Gas and electricity meter based on pressure difference and size paging calibration conversion

Abstract

The gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention includes: an acquisition module, including multiple sensors, which acquire the temperature and humidity, air source pressure and probe pressure difference signals of the workpiece through multiple acquisition channels; a signal processing module, which adjusts and filters the acquired signals, and outputs them to the control module after signal conversion; the control module calibrates the pressure difference signal based on the acquired signal through the air source pressure and pressure difference compensation algorithm; based on the compensated pressure difference signal, the pressure difference signal is converted into the corresponding workpiece size through the pressure difference size paging conversion algorithm; based on the converted size data, the size data at different temperatures is calibrated using the temperature and size compensation algorithm, thereby realizing accurate measurement of the real-time data of the workpiece; and based on the multi-channel synchronous acquisition technology, the corresponding workpiece statistics are calculated according to the multi-channel data and workpiece type configured by the user, thereby realizing measurement of multiple sizes of the workpiece.

Description

Technical Field

[0001] The invention relates to a testing device, in particular to a gas and electricity meter based on pressure difference and size paging calibration conversion. Background Art

[0002] With the introduction of Industry 4.0 and the continuous advancement of intelligent manufacturing, the processing and inspection of more and more parts are becoming intelligent and digital; however, in traditional production management, there are still obvious deficiencies in quality supervision: First, most companies still use manual measurement and random inspections, which is time-consuming and labor-intensive, and difficult to ensure measurement accuracy, which can easily lead to quality problems; second, there is a lack of persistence in data storage management, and no analysis of quality data, making it difficult to detect production problems in a timely manner, which can easily cause large amounts of financial losses to the company.

[0003] Measuring instruments with high measurement accuracy, ease of use and low cost are gaps that urgently need to be filled in the domestic measurement industry.

[0004] As a new type of measuring tool, the pneumatic-electrical meter uses gas as the measuring medium, converting length signals into airflow signals, which are then converted into electrical signals via a gas-to-electric converter for comparative measurement. Pneumatic-electrical measurement is based on the principles of fluid dynamics and fluid statics, and uses the pressure and flow characteristics of compressed air to measure the structure and physical dimensions of workpieces. Because it uses gas as the measuring medium, pneumatic-electrical meters offer a wider range of measurement options than other measuring instruments, minimize human error, and avoid direct contact between the measuring head and the measured surface, making them a key tool for high-precision measurement.

[0005] The main problems of the gas-electricity meters currently in use are as follows: (1) They are easily affected by environmental factors such as unstable gas source pressure, temperature and humidity changes, etc., resulting in unstable workpiece size measurement accuracy; (2) The sampling accuracy and sampling rate are insufficient, resulting in too few data samples, affecting the size measurement accuracy; (3) The pressure difference-size conversion adopts a linear conversion method, which cannot be applied to the situation where the actual differential pressure and size relationship curve is nonlinear, resulting in measurement errors. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the present invention provides a gas and electricity meter based on pressure difference and size paging calibration conversion. It uses the compensation algorithm of gas source pressure and humidity for pressure difference, and the compensation algorithm of temperature for workpiece size, and uses temperature, humidity and air pressure as environmental variables for nonlinear fitting to obtain a polynomial calibration function to calibrate the actual measured size data, thereby realizing multi-channel, high-speed and high-precision multi-size measurement.

[0007] In order to achieve the above object, the present invention provides a gas and electricity meter based on pressure difference and size paging calibration conversion, which includes:

[0008] The acquisition module includes multiple sensors, which collect the temperature and humidity of the workpiece, the air source pressure, and the probe pressure difference signal through multiple acquisition channels;

[0009] The signal processing module adjusts and filters the collected signals and outputs them to the control module after signal conversion;

[0010] The control module calibrates the pressure differential signal based on the collected signal using the air source pressure and pressure differential compensation algorithm. Based on the compensated pressure differential signal, the pressure differential signal is converted into the corresponding workpiece size using the pressure differential size paging conversion algorithm. Based on the converted size data, the temperature and size compensation algorithm is used to calibrate the size data at different temperatures to complete the real-time size measurement of the workpiece.

[0011] Based on the verified and converted dimensional data, the statistics of the configured workpiece are calculated according to the multiple acquisition channel data and the measured workpiece type configured by the user; based on the statistics of the workpiece, the real-time dimensions of each channel are alarmed and pre-warning judged, and the real-time dimensions, statistics and pre-warning alarm information corresponding to each channel are displayed.

[0012] Preferably, the step of collecting the pressure difference by the collection module includes:

[0013] Real-time differential pressure data is acquired through a multi-channel differential pressure acquisition process. If the number of acquired data reaches the set acquisition number, the multi-channel data extraction and single-cycle data processing process is executed to extract and process the data.

[0014] After a single data acquisition is completed, a pressure difference data in the FIFO operation structure is taken out for judgment. If the pressure difference is greater than the preset trigger range value, the workpiece is not currently placed or the workpiece is not placed as required, then the variable of the number of times the pressure difference exceeds the threshold is incremented by 1, and the pressure difference data judgment is performed again at the beginning of the next round of measurement refresh cycle;

[0015] If the pressure difference is within the trigger range, the variable of the number of times the pressure difference exceeds the threshold is cleared; if the number of times the pressure difference exceeds the threshold is greater than the set value, an alarm is issued and the real-time measurement ends, and the measurement starts after the user places the workpiece in the specified position.

[0016] Preferably, during the workpiece measurement process, the steps of the multi-channel data extraction and single-cycle data processing flow are specifically as follows:

[0017] Extraction steps:

[0018] Extract all unextracted data in the FIFO operation structure array within the corresponding cycle. The pressure difference storage array in the FIFO operation structure is stored in FIFO form, that is, the data stored first will be kicked out of the array first after the array is full.

[0019] Calculate the standard deviation of the extracted data. The standard deviation calculation formula is:

[0020]

[0021] Among them, N is the number of data, x i is the data at the corresponding position in the array, is the average value of all data in the array; according to the normal distribution characteristics of the data, 3σ is used to eliminate outliers and all data outside the range of x±3σ are eliminated;

[0022] Calculate the average of the eliminated data, store the average value in the pressure difference measurement storage array, and record the number of storages;

[0023] Data processing steps:

[0024] The data after single-cycle processing is stored in the pressure difference measurement storage array. When the data in the array reaches the number of pressure difference real-time data processing, the data in the corresponding array is processed;

[0025] The data is processed using the Gaussian filtering method and the average is calculated to obtain the real-time pressure difference at the current moment;

[0026] After the current sampling and data processing are completed, all variables of the current sampling are cleared and the next round of data sampling and processing begins again.

[0027] Preferably, the steps of the gas source pressure and pressure difference compensation algorithm include:

[0028] Calculate the air source pressure and pressure difference compensation value: Use the air source pressure and humidity as parameters to perform pressure difference compensation. The relationship between the air source pressure, humidity and pressure difference is:

[0029] △DP=f(Gsp,H)

[0030] Where Gsp is the source air pressure, △DP is the pressure differential compensation value, H is the current humidity, Gsp and △DP are in a polynomial relationship, H and the △DP-Gsp curve are in an interval relationship, and f is the polynomial function of the source air pressure Gsp and the pressure differential compensation value △DP in the specified temperature range;

[0031] Determine the current humidity: If the current humidity exceeds the system set humidity, the system prompts that the humidity is too high and needs to be confirmed; if the current humidity is lower than the system set humidity, the current humidity is determined to correspond to the interval of the △DP-Gsp compensation curve, and the fitting coefficient of the △DP-Gsp compensation curve of the corresponding interval is called to compensate the pressure difference of the air source pressure. The calculation formula is:

[0032] ΔDP=f(Gsp)=a6*Gsp 6 +a5*Gsp 5 +a4*Gsp 4 +a3*Gsp3 +a2*Gsp 2 +a1*Gsp+a0;

[0033] Among them, the gas source pressure Gsp uses a multi-order polynomial fitting curve to compensate the pressure difference compensation value △DP, α 0～6 is a multi-order polynomial compensation coefficient, which is obtained by the corresponding compensation coefficient acquisition algorithm;

[0034] The pressure difference compensation value △DP is used to compensate the current real-time pressure difference to obtain the compensated real-time pressure difference. The formula is:

[0035] DP=DP c +ΔDP;

[0036] Among them, DP is the real-time pressure difference after compensation, DP c is the real-time pressure difference of each channel, and △DP is the pressure difference compensation value obtained by converting the compensation polynomial of the gas source pressure to the pressure difference.

[0037] Preferably, an algorithm for obtaining a compensation coefficient corresponding to the air source pressure and the pressure difference is used. When obtaining the compensation coefficient, if the deviation between the size of the workpiece to be measured and the size of the currently calibrated workpiece is large, the compensation calibration of the air source pressure to the pressure difference is performed again. If the deviation is small, calibration is performed using the coefficient compensation algorithm. The specific steps for obtaining the compensation coefficient include:

[0038] Regularly obtain the current real-time humidity of the environment;

[0039] Determine whether the current ambient humidity is within the selected humidity range. If so, proceed to the next step; otherwise, prompt the user to adjust the ambient humidity or modify the humidity range.

[0040] If the current humidity meets the requirements, the user is prompted to put in the standard part, enter the standard part size and probe model, and obtain the calibration data bound to the standard part size and probe model;

[0041] Divide the calibration intervals into multiple intervals according to the set standard air source pressure, obtain the air source pressure value and pressure difference value in all calibration intervals, adjust the air source pressure to the standard pressure, and obtain the air source pressure and pressure difference compensation calibration coefficients for the current humidity; use a univariate polynomial fitting method to perform compensation calibration, and obtain the fitting coefficients by the least squares method. The pressure difference and the air source pressure are in a univariate sixth-order polynomial function relationship;

[0042] If the humidity range is switched and the calibration coefficients are re-fitted before the switch, the calibration coefficients of the current humidity range will be saved. The system will pop up a dialog box asking whether to save the fitting coefficients. Select to save the fitting coefficients before switching the humidity range.

