Online signal calibration device and natural gas metering management system

Abstract

This invention discloses an online signal calibration device and a natural gas metering management system, including a signal input conversion module, a reference voltage module, an output modulation module, an AD sampling module, and a standard signal modulation module. The signal input conversion module is used to generate a corresponding PWM signal based on a given value. The reference voltage module is used to generate a reference voltage and derive the corresponding output voltage based on the real-time acquired current and the resistance value to be simulated. The reference voltage is modulated by the PWM signal, and the output voltage is controlled by the output modulation module after modulation. The AD sampling module samples the current and the output voltage. The standard signal modulation module modulates the sampled current and the output voltage to generate a standard signal and output it.

Description

Technical Field

[0001] This invention relates to the field of instrument calibration technology in natural gas metering management, specifically to an online signal calibration device and a natural gas metering management system, system, equipment, and storage medium. Background Technology

[0002] In the natural gas production process, to ensure production safety, it is necessary to collect information such as pressure differential, pressure, and temperature of the natural gas in the pipeline. The collected signals are transmitted to a signal acquisition module via an isolator for analog-to-digital conversion. The signal acquisition module then transmits the digital signal to the metering system. One function of the isolator is to perform standard conversion on the collected signals. The principle is that a standard signal is pre-set for the isolator, and the isolator converts the collected signals according to this standard signal. However, during long-term use, due to wear and tear of internal components and potential influences from the external environment, the standard signal may change. Therefore, the isolator needs to be calibrated periodically.

[0003] The temperature of natural gas is typically measured using a resistance temperature detector (RTD), which generates a resistance signal in the circuit. Therefore, when converting the resistance signal from the RTD in the isolator, the reference standard signal is an analog resistance signal. In existing technologies, analog resistance is generally generated using multi-range resistor chips or DAC (digital-to-analog converter) chips. However, multi-range resistor chips can only guarantee the accuracy of the generated analog resistance within a narrow range through precise program compensation. DAC chips are more expensive, and their control circuit is a microcontroller with analog-to-digital conversion capabilities, containing internal program code, which may lead to inaccurate analog resistance readings due to program issues. Summary of the Invention

[0004] To address the aforementioned shortcomings, one aspect of this invention is to provide an online signal calibration device that can ensure the accuracy of analog signals over a large range, without requiring program intervention for compensation, thus eliminating the problem of inaccurate analog signals caused by program errors.

[0005] An online signal calibration device includes a signal input conversion module, a reference voltage module, an output modulation module, an AD sampling module, and a standard signal modulation module. The signal input conversion module generates a corresponding PWM signal based on a given value. The reference voltage module generates a reference voltage and derives a corresponding output voltage based on real-time acquired current and the resistance value to be simulated. The reference voltage is modulated by the PWM signal, and the output voltage is then controlled by the output modulation module. The AD sampling module samples the current and output voltage. The standard signal modulation module modulates the sampled current and output voltage to generate and output a standard signal.

[0006] This solution uses PWM frequency modulation and a reference voltage feedback resistor to ensure the accuracy of analog signals over a large range of -100 to 800°C, without requiring compensation from program parameters.

[0007] A preferred embodiment of the present invention further includes an isolation module, wherein the PWM signal passes through the isolation module and is then connected to the reference voltage module.

[0008] The beneficial effect is that by setting up the isolation module, digital signals and analog signals can be isolated, avoiding mutual interference between signals.

[0009] A preferred embodiment of the present invention is that a single-stage voltage divider circuit and a multi-stage filter circuit are sequentially connected between the reference voltage module and the output modulation module.

[0010] The beneficial effects are as follows: by using a first-stage voltage divider circuit connected between the reference voltage module and the output modulation module, the modulation voltage generated from the reference voltage module is divided; by using a multi-stage filtering circuit, signals of different frequencies are selectively filtered, high-frequency noise and interference signals are weakened, and signal transmission quality is improved.

[0011] A preferred embodiment of the present invention is that a first integrated operational amplifier module is connected between the final stage of the multi-stage filter circuit and the output modulation module, and a capacitor for capacitive reactance matching is connected to the positive input terminal of the first integrated operational amplifier module.

