Principle, type and advantages and disadvantages of prepaid water meter

Principle, type and advantages and disadvantages of prepaid water meter

First, concept and principle

Prepaid water meter is a new type of water meter that uses modern micro-electronic technology, modern sensing technology and intelligent stored value card technology to measure water consumption and transfer water data and settle transactions. It is a new type of intelligent metering instrument that is manufactured by adding electronic control module and electronic control valve to the traditional mechanical water meter.

Prepaid water meter is divided into IC card water meter, TM card water meter and code water meter according to stored value card technology, commonly known as card water meter.

Ii. Working process

Insert the stored value card containing the amount or purchase information into the reader of the water meter. After the microprocessor identifies and downloads the amount, the electronic control valve is opened and the user can use water normally. When the user uses water, the water acquisition device starts to collect the water consumption, and converts the required electronic signal to the microprocessor for measurement, and displays it on the LCD screen. When the amount of water used by the user drops to a certain value, the alarm device of the water meter will automatically make corresponding alarm or warning to close the valve, prompting the user to pay for water with the card. If the amount of water is exceeded, the water meter will automatically close the electronic control valve and cut off the water supply. After the user pays, insert the IC card that has been paid and automatically open the valve for water supply.

3. Paid software

There is no guiding standard for the charging software of prepaid water meters in the country. It is developed by manufacturers according to their own product performance and characteristics. Each manufacturer has its own set of mature and finalized software. With the development of software technology, the charging software of prepaid water meter is a very simple procedure, and the database is not complicated. Manufacturers can add some functions on their own software according to the needs of different water companies, such as statement, acceptance, audit, bill printing, ladder water price, water hoarding, etc. The main features of all developers' charging procedures for prepaid water meters include the following:

1. Daily business: account opening, issuing cards, selling water to recharge, reporting loss and replacing water meters;

2, operator permission setting function: in the personnel who need to contact the management software, by setting different permissions, restrict some operations that may cause harm to the normal use of the system, or illegal modification or deletion of management information, user records and other important data.

3, water analysis function: according to the date, the user can buy water water analysis;

4, data browsing query function: can be user query, recharge query, card query, table query, card reading query;

5. Bill setting and printing function: Different software users will have different requirements on the format and content of the water sales invoice (receipt). The management software can modify the printing of the invoice by the software operator according to the actual situation.

6, data summary and analysis function, suspicious user monitoring function: the operator can set the query method of summary freely, summary time range, and can produce report details as required. For example, the list of users whose cumulative number of magnetic disturbances is not zero; Analysis of users' water purchase status in the last time (*** list of users in the last recharge days in descending order. Users who do not recharge for a long time may be problem users); *** Analysis of abnormal status of water meter purchased recently (the list shows users with low battery of water meter and valve failure); Automatically screen and summarize the suspicious users whose water purchase situation does not conform to common sense, and compile a list of suspicious users for managers' reference.

7. Statistical statement: make statistics of recharge data and analyze the data in the returned water meter.

8. Backup and recovery: For the safety of the system, operators are required to perform backup operations regularly. If an accident occurs, you can restore the backup data.

9, step water price function: set the water price of different steps, can automatically calculate the step water charge;

10. Water hoarding function;

Here needs to be right "ladder water price" function realization makes a little explanation. Step water price is a new charging method proposed with the development of "one household, one meter" in recent years. Smart water meter manufacturers also advertise that their products can realize step water price. Indeed, the function of step water price can be fully realized with smart pre-paid water meter. However, only when both charging software and charging meter have the function of step water price, can the function of step water price be calculated.

Because the software program that can realize the function of stepped-water pricing is very simple, smart water meter manufacturers can solve it. To realize the function of stepped-water pricing, the charging software and charging water meter need to be replaced.

Step water meter displays "used amount and remaining amount" on LCD screen, while non-step water meter displays "used amount (M3)". If step water meter does not need to use step function, set all steps as one parameter.

Four, IC card water meter

According to the schematic diagram of the prepaid water meter, if the stored value card is an IC card, the water meter is an IC card water meter. It is composed of base table, power supply (battery), IC card reader, LCD communication interface, display, microcomputer control module, valve control mechanism, peak alarm device.

Base table can use rotor type water meter (wet or dry), or volumetric water meter, most manufacturers use rotor type water meter as IC card water meter base table. The sensor is mounted on a reading plate or in a counting gear set.

IC card reader is divided into card type and induction type. Insert card type with magnetic card, a plug can be simple and convenient, but the card's contact surface is easy to wear, card holder external vulnerable to damp environment and artificial attack interference, but with the development of IC card technology, technology has been mature, damp and attack problems have been improved, IC card water meter manufacturers mostly use this way of IC card reader. Inductive IC card also known as radio frequency card, commonly known as non-contact IC card, the use of this way is not much.

The power supply uses built-in lithium battery and ordinary alkaline dry battery pack. Lithium battery has high energy, small leakage and long life. The current IC card water meter is mostly powered by lithium battery. Battery power (life) is a crucial performance index in the use of intelligent prepaid water meter, which should be paid great attention to in the selection.

At present, IC card water meter electronic control valves are mainly ball valve, ceramic valve and diaphragm valve. Ball valve due to the requirements of the driving torque, due to scaling or wear in use, it is easy to leak, switch failure and other problems, IC card water meter using such valves more, in the use of the most problems. Ceramic valve has long service life, high switching reliability, small pressure loss, and is not easy to scale in use.

Another important performance index of IC card water meter is the main chip of card and electronic control module. IC card piece has two kinds, namely logical encryption card and CPU card. Logical encryption card is simple in design, low in cost, but low in security, easy to be decrypted and copied, mainly used in the stand-alone IC card charging system; CPU card has a large capacity, as the IC card water meter information transmission medium has a high security, because the 3DES algorithm is used to ensure the security of the system, it is not easy to be decrypted and copied, the network version of IC card charging system uses this card. The quality performance of the main chip of the electronic control module (namely the microprocessor part in the schematic diagram) determines the reliability and stability of the IC card water meter's water acquisition, processing, display and data storage.