[0043] After the fitting coefficients are saved, the user is prompted to adjust the calibration environment humidity to within the set humidity range; repeat the above steps to obtain the air source pressure and pressure difference compensation calibration coefficients corresponding to the set humidity range.

[0044] Preferably, the specific steps of the pressure difference size conversion performed by the pressure difference size paging conversion algorithm include:

[0045] Divide the pressure difference values ​​into pages, place the standard parts in the specified positions, obtain the corresponding pressure difference values, and based on the current pressure difference value, turn the current pressure difference page to the corresponding page and fill in the current pressure difference value in the corresponding numerical item; if the pressure difference values ​​between each page are equal at the beginning and end, proceed to the next step;

[0046] The pressure difference and size are converted using a multi-order polynomial, and the formula is:

[0047] SV i =b 6i *DP 6 +b 5i *DP 5 +b 4i *DP 4 +b 3i *DP 3 +b 2i *DP 2 +b 1i *DP+b i ;

[0048] Among them, SV i is the real-time size of the corresponding page after conversion, b 6i 、b 5i 、b 4i 、b 3i 、b 2i 、b 1i 、b i is the polynomial fitting coefficient of the corresponding page, which is obtained by the corresponding pressure difference size conversion coefficient acquisition algorithm, and DP is the real-time pressure difference after compensation by the air source pressure.

[0049] Preferably, the steps of the pressure difference size conversion coefficient acquisition algorithm include:

[0050] Obtain the real-time pressure differential value and the input pressure differential value, and the system determines whether the current pressure differential value is within the set range. If so, the current pressure differential value is filled in the pressure differential value of the corresponding calibration item;

[0051] According to the dimension values ​​of the starting item and the ending item and the total number of calibration items, the dimension values ​​of the pressure difference are divided, and the reference values ​​of all calibration dimensions on the current page are obtained and corrected;

[0052] Select the corresponding calibration item size value, and the user places the corresponding standard part according to the selected calibration item size value, and fills in the actual size value that is smaller than the previous calibration item size value and larger than the next calibration item size value in the interface;

[0053] If all the standard part dimensions and corresponding differential pressure values ​​on this page meet the requirements, calibration will begin. If there are modifications to the differential pressure and dimension input values, the modified data will be saved and the dimension values ​​will be calculated using a multi-order polynomial function. The dimension values ​​and corresponding differential pressure values ​​of all groups on the current page will be fitted using the least squares method to obtain the coefficients of the corresponding multi-order polynomial function. The calibration coefficients will be displayed on the interface.

[0054] Perform page conversion operations in the pressure difference size conversion coefficient acquisition interface. The page conversion operations include: adding a page, deleting a page, turning up a page, and turning down a page.

[0055] Preferably, the steps of the temperature and size compensation algorithm include:

[0056] Determine whether the current temperature is within the temperature range set in the temperature and dimension value compensation coefficient acquisition algorithm. If so, call the temperature and dimension value compensation coefficient acquisition algorithm to perform polynomial calculations, obtain temperature compensation, and calibrate the dimension value.

[0057] If the current temperature exceeds the set range and the number of times it exceeds the threshold is greater than the set value, the system will issue an alarm.

[0058] Preferably, the specific calculation steps of the temperature and size compensation coefficient acquisition algorithm are as follows:

[0059] The workpiece size values ​​at different temperatures are obtained, and the least squares method is used to fit the obtained multiple sets of data to obtain a univariate polynomial function of temperature relative to the size value.

[0060] Preferably, the acquisition module includes: a probe module and a temperature and humidity sensor, an air pressure sensor; the signal processing module includes: a workpiece pressure difference acquisition signal processing module and an air source pressure acquisition signal processing module connected to the control module through a parallel FMC bus; the gas-electric instrument also includes a touch screen connected to the control module through a serial port.

[0061] Preferably, the step of multi-dimensional measurement includes:

[0062] Perform stacking processing on the real-time dimension values ​​after each round of compensation calibration to obtain the workpiece dimension value of the current channel;

[0063] Calculate the taper, roundness, straightness, cylindricity and flatness of the workpiece currently being measured based on the user-configured statistical information of the workpiece and the current channel data;

[0064] Configure warning values ​​and upper and lower deviation values ​​for each channel based on calculated statistics, and make alarms and early warning judgments for the real-time size values ​​of each channel;

[0065] The real-time dimensions, statistics and alarm information of the workpiece measured by each channel are displayed on the touch screen.

[0066] Preferably, the calculation steps for measuring the taper, roundness, straightness, cylindricity and flatness of the workpiece include:

[0067] For conical or frustum workpieces, calculate the corresponding taper, specifically:

[0068] The calculation formula of cone taper is: cone taper = base diameter / cone height,

[0069] The calculation formula of the cone taper is: cone taper = |upper base diameter-lower base diameter| / cone height,

[0070] Among them, the diameter of the cone base is D, the height of the cone is H, and the size of the workpiece at each channel is CS i , the vertical spacing between adjacent channels is CVD i , where i is the channel number, then:

[0071] Cone taper = D / H = |CS i -CS i-1 | / CVD i ,

[0072] Cone taper = |CS i -CS i-1 | / CVD i ,

[0073] For circular workpieces, the roundness is calculated by rotating the workpiece and collecting multiple data from the same channel. The calculation method is the difference between the maximum and minimum size values ​​in the multiple sampling data. The number of sampling data is set through the measurement setting interface. The standard deviation is used to eliminate sudden changes in the multiple sampling data.

[0074] For cylindrical workpieces, statistics on straightness, cylindricity and flatness are performed;

[0075] Straightness is the maximum runout deviation of all channel dimensions. The maximum and minimum values ​​of all measurement channel dimensions are counted. Straightness is the difference between the maximum and minimum dimensions.

[0076] The cylindricity is determined by rotating the same cylindrical workpiece and collecting data from each channel. The cylindricity of the corresponding workpiece is then obtained by performing statistical analysis on the scattered differences of all the data from each channel.

[0077] The gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention has the following beneficial effects:

[0078] 1. To address the impact of environmental factors such as temperature, humidity, and air pressure on workpiece dimensional measurement, the present invention uses multiple sensors through multiple acquisition channels to collect signals from the source air pressure, the temperature and humidity within the measurement environment, and the pressure difference. When collecting environmental data, a high-precision signal processing module with strong anti-interference capabilities is used to process it, capable of outputting accurate environmental signals.

[0079] 2. Based on the collected gas source pressure, humidity and pressure difference signals, through the compensation algorithm of gas source pressure and humidity for pressure difference, and the compensation algorithm of temperature for workpiece size, temperature, humidity and air pressure are used as environmental variables for nonlinear fitting to obtain a polynomial calibration function to calibrate the actual measured size data, so that the gas and electricity meter can accurately measure the workpiece size under different environments.

[0080] 3. The present invention realizes multi-channel synchronous sampling and dimension measurement through multi-channel synchronous sampling technology. At the same time, according to the multi-channel data and workpiece measurement settings, it can realize the calculation of statistical quantities such as the straightness, roundness, coaxiality, perpendicularity, and flatness of the axis line of different types of workpieces, thereby realizing multi-dimensional measurement of workpieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 The principle block diagram of the gas and electricity meter system based on pressure difference and size paging calibration conversion provided by the present invention;

[0082] Figure 2 A cross-sectional view of the probe structure in the gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0083] Figure 3 Schematic diagram of the probe structure and the differential pressure sensor connected to the gas and electricity meter based on pressure differential and size paging calibration conversion provided by the present invention; wherein 1-pressure stabilizing chamber; 2-throttle orifice; 3-back pressure chamber; 4-nozzle baffle mechanism; 5-differential pressure sensor;

[0084] Figure 4 A flow chart for collecting pressure difference values ​​for each channel in the gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0085] Figure 5 A flow chart for obtaining the gas source pressure (humidity)-pressure difference compensation calibration coefficient of the gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0086] Figure 6 A flow chart for obtaining the multi-channel pressure difference-dimension value conversion coefficient of the gas and electricity meter based on pressure difference and dimension paging calibration conversion provided by the present invention;

[0087] Figure 7A flow chart of page conversion operations on a touch screen in a gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0088] Figure 8 A schematic diagram of a human-computer interaction interface for implementing page switching using a pressure difference-size conversion coefficient in a gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0089] Figure 9 The test program settings for the gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0090] Figure 10 A system operation flow chart of the gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0091] Figure 11 、 Figure 12 A circuit diagram of the acquisition module and signal processing module in the gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0092] Figure 13 A circuit diagram of the temperature and humidity sensor module in the gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0093] Figures 14 to 19 A circuit diagram of voltage conversion in a power module in a gas and electricity meter based on pressure difference and size paging calibration conversion provided by the present invention;

[0094] Figure 20 The present invention provides a flow chart of workpiece statistics calculation, display and alarm in a gas and electricity meter based on pressure difference and size paging calibration conversion. DETAILED DESCRIPTION

[0095] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0096] like Figure 1As shown, the present invention provides a gas-electricity meter based on pressure difference and size paging calibration conversion (hereinafter referred to as "gas-electricity meter"), including: an acquisition module, a signal processing module, and a control module. The acquisition module collects the temperature and humidity, gas source pressure and probe pressure difference signals of the workpiece through multiple acquisition channels; the signal processing module adjusts and filters the collected signals, and outputs them to the control module after signal conversion. The control module (main MCU) calibrates the pressure difference signal based on the collected signal through the gas source pressure and pressure difference compensation algorithm; based on the compensated pressure difference signal, the pressure difference signal is converted into the corresponding workpiece size through the pressure difference size paging conversion algorithm; based on the converted size data, the temperature and size compensation algorithm is used to calibrate the size data at different temperatures to complete the real-time size measurement of the workpiece. Based on the verified and converted size data, the statistics of the configured workpiece are calculated according to the multiple acquisition channel data and the measured workpiece type configured by the user; based on the statistics of the workpiece, the real-time size of each channel is alarmed and warned, and the real-time size, statistics and warning alarm information corresponding to each channel are displayed, thereby realizing multi-size measurement.