[0012] The beneficial effects are as follows: the first integrated operational amplifier module plays the role of voltage divider and control of the output voltage of the output modulation module in the circuit. A capacitor for capacitive reactance matching is connected to the positive input terminal of the first integrated operational amplifier module. This capacitor plays the role of capacitive reactance matching, that is, by adjusting the capacitance value, signals of a specific frequency can be filtered out, thereby achieving the purpose of signal filtering and noise suppression, and improving the performance and stability of the circuit.

[0013] A preferred embodiment of the present invention is that a two-stage voltage divider circuit and a filter circuit are connected between the first integrated operational amplifier module and the output modulation module.

[0014] The beneficial effects are: by setting up a two-stage voltage divider circuit, it is easier to sample the output voltage in the future; by setting up a filter circuit, interference signals are filtered out, thus improving the accuracy of the output signal.

[0015] A preferred embodiment of the present invention is that the output modulation module adopts a first MOS transistor, and one end of the drain of the first MOS transistor is connected to the negative feedback terminal of the first integrated operational amplifier module.

[0016] The beneficial effects are as follows: since the drain terminal of the first MOSFET is connected to the negative feedback terminal of the first integrated operational amplifier module, a closed-loop control is formed. The closed-loop gain is not affected or is only slightly affected by changes in the parameters of the external components, thereby improving the gain stability and reducing nonlinear distortion.

[0017] A preferred embodiment of the present invention is that a capacitor for isolating external signal interference is connected on the line between the drain of the first MOS transistor and the negative feedback terminal of the first integrated operational amplifier module.

[0018] The beneficial effect is that by connecting a capacitor to isolate external signal interference on the line between the drain of the first MOSFET and the negative feedback terminal of the first integrated operational amplifier module, interference from external signals, such as those generated by the ground terminal, can be reduced.

[0019] A preferred embodiment of the present invention is that the other end of the drain of the first MOSFET is connected to one pin of the intelligent temperature isolation processor, and the source of the first MOSFET is connected to another pin of the intelligent temperature processor.

[0020] The beneficial effect is that, through the above design, the present invention achieves working temperature calibration, thereby ensuring more accurate analog output.

[0021] A preferred embodiment of the present invention is that a second integrated operational amplifier module is connected between the output modulation module and the AD sampling module. The output terminal of the second integrated operational amplifier module is connected to one end of a resistor, and the other end of the resistor is connected in sequence to a multi-stage impedance matching circuit. The resistor is used to generate a real-time current when the output voltage is applied.

[0022] A preferred embodiment of the present invention is that the output terminal of the isolation module is also connected to the input terminal of the AD sampling module, and the AD sampling module is used to perform control sampling according to the PWM signal.

[0023] A preferred embodiment of the present invention is as follows: the standard signal modulation module includes three sets of standard signal modulation sub-modules respectively connected to multiple output pins of the AD sampling module. Each set of standard signal modulation sub-modules includes an impedance matching circuit connected to the output pin of the AD sampling module, a standard signal modulation output circuit connected to the impedance matching circuit, and a third integrated operational amplifier module connected to the standard signal modulation output circuit. The standard signal modulation output circuit uses a second MOS transistor. The analog resistance generated on the line between the impedance matching circuit and the drain of the second MOS transistor, respectively, and on the same line in the other two sets of standard signal modulation sub-modules, serves as the standard signal output.

[0024] The second aspect of this invention provides a natural gas metering management system, including the online signal calibration device described in any of the preceding claims, and a main control module. The main control module is used to automatically control a relay to disconnect the connection with the thermal resistor when calibration of the isolator in the natural gas metering system is required, and automatically control the online signal calibration device to generate a calibration signal to calibrate the isolator. Thus, it automatically controls the switching of lines to complete the signal calibration when calibration is needed.

[0025] This achievement, by employing PWM frequency modulation and a reference voltage feedback resistor, ensures the accuracy of analog signals across a wide temperature range of -100 to 800°C without requiring program parameter compensation. It also avoids mutual interference between signals, improving signal transmission stability and quality. Furthermore, this design enables operating temperature calibration, thereby ensuring more accurate analog output.

