What is the principle of LVDT displacement sensor?
Release date: May 20, 2019
With the continuous improvement of automation level in China, the amount of sensors is increasing, and the development of high-tech displacement sensor products has broad prospects. LVDT displacement sensor has the characteristics of high precision, good dynamic characteristics, reliable work, easy to use and so on. How about the application of LVDT displacement sensor in industrial automation?
1. Remote positioning feedback
The energy and petroleum industries often need to obtain the location feedback information of remote location. The long distance transmission signal usually uses the current transmitter, but does not use the voltage signal transmission. Voltage signal is easily affected by "voltage drop" and other external factors. The LVDT displacement sensor can provide 4 to 20 mA in positive proportion to the sensor position
Signal is also a standard in the process control industry. The position transmitter adopts double loop power supply. In other words, the two-wire loop not only provides position signal, but also supplies power to the sensor, which saves the trouble of extra power supply for remote sensor. Due to the application of weak current, LVDT displacement sensor has high security, and is suitable for hazardous applications.
2. Pneumatic linear sliding positioning feedback
Many mounting machines need positioning confirmation. These sensors and linear potentiometers are often used to provide positioning. There is a defect in the use of endpoint sensors, that is, zero repeatability will gradually decrease. In addition, endpoint sensors cannot provide intermediate data between fully extended and fully retracted positions. The initial use effect of linear potentiometer is not bad, but the contact type vernier and conductive film used in it will decline after using for a period of time. In the application of partial jitter action in the travel, this problem will be particularly prominent when using potential timing. LVDT displacement sensor can provide low cost and non-contact solution for short stroke positioning feedback of pneumatic linear positioning equipment.
3. Ball valve positioning
LVDT displacement sensor is suitable for sensing the position of ball valve and actuator, with long service life and high reliability. It provides a better solution than potentiometer and resistance element.
4. Injection molding machine
The injection molding machine uses pressure sensor and LVDT to control and measure the hydraulic pressure and air pressure of the actuator used to open and close the mold and control the feeding. LVDT displacement sensors are particularly suitable for applications that require high accuracy, repeatable overload protection, zero and span errors. This kind of sensor does not need to be adjusted during the production, so it is easy to install and maintain. It reduces the installation cost and has good performance. In addition, due to the small size of the product and the use of stainless steel shell, the cleaning work after material spillage is simplified.
5. Long stroke cylinder displacement
LVDT displacement sensor can withstand the high pressure on the probe, which is very suitable for industrial pneumatic cylinder. The maximum working pressure of this product is 5000PSI and the frequency response is 100Hz,
The precision is as high as 0.05%, which is undoubtedly the ideal choice for closed-loop positioning control of 3D automatic mounting mechanism. The information output according to the standard speed is fed back to the proportional control system to improve the material handling efficiency.
6. Valve positioning
LVDT displacement sensor not only can withstand the high temperature of gas turbine and steam turbine, but also has small volume and can be installed in the actuator, so it is especially suitable for controlling the valve positioning. The main body of LVDT displacement sensor is installed on the valve, and the magnetic core is installed on the opening and closing parts. The LVDT displacement sensor then feeds back an accurate analog signal to the control system, which is proportional to the opening and closing of the valve. The LVDT measures lengths ranging from ± 0.005 to ± 10 inches and can be used in control loops, particularly for such applications.