[0097] Specifically, the present invention uses multiple sensors to collect signals such as temperature and humidity, air source pressure, and multi-channel probe pressure difference through multiple acquisition channels, and provides accurate pressure difference signals through a high-precision anti-interference signal processing module. Based on the processed acquisition signals, the control module uses the air source pressure and humidity compensation algorithm for pressure difference and the temperature compensation algorithm for workpiece size to calculate the influence of factors such as temperature, humidity, and air pressure in the environment on the workpiece size test results. It uses the air source pressure and humidity compensation algorithm for pressure difference and the temperature compensation algorithm for workpiece size to perform nonlinear fitting on temperature, humidity, and air pressure as environmental variables to obtain a polynomial calibration function to calibrate the actual measured size data, thereby enabling the gas and electricity meter to achieve accurate size measurement under different environments. In response to the nonlinear situation of pressure difference-size conversion, and in order to improve the conversion accuracy of pressure difference-size, a paging conversion method is adopted to segment the measurement interval and use the corresponding polynomial conversion algorithm to fit the pressure difference data into a size signal, thereby improving measurement efficiency. In addition, during the conversion, operations such as adding pages, deleting pages, and jumping pages are performed within the measurement interval, further improving the flexibility of pressure difference-size conversion.

[0098] In the present invention, the signal processing module includes: a workpiece pressure difference acquisition signal processing module and a gas source pressure acquisition signal processing module, and the two communicate with the control module through a parallel FMC bus.

[0099] The workpiece pressure differential acquisition signal processing module converts the pressure differential sensor's analog signal into a digital signal that can be processed by the main MCU. It comprises a cascaded operational amplifier, filtering circuit, and multiple high-precision analog-to-digital converters (ADCs). The operational amplifiers adjust the pressure differential analog signal proportionally to ensure that the output analog signal meets the voltage conversion range of the ADC. The filtering circuits are low-pass filters that remove high-frequency interference from the operational amplifier output signal. The multiple high-precision ADCs utilize an 8-channel, 18-bit synchronous sampling ADC, which achieves multi-channel synchronous conversion of analog signals via a parallel FMC bus, providing the main MCU with abundant raw data.

[0100] The air source pressure acquisition and signal processing module and the workpiece pressure differential acquisition and signal processing module perform the same function: converting the air source pressure analog signal into a digital signal that can be processed by the main MCU. To improve the accuracy of each channel's dimensional measurement, the air source pressure of each channel is collected separately and calibrated using an air source pressure-pressure differential calibration algorithm.

[0101] In this embodiment, the acquisition module includes:

[0102] Temperature and humidity acquisition module, consisting of temperature and humidity sensors;

[0103] The probe module includes a probe and a pressure differential sensor. The probe needs to select the appropriate probe form and appropriate probe size according to the structure and position of the measured part, so that the relationship between the pressure difference and the change of the gap during measurement is approximately linear, making the measurement result more accurate. The pressure differential sensor collects the pressure difference between the air pressure of the air source after passing through the pressure regulating valve and the air pressure at the probe nozzle, and converts the corresponding pressure differential analog signal into a digital signal through the signal processing module and sends it to the main MCU. Figure 2 As shown in , it is a cross-sectional view of the probe structure; Figure 3 The figure shows the schematic diagram of the probe structure connected to the pressure differential sensor. In the figure, 1 is the pressure stabilizing chamber, 2 is the throttle hole, 3 is the back pressure chamber, 4 is the nozzle baffle mechanism, and 5 is the pressure differential sensor. b is the gas source pressure, P x is the air pressure at the nozzle, d1 is the orifice diameter, d is the nozzle diameter, and x is the gap between the workpiece and the probe.

[0104] The acquisition module collects environmental data via the IIC bus, with a timer set to the measurement refresh cycle. When the measurement refresh cycle is reached, temperature and humidity measurements are taken. The air pressure of each air source is collected to ensure accurate compensation of the pressure differential. The air pressure of each air source is also acquired via the FMC parallel bus. The FMC bus acquires air pressure in the same manner as the instantaneous pressure differential.

[0105] like Figure 4 As shown, in this embodiment, for pressure difference acquisition, the signal processing module uses an 8-channel, 18-bit synchronous, model AD7609 sampling chip to realize analog-to-digital conversion of the pressure difference signal, and the main MCU obtains the 8-channel sampling data converted by AD7609 through the parallel bus FMC.

[0106] The collection steps include:

[0107] S1.0: Stop AD7609 sampling operation: Set the analog-to-digital conversion start IO level to high level and turn off the analog-to-digital conversion IO output PWM control timer.

[0108] S1.1: Configure the AD7609 to detect the BUSY signal after the conversion is completed, and disable the external interrupt of the BUSY signal. After the AD7609 completes the conversion, it will output a falling edge signal through the BUSY pin, and the MCU will capture this signal through the external interrupt.

[0109] S1.2: AD7609 reset operation: The main MCU outputs a high-level pulse of no less than 50nS to the RESET pin connected to the AD7609. After the pulse is output, the hardware is set to a low level.

[0110] S1.3: Output a low-level pulse to the AD7609 analog-to-digital start conversion port. This pulse can start the AD7609 to perform an AD conversion, avoiding the first data obtained from the AD7609 being 0.

[0111] S1.4: Clear the relevant variables in the pressure differential sampling data FIFO storage structure variable. The pressure differential sampling data is stored in two structure variables. FIFO (First In First Out) is a first-in, first-out data buffer used to store and read data in an orderly manner.

[0112] One of the structure variables is an 8-channel single-sample data storage variable. This structure variable contains 8-channel AD conversion data. Single-channel data is divided into two 16-bit data. Therefore, it includes 16 arrays with a length of 16 bits and 16 arrays with a length of 32 bits.

[0113] Another structure variable is a FIFO operation structure stored by number, which includes a data storage FIFO array, an array read data position variable, an array write data position variable, an array storage data number variable, and a FIFO full flag.

[0114] S1.5: Configure the AD7609 analog-to-digital converter chip to operate in automatic acquisition mode.

[0115] First, configure the main MCU's PWM pulse output timer to regularly output PWM pulses to the AD7609's start-conversion port. The pulse frequency is calculated based on the user-set instantaneous sample count and measurement refresh rate: pulse frequency = instantaneous sample count * measurement refresh rate. The measurement refresh rate is the number of times the measured dimensional data is calculated and displayed per second, and the instantaneous sample count is the number of simultaneous eight-channel differential pressure samples taken during the measurement refresh cycle. Finally, set and enable the conversion completion detection BUSY interrupt signal.

[0116] After completing the multi-channel differential pressure acquisition settings, the main MCU timer will periodically send high-frequency PWM pulses to the start conversion port of the AD7609. The AD7609's 8-channel synchronous AD conversion speed can reach up to 200kHz. After each conversion of the AD7609 is completed, the AD7609's BUSY port will generate a falling edge signal, and the main MCU will obtain the falling edge through an external interrupt.

[0117] Based on the external interrupt, it is determined whether the AD7609 has completed the conversion. If it is completed, the multi-channel sampling data reading, conversion, and storage process will be executed to obtain the pressure difference data. The steps are as follows:

[0118] S1.6: Obtain the 8-channel single-shot sampling data of the corresponding address in sequence through the FMC bus. Each channel of data occupies 18 bits and is stored in two 16-bit array elements. D[17:2] of the 18-bit data is stored in the first array element sNowAdc[0], and D[1:0] is stored in the high bit of the second array element sNowAdc[1]. Therefore, the array has a total of 16 elements for storing 8-channel voltage difference data.

[0119] S1.7: Process the 16 elements of the array. Convert the two elements corresponding to each data channel into 32-bit data and perform a shift operation, specifically: sNowAdc[0]*4+sNowAdc[0] / 16384. Store the corresponding 8 data in an array containing 8 elements.

[0120] S1.8: Store the eight data points in the 8-channel differential pressure storage array into the corresponding positions of the FIFO array in the FIFO operation structure. The FIFO operation structure contains a write data position variable. Each time a data point is written, the position data variable is incremented by 1. If the variable is greater than the FIFO size, the variable is cleared to zero, thus implementing a circular write within the FIFO. In addition, the FIFO operation structure contains a variable for recording the number of unread data points in the FIFO array. Each time a data point is written to the FIFO, the variable is incremented by 1. If the variable is greater than the FIFO size, the FIFO full flag in the FIFO operation structure is set to 1.

[0121] The AD7609 starts the conversion port and periodically receives the PWM pulse sent by the MCU. The MCU will acquire the pressure difference signal according to the PWM pulse frequency. The system main loop determines in real time whether the number of sampled data reaches the instantaneous sampling number set by the system. If so, multi-channel data extraction and single-cycle data processing will be carried out. At the same time, if the user does not press the stop detection button, the AD7609 sampling data acquisition will continue.