[0026] This invention provides a natural gas metering and management system, including the online signal calibration device described in any of the above claims, and a main control module. The main control module is used to automatically control a relay to disconnect the connection with the thermal resistor when calibration of the isolator in the natural gas metering system is required. This automatically controls the online signal calibration device to generate a calibration signal to calibrate the isolator. Thus, it automatically controls the switching of circuits when calibration is needed to complete the signal calibration. Attached Figure Description

[0027] Figure 1 This is a circuit diagram of the online signal calibration device of the present invention. Detailed Implementation

[0028] In the following, the terms “comprising” or “may include” as used in various embodiments of the invention indicate the presence of an inventive function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in various embodiments of the invention, the terms “comprising,” “having,” and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0029] The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of the invention. Unless otherwise specified, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. The terms (such as those defined in commonly used dictionaries) are to be interpreted as having the same meaning as in the context of the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning unless clearly defined in the various embodiments of the invention.

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0031] As attached Figure 1 The online signal calibration device shown includes a signal input conversion module, an isolation module, a reference voltage module, a first integrated operational amplifier module, an output modulation module, a second integrated operational amplifier module, an AD sampling module, and a standard signal modulation module.

[0032] The signal input conversion module is used to generate a corresponding PWM signal based on a given value (referring to the resistance value input by the user; for example, if a 40Ω analog resistance is desired, then 40 is input). Specifically, this is generated by a central processing module, which is an ST STM32F103ZET6 MCU. The generated PWM signal is input through pin 3 of the isolation module, and output through pin 14 of the isolation module and resistor R101 to pin 6 of the reference voltage module. The reference voltage module is used to generate a reference voltage. In this embodiment, pins 1 and 5 of the reference voltage module are connected to a 2.5V reference voltage, and pins 2 and 3 are grounded. The output from pin 4 of the reference voltage module is output to the first integrated operational amplifier module via a first-stage voltage divider circuit and a multi-stage filter circuit. Specifically, the output from pin 4 of the reference voltage module is first divided by resistors R100 and R103, then filtered and rectified sequentially by resistors R99 and capacitors C94, R98 and C93, R97 and C92, and C91, and finally input to pin 3 of the first integrated operational amplifier module via capacitive matching by capacitor C90. In this embodiment, a two-stage voltage divider circuit and a filter circuit are connected between the first integrated operational amplifier module and the output modulation module. Specifically, the first integrated operational amplifier module... The output from pin 6 of the first operational amplifier module is fed into the output modulation module after being divided by resistors R102 and R104 and filtered by capacitor C95. In this embodiment, the output modulation module uses a first MOSFET, specifically the input is to the gate (G) of the first MOSFET. The drain (D) end of the first MOSFET is connected to the negative feedback terminal of the first integrated operational amplifier module via a filter to ground through resistor R96 and capacitor C89, and capacitors R105 and C98. Capacitors C89 and C98 form a capacitor on the line between the drain of the first MOSFET and the negative feedback terminal of the first integrated operational amplifier module to isolate external signal interference. Resistor C97 is also connected between the line between pin 6 of the first integrated operational amplifier module and resistor R102 and the negative feedback terminal of the first integrated operational amplifier module.

[0033] One end of the drain (D) of the first MOSFET is connected to the ambient temperature input RA (pin 1 of CZ8), and the other end is connected to pin 2 of the negative feedback terminal of the first integrated operational amplifier module via resistor R105. This provides real-time feedback of the analog signal output, thereby changing the output voltage of the operational amplifier to control the first MOSFET. The source (S) terminal is connected to the ambient temperature input RB (pins 2 and 3 of CZ8) via resistors JR1 and JR2. The upper ends of resistors JR1 and JR2 are connected to the amplification circuit and the impedance matching circuit, then to the AD sampling module to acquire the real-time current value. By using the user-defined resistance value and the acquired current value, the voltage of the first MOSFET is controlled, thus obtaining the desired analog resistance value.

[0034] In this embodiment, a second integrated operational amplifier module is connected between the output modulation module and the AD sampling module. Specifically, the source (S) terminal of the first MOSFET is filtered and input to pin 3 of the second integrated operational amplifier module via resistor R106 and capacitor C102. Pin 6 of the second integrated operational amplifier module is connected to one end of resistor R108, which is used to generate real-time current when the output voltage is applied. Pin 6 of the second integrated operational amplifier module is connected to the negative feedback terminal of the second integrated operational amplifier module via a parallel resistor R117 and capacitor C105. A resistor R120 is also connected between the negative feedback terminal of the second integrated operational amplifier module and ground.

