As most of the meter reading system, are read the pulse issued by the pulse in the transmission process is very susceptible to interference, resulting in reading the table wrong. To eliminate this reading table error, you must use such a meter reading system, the data acquisition device on the table, the header collector and the collector through a simple transmission control protocol for transmission, which can effectively prevent the data in the transmission Process due to interference, and caused by reading the table wrong.
Impulse pulse on the table can be divided into: Reed switch, Hall element type and photoelectric conversion type. Hall element type basic principle is in the ordinary dial count water meter (or gas meter) in the installation of Hall elements and magnets, can constitute a magnetic conversion technology based on the sensor. The Hall element is fixedly mounted near the counting dial, and the permanent magnet is mounted on the counting disk. When the turntable is rotated every revolution, the permanent magnet generates a metering pulse at the signal end through the Hall element. Reed switch type basic principle is: in the ordinary dial count water meter (or days of gas meter) in the installation of reed and magnet, reed fixed fixed in the dial around the disk, the permanent magnet installed in the counting disk, when the turntable Each revolution, the permanent magnet through the reed tube once in the signal side to produce a metering pulse. The basic principle of photoelectric conversion is: in the meter's turntable installed a photoelectric converter, turntable has a slot, turn the turntable turn, the groove through the photoelectric converter, complete a photoelectric conversion, the output of a pulse.
The accuracy of the number of pulses will determine the accuracy of the remote metering system. From the current actual construction of the situation, the remote gas meter, meter pulse accuracy is higher. The water meter is not satisfactory, or even very bad. The main reasons are two aspects: the quality of the reed tube is not high, water pipe water hammer phenomenon, issued a large number of pulses (by pulse).
In the pipeline system, if the flow of the flow occurs, the flow rate and pressure of the flow rate change with time, and the change range depends on the initial flow pattern, the pipeline system characteristics, the transient formation condition and so on. Due to sudden changes in the flow rate caused by a series of rapid pressure alternating movements of the hydraulic shock phenomenon, the pipeline will be violent vibration and large sound, this phenomenon known as the water hammer phenomenon. In daily life, we often meet the water pipe violent jitter and sound of the situation, that is, water hammer phenomenon. It is this violent jitter that causes the reed reed in a very short time, frequently sucking in, sending a lot of pulses.
In the remote metering system, the most inaccurate water meter pulse is caused by the above reasons. These conditions have seriously hindered the development of remote metering systems. Water hammer phenomenon is extremely complex, with the pipeline wall friction, pressure, liquid flow rate and so have a relationship, we can not fundamentally solve it. But in actual work, we increase the width of the pulse to filter out some clutter. We can in the hardware and software, set a certain judgment function, to filter out the wrong pulse. In this way, we collected from the front of the data is more accurate.
At present, the quality of domestic far-reaching water meter is indeed worrying, has seriously hindered the development of three-table remote system. Therefore, in order to fundamentally solve the problem, we must start from the principle, the development of new remote gas meter, meter and water meter.