Multi-user smart meter is a kind of power data acquisition instrument with MCU as the core and large-scale power collection module. It has multi-user power collection. Advanced functions such as remote data transmission, user power supply control, and multi-rate electricity metering are small in size and powerful in function. They are popular among users such as college student residences and intelligent communities.

In order to improve the flexibility of meter usage, there are some programmable parameters, such as meter number, metering number, communication rate, meter pulse constant, complex The time period value of the rate period, the power supply status of each household, and the measured data, that is, the power consumption of each user. Once these data are damaged by interference, not only the instrument can not work normally, but also cause economic losses to the user and cause economic disputes. Therefore, the reliability, security and non-volatility of the data must be guaranteed.

The power consumption of each user is converted into a pulse proportional to the amount of electricity through a large-scale energy metering integrated circuit (such as BL0933, ADE7755, etc.) After the photoelectric coupling circuit is passed, the switch input interface is taken into the memory by the CPU, and the CPU accumulates the power consumption of each user according to the collected pulse amount, stores it in the non-volatile memory, and displays it by the display. The circuit turns to show the electricity consumption of each household. Remote transmission of measurement data is realized by a remote communication interface circuit (such as RS485, CAN bus).

In order to improve the reliability of the instrument, optical isolation circuits are designed in the data acquisition circuit and the remote transmission circuit, and the independent design of X5045 chip is designed. The watchdog circuit, in order to achieve non-volatile storage of parameters and data, the instrument uses two kinds of memory, one is 512 bytes of non-volatile memory inside the X5045; the other is independent direct interface with the CPU Nonvolatile memory W24C16. The two memories work together with software measures to achieve non-volatile, highly reliable storage of data.