[0035] In this embodiment, the other end of resistor R108 is connected to a multi-stage impedance matching circuit in sequence. Specifically, the other end of resistor R108 is connected to one end of resistor R107 and one end of resistor R111, the other end of resistor R107 is connected to a 2.5V power supply, the other end of resistor R111 is grounded, and the other end of resistor R108, after passing through resistor R107 and resistor R111, passes through resistor R109 and capacitor C104 in sequence, and then through resistor R110 and capacitor C103 for filtering and rectification before being input to pin 5 of the AD sampling module. In this embodiment, the AD sampling module uses the AD7792 chip.

[0036] In this embodiment, the standard signal modulation module includes three sets of standard signal modulation sub-modules that are respectively connected to multiple output pins of the AD sampling module. The first set of standard signal modulation submodules includes a parallel resistor R143 and a capacitor C106 connected in series with pin 7 of the AD sampling module, and a parallel resistor R142 and a capacitor C107. The first set of standard signal modulation submodules also includes a third integrated operational amplifier module. Pin 3 of the third integrated operational amplifier module is connected to one end of resistor R149 and resistor R151 respectively. The other end of resistor R149 is connected to a 2.5V power supply, and the other end of resistor R151 is grounded. A capacitor C127 is also connected between the 2.5V power supply and ground. Pin 1 of the third integrated operational amplifier module is connected to the standard signal modulation output circuit. In this embodiment, the standard signal modulation output circuit uses a second MOSFET. Specifically, pin 1 of the third integrated operational amplifier module is connected to the gate (G) of the second MOSFET via resistor R150 and capacitor C126. One end of the source (S) of the second MOSFET is connected to the negative feedback terminal of the third integrated operational amplifier module, and the other end is connected to one end of resistor RJ1. The other end of resistor RJ1 is connected to a 2.5V power supply. Resistor R152 is connected to the drain (D) of the second MOSFET.

[0037] The output terminal of the AD sampling module has a resistor R145 and a capacitor C122 connected in series in parallel, and a resistor R144 and a capacitor C123 connected in parallel in series. The output terminals of the AD sampling module have a resistor R147 and a capacitor C124 connected in series in parallel, a resistor R146 connected in series, and a capacitor C125 and a resistor R148 connected in parallel in series.

[0038] In this embodiment, the analog resistors generated on the line between the impedance matching circuit and the drain of the second MOS transistor, respectively, and on the same lines as those in the other two sets of standard signal modulation submodules, are used as standard signal outputs, as shown in the attached diagram. Figure 1 The analog resistances generated between RA and RB, and between RA and RC, are shown as standard signal outputs.

[0039] In this embodiment, pins 11, 12, and 13 of the isolation module are also connected to pins 15, 16, and 1 of the AD sampling module, which is used to perform control sampling based on the PWM signal.

[0040] This invention derives the corresponding output voltage based on the real-time acquired current and the resistance value to be simulated. The reference voltage is modulated by a PWM signal, and the output voltage is controlled by the output modulation module after modulation. The AD sampling module samples the current and the output voltage, and the standard signal modulation module modulates the sampled current and the output voltage to generate a standard signal and output it.

[0041] An output buffer is employed to allow for a low-impedance analog output while using a high-impedance filter resistor. The output of the first integrated operational amplifier module is connected to resistor R106, and the output of the second integrated operational amplifier module is directly connected to the inverting input of the second integrated operational amplifier. The second integrated operational amplifier module, connected to resistor R108, forms a buffered follower, improving gain accuracy. This buffer is powered by an external high-precision 2.5V reference to obtain a stable full-scale output, thus ensuring the PWM signal swing remains between a low potential and an accurate high level.

[0042] This power supply trimming / margin adjustment application circuit, when connected to a high level, selects "sample / hold" operation. The output is high impedance (no margin adjustment) at startup. A continuous high level on input VDD1 will cause the output to hold its value indefinitely, while a continuous low level AD-DIN2 will place the output in a high-impedance state. Therefore, a PWM burst pulse (followed by a high level) can be used to trim the power supply upon power-up. Pulling the PWM signal low cleanly exits the margin adjustment operation, resulting in a stable power output.

