on a single measuring body to create multiple level sensors or controllers.
③ Because all electronic components inside the sensor are encapsulated with epoxy resin, there are no mechanical moving parts inside the sensor. Therefore, the capacitive liquid level sensor is highly reliable, has a long lifespan, and requires no maintenance.
