CN105116366B - Quick correction method based on adjustment meter constant - Google Patents

Abstract

The invention discloses a fast meter calibration method based on adjusting the pulse constant, which includes the following steps: 1) adjusting the pulse constant of the electric meter to N times the original by adjusting the frequency division coefficient in the production process; 2) measuring the chip in the electric meter Connect a resistor in series with the SPI bus between the MCU in the meter to eliminate interference or jitter; 3) Calibrate the meter through software to meet the meter error requirements; 4) After the production calibration is completed, restore the frequency division factor to Normal state, and remove the series resistance on the SPI bus in step 2), so as to restore the pulse constant of the meter to the original value. The invention adjusts the pulse constant of the electric meter to the original N times by adjusting the frequency division coefficient during production, and eliminates the interference or jitter on the data signal transmission SPI bus, and restores the frequency division coefficient to the normal state after the production correction is completed , greatly improve production efficiency and reduce production costs, and have good application prospects.

Description

A Quick Meter Calibration Method Based on Adjusting Pulse Constant

technical field

The invention belongs to the technical field of electric meter calibration, and in particular relates to a fast meter calibration method based on adjusting pulse constants.

Background technique

At present, the three-phase smart meters on the market use special metering chips to complete power collection (such as ADE7858, ATT7022, RN8302, etc.), but these metering chips use software calibration to meet the requirements of meter errors. Software calibration Using the pulse constant of the meter to calibrate and check the meter, the production cycle is long and the production efficiency is low, especially for the three-phase smart meter with small current, such as 57.7V, 1.5 (6) A meter under the current of 1% In , the interval between each pulse is about 70 seconds, which greatly increases the time for software calibration, which is very inconvenient to use and low in efficiency.

Contents of the invention

The technical problem solved by the invention is to overcome the problems of long production cycle and low production efficiency of the three-phase smart electric meters on the market which adopt software calibration. In the method of fast meter calibration based on the pulse constant adjustment method of the present invention, the pulse constant of the electric meter is adjusted to N times of the original by adjusting the frequency division coefficient during production, and the interval time of each pulse is shortened to 1/N second. After the calibration is completed, the frequency division coefficient is restored to the normal state, which can greatly improve the production efficiency and reduce the production cost, and has a good application prospect.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A kind of fast calibration method based on adjusting the pulse constant is characterized in that: comprising the following steps,

Step (1), adjust the pulse constant of the meter to the original N times by adjusting the frequency division coefficient in the production process, so that the interval between two adjacent pulses is shortened to the original 1/N times;

Step (2), connecting a resistor in series with the SPI bus between the metering chip in the meter and the MCU in the meter, the resistor and the parasitic capacitance on the metering chip form a low-pass filter to eliminate interference or jitter on the SPI bus;

Step (3), calibrate the electric meter through software to meet the meter error requirements;

Step (4), after the production calibration is completed, restore the frequency division factor to the normal state, and remove the resistor connected in series on the SPI bus in step (2), so as to restore the pulse constant of the meter to the original value.

The aforementioned fast meter calibration method based on adjusting the pulse constant is characterized in that: the value of N is between 2-4.

The aforementioned fast meter calibration method based on adjusting the pulse constant is characterized in that: step (1), the method of adjusting the pulse constant of the meter to the original N times by adjusting the frequency division coefficient in the production process is to short-circuit the meter inside the meter The pins of each frequency divider of the chip are realized.

The aforementioned fast meter calibration method based on adjusting the pulse constant is characterized in that: step (2), a resistor is connected in series with the SPI bus between the metering chip in the meter and the MCU in the meter, and the resistance value of the resistor is 10~100Ω.

The aforementioned fast meter calibration method based on adjusting the pulse constant is characterized in that: step (4), after the production calibration is completed, the method of restoring the frequency division coefficient to the normal state is to disconnect each frequency divider of the metering chip in the meter The shorted pins are implemented.

The aforementioned fast meter calibration method based on adjusting the pulse constant is characterized in that: step (2), a capacitor is connected in parallel to the SPI bus between the metering chip in the meter and the MCU in the meter, and the capacitance value is 10pF.

The beneficial effects of the present invention are: the rapid meter calibration method based on adjusting the pulse constant of the present invention adjusts the pulse constant of the electric meter to the original N times by adjusting the frequency division coefficient during production, and the interval time of each pulse is shortened to 1 /N seconds, and eliminate the interference or jitter on the SPI bus of data signal transmission, and restore the frequency division coefficient to the normal state after the production calibration is completed, so that the production efficiency can be greatly improved and the production cost can be reduced, which has a good application prospect .

Description of drawings

Fig. 1 is a flow chart of the fast meter calibration method based on adjusting the pulse constant of the present invention.

Fig. 2 is a schematic circuit diagram of eliminating interference or jitter on the SPI bus of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the fast meter calibration method based on adjusting the pulse constant of the present invention adjusts the pulse constant of the electric meter to the original N times by adjusting the frequency division coefficient during production, and then the interval time of each pulse is shortened to 1/ N seconds, and eliminate the interference or jitter on the SPI bus of the data signal transmission, and restore the frequency division factor to the normal state after the production calibration is completed, so that the production efficiency can be greatly improved and the production cost can be reduced. Specifically, the following steps are included.

