CN112082627A - Software metering calibration processing method based on optical signal sampling - Google Patents

Abstract

The invention provides a software metering calibration processing method based on optical signal sampling, which tests indicating value errors at different flow rates through a bell-type gas calibrating device to obtain an indicating value error curve of an uncalibrated base table: connecting two adjacent points for error curve fitting, respectively obtaining the standard flow rate and the uncalibrated flow rate of the two selected adjacent points, calculating the calibration coefficient of each two adjacent points, obtaining the calibration coefficient query table of the gas meter, storing the calibration coefficient query table in the data memory of the gas meter, and carrying out metering calibration processing through the obtained calibration coefficient query table. Aiming at photoelectric direct reading, the method of the invention cancels a calibration gear, thereby reducing the product cost, simplifying the device structure of the product, simplifying the production process and obviously having errors superior to those of mechanical calibration.

Description

Software metering calibration processing method based on optical signal sampling

Technical Field

The invention relates to a software metering calibration processing method based on optical signal sampling for a membrane type gas meter.

Technical Field

The method comprises the following steps of (1) obtaining signals by a Hall pulse type and photoelectric direct reading signals. The Hall signal acquisition needs to add magnetic steel on the character wheel and needs to add a Hall detection element outside the character wheel. The photoelectric direct reading information needs to read the position state of the character wheel by reading the infrared transmitting device and the receiving device inserted into the character wheel. Whether the Hall pulse signal is picked up or the photoelectric direct signal is picked up, a group of calibration gears are required to be additionally arranged on the base meter for mechanical calibration, so that the metering precision of the base meter can meet the metering requirement. The mechanical gear calibration structure is complex, the production cost is high, the time and the labor are consumed, the calibration coefficient is single, and the error calibration requirement cannot be met.

Disclosure of Invention

The invention aims to solve the problems existing in mechanical gear calibration, and provides a software metering calibration processing method based on optical signal sampling, which cancels a calibration gear, thereby reducing the product cost, simplifying the device structure of the product and simplifying the production process.

In order to realize the content of the invention, the invention adopts the following technical scheme:

the optical signal acquisition principle;

according to the characteristics of a base meter of the diaphragm gas meter, the gas volume of a driving wheel of the base meter rotating for one circle is the rotary volume Vc of the base meter, and the rotary volume Vc is needed to be calibrated and calculated during metering.

The optical signal acquisition turntable shown in fig. 1 is added on the driving wheel, the optical signal detection end sequentially receives N signals which change according to a strict sequence when the optical signal detection end rotates for one circle, and the accumulated air volume corresponding to every two adjacent signals is Vc/N.

A software measurement calibration processing method based on optical signal sampling comprises the following steps:

step 1, calculating ventilation flow rate

When the gas meter is at different flow rates of ventilating, the error of the gas volume and the rotation volume of the driving wheel rotating for one circle is different, so that the gas meter needs to be calibrated in a segmented mode according to different flow rates. And recording the time interval T of sampling the N changed optical signals by a low-power-consumption timer on the singlechip, wherein the current uncalibrated gas flow rate Q' is Vc/T.

Wherein Vc is the revolution volume of the base meter, namely the volume of gas generated by one rotation of the driving wheel of the base meter.

Step 2, calibrating the ventilation flow rate;

the indicating value error under different flow rates is tested through a bell-type gas calibrating device, and an indicating value error curve of an uncalibrated base table is obtained:

E＝((Qi-Qref)/Qref)*100％

in the formula:

e- -indicates the error in value, expressed in percent (%);

qi- - -volume displayed by gas meter, unit is cubic meter (m3)

Qref- -volume actually passing through the meter in cubic meters (m3)

Connecting two adjacent points for error curve fitting, and then on each broken line, the relationship between the standard flow rate and the uncalibrated flow rate is as follows:

Q＝KQ’+B--------①

wherein Q is a standard flow rate and Q' is an uncalibrated flow rate; k and B are calibration coefficients; for two selected adjacent points (Qi, Qi ') and (Qi +1, Qi + 1'), the standard flow rate is obtained by sonic nozzle metrology, where i ∈ {1, 2, … n }, and n is the number of points present in the error curve fitting process of the indicative error curve.