[0122] The system sets the periodic acquisition data flag and two FIFO operation structures to store the AD7609 sampled data. In odd cycles, the data is stored in the FIFO array in the FIFO1 structure, and in even cycles, the data is stored in the FIFO array in the FIFO2 structure. At the same time, the odd cycle extracts the data in the FIFO2 structure that has completed sampling during the even cycle, and the even cycle extracts the data in the FIFO operation structure that has completed sampling during the odd cycle, thereby realizing data synchronous processing while collecting pressure difference data, improving data processing efficiency and dimensional measurement accuracy.

[0123] After a single data sampling is completed, a pressure difference data in the FIFO operation structure is taken out for judgment to determine whether it is greater than the trigger range value set by the user in the measurement setting interface; if the workpiece is not currently placed or the workpiece is not placed as required, the pressure difference exceeds the threshold value variable is incremented by 1, and the pressure difference data judgment is performed again at the beginning of the next round of measurement refresh cycle; if the pressure difference is within the trigger range, the pressure difference exceeds the threshold value variable is cleared to zero, and it is determined whether the pressure difference exceeds the threshold value number of times is greater than the set value. If so, the system will alarm and end the real-time measurement process, waiting for the user to place the workpiece and click "Measure" before starting the measurement again.

[0124] The specific steps of the multi-channel data extraction and single-cycle data processing process include:

[0125] S1.9: Extract all unextracted data in the FIFO operation structure array within the corresponding cycle. The pressure difference storage array in the FIFO operation structure is stored in FIFO form, that is, when the array is full, the data stored first is kicked out of the array first.

[0126] S1.10: Calculate the standard deviation of the extracted data. The standard deviation calculation formula is:

[0127]

[0128] Among them, N is the number of data, x i is the corresponding position data in the array, is the average value of all data in the array. Based on the normal distribution characteristics of the data, 3σ is used to eliminate outliers and all data outside the range of x±3σ are eliminated.

[0129] S1.11: Calculate the average of the eliminated data, store the average value in the pressure difference measurement storage array, and record the number of stored values.

[0130] S1.12: The data after single-cycle processing will be stored in the pressure difference measurement storage array in sequence. When the data in the array reaches the number of pressure difference real-time data processing, the array data is processed. The Gaussian filtering method is also used for data processing and the average is calculated. The obtained pressure difference value is the real-time pressure difference at the current moment.

[0131] After this round of sampling and data processing is completed, all variables sampled in this round are cleared and the next round of data sampling and processing is restarted to ensure the independence of the next and current data.

[0132] In a single round of data collection and processing, a single-cycle big data collection method is used to obtain a large amount of data, and the average processing is performed to obtain the instantaneous pressure difference value; then the data of a specified single cycle number is processed to obtain a relatively stable real-time pressure difference value; the cycle index and cycle number data variables of a single cycle can be adjusted, which facilitates parameter adjustment according to environmental conditions, thereby improving measurement accuracy.

[0133] In this embodiment, based on the collected pressure difference, air source pressure, and temperature and humidity data, an air source pressure and pressure difference compensation algorithm is used to calibrate the effect of the air source pressure on the pressure difference. The steps include:

[0134] Calculate the source air pressure (humidity) and pressure difference compensation value:

[0135] S2.0: Changes in the air source pressure will affect the actual pressure difference value, and humidity will also affect the air source pressure. Therefore, the air source pressure and humidity are used as parameters for pressure difference compensation. The relationship between air source pressure, humidity and pressure difference:

[0136] △DP=f(Gsp,H),

[0137] Where Gsp is the source air pressure, △DP is the pressure differential compensation value, H is the current humidity, Gsp and △DP are in a polynomial relationship, H and the △DP-Gsp compensation curve are in an interval relationship, and f is the polynomial function of the source air pressure Gsp and the pressure differential compensation value △DP in the specified temperature range.

[0138] S2.1: First determine the current humidity. If the humidity exceeds the system set humidity, the system prompts that the humidity is too high and requires user confirmation. Otherwise, further determine the interval of the △DP-Gsp compensation curve corresponding to the current humidity, and call the fitting coefficient of the △DP-Gsp compensation curve of the corresponding interval to compensate the pressure difference of the air source pressure. The calculation formula is:

[0139] ΔDP=f(Gsp)=a6*Gsp 6 +a5*Gsp5 +a4*Gsp 4 +a3*Gsp 3 +a2*Gsp 2 +a1*Gsp+a0;

[0140] Among them, Gsp compensates the pressure difference compensation value △DP using a 6th-order polynomial fitting curve, α 0～6 It is a multi-order polynomial compensation coefficient, which is obtained by the compensation coefficient acquisition algorithm corresponding to the air source pressure (humidity)-pressure difference.

[0141] S2.2: After obtaining the pressure differential compensation value △DP, compensate the current real-time pressure differential to obtain the compensated real-time pressure differential. The formula is:

[0142] DP=DP c +ΔDP;

[0143] Among them, DP is the real-time pressure difference after compensation, DP c is the real-time pressure difference of each channel obtained by the real-time pressure difference acquisition process of each channel, and △DP is the pressure difference compensation value obtained by converting the gas source pressure to the pressure difference compensation fitting polynomial.

[0144] In the present invention, because varying humidity affects the change in air pressure across the differential pressure sensor, and thus affects the final sensor pressure differential value acquisition, differential pressure compensation is required for varying humidity levels. Considering the impact of air pressure on differential pressure, the differential pressure is a bivariate polynomial function of the source air pressure and ambient humidity. Considering the weights of the influence of humidity and source air pressure on air pressure, the humidity influence weight is low. To reduce the number of humidity acquisitions and ease the difficulty of setting ambient humidity, humidity is interval-calibrated during calibration, setting constant humidity environments at different humidities, and then performing compensation calibration for varying source air pressures.

[0145] Among them, when obtaining the compensation coefficient corresponding to the gas source pressure and the pressure difference, if the deviation between the size of the workpiece to be measured and the size of the currently calibrated workpiece is large, the compensation calibration process of the gas source pressure to the pressure difference is repeated (that is, the above steps are repeated). If the deviation is small, the coefficient compensation algorithm is used for calibration, such as Figure 5 The specific steps for obtaining the compensation calibration coefficient corresponding to the gas source pressure and pressure difference include:

[0146] S2.10: Get the humidity collected by the temperature and humidity sensor. The main MCU communicates with the temperature and humidity sensor through the IIC bus to obtain the current ambient humidity. The main MCU obtains the humidity regularly through the timer and takes out the humidity data for use when executing the current process.

[0147] S2.11: Determine whether the current ambient humidity is within the selected humidity range. If so, proceed to the next step. Otherwise, prompt the user to adjust the ambient humidity or modify the humidity range.

[0148] In this embodiment, the gas and electricity meter system divides the humidity range into four levels, namely 30% to 40%, 40% to 50%, 50% to 60%, and 60% to 70%. If it is lower than 30% or higher than 70%, the system will alarm to remind the user that the current environmental humidity is abnormal and the equipment cannot work normally.

[0149] S2.12: If the humidity meets the requirements, the user is prompted to insert the standard part and enter the standard part size value, and enter the probe model in the current calibration interface. The final calibration data will be bound to the standard part size and probe model. When setting up the measurement, the user can select the compensation coefficient of the air source pressure (humidity) to the pressure difference for each channel size measurement based on the actual probe model and the size of the part to be measured.

[0150] S2.13: Perform the air source pressure adjustment and acquisition process.

[0151] Adjust according to the set standard air source pressure to obtain the current pressure difference value. In this embodiment, the set standard air source pressure is preferably 0.3MPa. To ensure the accuracy of the calibration, the air source pressure calibration interval is divided according to the standard air source pressure, the air source pressure calibration starting pressure, and the air source pressure calibration ending pressure. The system is divided into 20 calibration intervals in total. The starting pressure to the standard air source pressure is divided into 10 equal parts into 10 calibration intervals, and the standard air source pressure to the ending pressure is divided into 10 equal parts into 10 calibration intervals.

[0152] S2.14: Collect and record the gas source pressure and corresponding pressure difference for the above 10 intervals in turn.

[0153] Each time the user selects one of the intervals to collect the corresponding gas source pressure, the user adjusts the pressure of the pressure regulating valve input to the gas source pressure to adjust it to the currently selected pressure interval, and then selects the "Input Pressure" button in the interface to complete the collection of the gas source pressure in this interval. At this time, the pressure difference value of the current channel is obtained and recorded.

[0154] S2.15: After completing the acquisition of the gas source pressure and corresponding pressure difference in all intervals, adjust the gas source pressure to the standard gas source pressure. The pressure accuracy requirement is high and the error is required to be within 0.1% to ensure the accuracy of the reference pressure. After pressing the "Input Pressure" button, the gas source pressure is compared with the standard pressure. If the error is greater than 0.1% (settable), the user is prompted to readjust the gas source pressure until it meets the error requirement. After completing the gas source pressure input, the current channel pressure difference value is obtained in real time and recorded.

[0155] S2.16: After completing the collection of all air source pressure and pressure difference values, the air source pressure-pressure difference compensation calibration coefficient can be obtained for the current humidity. The compensation calibration is performed by fitting a univariate polynomial. The fitting coefficient is obtained by the least squares method. The pressure difference and the air source pressure are in a univariate sixth-order polynomial function relationship.

[0156] S2.17: If the user switches humidity ranges on this screen and has already refitted the calibration coefficients before switching, the calibration coefficient saving process for the current humidity range will be executed. A dialog box will pop up asking if the coefficients should be saved. The user will then select to save the coefficients before switching to the new humidity range. After the coefficient saving process is complete, the user will be prompted to adjust the calibration environment humidity to within the set humidity range. The air source pressure-pressure differential compensation calibration coefficients for the corresponding humidity range will then be obtained using the method described above.

[0157] S2.18: If you click the "Exit" button, the current humidity range calibration fitting coefficient saving process will be executed and then exit this interface.

