How to adjust the magnetic flap level meter 4-20ma?

　　Magnetic Flap Level Gauge is applied to liquid level measurement in petroleum, chemical, electric power, environmental protection and other industries for its advantages of simple structure, intuitive measurement, safety and reliability. As a commonly used analog signal in industrial automation control system, 4-20mA current signal can be easily connected with PLC, DCS and other control systems to realize remote monitoring and control of liquid level. In this article, we will introduce the debugging method of 4-20mA signal of magnetic flip-flop level meter in detail, which will help you quickly master the related skills.

　　First, magnetic flip-plate level meter 4-20mA working principle

　　The 4-20mA signal output of magnetic flip-flop level meter is usually realized by the built-in magnetostrictive level transmitter. The working principle is as follows:

　　When the liquid level changes, the float moves up and down with the liquid level, driving the magnetic steel assembly to move. Changes in the magnetic field of the magnet assembly are sensed by the magnetostrictive waveguide rod installed outside the measuring tube. A torsion wave is generated inside the waveguide and converted into an electrical signal by the detection coil. The electrical signal is amplified, filtered, A/D converted, temperature compensated and finally converted to 4-20mA current signal output. Second, the preparatory work before commissioning

　　In the magnetic flap level meter 4-20mA signal before commissioning, you need to do the following preparatory work:

　　Carefully read the product manual: understand the specific parameters of the type of magnetic flap level meter, performance indicators, wiring and debugging methods. Prepare debugging tools: Commonly used debugging tools include multimeter, screwdriver, movable wrench, 24V DC power supply and so on. Ensure safety: Pay attention to the safety of electricity during the commissioning process to prevent electric shock accidents. Disconnect the power supply for wiring and checking. Understand the site conditions: master the nature of the measured medium, temperature, pressure and other parameters, in order to correctly set the parameters of the liquid level meter. Third, magnetic flap level meter 4-20mA signal debugging steps

　　Magnetic flip-flop level meter 4-20mA signal debugging generally need to zero, full point and linearity of the three aspects of calibration. Specific steps are as follows:

　　1. Zero calibration

　　Install the level meter in an empty container or simulate an empty tank, make sure there is no liquid in the measuring pipe. Turn on the power supply of the liquid level meter and use the multimeter to measure the 4-20mA circuit current value. Adjust the “Zero” or “L” adjusting potentiometer on the level meter, so that the output current value is 4mA. Observe whether the current value is stable or not, if it is not stable, you need to re-adjust it until it is stable. 2. Full-point calibration

　　Slowly fill the level into the container until it reaches the upper limit of measurement. Measure the current value of 4-20mA circuit with multimeter. Adjust the “full point” or “H” potentiometer on the level meter so that the output current value is 20mA. Observe whether the current value is stable or not. If it is not stable, re-adjust it until it is stable. 3. Linearity Calibration

　　Linearity refers to the linear relationship between the output current value of the level meter and the actual level value. Ideally, the two should be proportional. Linearity calibration needs to be measured and adjusted at several liquid level points, usually choosing 25%, 50%, 75% and other points for calibration.

　　Adjust the liquid level to 25%, 50%, 75%, etc. and record the actual liquid level value corresponding to each position. Use a multimeter to measure the output current value corresponding to each liquid level point. Calculate the linearity error based on the actual liquid level value and the measured current value. If the linearity error exceeds the allowable range, it needs to be corrected by adjusting the linearity adjustment potentiometer on the level meter. Repeat steps 1-4 until the linearity error of all liquid level points is within the allowable range. Precautions

　　When debugging the 4-20mA signal of magnetic flap level meter, you need to pay attention to the following points:

　　Select the appropriate range: the measurement range of the liquid level meter should cover the range of actual liquid level changes, and leave a certain safety margin. Correctly select the installation location: the liquid level meter should be installed to avoid eddy currents, bubbles and other factors of interference, and at the same time, easy to observe and maintain. Pay attention to the wiring: different models of liquid level meter wiring may be different, wiring must be carefully read the instructions to avoid connecting the wrong line. Influence of ambient temperature: Changes in ambient temperature will affect the measurement accuracy of the liquid level meter, and it is necessary to carry out the corresponding temperature compensation. Regular maintenance: regularly check the operating status of the liquid level meter, clean the measuring tube to ensure its normal operation. V. Conclusion

　　The debugging of the 4-20mA signal of the magnetic flap level meter is an important part to ensure its normal operation. Through the steps described in this article, you can quickly master the debugging method to ensure that the level meter accurately and reliably measure the liquid level information, providing reliable data support for industrial automation control systems.