CN104714404A

CN104714404A - Method for improving clock precision in electric energy meter

Info

Publication number: CN104714404A
Application number: CN201410835559.6A
Authority: CN
Inventors: 李维特; 姚徐旭
Original assignee: Holley Technology Co Ltd
Current assignee: Holley Technology Co Ltd
Priority date: 2014-12-30
Filing date: 2014-12-30
Publication date: 2015-06-17

Abstract

The invention provides a method for improving clock precision in an electric energy meter. The method for improving the clock precision in the electric energy meter is achieved by arranging a TCXO crystal oscillating unit in a single chip microcomputer of the electric energy meter. The method for improving the clock precision in the electric energy meter comprises the first step that an RTC clock of the single chip microcomputer is configured through an outer RTC source or an inner RTC source; the second step that interruption function second pulse output is arranged on the TCXO crystal oscillating unit; the third step that the current time of the TCXO crystal oscillating is set; and the forth step that the current time is calculated through a counter in the single chip microcomputer.

Description

A kind of method improving electric energy meter internal clock precision

Technical field

The present invention relates to a kind of Curve guide impeller of the clock of power meter system based on TCXO crystal oscillator.

Background technology

Clock is as one of electronic type intelligent electric energy meter important function, ensure that the precision of clock is necessary with safety, the invention application to be design presentation a kind of method that clock of power meter realizes, improves the clock accuracy of electric energy meter, improves the reliability of clock.

The clock at present our electric energy meter used mainly contains two kinds, soft clock and hardware clock.Soft clock: the inside RTC clock of so-called soft clock and stm32 single-chip microcomputer, uses the passive crystal oscillator of an outside 32.768KHz as its clock reference, although it is the internal resource of single-chip microcomputer, use easily and safety, its precision is not very high.Hardware clock: the clock chip of so-called hardware clock and single-chip microcomputer outside, as DS3231, RX8025T etc., the 32.768KHz crystal oscillator of the most of built-in high stability of these clock chips, although the precision of hardware clock can ensure, but due to real-time communication can be excessive occupying system resources, so system clock can not rely on hardware clock completely.

In this case, we need soft clock and hardware clock to combine to ensure our system clock, on the one hand in order to reduce the precision that take and ensure clock of hardware clock to system resource, we per minutely can read a hardware clock, carry out synchronous with this time data with system clock simultaneously, to ensure the accurate of clock minute data, on the other hand in order to obtain the number of seconds certificate of clock, we use the inner RTC of single-chip microcomputer as number of seconds certificate, even if the precision of inner RTC is not very high, but often will once through after one minute synchronously, be equivalent to calibrate clock, namely our system clock ensure that precision to the full extent like this, in turn ensure that security.

Summary of the invention

The embodiment of the present invention solves aforementioned drawback, design a kind of method improving electric energy meter internal clock precision, TCXO crystal oscillator is the active crystal oscillator of the high stability that a built-in temperature compensates, its error within the scope of total temperature can reach ± 5ppm, so we just think can using the clock reference of TCXO crystal oscillator as single-chip microcomputer inside RTC, replace the external passive crystal oscillator of 32.768KHz, remove outside hardware clock simultaneously.The synchronizing process of clock can be saved like this when guaranteeing precision, reducing the probability of makeing mistakes.

In one embodiment, a kind of High Accuracy Clock Curve guide impeller of ammeter, its precision can reach equivalent standard with the precision of clock chip, it utilizes single-chip microcomputer internal resource, eliminates the communication of single-chip microcomputer and external chip, and original basis improves security, present single clock source is replaced with in original doubleclocking source, eliminate synchronous process, decrease the amendment number of times to system clock, increase the reliability of system clock.

Technical scheme: a kind of implementation method improving clock of power meter precision, realizing by arranging TCXO crystal oscillator unit in the single-chip microcomputer of described electric energy meter, comprising step as follows: the RTC clock 1) being configured single-chip microcomputer by an outside RTC source or inner RTC source; 2) arrange interrupt function pulse per second (PPS) to described TCXO crystal oscillator unit to export; 3) current time of described TCXO crystal oscillator is set; And 4) calculate current time by the counter in described single-chip microcomputer.