[0158] In this embodiment, after the calculation of the air source pressure (humidity)-pressure difference compensation value is completed, the compensated pressure difference is converted into the corresponding dimension value. The pressure difference-dimension value conversion is performed in a page conversion manner, and the steps include:

[0159] S3.0: Paginate the pressure differential values, place the standard parts in the specified position, obtain the corresponding pressure differential values, and based on the current pressure differential value, turn the current pressure differential page to the corresponding page, and fill in the current pressure differential value in the corresponding numerical item; if the pressure differential values ​​between each page are equal at the beginning and end (that is, the maximum pressure differential value of the previous page is equal to the minimum pressure differential value of the current page, and the maximum pressure differential value of the current page is equal to the minimum pressure differential value of the next page, thereby ensuring that the current real-time pressure differential value is within the pressure differential conversion range established by the user), then execute the next step.

[0160] S3.1: The pressure difference-to-dimension conversion uses a 6th-order polynomial conversion, the formula is:

[0161] SV i =b 6i *DP 6 +b 5i *DP 5 +b 4i *DP 4 +b 3i *DP 3 +b 2i *DP 2 +b 1i *DP+b i ;

[0162] Among them, SV i is the real-time size of the corresponding page after conversion, b6i 、b 5i 、b 4i 、b 3i 、b 2i 、b 1i 、b i = DP represents the polynomial fitting coefficients on the corresponding page, obtained using the pressure differential dimension conversion coefficient acquisition algorithm. Different channels have different coefficients, and the polynomial calculation is performed using the corresponding channel coefficients. DP represents the real-time pressure differential after compensation using the source air pressure. It should be noted that the order of the polynomial can be set based on the actual application scenario.

[0163] In this invention, the pressure-to-dimension conversion algorithm uses multiple workpieces for each channel for page-by-page calibration, then performs a polynomial fit on each page of data to accurately determine the conversion coefficients for the corresponding pressure-to-dimension values ​​on each page. Furthermore, when performing page-by-page calibration, the last dimension value on the previous page is guaranteed to be the same as the first dimension value on the current page, ensuring a seamless calibration interval.

[0164] like Figure 6 As shown, the specific steps of the pressure difference size conversion coefficient acquisition algorithm include:

[0165] S3.10: Before calibration in each calibration page interface of each channel, complete the input of each standard part size value and the acquisition of the corresponding pressure difference value. The polynomial coefficients for the conversion between pressure difference and size value are realized by polynomial fitting of multiple sets of pressure difference values ​​and corresponding standard part sizes.

[0166] In this calibration interface, the pressure differential value of the channel currently selected by the user is obtained in real time and displayed on the interface. At this time, the user can click the "Enter Pressure Differential" button, and the system will determine whether the current pressure differential indication is within the set range. If so, the current pressure differential indication is filled in the pressure differential value of the corresponding calibration item. The pressure differential setting range of the calibration item is filled in here to ensure the accuracy of the calibration. The pressure differential sensor is converted by the AD7609 sampling chip and input into the main MCU as 18-bit data, of which the highest bit is the sign bit. After removing the sign bit, the data range is 0 to 131071. When performing pressure differential size conversion, the area with higher conversion accuracy is generally around the middle value of the data. Therefore, the pressure differential setting range can be set to 30,000 to 60,000. If it exceeds this range, the user is prompted to reset the range or adjust the device to obtain a pressure differential value within this range.

[0167] S3.11: Use the method of quickly dividing dimension values. After the user clicks the "Divide Dimension Values" button, the dimension values ​​of the starting and ending items and the total number of calibration items are divided equally to obtain all the calibration dimension reference values ​​on this page, thereby realizing the rapid input of standard part dimensions. After the dimension division, the dimension values ​​obtained by automatic division can be modified.

[0168] S3.12: When the user selects the corresponding calibration item size value, the system prompts the user to place the corresponding size standard part according to the size value and fill in the actual size of the current standard part in the interface.

[0169] In order to ensure the correctness of the user-input data and the final fitting coefficient, the user-input standard part size is constrained, requiring that the current standard part size must be smaller than the previous calibration item size value and larger than the next calibration item size value. If this requirement is not met, the user is prompted to re-enter the standard part size value.

[0170] S3.13: After completing the input of all standard part dimensions and corresponding pressure differential values ​​on this page and they all meet the set requirements, you can start obtaining the calibration coefficients.

[0171] The user clicks the "Start Calibration" button to determine whether any modifications exist for the pressure differential and dimensional input values. If so, the modified data is stored. The relationship between dimension and pressure differential is a sixth-order polynomial, with the pressure differential being the input parameter. The dimension value is calculated using a sixth-order polynomial function. A least squares fit is performed on the dimension values ​​and corresponding pressure differential values ​​for all groups on this page to obtain the coefficients of the corresponding sixth-order polynomial function, which are also displayed on the interface.

[0172] S3.14: Perform page conversion operations in the pressure difference size conversion coefficient acquisition interface. The page conversion operations include: adding a page, deleting a page, turning up a page, and turning down a page. Figure 7 It should be noted that when performing page conversion, the pressure difference values ​​of each page must be equal at the beginning and end to ensure the continuity between pages.

[0173] The specific switching steps include:

[0174] (1) If the "Previous Page" button is clicked, it is first determined whether the current page is the home page. If so, the user is prompted that the page is the home page. Otherwise, the calibration page switching process is executed.

[0175] This process first determines whether the calibration parameters on the current page have been modified. If so, a parameter save dialog box pops up and the calibration parameters are saved based on the user's selection. It then determines whether the calibration coefficients have been updated. If so, the calibration coefficients are saved. The calibration parameters and coefficients are stored in temporary variables upon entering the interface. When exiting this page, the user can compare the current parameters with the parameters stored in the temporary variables to determine whether the parameters have been modified.

[0176] (2) After the calibration parameters and calibration coefficients are saved, the current page record variable is reduced by 1, and then the calibration parameters and calibration coefficients are obtained according to the current page. Finally, the current calibration page is closed, and the corresponding calibration page is opened according to the current page and the calibration parameters and calibration coefficients are displayed.

[0177] (3) The execution process of clicking the "Next Page" button is similar to that of clicking the "Previous Page" button. The difference is that when clicking the "Next Page" button, it is necessary to determine whether it is the last page. If it is the last page, the user is prompted that it is the last page. Otherwise, the page switching process is executed.

[0178] (4) If you click the "Add Page" button, it will first determine whether the current page is the maximum page set by the system. If so, the user will be prompted that it is the maximum page and cannot add a page. Otherwise, it will determine whether the current page is equal to the total page number. If so, the calibration page adding process will be executed. Otherwise, the user will be prompted to turn to the last page before adding a page. The calibration page adding process will first determine whether there are calibration parameters and calibration coefficient modifications on the current page. If so, it will be saved according to the user's operation, and then the current page storage variable will be added by 1, and the total page number will be updated. The calibration reference size values ​​of each item will be calculated based on the current page. In the calibration interface, the end data of the calibration reference value of the next page and the number of calibration items can be entered. The spacing value of the size reference value of each calibration item is (calibration reference value end data - current page calibration end data) / number of calibration items. The calibration size reference value of each item on the next page will be calculated based on this spacing value. Close the current calibration page, open the corresponding calibration page based on the current page and display the calibration size value.

[0179] (5) If the "Delete Page" button is clicked, it is first determined whether the current page is equal to the total page number. If so, it is further determined whether the current page is the first page. If it is the first page, the user is prompted that there is only one page and the page cannot be deleted. Otherwise, the calibration page deletion process is executed. The calibration page deletion process first determines whether the current page calibration parameters and calibration coefficients have been modified. If so, they are saved according to the user operation. Then, the current page storage variable is subtracted by 1 and the total page number is updated. The current page calibration parameters and calibration coefficients are obtained according to the current page storage variable. Finally, the current calibration interface is closed, and the corresponding calibration page is opened according to the current page and the calibration parameters and calibration coefficients are displayed.

[0180] (6) Click the "Exit" button in each calibration page to exit the pressure difference-dimension value conversion coefficient acquisition interface, and the calibration interface exit process will be executed. This process will first save the calibration parameters and calibration coefficients of the previous calibration page, and then judge the correlation between the parameters of each calibration page. The calibration fitting curve of each page must ensure the continuity of the pressure difference, and the calibration dimension values ​​cannot jump. Only in this way can the accuracy of the pressure difference and dimension conversion be achieved. If the pressure difference in the fitting curve is discontinuous, the interrupted disconnected area cannot be converted. If the calibration dimension value jumps, the dimension jump phenomenon may occur when converting near the same pressure difference in the actual conversion. In order to ensure that the calibration curve of each page has no jumps on the size axis, the starting size value of each page and the ending size value of the previous page, as well as the ending size value of each page and the starting size value of the next page must be within a certain distance. The distance can be set on each calibration page. When exiting the page, the starting size value and the ending size value of all current pages are judged. If there is a setting greater than the spacing value, the user is prompted that there is an incorrectly set page; in order to ensure the continuity of the calibration curve of each page on the pressure difference axis, it must be ensured that the starting pressure difference value of each page is equal to the ending pressure difference value of the previous page, and at the same time, the ending pressure difference value of each page is equal to the starting pressure difference value of the next page. If there are different items, the user is prompted that there is an incorrectly set page. If the above size values ​​and pressure difference values ​​meet the requirements, exit the pressure difference-size conversion coefficient acquisition interface and return to the measurement calibration conversion interface. Its conversion calibration interface is as follows: Figure 8 shown.

