The technical status and development direction of remote water meters

　　1. The current status and development of pulse remote water meters. First, two types of pulse sensing methods have basically been eliminated from the metering field: photoelectric sensing and Hall sensing. The reason for their elimination is as follows:

　　1. Compared with other contact sensing methods such as reed switches, they have the disadvantage of consuming power themselves, which makes them unsuitable for some low-power working scenarios.

　　2. The disadvantage of false signals caused by critical point vibration cannot be overcome.

　　3. The inconvenience and faults caused by external power supply. Of course, the Hall sensing method has undergone updates and improvements for more than a decade. If no better method appears, it may remain, but compared to self-holding switches, the Hall sensing method is not advantageous in terms of reliability, accuracy, low power consumption, and low cost, which has led to its final decline. In contrast, the clumsiness and defects of the photoelectric sensing method need not be mentioned; it has been almost unheard of in use for over a year. The single reed switch sensing method has already become "notorious"; its main drawback is that it cannot solve the problems of multiple counts due to contact vibration and insensitivity leading to fewer counts. Products of this type that were applied in the field a few years ago have almost all been abandoned or replaced. However, in some cases where people are not very knowledgeable and do not pursue accuracy, there are still some users. Compared to single reed switches, double reed switches have made significant progress. The author has detailed the structural principles of this invention (a high-precision water meter with patent number: 99206865) in the article "The Generation and Development of Remote Water Meters in China." In practical use, the sensitivity limitations of double reed switches can lead to data loss when the magnetic force is weak and simultaneous sensing issues when the magnetic force is strong. Additionally, the collector needs to detect both switches, which requires adding an interface. If it also detects short circuits, open circuits, etc., like other remote meters, it becomes even more complex. In the article "The Generation and Development of Remote Water Meters in China," the author extensively demonstrates the superiority of self-holding switch remote water meters. Three years later, this remote method still retains its original characteristics technically, but has undergone significant improvements and corrections in production processes, with product specifications reaching hundreds of types and manufacturing molds exceeding a hundred sets. Actual usage has expanded from the original thirty thousand units to over five hundred thousand sets, and it is being promoted and expanded at an even faster pace. Self-holding switch remote water meters have completely transitioned from a technical project to a mature product and have successfully risen to become a commodity with a certain Brand, dominating the metering market with their accuracy, reliability, low cost, and ease of use. This process aligns perfectly with the author's design philosophy. Self-holding switch remote water meters will become the mainstream product of remote water meters.

　　2. The current status and development of direct-reading remote water meters. Direct-reading remote water meters can be roughly divided into four categories: photoelectric, contact, imaging, and counting types. They share two common advantages:

　　1. The data read from the meter is the data displayed on the dial, not pulses.

　　2. They do not consume power during normal operation, only powering on at the moment of data reading, so they are not afraid of power outages. Theoretically, the data read and the dial data are always synchronized. Therefore, since the concept of direct-reading remote water meters emerged before 2000 and the actual product application in the field after 2002, it has been a subject of inquiry and attention. By 2003, the concept of direct-reading remote meters was specifically included in the national standard formulation process. The emergence of direct-reading remote meters has sparked a heated discussion about whether "pulse" remote meters still have vitality, further increasing their attention. The earliest direct-reading remote water meters were photoelectric types, structured as follows: five reflective surfaces are set on the circumference of each water meter digit wheel, and five photoelectric couplers are set at corresponding positions to determine the position of the counting wheel based on whether the couplers reflect. If you want to read several digits, sensors are installed on several digit wheels. For example, to read a 5-digit number, 5×5=25 pairs of sensing devices are installed. This type of direct-reading water meter has all components located around the digit wheel inside the meter, so dry water meters are generally used. The structure of contact direct-reading remote water meters involves installing a synchronous telecommunication device on each pointer shaft under the dial of a pointer water meter, determining the position indicated by the pointer based on the resistance value measured by the contact potentiometer. This type of direct-reading water meter can be used with wet water meters. The structure of imaging direct-reading remote water meters is relatively simple; a camera is installed in front of the mechanical digit display window to transmit the captured digital image. Counting direct-reading remote water meters have a chip that collects pulses installed in each water meter, powered by a battery to maintain operation, storing recorded and accumulated data in the chip, with the data read from the chip being synchronized with the dial data. Additionally, there are barcode direct-reading types of direct-reading remote water meters, which will not be discussed here. Although direct-reading remote water meters have outstanding advantages, their actual promotion and popularization effects are not ideal. A comprehensive analysis reveals the following issues:

　　1. The photoelectric and contact methods are structurally too complex.

　　1. Under the current value conditions of civilian water meters, the cost of creating such high-precision products contradicts the market's acceptance level.

　　2. They all change the original structure of standard water meters, destroying the "standard, reliable, precise, and mature" products that humanity has accumulated and created over decades in an instant. Whether a mature structure and standard can be established in a short time is questionable.

　　3. Whether such complex products can withstand the test of mass production and long-term lifespan remains to be explored, as many issues have already been exposed. Imaging direct-reading water meters have not changed the original mechanical standards of water meters, and their structure is relatively simple, but image processing is too complex, and translating the blurred numbers in the image into digital form is also a challenge. They are not compatible with many current bus-based and wired metering systems. The above three methods arise from a single idea: replacing electronic accumulation with mechanical accumulation. Why? Why seek difficulty when electronic technology has developed to this point? Can't even "accumulation" be accomplished? Below, I will discuss counting direct-reading remote water meters. By adding a microchip and a button battery to the existing switch-type remote water meter module, a remote water meter that can accumulate and store data while also communicating information can be created. Its output consists of only two lines, and as long as it is connected to the bus, the entire installation is complete, allowing the reading station to read water meter data at any time. Its functions and roles are the same as the previous three direct-reading meters; each water meter can operate independently of the bus. Even if there is a power outage, the water meter is disconnected, or the water meter is moved, it does not affect the water meter counting. Its success relies on three mature technologies: 1. Self-holding switch sensing, 2. Accumulation storage chip supported by lithium batteries.

　　4. Bus transmission under standard communication protocols. Since the above technologies have undergone years or decades of maturation, they are compatible with conventional products in terms of production processes, raw material supply, service systems, etc. Therefore, its success is "guaranteed." Counting direct-reading remote water meters will become the mainstream product of direct-reading remote water meters.