In another embodiment, design a kind of clock modulation circuit plate of electric energy meter, it is only made up of single-chip microcomputer and the power supply be attached thereto, at least one TCXO crystal oscillator unit is set in described single-chip microcomputer, for generation of electric energy meter inside RTC clock, the clock source of any other single-chip microcomputer outside is not wherein set on described circuit board.

Embodiment

Improve the implementation method of clock of power meter precision, comprise step as follows: configuration single-chip microcomputer RTC clock; Arrange interrupt function pulse per second (PPS) to export; Current time is set; Current time is calculated by counter.

In one embodiment, the outside or inside being included in electric energy meter further carries out the step of different condition or environmental testing simultaneously.

Such as, described step includes electric fast transient burst of pulses testing procedure.Add three-phase supply at electric energy meter ABCN, add the pulse train of+4.4KV and-4.4KV, frequency 5KHz at ABCN, ABC, N respectively, each test 60 seconds, on pretreatment, observe clock respectively after process of the test neutralization test and whether change.

industrial applicibility is analyzed

(1) electric fast transient burst of pulses test:

pilot project	the test of electricity fast transient burst of pulses
		testing tool	quick burst of pulses test instrument
method of testing	add three-phase supply at electric energy meter ABCN, add the pulse train of+4.4KV and-4.4KV, frequency 5KHz at ABCN, ABC, N respectively, each test 60 seconds, on pretreatment, observe clock respectively after process of the test neutralization test and whether change.
		criterion	clock should be unchanged
test result	qualified

(2) ESD test:

(3) AC voltage test:

pilot project	aC voltage test
		testing tool	pressure-resistant tester
method of testing	electric energy meter reference voltage more than 40V connection together, reference voltage below 40V connection together and ground connection, add 4.4KV trial voltage between the ends, 5-10 is raised to 4.4KV by 0 in second, and maintain 60 seconds, this test carries out 20 times repeatedly.
		criterion	clock should be unchanged
test result	qualified

accuracy test

(1) normal temperature accuracy test:

Pilot project	Normal temperature accuracy test
		Testing tool	Error of time of day tester
Method of testing	Under normal temperature 23 degree, make a call to the error of 10 points continuously, each 1 minute, then average as error of time of day
		Criterion	Be less than 0.02 second every day
Test result	Qualified

(2) environment temperature is on the impact of error of time of day:

pilot project	environment temperature is on the impact of error of time of day
		testing tool	error of time of day tester, high-low temperature chamber
method of testing	measure error of time of day, measure once under environment temperature 60 degree of conditions, measure once for 23 degree ,-25 degree are measured once.Temperature coefficient calculates: this experiment measuring two value, and namely 23 degree of temperature gap t1-t0 spending temperature coefficient two temperature ranges calculated with 60 degree of temperatures coefficient calculated and 23 degree and-25 equal 37 degree and 48 degree respectively.
		criterion	two temperatures coefficient all should meet often spends 0.01 second every day, and at-25 degree, the error of time of day of 23 degree and 60 degree three temperature spots is no more than 1 second every day.
test result	qualified

technique effect

Electric energy meter adopts this programme compared with former scheme, simplify the clock system structure of electric energy meter, the clock of electric energy meter can be made to rely on independent clock source, decrease the series of problems because clock synchronous causes, ensure that the reliability of clock system, meanwhile, eliminate external clock chip, decrease the area of pcb board, decrease the cost of electric energy meter from components and parts and process aspect all to a great extent.

Claims

1. improve a method for electric energy meter internal clock precision, it is characterized in that, realizing by arranging TCXO crystal oscillator unit in the single-chip microcomputer of described electric energy meter, comprising step as follows: the RTC clock 1) being configured single-chip microcomputer by an outside RTC source or inner RTC source; 2) arrange interrupt function pulse per second (PPS) to described TCXO crystal oscillator unit to export; 3) current time of described TCXO crystal oscillator is set; And 4) calculate current time by the counter in described single-chip microcomputer.

2. the clock modulation circuit plate of an electric energy meter, it is characterized in that, only be made up of single-chip microcomputer and the power supply be attached thereto, at least one TCXO crystal oscillator unit is set in described single-chip microcomputer, for generation of electric energy meter inside RTC clock, the clock source of any other single-chip microcomputer outside is not wherein set on described circuit board.