Radar water level meter in the actual observation due to wind, waves, floating objects and winter ice, and other external environmental interference, there will be monitoring data jump phenomenon, affecting the accuracy of data acquisition.
Today we will take a look at the causes of data jumping and solutions.
I. Causes of radar water level meter data jump
1. The instrument itself, the principle of radar water level meter measuring water level is to launch the unit to run at the speed of light pulse radar wave, when the pulse meets the liquid level surface reflected back by the instrument receiver unit received, by converting the distance signal into a liquid level signal, that is, the radar water level meter launch radar wave – water surface reflected radar wave – radar water level meter receive radar wave, thereby calculating the height of the liquid level.
In the actual flow measurement process, the radar water level meter flow measurement index is directly related to the signal quality of the transmitting and receiving process, especially the reflecting signal strength of the radar wave on the flow measurement surface has an important impact.
In the process of measuring the flow, the surface waves and trees and weeds, and other floating objects will affect the water level meter reflected wave signal, resulting in the radar water level meter can not receive the signal or the received reflected wave signal is too weak, resulting in the water level meter flow measurement data jump or data failure.
2. RTU setting reasons, most of the radar water level meters used in the water conservancy industry are installed in the field, mainly using solar panels for power supply.
Due to the limitation of power supply equipment capacity, the conventional way is to implement a regular power supply to the radar water level meter through RTU. In the actual measurement, the radar water level meter needs to be preheated by about 20s before measuring the flow, but the temperature of the outside world has a greater impact on the length of the equipment preheat, the high temperature in summer (above 45 ℃), the equipment preheat takes about 28s, the low temperature in winter (- 10 ℃ below) will increase to about 45s, as the RTU set preheat time is generally in 20s, if the radar water level meter is not set in time within the time If the radar water level meter does not return data within the set time, the RTU will display the preset data 9999.99, indicating that the data is invalid, which is also one of the reasons for the observation of jump data.
II. Solutions
1. Increase the radar water level meter transmitting power, enhance the radar signal reflection strength
2. Change the power supply mode of RTU and radar water level meter to ensure stable working condition
3. Filter and calculate the average value of the measured flow data several times
4. Receive data discriminatory filtering
5. Encrypted acquisition frequency, improves the accuracy of measurement data
With the continuous progress of science and technology, radar water level meter has been widely used in the automatic water measurement system because of its low cost, high flexibility and reliability, low power consumption, and other characteristics. However, how to exclude the daily work of the fault that the collection of data jumping problem, becomes a problem of grass-roots water pipe work.