[0043] This embodiment also discloses a natural gas metering management system, including the online signal calibration device described in any of the above embodiments, and a main control module. The main control module is used to automatically control the connection with the thermal resistor by controlling a relay when the isolator in the natural gas metering system needs to be calibrated, and automatically control the online signal calibration device to generate a calibration signal to calibrate the isolator.

[0044] This invention provides an online signal calibration device that ensures the accuracy of analog signals over a large range without requiring program compensation, thus eliminating the problem of inaccurate analog signals due to program errors. It also provides a natural gas metering management system, including the online signal calibration device described above, and a main control module. The main control module is used to automatically control a relay to disconnect the connection to the thermal resistor when calibration of the isolator in the natural gas metering system is required, and automatically control the online signal calibration device to generate a calibration signal to calibrate the isolator. Thus, it automatically controls the switching of circuits to complete the signal calibration when calibration is needed.

[0045] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. An online signal calibration device, characterized in that, The system includes a signal input conversion module, a reference voltage module, an output modulation module, an AD sampling module, and a standard signal modulation module. The signal input conversion module generates a corresponding PWM signal based on a given value. The reference voltage module generates a reference voltage and derives the corresponding output voltage based on the real-time acquired current and the resistance value to be simulated. The reference voltage is modulated by the PWM signal, and the output voltage is controlled by the output modulation module. The AD sampling module samples the current and output voltage. The standard signal modulation module modulates the sampled current and output voltage to generate a standard signal and output it.

2. The apparatus as claimed in claim 1, characterized in that, It also includes an isolation module, through which the PWM signal passes and is then connected to the reference voltage module.

3. The apparatus as described in claim 1, characterized in that, A single-stage voltage divider circuit and a multi-stage filter circuit are connected sequentially between the reference voltage module and the output modulation module.

4. The apparatus as claimed in claim 1, characterized in that, A first integrated operational amplifier module is connected between the final stage of the multi-stage filter circuit and the output modulation module, and a capacitor for capacitive reactance matching is connected to the positive input terminal of the first integrated operational amplifier module.

5. The apparatus as claimed in claim 1, characterized in that, A two-stage voltage divider circuit and a filter circuit are connected between the first integrated operational amplifier module and the output modulation module.

6. The apparatus as claimed in claim 1, characterized in that, The output modulation module employs a first MOSFET, with one drain (D) terminal connected to the negative feedback terminal of the first integrated operational amplifier module. A capacitor for isolating external signal interference is connected on the line between the drain of the first MOSFET and the negative feedback terminal of the first integrated operational amplifier module. The other drain terminal of the first MOSFET is connected to one pin of the intelligent temperature isolation processor, and the source (S) terminal of the first MOSFET is connected to another pin of the intelligent temperature processor.

7. The apparatus as claimed in claim 1, characterized in that, A second integrated operational amplifier module is connected between the output modulation module and the AD sampling module. The output terminal of the second integrated operational amplifier module is connected to one end of a resistor, and the other end of the resistor is connected in sequence to a multi-stage impedance matching circuit. The resistor is used to generate a real-time current when the output voltage is applied.

8. The apparatus as claimed in claim 1, characterized in that, The standard signal modulation module includes three sets of standard signal modulation sub-modules connected to multiple output pins of the AD sampling module. Each set of standard signal modulation sub-modules includes an impedance matching circuit connected to the output pin of the AD sampling module, a standard signal modulation output circuit connected to the impedance matching circuit, and a third integrated operational amplifier module connected to the standard signal modulation output circuit. The standard signal modulation output circuit uses a second MOS transistor. The analog resistance generated on the line between the impedance matching circuit and the drain of the second MOS transistor, respectively, is the same as that generated on the same line in the other two sets of standard signal modulation sub-modules, and is used as the standard signal output.

9. A natural gas metering and management system, characterized in that, The online signal calibration device, including any of the above-mentioned features, further includes a main control module. The main control module is used to automatically control a relay to disconnect the connection with the thermal resistor when calibration of the isolator in the natural gas metering system is required. This automatically controls the online signal calibration device to generate a calibration signal to calibrate the isolator. Thus, it automatically controls the switching of circuits when calibration is needed to complete the signal calibration.

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