[0181] In the present invention, since the workpiece has the phenomenon of thermal expansion and contraction, it is necessary to perform temperature compensation on the workpiece size. The workpiece executes the temperature-size value compensation process to perform temperature compensation on the real-time size after the pressure difference-size corresponding page conversion. The specific steps include:

[0182] Determine whether the temperature is within the temperature range set in the temperature-dimension value compensation calibration process. If so, call the temperature-dimension value compensation calibration polynomial coefficient to perform polynomial calculation to obtain the calibrated dimension value after temperature compensation. The calculation method of the polynomial is the same as the above-mentioned pressure difference-dimension polynomial calculation method; if the temperature exceeds the set range and the number of times the threshold is exceeded is greater than the set value, the system will issue an alarm.

[0183] In the present invention, the temperature and dimension compensation coefficient acquisition algorithm is used to compensate for the real-time dimension during the measurement process. The specific steps include:

[0184] The workpiece dimensional values ​​at different temperatures were collected, and the least squares method was used to fit the multiple sets of data to obtain a univariate polynomial function of temperature relative to dimensional value.

[0185] The present invention also includes a measurement setting step for setting the reference value, early warning value, and alarm value of each channel, and can realize the channel pressure difference conversion trigger setting.

[0186] The specific parameters of early warning and alarm include baseline value, early warning upper limit, early warning lower limit, alarm upper limit and alarm lower limit. According to these parameters, the early warning range is: greater than (baseline value - alarm lower limit) and less than (baseline value - early warning lower limit) or greater than (baseline value + early warning upper limit) and less than (baseline value + alarm upper limit), and the alarm range is less than (baseline value - alarm lower limit) or greater than (baseline value + alarm upper limit).

[0187] The specific steps for setting up the test program are:

[0188] The user can enter the measurement program selection interface by clicking the "Measurement Program Selection" button on the setting interface. Entering this interface will execute the measurement program operation process. Through this process, the user can view the compensation calibration parameters such as gas source pressure, pressure difference, temperature, etc. selected for each measurement program. The interface can also be used to create, configure, delete, and upload measurement programs.

[0189] In the air source pressure-differential pressure compensation calibration interface and the temperature-size compensation calibration interface, the interface provides input for "calibration number", "probe model", "workpiece model", and "standard air source pressure". Each calibration number corresponds to a probe model, workpiece model, and standard air source pressure value. The current compensation calibration coefficient can be saved according to the calibration number, and the associated probe model, workpiece model, and standard air source pressure value can be saved. In addition, calibration numbers can be added, deleted, and selected in this interface. Adding / deleting calibration numbers can add or delete a group of compensation calibration coefficients and related original parameters. Selecting a calibration number obtains the corresponding number compensation calibration coefficient and original parameters. In the interface, the original parameters can be retrieved and the compensation calibration coefficient calculated.

[0190] In the pressure differential-size conversion calibration, each channel can set the "calibration number", "probe model", "workpiece model", and "standard air source pressure" input. The operation method is similar to the above-mentioned air source pressure-pressure differential compensation calibration interface.

[0191] Enter the measurement program interface, and the program name selected by the user last time is selected by default. A program name includes the pressure difference-size conversion calibration number, gas source pressure-pressure difference compensation calibration number, and temperature-size conversion calibration number selected for each channel. The user can select and adjust the corresponding number according to the model of the currently detected workpiece, the probe model, and the standard gas source pressure. Adding a new program is to add a new detection workpiece parameter. By default, all parameters are empty. The user can select from the currently completed calibration number, or enter the corresponding calibration interface to obtain the calibration coefficient. The parameters in the currently selected program name are calibrated on the corresponding calibration page. The setting items of the test program are as follows: Figure 9 shown.

[0192] The present invention also features a slave MCU that transmits raw data waveforms to the touch screen via a serial port. This raw data waveform allows for viewing any sudden changes in the workpiece measurement channel data. The system's master MCU transmits the real-time dimensions and real-time dispersion of each channel to the touch screen via the serial port, where they are displayed as waveforms on the data interaction interface. The dual MCUs enable separate data transmission, reducing processing pressure on the master MCU and improving its ability to process real-time dimensions.

[0193] In the present invention, the gas and electricity meter also includes: a power supply module for powering the working system of the gas and electricity meter; a display screen for displaying and configuring measurement data; and a serial communication touch screen, through which the user interacts with the gas and electricity meter through a human-machine interface.

[0194] Among them, the interface of the serial communication touch screen includes:

[0195] Main interface: displays the measurement results and statistical data of each channel of the workpiece in real time, and provides operation buttons for the setting interface and data interaction interface entrance.

[0196] Settings interface: provides operation buttons for measurement and calibration conversion interface, measurement settings interface, measurement program selection interface and return to the main interface.

[0197] Air source pressure compensation calibration interface: This interface implements compensation calibration of air source pressure (humidity) - pressure difference, obtains humidity, air source pressure and pressure difference in the calibration environment in real time, and obtains calibration coefficients through polynomial fitting.

[0198] Differential Pressure-Dimension Conversion: This interface implements differential pressure-dimensional conversion, acquiring the differential pressure values ​​for each workpiece channel in real time. Standard workpiece dimensions can be manually input, and the 6th-order polynomial coefficients are obtained through polynomial fitting. This interface allows for page-by-page conversion of the conversion size range, improving conversion accuracy and eliminating fitting errors that can occur with single-page fitting.

[0199] Temperature-Dimension Compensation Calibration: This interface implements temperature-dimensional compensation calibration. Metal workpieces experience thermal expansion and contraction, so dimensional compensation is performed for workpieces at different temperatures. Dimensional values ​​are acquired in real time through pressure differential dimensional conversion, while temperature values ​​are acquired in real time through a temperature sensor. Polynomial fitting is then used to determine the temperature-dimensional compensation curve fitting coefficients.

[0200] Measurement setting interface: This interface sets the measurement parameters of each channel size, including the workpiece reference value, upper and lower deviation thresholds, and warning values. It can also set the no-workpiece judgment condition and synchronize channel setting parameters.

[0201] Measurement program selection interface: This interface provides measurement program selection, adding, deleting and other functions. Through this interface function, it is possible to save the measurement parameters of different workpieces, save multiple sets of parameters, and switch parameters according to the actual workpiece to be inspected.

[0202] Data interaction interface: This interface realizes the real-time curve display of the measurement data of each channel of the workpiece, including the real-time change curve of the workpiece's real-time size, dispersion and standard deviation, and records user operation records in the form of data tables.

[0203] like Figure 10 As shown in the figure, the operation process of the gas and electricity meter is as follows:

[0204] After the system is powered on, the hardware initialization process is executed.

[0205] The current system is an embedded system, and the main hardware included is temperature and humidity sensor, differential pressure sensor, air source pressure sensor, serial communication touch screen, signal processing circuit and power supply circuit.

[0206] First, perform hardware initialization. The specific steps include:

[0207] (1) Initialize the IIC communication port of the temperature and humidity acquisition sensor and initialize the relevant registers of the sensor.

[0208] Pin configuration for the AD sampling chip for differential pressure and source pressure analog signals, as well as FMC bus initialization for the parallel output of the AD sampled digital signals, are used to set the input range, reset, and start conversion pins. FMC bus initialization also allows for settings such as read / write addresses, read / write time parameters, and read / write mode parameters.

[0209] Initialize the touch screen serial communication interface and set the port, baud rate, receive interrupt, etc. for the RS232 serial communication between the MCU and the touch screen.

[0210] (2) After completing hardware initialization, execute the peripheral self-test process. The self-test process first performs a touch screen communication self-test. The touch screen sets the self-test bit and determines the communication status between the MCU and the touch screen by reading the touch screen self-test bit. Perform air source pressure detection and temperature and humidity detection. If the detection parameters exceed the system-set threshold, the detection value is displayed on the touch screen and the user is prompted to check the air source pressure and equipment environment.

[0211] (3) The data initialization process reads the various detection parameters from the power-off storage module and stores them in related variables.

[0212] Specific test parameters include:

[0213] 1. Air source pressure (humidity) - pressure difference compensation calibration coefficient;

[0214] 2. Multi-channel coefficients for pressure difference-dimension value conversion;

[0215] 3. Temperature-dimension value compensation calibration coefficient;

[0216] 4. Measurement setting parameters, mainly the reference value, warning value and alarm value parameters of each channel of the workpiece;

[0217] 5. The user selects the measurement program number.

[0218] Among the above parameters, the algorithm for obtaining the compensation coefficient for the air source pressure (humidity)-pressure difference is applicable to pressure difference compensation during all workpiece size measurement processes. The pressure difference-dimension value conversion, temperature-dimension value compensation coefficient acquisition, and measurement setting parameters require different settings for different workpieces. Therefore, different parameters are stored for each workpiece and can be switched and selected through the measurement program interface.

[0219] After entering the main interface of the system, real-time measurement of the dimensions of each position of the workpiece, measurement conversion and calibration operations, and real-time curves and user operation records are performed according to user operations.

[0220] Main interface dimension measurement process: This process includes acquiring real-time differential pressure values ​​for each channel, converting and calibrating differential pressure values ​​for each channel, calculating workpiece statistics, displaying alarms, and stopping inspection. This interface primarily implements dimension acquisition and processing for each channel, performing statistical calculations and alarm control based on the dimension data.

[0221] Settings interface: This interface includes the entry operations of the measurement and calibration conversion interface, measurement settings interface, and measurement program selection interface. The measurement and calibration conversion interface can perform gas source pressure (humidity) - pressure difference compensation calibration, multi-channel pressure difference - dimension value conversion, and temperature - dimension value compensation calibration.

[0222] Data interaction interface: This interface displays the real-time waveform of dimensional measurement results and records user operations, alarm information, etc. in a list format.

