Clock calibration method of wireless meter reading system and clock calibration method of distributed system

Abstract

The invention discloses a clock calibration method of a wireless meter reading system. The method comprises the following steps of: carrying out timed communication for time calibration in a set time interval, wherein a main module of each group initiates the timed communication and sends self time to each submodule, and the submodule immediately updates individual time with the received time; synchronizing time between a hand-held meter reading machine with a standard clock and a meter body, storing the clock of the hand-held meter reading machine by the meter body, and recording the offset between the clock of the hand-held meter reading machine and a old clock, wherein the meter body still operates with a old clock without immediate update; synchronizing time between the hand-held meter reading machine and the main module in each group; starting timed relay communication by each main module by adopting the old clock in a time calibration interval right after time synchronization, and sending a new clock to all submodule members in the group through a clock calibration command, wherein the new clock is subsequently adopted in the whole group. The clock calibration method of the wireless meter reading system, which is proposed by the invention, can be used for eliminating clock offset in the groups of the meter body to ensure the clock accuracy in the groups and effectively avoid timed communication conflicts.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, relates to a wireless meter reading system, in particular to a clock calibration method of the wireless meter reading system; at the same time, the invention also relates to a distributed system clock calibration method. Background technique [0002] In a distributed system, each module has its own time. When the distributed system adopts the fixed time communication method, it is necessary to ensure that the time of each module is consistent to ensure the reliability of communication. [0003] A wireless meter reading system includes several management servers, several handheld meter reading machines, and several gas meters, and is divided into N groups according to the installation locations of the gas meters. Each group uses a fixed-time communication method. At a fixed time every day, the main module of the group initiates communication, and the sub-module responds. It is nece...

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Problems solved by technology

[0005] 1. The clocks of each gas meter module always have errors, and the accumulation of errors is very considerable. For example, the difference is 1S every day, and the difference is 30S in a month. How to solve the cumulative error

[0006] 2. In the gas meter group, once the clock of a certain module deviates, the existing system cannot correct it

[0007] 3. The existing system cannot guarantee the accuracy of clocks between groups, and at the same time cannot guarantee that regular communication does not conflict

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