A signal processing system and method for an electrochromatographic mud concentration meter

Abstract

The present invention relates to a signal processing system and method for an electrical chromatography mud concentration meter, belonging to the technical field of dredging engineering, and characterized in that it is composed of a sensor electrode, an excitation signal generating unit, a signal acquisition processing unit, an image reconstruction unit and a control unit; wherein: the sensor electrode acquires the information of the electrical chromatography mud concentration; the excitation signal generating unit receives the information output by the sensor electrode, and performs analog-to-digital conversion on the information; the signal acquisition processing unit receives the digital signal of the excitation signal generating unit, and performs gating, amplification, filtering, and signal conversion processing on the digital signal; the image reconstruction unit receives the information of the control unit, and reconstructs the information. The present invention can overcome the problems of large signal processing volume, fast processing speed, and complex algorithm structure.

Description

Technical Field

[0001] The invention belongs to the technical field of dredging engineering, and in particular relates to an electrical chromatography mud concentration meter signal processing system and a processing method. Background Art

[0002] The concentration meter is an important instrument for dredging ships. Its main function is to detect the mud concentration of the dredging conveying system (pipeline), and to calculate the instantaneous output and cumulative output by integrating with the flow rate data, which provides an important basis for operators to carry out reasonable and efficient dredging operations. It is an indispensable equipment for dredging ships today. This equipment is of great significance to improving dredging efficiency and quality, reducing energy consumption, and realizing modern scientific management.

[0003] At present, the concentration measurement of dredging ships generally adopts radioactive source concentration meters. However, radioactive materials bring a series of disadvantages, such as: they are extremely dangerous, with great risks of endangering the personal safety of crew members and seriously polluting the environment; the management and supervision responsibilities are heavy; transportation, maintenance, and recycling are difficult and costly; there are policy restrictions on the areas where radioactive sources are used; maintenance is frequent and complicated, and frequent calibration is required; single sector detection leads to precision errors and uncertainty in measurement results.

[0004] Electrical tomography technology has the advantages of no radiation, fast response speed and low price. Applying this technology to dredged mud concentration measurement requires solving the following problems:

[0005] Since analog devices have inherent defects in speed, accuracy and stability, in order to overcome the problems of large signal processing volume, fast processing speed and complex algorithm structure. Summary of the invention

[0006] The present invention aims to solve the technical problems existing in the known technology and provides a signal processing system and a processing method for an electrical chromatography mud concentration meter.

[0007] The first object of the present invention is to provide an electrical chromatography mud concentration meter signal processing system, which is composed of a sensor electrode, an excitation signal generating unit, a signal acquisition processing unit, an image reconstruction unit and a control unit; wherein:

[0008] The sensor electrode is a sensor electrode for acquiring the concentration information of the electrical chromatography mud;

[0009] The excitation signal generating unit receives information output by the sensor electrode and performs analog-to-digital conversion on the information;

[0010] The signal acquisition processing unit receives the digital signal from the excitation signal generating unit, and performs gating, amplification, filtering, and signal conversion processing on the digital signal;

[0011] The control unit receives the output signal of the signal acquisition processing unit, and performs programming control on the output signal, establishes a lookup table in the FPGA, stores the control words of all states of each signal acquisition channel in the order of the detection sequence number, and records the current detection sequence number by an 8-bit sequence number register. When the switch state needs to be changed, the control module controls the timing of the excitation circuit and the measurement circuit according to the control word in the sequence number register in the lookup table, controls the magnitude of the excitation current value to achieve accurate measurement of each channel under various working conditions, and sends the measurement value data frame to the image reconstruction unit;

[0012] The image reconstruction unit receives information from the control unit and reconstructs the information.

[0013] Further: the excitation signal generating unit is composed of an FPGA, a D / A converter and a power supply circuit group.

[0014] Further: the FPGA includes a DCM module, a DDS module, a digital and analog conversion module, a phase-sensitive modulation, an asynchronous FIFO module, an EMIF interface module and a microprocessor.

[0015] Further: the signal acquisition and processing unit includes an electrode state selection circuit, a filtering circuit, an excitation circuit, a measurement circuit, a control circuit, and a communication circuit.

[0016] Further: the measuring circuit includes a differential amplifier and an adjusting resistor for controlling the gain of the differential amplifier; the differential amplifier is respectively connected to the two ends of the measured resistor through two RC amplification circuits.

[0017] Further: The model of the differential amplifier is AD8129AR.

[0018] Further: the control unit is composed of a main processor and a coprocessor FPGA.

[0019] Further: the image reconstruction unit is composed of a host computer processor and an imaging PC.

[0020] The second object of the present invention is to provide a method for processing signals of an electrical chromatography mud concentration meter, comprising the following steps:

[0021] S1. The excitation signal generating unit generates an excitation signal source.