[0223] like Figure 11 、 Figure 12 As shown, in the present invention, the acquisition module, the differential operational amplifier, the filtering circuit, and the AD9609 high-precision acquisition chip form a high-precision anti-interference pressure difference conversion circuit, which realizes high-precision and interference-free AD conversion of the pressure difference analog signal and provides an accurate pressure difference signal for the measurement system.

[0224] The conversion circuit uses a differential operational amplifier circuit to implement differential pressure signal processing, improves the signal-to-noise ratio, and can suppress common-mode interference; the filtering circuit realizes the filtering of high-frequency interference signals, and the high-precision multi-channel synchronous acquisition circuit realizes high-speed synchronous sampling of differential pressure signals, providing rich processing data for the measurement system, thereby improving measurement accuracy.

[0225] The circuit also includes an isolation circuit and an AC coupling circuit connected in sequence, which are arranged between the acquisition circuit and the filter circuit. The output end of the filter circuit is connected to a differential operational amplifier, which amplifies and outputs the acquired voltage difference signal.

[0226] The pressure sensor in this circuit is suitable for differential pressure measurement. Its core component is a silicon piezoresistive pressure-sensitive chip. The front and back sides of the chip sense different pressures through a pressure nozzle, creating a pressure differential and generating a voltage signal proportional to the pressure difference. An internal circuit chip digitally compensates for sensor offset, sensitivity, temperature drift, and nonlinearity.

[0227] Signal processing circuit: The sensor passes through the bridge amplification circuit composed of operational amplifiers, and then passes through the IOS100 photoelectric isolation circuit to isolate the acquisition circuit and processing circuit, thereby increasing system stability.

[0228] Due to the characteristics of the acquisition circuit, the output signal is mainly concentrated in the range of -15-1V, with the center of the signal at -7V, which causes problems for post-processing. Therefore, a capacitor AC coupling circuit is used to center the signal at 0V. It is then filtered by a 10kHz active filter circuit and then amplified to the AD9609 high-precision acquisition chip.

[0229] The humidity sensor acquisition circuit is shown in Figure 13, and the power supply circuit is shown in Figures 14 to 19 As shown in the figure, the power supply circuit works as follows: 220V input is stepped down to +5V via a power frequency transformer, and then boosted to 24V via a DC-DC converter. This approach offers the advantage that if the external 220V power source fluctuates, directly stepping down to 24V may cause fluctuations in the 24V supply. However, by first stepping down to 5V and then stepping up to 24V, the 5V voltage acts as a buffer, ensuring a stable 24V supply.

[0230] The power supply circuit uses a DC-DC converter to step down 24V to ±15V for the data acquisition circuit. Another DC-DC converter also steps down 24V to ±15V for the signal processing circuit of the IOS100 optoelectronic isolation chip. The ±15V signal processing voltage is then stepped down to ±5V to power the op amps in the post-processing circuit and the microcontroller's peripheral chips. Finally, the 5V voltage is stepped down to 3.3V for the microcontroller.

[0231] In the present invention, based on multi-channel synchronous acquisition technology, multi-channel synchronous sampling and dimension measurement are realized. According to the user's settings for multi-channel data and workpiece measurement, the control module can also realize the calculation of statistical quantities such as the straightness, roundness, coaxiality, perpendicularity, and flatness of the workpiece axis, thereby realizing the measurement of multiple dimensions of the workpiece.

[0232] like Figure 20As shown, the specific steps include:

[0233] S4.0: To ensure the stability of data measurement and display, the real-time dimension values ​​that have undergone multiple compensation calibrations in each cycle are stacked and stored in a stack array. When the stack is full, the data first stored in the stack is discarded according to the test dimension stack size set by the user, and the remaining data in the stack array is moved forward by one storage unit. The newly acquired real-time dimension value is then placed in the last storage unit of the stack, thus realizing a first-in-first-out stack operation.

[0234] After each round of cycle data completes the stacking operation, the data in the stack array is filtered by standard deviation, mutation points are eliminated, and the average value is calculated. This average value is used as the final workpiece size value of the current processing channel.

[0235] S4.1: Calculates the taper, roundness, straightness, cylindricity, and flatness of the workpiece based on the user-selected statistical information and the current channel data. For different workpiece types, indirect statistics are calculated based on the measurements of different workpiece dimensions at different locations using each channel.

[0236] S4.10: For conical or frustoconical workpieces, calculate the taper.

[0237] The calculation formula of cone taper is: cone taper = base diameter / cone height;

[0238] The calculation formula for the frustum taper is: frustum taper = |upper base diameter-lower base diameter| / frustum height.

[0239] Among them, the diameter of the cone base is D, the height of the cone is H, and the size of the workpiece at each channel is CS i , the vertical spacing between adjacent channels is CVD i , where i is the channel number, then:

[0240] Cone taper = D / H = |CS i -CS i-1 | / CVD i ,

[0241] Cone taper = |CS i -CS i-1 | / CVD i ,

[0242] Therefore, the taper of a frustum or cone can be calculated using the dimensions of two adjacent channels and the vertical spacing between them. The vertical spacing between adjacent channels is a fixed value, which can also be entered by the user through the measurement settings interface. After the taper values ​​obtained from all adjacent channels are calculated, all data can be averaged to obtain the total taper of the workpiece.

[0243] S4.11: For circular workpieces, such as cylindrical, spherical, and conical workpieces, the workpiece can be rotated to collect multiple data from the same channel of the workpiece and then the roundness calculation is performed. The calculation method is the difference between the maximum and minimum size values ​​in the multiple sampling data. The number of sampling data can be set through the measurement settings interface. The sudden changes in the multiple sampling data can be eliminated by standard deviation to prevent the concave and convex points on the workpiece from affecting the accuracy of the roundness calculation.

[0244] S4.12: For cylindrical workpieces, straightness, cylindricity, and flatness can be counted.

[0245] Straightness is the maximum runout deviation of all channel dimensions. The maximum and minimum values ​​of all measurement channel dimensions are counted, and straightness is the difference between the maximum and minimum dimensions.

[0246] Cylindricity is determined by rotating the same cylindrical workpiece and collecting data from each channel. The resulting deviation is then statistically analyzed for all data from each channel, representing the workpiece's cylindricity. Because workpiece dimensions fluctuate at different locations, the deviation in the workpiece dimension measurements is used to determine if the workpiece has completed the rotation operation. Ten consecutive dimension values ​​collected from the current channel (this value can be adjusted through the interface) are evaluated. If the deviation of these ten data points is less than the set threshold, cylindricity calculation begins and the raw data is stored. This method is also used to determine the end of cylindricity data collection. Cylindricity calculation is performed after data collection is complete.

[0247] S4.2: Based on the warning values ​​and upper and lower deviation values ​​for each channel on the measurement settings interface, an alarm and warning judgment is performed on the real-time dimension value of each channel. If the difference between the real-time dimension value of the current channel and the system-set reference value for that channel is greater than the upper or lower alarm deviation set for the current channel, the system will sound a buzzer alarm and a prompt message will pop up on the main touch screen interface. If it is less than the alarm value, a determination is made as to whether the difference is greater than the warning value. If so, a buzzer warning is issued and the warning is displayed on the main touch screen interface. Here, for alarms and warnings, the buzzer alarm is distinguished by different alarm frequencies, and the main touch screen interface distinguishes the real-time dimension by different colors.

[0248] S4.3: The main MCU sends the real-time dimensions of the workpiece obtained by each measurement channel, the user-set measurement statistics, and alarm information to the touch screen. The touch screen will display the real-time dimensions of the workpiece in different colors according to the alarm information and display the statistics selected by the user.

[0249] Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

Claims

1. Gas and electricity meter based on pressure difference and size paging calibration conversion, characterized by: include: The acquisition module includes multiple sensors, which collect the temperature and humidity of the workpiece, the air source pressure, and the probe pressure difference signal through multiple acquisition channels; The steps of collecting pressure difference by the collection module include: Real-time differential pressure data is acquired through a multi-channel differential pressure acquisition process. If the number of acquired data reaches the set acquisition number, the multi-channel data extraction and single-cycle data processing process is executed to extract and process the data. After a single data acquisition is completed, a pressure difference data in the FIFO operation structure is taken out for judgment. If the pressure difference is greater than the preset trigger range value, the workpiece is not currently placed or the workpiece is not placed as required, then the variable of the number of times the pressure difference exceeds the threshold is incremented by 1, and the pressure difference data judgment is performed again at the beginning of the next round of measurement refresh cycle; If the pressure difference is within the trigger range, the variable for the number of times the pressure difference exceeds the threshold value will be cleared; if the number of times the pressure difference exceeds the threshold value is greater than the set value, an alarm will be issued and the real-time measurement will end. The user will wait for the workpiece to be placed in the specified position before starting the measurement. The steps of the multi-channel data extraction and single-cycle data processing process are specifically as follows: Extraction steps: Extract all unextracted data in the FIFO operation structure array within the corresponding cycle. The pressure difference storage array in the FIFO operation structure is stored in FIFO form, that is, the data stored first will be kicked out of the array first after the array is full. Calculate the standard deviation of the extracted data. The standard deviation calculation formula is: Among them, N is the number of data, x i is the data at the corresponding position in the array, is the average value of all data in the array; according to the normal distribution characteristics of the data, 3σ is used to eliminate outliers and all data outside the range of x±3σ are eliminated; Calculate the average of the eliminated data, store the average value in the pressure difference measurement storage array, and record the number of storages; Data processing steps: The data after single-cycle processing is stored in the pressure difference measurement storage array. When the data in the array reaches the number of pressure difference real-time data processing, the data in the corresponding array is processed; The data is processed using the Gaussian filtering method and the average is calculated to obtain the real-time pressure difference at the current moment; After the current sampling and data processing are completed, all variables of the current sampling are cleared and the next round of data sampling and processing begins again. The control module calibrates the pressure differential signal based on the collected signal through the air source pressure and pressure differential compensation algorithm; based on the compensated pressure differential signal, the pressure differential signal is converted into the corresponding workpiece size through the pressure differential size paging conversion algorithm; When the pressure difference size paging conversion algorithm performs page conversion operations, the pressure difference values ​​of each page are equal at the beginning and end, and the starting size value of each page and the ending size value of the previous page and the ending size value of each page and the starting size value of the next page are within a certain distance.

