Measuring method of dry reed switch pulse type fluid meter

Abstract

The invention provides a reed pipe pulse type fluid flow meter metering method. A controller MCU (Micro-programmed Control Unit) is used for setting 1 / 2 of pulse interval time corresponding to a rated maximum flow of a fluid flow meter to a minimum phase time threshold value Tmin, and setting 1 / 2 of pulse interval time corresponding to a rated minimum flow of the fluid flow meter to a maximum phase time threshold value Tmax; meanwhile, a main counter, an auxiliary counter and a general counter are arranged; each of the main counter and the auxiliary counter corresponds to two reed pipes; whether the main counter and the auxiliary counter are effective or not is judged and counting is performed according to the comparison of the pulse interval time, the Tmin and the Tmax. The reed pipe pulse type fluid flow meter metering method provided by the invention has the beneficial effects that shake pulses can be effectively removed, and excessive metering of the flow is avoided; meanwhile, the condition that the pulse is not triggered caused by the fact that the rotary speed of a word wheel at the end is too fast can be made up and the missed counting of the flow is avoided, so that the fluid metering accuracy of the flow meter is effectively improved.

Description

technical field [0001] The invention relates to the metering technology of a reed switch pulse type fluid meter, in particular to a metering method of a reed switch pulse type fluid meter. Background technique [0002] The reed switch pulse fluid meter uses a permanent magnet to trigger the closing or opening of the reed switch to generate pulses, and calculates the pulse data to calculate the fluid flow. Specifically, a permanent magnet is embedded between the last character wheels of the meter, and dry reed switches are symmetrically arranged on both sides of the last character wheel. When fluid flows in the pipeline and drives the rotating system to rotate, the rotating system will Drive the last character wheel to rotate, and the permanent magnet set on the last character wheel also rotates accordingly. When the permanent magnet passes through the dry reed tubes symmetrically arranged on both sides of the last character wheel, the reed tube reeds are attracted; the perma...

AI Technical Summary

Problems solved by technology

However, the generation of the reed switch pulse is not completely accurate, that is, the conduction or disconnection of the reed switch is not completely accurate

When the permanent magnet gradually approaches or leaves the reed switch, the reed will gradually attract or gradually disconnect under the action of the magnetic force, or when the magnet stays near a certain reed switch (0-9 ten evenly distributed around the wheel) Number, the embedded permanent magnet occupies a number width, so the probability of the magnet staying near one reed switch is 1 / 10, and the probability of staying near two reed switches is 2 / 10; if the permanent magnet conducts the reed switch If the number range is 3 numbers, the possibility of the two reed switches being connected is 6 / 10. Therefore, whenever the fluid stops, the probability of the permanent magnet staying near a certain reed switch is 2 / 5 to 3 / 5 ), if there is a large vibration in the outside world at this time (such as passing a large truck nearby, etc.), the reed may vibrate, thereby triggering a series of pulses (that is, jitter pulses), causing the MCU to count multiple times. "

On the other hand, when the last character wheel rotates at a faster speed (close to the maximum allowable speed), the permanent magnet will rotate through the reed switch at a faster speed. If the reed response lags behind, that is, the reed has not been The permanent magnet has left the reed switch when it is attracted, and the reed switch fails to generate pulses in time, causing the MCU to count but not count, that is, the flow "leaks" (experiment shows: the probability of leakage is 2 / 10,000)

Whether it is flow "over-metering" or flow "leaking meter", the result is that the accuracy of fluid measurement is reduced. Obviously, there is a possibility of flow "over-metering" in the prior art reed switch pulse type fluid meter. ", or the flow "leak meter", which makes the accuracy of fluid measurement low and other issues

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