Why should the ultrasonic flowmeter be installed in the best installation location?
In order to achieve the best flow measurement performance of the ultrasonic flowmeter, the optimal installation position will greatly increase the signal strength of the ultrasonic wave, so that it can measure the fluid flow in the pipe with the best ultrasonic transmission efficiency.
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What are RSSI and Q-values?
RSSI: the abbreviation of Received Signal Strength Indication, usually not expressed in any unit, but only in degrees, such as percentages, grids, etc., to display the current signal strength to the user.
Q value: It is an indicator of signal validity, which is used to express the clarity of the signal.
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The relationship between RSSI and Q value
Take the voice expressed in spoken language as an example to illustrate: when talking to others, the state where you can best understand the words of others should be when the other party’s volume is loud enough, the words are clear, and the meaning is clear. The best scenario is when the volume is loud, the speech is the clearest; the second is when the volume is low, but the speech is still clear; the next is when the volume is loud, but the speech is not clear, and the worst is when the volume and speech intelligibility are both not clear. In the above case, the volume is compared to RSSI, that is, the signal strength; while the clarity of words and clear semantics can be compared to the Q value, that is, the effectiveness of the signal itself. In addition, in the ranking difference between the second and third order, the semantic clarity (Q value) will be more important than the sound volume (RSSI).
For the above relationship, we can use the following figure to briefly illustrate the relationship between RSSI and Q value, as well as the criteria for judging from the best to the worst signal.
Best to worst signal quality：
4 (large RSSI, large Q value) > 3 (small RSSI, large Q value) > 2 (large RSSI, small Q value) > 1 (small RSSI, small Q value)
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How to combine RSSI and Q-value to evaluate the best installation location?
As with the above-mentioned examples of oral expressions and the description of the quality level, the user must evaluate the best standard that can be achieved by RSSI and Q quality according to the current situation of the plant and equipment, space arrangement, installation convenience, and other needs. Mark the selected feasible installation positions on the above quadrants, so as to know the best installation positions for individual users.
In addition, to judge the "best installation position of the ultrasonic flowmeter", we must also refer to the two values of ToM/ToS, which will be explained in a separate article.
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