Then K and B in formula (i) can be calculated as:

K＝(Qi+1-Qi)/(Qi+1’-Qi’)---------②

B＝Qi-KQi’＝Qi-Qi(Qi+1-Qi)/(Qi+1’-Qi’)--------③

the calibration coefficients of every two adjacent points are calculated by adopting the method, and the calibration coefficient lookup table of the gas meter can be obtained and stored in the data memory of the gas meter.

Step 3, calculating the accumulated air quantity;

recording the time interval delta t of sampling two signal changes through a low-power-consumption timer, and inquiring a corresponding calibration coefficient of the current uncalibrated flow velocity in a calibration coefficient inquiry table of the base table to obtain (Kn, Bn), wherein the actual accumulated gas quantity S is calculated according to the following formula:

s ═ knvc/N + Δ tBn, unit (L)

The invention has the following beneficial effects:

aiming at photoelectric direct reading, the method of the invention cancels the calibration gear, thereby reducing the product cost, simplifying the device structure of the product and simplifying the production process. From a comparison of the test results, the overall error with the software calibration method is significantly better than with the mechanical calibration.

Drawings

FIG. 1 is a diagram of an optical signal-taking carousel;

FIG. 2 is a signal level diagram of the sequential outputs of the optical pick-up turntable as it rotates;

FIG. 3 is a graph of base table metering error.

Detailed Description

The invention is further explained below with reference to the figures and examples.

A software measurement calibration processing method based on optical signal sampling comprises the following steps:

step 1, calculating ventilation flow rate

When the gas meter is at different flow rates of ventilating, the error of the gas volume and the rotation volume of the driving wheel rotating for one circle is different, so that the gas meter needs to be calibrated in a segmented mode according to different flow rates. And recording the time interval T of sampling the N changed optical signals by a low-power-consumption timer on the singlechip, wherein the current uncalibrated gas flow rate Q' is Vc/T.

Wherein Vc is the revolution volume of the base meter, namely the volume of gas generated by one rotation of the driving wheel of the base meter.

Step 2, calibrating the ventilation flow rate;

the indicating value error under different flow rates is tested through a bell-type gas calibrating device, and an indicating value error curve of an uncalibrated base table is obtained:

E＝((Qi-Qref)/Qref)*100％

in the formula:

e- -indicates the error in value, expressed in percent (%);

qi- - -volume displayed by gas meter, unit is cubic meter (m3)

Qref- -volume actually passing through the meter in cubic meters (m3)

Connecting two adjacent points for error curve fitting, and then on each broken line, the relationship between the standard flow rate and the uncalibrated flow rate is as follows:

Q＝KQ’+B--------①

wherein Q is a standard flow rate and Q' is an uncalibrated flow rate; k and B are calibration coefficients; for two selected adjacent points (Qi, Qi ') and (Qi +1, Qi + 1'), the standard flow rate is obtained by sonic nozzle metrology, where i ∈ {1, 2, … n }, and n is the number of points present in the error curve fitting process of the indicative error curve.

Then K and B in formula (i) can be calculated as:

K＝(Qi+1-Qi)/(Qi+1’-Qi’)---------②

B＝Qi-KQi’＝Qi-Qi(Qi+1-Qi)/(Qi+1’-Qi’)--------③

the calibration coefficients of every two adjacent points are calculated by adopting the method, and the calibration coefficient lookup table of the gas meter can be obtained and stored in the data memory of the gas meter. Where n is the number of points present in the error curve fitting process of the indicative error curve.

Step 3, calculating the accumulated air quantity;

recording the time interval delta t of sampling two signal changes through a low-power-consumption timer, and inquiring a corresponding calibration coefficient of the current uncalibrated flow velocity in a calibration coefficient inquiry table of the base table to obtain (Kn, Bn), wherein the actual accumulated gas quantity S is calculated according to the following formula:

example 1:

according to the characteristics of a base meter of the diaphragm gas meter, the gas volume of a driving wheel of the base meter rotating for one circle is the revolution volume of the base meter, calibration and calculation are carried out by taking the revolution volume as a reference during metering, and the revolution volume is explained by taking 1.2L as an example in the following description.

The optical signal-taking turntable shown in fig. 1 is added on the driving wheel, and a total of 12 signals are rotated for one circle, as shown in fig. 2, the accumulated air volume corresponding to every two adjacent signals is 0.1L.

