The radar level antenna transmits a narrow microwave pulse down through the antenna. After the microwave touches the surface of the measured medium, it is reflected back to be received by the antenna system again, and the signal is transmitted to the electronic circuit and automatically converted into the level signal. Because the microwave propagation speed is extremely fast, the time used for the electromagnetic wave to reach the target and return to the receiver by reflection is almost instantaneous. Radar level meter is suitable for non-contact continuous measurement of liquid, slurry and granular material level, suitable for occasions with large changes in temperature and pressure, and occasions with inert gas and volatile. It uses the microwave pulse measurement method, can work normally in the industrial frequency band, due to the low beam energy, can be installed in a variety of metal and non-metal containers or pipelines, harmless to the human body and the environment.However, its measurement accuracy is also affected by some factors, such as current.

There are two kinds of currents that affect the measurement accuracy of 5900s radar level gauges:

The first is AC interference, which can be divided into ground interference and interline interference. Ground interference refers to one end of the two output ends of the radar level meter, and the AC voltage to ground is called ground interference voltage. This interference is also called longitudinal, series mode, or series state interference. Under normal circumstances, the interference voltage to the ground can reach several volts or even more than 100 volts. Interline interference refers to the AC voltage between the output terminals of the radar level meter under external influence, which is also called transverse, common mode or common mode interference. In general, the interference voltage between lines can reach several millivolts or even tens of millivolts. The main sources of AC interference are: electromagnetic induction is the main source of interline interference, high temperature leakage, high voltage electric field interference, ground current interference, suction leakage, AC interference can also be introduced in the equipment temperature measurement..

The second type is DC interference, in the radar level measurement loop, when there is additional DC current voltage, it is DC interference. In severe cases, the measuring instrument will not work normally, DC interference sources include additional thermoelectric potential, chemical potential, when the radar level meter and DC power supply contact, leakage current will generate interference voltage through the measurement loop.