2. The gas and electricity meter based on pressure difference and size paging calibration conversion according to claim 1 is characterized in that: The steps of the gas source pressure and pressure difference compensation algorithm include: Calculate the gas source pressure and pressure difference compensation value: The air source pressure and humidity are used as parameters for pressure difference compensation. The relationship between the air source pressure, humidity and pressure difference is: △DP=f(Gsp,H) Where Gsp is the source air pressure, △DP is the pressure differential compensation value, H is the current humidity, Gsp and △DP are in a polynomial relationship, H and the △DP-Gsp curve are in an interval relationship, and f is the polynomial function of the source air pressure Gsp and the pressure differential compensation value △DP in the specified temperature range; Determine the current humidity: If the current humidity exceeds the system set humidity, the system prompts that the humidity is too high and needs to be confirmed; if the current humidity is lower than the system set humidity, the current humidity is determined to correspond to the interval of the △DP-Gsp compensation curve, and the fitting coefficient of the △DP-Gsp compensation curve of the corresponding interval is called to compensate the pressure difference of the air source pressure. The calculation formula is: ΔDP=f(Gsp)=a6*Gsp 6 +a5*Gsp 5 +a4*Gsp 4 +a3*Gsp 3 +a2*Gsp 2 +a1*Gsp+a0; Among them, the gas source pressure Gsp uses a multi-order polynomial fitting curve to compensate the pressure difference compensation value △DP, α 0～6 is a multi-order polynomial compensation coefficient, which is obtained by the corresponding compensation coefficient acquisition algorithm; The pressure difference compensation value is used to compensate the current real-time pressure difference to obtain the compensated real-time pressure difference. The formula is: DP=DP c +ΔDP; Among them, DP is the real-time pressure difference after compensation, DP c is the real-time pressure difference of each channel, and △DP is the pressure difference compensation value obtained by converting the compensation polynomial of the gas source pressure to the pressure difference.

3. The gas and electricity meter based on pressure difference and size paging calibration conversion according to claim 2 is characterized in that: The air source pressure and pressure difference compensation coefficient acquisition algorithm, when obtaining the compensation coefficient, if the deviation between the size of the workpiece to be measured and the size of the currently calibrated workpiece is large, the air source pressure to pressure difference compensation calibration is performed again; if the deviation is small, the coefficient compensation algorithm is used for calibration; The specific steps for obtaining the compensation coefficient include: Regularly obtain the current real-time humidity of the environment; Determine whether the current ambient humidity is within the selected humidity range. If so, proceed to the next step; otherwise, prompt the user to adjust the ambient humidity or modify the humidity range. If the current humidity meets the requirements, the user is prompted to put in the standard part, enter the standard part size and probe model, and obtain the calibration data bound to the standard part size and probe model; Divide the calibration intervals into multiple intervals according to the set standard air source pressure, obtain the air source pressure value and pressure difference value in all calibration intervals, adjust the air source pressure to the standard pressure, and obtain the air source pressure and pressure difference compensation calibration coefficients for the current humidity; use a univariate polynomial fitting method to perform compensation calibration, and obtain the fitting coefficients by the least squares method. The pressure difference and the air source pressure are in a univariate sixth-order polynomial function relationship; If the humidity range is switched and the calibration coefficients are re-fitted before the switch, the calibration coefficients of the current humidity range will be saved. The system will pop up a dialog box asking whether to save the fitting coefficients. Select to save the fitting coefficients before switching the humidity range. After the fitting coefficients are saved, the user is prompted to adjust the calibration environment humidity to within the set humidity range; repeat the above steps to obtain the air source pressure and pressure difference compensation calibration coefficients corresponding to the set humidity range.

4. The gas and electricity meter based on pressure difference and size paging calibration conversion according to claim 1 is characterized in that: The specific steps of the pressure difference size paging conversion algorithm for pressure difference size conversion include: Divide the pressure difference values ​​into pages, place the standard parts in the specified positions, obtain the corresponding pressure difference values, and based on the current pressure difference value, turn the current pressure difference page to the corresponding page and fill in the current pressure difference value in the corresponding numerical item; if the pressure difference values ​​between each page are equal at the beginning and end, proceed to the next step; The pressure difference and size are converted using a multi-order polynomial, and the formula is: SV i =b 6i *DP 6 +b 5i *DP 5 +b 4i *DP 4 +b 3i *DP 3 +b 2i *DP 2 +b 1i *DP+b i ; Among them, SV i is the real-time size of the corresponding page after conversion, b 6i 、b 5i 、b 4i 、b 3i 、b 2i 、b 1i 、b i is the polynomial fitting coefficient of the corresponding page, which is obtained by the corresponding pressure difference size conversion coefficient acquisition algorithm, and DP is the real-time pressure difference after compensation by the air source pressure.

5. The gas and electricity meter based on pressure difference and size paging calibration conversion according to claim 4 is characterized in that: The steps of the pressure difference size conversion coefficient acquisition algorithm include: Obtain the real-time pressure differential value and the input pressure differential value, and the system determines whether the current pressure differential value is within the set range. If so, the current pressure differential value is filled in the pressure differential value of the corresponding calibration item; According to the dimension values ​​of the starting item and the ending item and the total number of calibration items, the dimension values ​​of the pressure difference are divided, and the reference values ​​of all calibration dimensions on the current page are obtained and corrected; Select the corresponding calibration item size value, and the user places the corresponding standard part according to the selected calibration item size value, and fills in the actual size value that is smaller than the previous calibration item size value and larger than the next calibration item size value in the interface; If all the standard part dimensions and corresponding differential pressure values ​​on this page meet the requirements, calibration will begin. If there are modifications to the differential pressure and dimension input values, the modified data will be saved and the dimension values ​​will be calculated using a multi-order polynomial function. The dimension values ​​and corresponding differential pressure values ​​of all groups on the current page will be fitted using the least squares method to obtain the coefficients of the corresponding multi-order polynomial function. The calibration coefficients will be displayed on the interface. Perform page conversion operations in the pressure difference size conversion coefficient acquisition interface. The page conversion operations include: adding a page, deleting a page, turning up a page, and turning down a page.

6. The gas and electricity meter based on pressure difference and size paging calibration conversion according to claim 5, characterized in that: The steps for converting the page are as follows: If the previous page button is clicked, it is first determined whether the current page is the home page. If so, the user is prompted that the page is the home page. Otherwise, the calibration page switching process is executed to complete the calibration parameters and calibration coefficients. Subtract 1 from the current page record variable, and obtain the calibration parameters and calibration coefficients based on the current page; close the current calibration page, open the corresponding calibration page based on the current page and display the calibration parameters and calibration coefficients; If you click the add page button, it will first determine whether the current page is the maximum page set by the system. If so, the user will be prompted that the page is already the maximum page and cannot be added. Otherwise, determine whether the current page is equal to the total page number. If so, execute the calibration page adding process. Otherwise, prompt the user to turn to the last page before adding a page. If you click the delete page button, first determine whether the current page is equal to the total page number. If so, further determine whether the current page is the home page. If it is the first page, the user will be prompted that there is only one page and the page cannot be deleted. Otherwise, the calibration page deletion process will be executed; Click the Exit button in each calibration page to exit the pressure difference-dimension value conversion coefficient acquisition interface.

7. The gas and electricity meter based on pressure difference and size paging calibration conversion according to claim 6, characterized in that: The calibration page switching process is as follows: Determine whether there is any calibration parameter modification on the current page. If so, a parameter save dialog box will pop up to save the calibration parameters. Determine whether the calibration coefficient is updated. If there is an updated coefficient, save the calibration coefficient; The calibration parameters and calibration coefficients are stored in temporary variables when entering the interface. When exiting this page, the current parameters are compared with the parameters stored in the temporary variables to determine whether the parameters have been modified.

8. The gas and electricity meter based on pressure difference and size paging calibration conversion according to claim 6, characterized in that: In the operation steps of switching pages, if the next page button is clicked, it is necessary to determine whether the current page is the last page. If it is the last page, the user is prompted that it is the last page. Otherwise, the page switching process is executed.

9. The gas and electricity meter based on pressure difference and size paging calibration conversion according to claim 6, characterized in that: The specific steps of the calibration page adding process include: Determine whether there are any calibration parameter and calibration coefficient modifications on the current page. If so, save them according to the user's operation. Add 1 to the variable stored in the current page, update the total page number, and calculate the reference size values ​​for each calibration based on the current page; On the calibration interface, enter the calibration reference value termination data and the number of calibration items on the next page. The reference value spacing for each calibration item is: Calculate the reference value of each calibration dimension on the next page based on the spacing value; Close the current calibration page, open the corresponding calibration page based on the current page and display the calibration size value.

10. The gas and electricity meter based on pressure difference and size paging calibration conversion according to claim 6, characterized in that: The specific steps of the calibration page deletion process are: Determine whether the calibration parameters and calibration coefficients of the current page have been modified. If so, save them according to the user operation; Execute the subtraction operation on the current page storage variable and update the total page number, and obtain the current page calibration parameters and calibration coefficients according to the current page storage variable; Close the current calibration interface, open the corresponding calibration page based on the current page, and display the calibration parameters and calibration coefficients.

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