A software measurement calibration processing method based on optical signal sampling comprises the following steps:

step 1, calculating ventilation flow rate

When the gas meter is at different flow rates of ventilating, the error of the gas volume and the rotation volume of the driving wheel rotating for one circle is different, so that the gas meter needs to be calibrated in a segmented mode according to different flow rates. The time interval Δ t of sampling 12 changed optical signals is recorded by a low power consumption timer, and the current uncalibrated gas flow rate Q' is 1.2L/Δ t

Step 2, calibrating the ventilation flow rate;

a typical metrological error curve for an uncalibrated base table is shown in figure 3:

according to the metering error curve, the gas flow rate is divided into the following 6 sections:

at each stage, the relationship between the standard flow rate and the uncalibrated flow rate is:

Q＝KQ’+B--------①

wherein Q is a standard flow rate and Q' is an uncalibrated flow rate; k and B are calibration coefficients; for two selected adjacent points (Qi, Qi ') and (Qi +1, Qi + 1')

Then K and B in formula (i) can be calculated as:

K＝(Qi+1-Qi)/(Qi+1’-Qi’)---------②

B＝Qi-KQi’＝Qi-Qi(Qi+1-Qi)/(Qi+1’-Qi’)--------③

the calibration coefficient of each segment is calculated by adopting the method, and the calibration coefficient lookup table of the gas meter can be obtained and stored in the data memory of the gas meter.

Step 3, calculating the accumulated air quantity;

recording the time interval delta t of sampling two signal changes through a low-power-consumption timer, and inquiring a corresponding calibration coefficient of the current flow rate in a calibration coefficient inquiry table of the base table to obtain (Kn, Bn), wherein the actual accumulated gas quantity S is calculated according to the following formula:

0.1Kn + Δ tBn, Unit (L)

Step 4, comparing actual calibration measurement results:

the actual measured error under this calibration coefficient table is as follows:

the error of the same base table using mechanical gear calibration is as follows:

Claims (1)

1. a software measurement calibration processing method based on optical signal sampling comprises the following steps:

step 1, calculating ventilation flow rate

When the gas meter is at different ventilation flow rates, the error between the gas volume and the rotation volume of the driving wheel rotating for one circle is different, so that the gas meter needs to be calibrated in a segmented manner according to different flow rates; recording the time interval T of sampling N changed optical signals by a low-power-consumption timer on the singlechip, wherein the current uncalibrated gas flow rate Q is Vc/T;

step 2, calibrating the ventilation flow rate;

the indicating value error under different flow rates is tested through a bell-type gas calibrating device, and an indicating value error curve of an uncalibrated base table is obtained:

E＝((Qi-Qref)/Qref)*100％

in the formula:

e- -indicates the error in value, expressed in percent (%);

qi- - -volume displayed by gas meter, unit is cubic meter (m3)

Qref- -volume actually passing through the meter in cubic meters (m3)

Connecting two adjacent points for error curve fitting, and then on each broken line, the relationship between the standard flow rate and the uncalibrated flow rate is as follows:

Q＝KQ’+B--------①

wherein Q is a standard flow rate and Q' is an uncalibrated flow rate; k and B are calibration coefficients; for two selected adjacent points (Qi, Qi ') and (Qi +1, Qi + 1'), the standard flow rate is obtained by metering through a sonic nozzle, wherein i belongs to {1, 2, … n }, and n is the number of points existing in the error curve fitting process of the indicating error curve;

then K and B in formula (i) can be calculated as:

K＝(Qi+1-Qi)/(Qi+1’-Qi’)---------②

B＝Qi-KQi’＝Qi-Qi(Qi+1-Qi)/(Qi+1’-Qi’)--------③

calculating the calibration coefficients of every two adjacent points by adopting the method, obtaining a calibration coefficient query table of the gas meter and storing the calibration coefficient query table in a data memory of the gas meter;

step 3, calculating the accumulated air quantity;

recording the time interval delta t of sampling two signal changes through a low-power-consumption timer, and inquiring a corresponding calibration coefficient of the current uncalibrated flow velocity in a calibration coefficient inquiry table of the base table to obtain (Kn, Bn), wherein the actual accumulated gas quantity S is calculated according to the following formula:

s ═ Kn × Vc/N + Δ tBn, units (L).

Images