Guided wave radar level gauge – actual operating accuracy
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This post was last edited by Xiaoxiao Suelang on 2016-8-4 at 16:17. Current operating conditions: The medium is highly corrosive; there may be a few bubbles on its surface. The liquid level fluctuates occasionally. The viscosity is not high, so no material accumulation occurs. Domestic guided-wave radars have been used, but they are unstable – in poor conditions, the error can reach 2 cm. There can also be abnormal fluctuations. Taking major brands such as E+H and Cologne as examples, the specification sheets usually indicate a range of plus or minus 3 MM. However, what is the typical accuracy in the actual use of different processes? Please, those who have used it, share your experience.
In an ideal situation, such as with still water, the value stated on the sample is exactly what it is; what is written down in black and white must be taken seriously. But since this medium contains foam and experiences severe fluctuations, should a waveguide be installed? Can it be ensured that there is no foam inside the waveguide? How to measure accuracy during severe fluctuations, and what serves as the basis for that, are all issues.
It depends on which manufacturer’s design can achieve what level of precision! The precision of guided wave radar can be very high! It really depends on your instrument itself
The accuracy in practical applications depends on the medium being measured as well as the operating conditions. As the original poster mentioned, the conditions you’re dealing with can be considered quite harsh. The situation described by the person on floor 2, where there is no steam and the water is at rest, represents ideal conditions. Since each factory operates under different conditions, the accuracy achieved in measuring the liquid level in each tank varies as well. I’m not sure which model of E+H you are using; E+H’s guided wave technology can achieve an accuracy of up to ±2 mm
The range is around 0.9m. The normal range of liquid level variation is between 0.67 and 0.70, and the liquid level value is used in interlocks. So, a 2cm error is definitely fatal for us.
What you really need to worry about is stability, that is, repeatability error. In this regard, you get what you pay for.
In terms of precision, there is no technical difference between domestic and imported versions of such devices. The 2-cm discrepancy may be caused by fluctuations in the medium, or by errors between the installation height and the length of the probe. It’s not yet clear what the measurement range is. If high precision is required, it’s necessary to calibrate several points on-site; by doing so, the error can be compensated for through the gauge’s built-in functions. Generally, the error can be kept within ±5 mm at heights above 0.8 meters, while at heights below 0.8 meters the error is larger. The closer to the blind zone, the greater the error; within this range, the deviation is roughly 10–30 mm. Additionally, the type of medium also plays a role in determining the accuracy.