Step (1), adjust the pulse constant of the meter to the original N times by adjusting the frequency division coefficient in the production process, so that the interval between two adjacent pulses is shortened to the original 1/N times, N is the frequency multiplication coefficient, For example, adjusting the internal frequency of the meter from 64 to 16 is equivalent to expanding the pulse frequency of electric energy by 4 times under the same input conditions, and at the same time expanding the pulse constant of the meter calibration station by 4 times. The pins of the frequency dividers of the metering chip in the meter are implemented. In order to reduce the jump of the meter error, the frequency multiplication factor N cannot be set too large. The value of 2-4 is more appropriate. The error value before and after frequency multiplication changes <0.01% , can basically be ignored, and the frequency division number of the high-frequency pulse in the original meter is required to be divisible by N, so that the error change caused by the pulse mantissa can be avoided

Step (2), connect a resistor in series with the SPI bus between the metering chip in the meter and the MCU in the meter. The resistor and the parasitic capacitance on the metering chip form a low-pass filter to eliminate interference or jitter on the SPI bus. The value is 10~100Ω. You can also connect a capacitor in parallel with the SPI bus between the metering chip in the meter and the MCU in the meter. The capacitor value is 10pF to improve the filtering effect. The circuit diagram is shown in Figure 2. The selection should be carried out according to the speed of the SPI bus and the signal of the external MCU;

Step (3), calibrate the electric meter through software to meet the meter error requirements;

Step (4), after the production calibration is completed, disconnect the short-connected pins of each frequency divider of the metering chip in the meter to restore the frequency division coefficient to the normal state, and remove the serial connection on the SPI bus in step (2). If there is a capacitor connected in parallel on the SPI bus, the capacitor will also be removed, so as to restore the pulse constant of the meter to the original value.

According to the fast meter calibration method based on adjusting the pulse constant of the present invention, one embodiment, such as a three-phase four-wire smart meter with a specification of 3×57.7/100V and 1.5(6)A, the normal pulse constant is 20000imp/kwh, If calibration and meter inspection are carried out according to the constant of 20000 imp/kwh during the production verification process, each meter basically takes 30 minutes, but if the constant of the smart meter is enlarged by 4 times by adjusting the frequency division coefficient, then the debugging and meter inspection The time can be shortened to 1/4 of the original, that is, the time for calibration and meter inspection is shortened to less than 8 minutes. After the production is completed, the frequency division coefficient is restored to the original state, which can greatly improve production efficiency and reduce production costs.

To sum up, the rapid meter calibration method based on adjusting the pulse constant of the present invention adjusts the pulse constant of the electric meter to the original N times by adjusting the frequency division coefficient during production, and the interval time of each pulse is shortened to 1/N Seconds, and eliminate the interference or jitter on the SPI bus for data signal transmission, and restore the frequency division factor to the normal state after the production calibration is completed, so that the production efficiency can be greatly improved and the production cost can be reduced, which has a good application prospect.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. a kind of quick correction method based on adjustment meter constant, it is characterised in that：Comprise the following steps,

Step（1）, original N times is adjusted to by adjusting divide ratio the meter constant of ammeter in process of production, makes phase Two adjacent interpulse periods shorten to original 1/N times；

Step（2）, a resistance of being connected on spi bus, resistance and meter are connected between computation chip and MCU in ammeter in ammeter The parasitic capacitance on chip is measured, low pass filter is constituted, interference or shake on spi bus is eliminated；

Step（3）, by software mode to ammeter calibration, reach the requirement of meter error；

Step（4）, after the completion of production correction, divide ratio is returned into normal state, and remove step（2）Middle SPI is total The resistance connected on line, so that the meter constant of ammeter is returned to original numerical value.

2. the quick correction method according to claim 1 based on adjustment meter constant, it is characterised in that：The N's takes It is worth between 2-4.

3. the quick correction method according to claim 1 based on adjustment meter constant, it is characterised in that：Step（1）, The meter constant of ammeter, which is adjusted to N times original of method, by adjusting divide ratio in production process is, in short circuit ammeter The pin of each frequency divider of computation chip is realized.

4. the quick correction method according to claim 1 based on adjustment meter constant, it is characterised in that：Step（2）, A resistance of being connected on spi bus is connected in ammeter between computation chip and MCU in ammeter, resistance is 10 ~ 100 Ω.

5. the quick correction method according to claim 1 based on adjustment meter constant, it is characterised in that：Step（4）, After the completion of production correction, the method that divide ratio is returned into normal state is to disconnect each frequency divider of computation chip in ammeter Short circuit pin realize.

6. the quick correction method according to claim 1 based on adjustment meter constant, it is characterised in that：Step（2）, will Each wire in ammeter in computation chip and ammeter between MCU in connection spi bus passes through capacity earth, the electric capacity of each electric capacity It is worth for 10pF.