[0022] S2, the signal acquisition processing unit receives the digital signal from the excitation signal generating unit, uses the AD8129AR differential to single-ended amplifier, which has a very high common mode rejection ratio at high frequencies, converts the differential signal into a single-ended signal, and performs gating, amplification, filtering, and signal conversion processing on the digital signal;

[0023] S3, the control unit receives the output signal of the signal acquisition processing unit, and performs programming control on the output signal, the control module realizes the timing control of the excitation circuit and the measurement circuit, and controls the magnitude of the excitation current value to realize the accurate measurement of each channel under various working conditions;

[0024] S4, the control module sends a measurement value data frame to the image reconstruction unit;

[0025] S5. The image reconstruction unit receives the information from the control unit and reconstructs the information.

[0026] The advantages and positive effects of the present invention are:

[0027] By adopting the above technical solution: the present invention is designed for the dredging engineering industry; the system structure is flexible, easy to modularize, has strong versatility and real-time signal processing capabilities, and integrates the real-time signal processing advantages of the host computer, the logic control of FPGA and the hardware programmable advantages, and has the characteristics of fast data processing speed, large amount of processed data, stable signal transmission and clear imaging, etc., which plays an important role in the research and development of new electrical chromatography mud concentration meters;

[0028] This system adopts the "four-electrode mode" of adjacent current excitation and adjacent voltage measurement. The signal acquisition and processing unit measures the equivalent resistance value between any pair of electrodes under the control of FPGA, obtains data at different observation angles for image reconstruction, and realizes the visualization measurement of the conductivity distribution image in the sensitive field and the real-time measurement of the medium concentration. This method has a comprehensive sensing range, and the measurement results have a vivid and intuitive display effect. It can effectively solve the nuclear radiation risk and environmental pollution problems caused by the use of radioactive sources in traditional measurement technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a system block diagram of a preferred embodiment of the present invention;

[0030] FIG2 is a hardware circuit diagram of a preferred embodiment of the present invention;

[0031] FIG3 is a schematic diagram of a measurement circuit according to a preferred embodiment of the present invention;

[0032] Figure 4 A potential distribution diagram of a measuring device according to a preferred embodiment of the present invention;

[0033] FIG5 is a flow chart of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0035] The measurement process must obey Maxwell's equations (electric field), Radon transform (concentration) and cross-correlation principle (velocity).

[0036] The calculation principle of the concentration meter of the present invention is based on the Maxwell Garnett equation shown in formula (1), which is described as follows:

[0037] (1)

[0038] represents the content (i.e. concentration), The conductivity of water, represents the conductivity of sediment, Represents the average conductivity of the mixture (water containing sediment in the transport).

[0039] According to the principle of electrical tomography, in the single-electrode excitation mode, there is a definite relationship between the size of the boundary measurement value and the conductivity; through the sensitivity matrix, there is also a definite relationship between the grayscale value of the measurement section and the boundary measurement value, so the concentration of the measurement section can be calculated by measuring the grayscale value of the interface.

[0040] Based on the above principles, in order to further understand the technical content, characteristics and effects of the present invention, the following detailed description is given in conjunction with the accompanying drawings:

[0041] See also Figures 1 to 5 , an electrical chromatography mud concentration meter signal processing system, composed of sensor electrodes, an excitation signal generating unit, a signal acquisition processing unit, an image reconstruction unit and a control unit. Among them:

[0042] The sensor electrode is a sensor electrode for acquiring the concentration information of the electrical chromatography mud;

[0043] The excitation signal generating unit receives information output by the sensor electrode and performs analog-to-digital conversion on the information;

[0044] The signal acquisition processing unit receives the digital signal from the excitation signal generating unit, and performs gating, amplification, filtering, and signal conversion processing on the digital signal;

[0045] The control unit receives the output signal of the signal acquisition processing unit and performs programming control on the output signal. The control module (also called the control program) realizes the timing control of the excitation circuit and the measurement circuit, controls the magnitude of the excitation current value to realize the accurate measurement of each channel under various working conditions, and sends the measurement value data frame to the image reconstruction unit.

[0046] The image reconstruction unit receives information from the control unit and reconstructs the information.

[0047] The signal acquisition and processing unit includes an electrode state selection circuit, a filtering circuit, an excitation circuit, a measurement circuit, a control circuit, a communication circuit, etc.; the image reconstruction unit is completed by a host computer.

[0048] For the excitation circuit, this system adopts the electrode measurement mode of adjacent current excitation and adjacent voltage measurement. The potential distribution of the sensitive field is shown in the attached figure. Figure 4 As shown in the figure, each pair of excitation electrodes can be equivalent to 15 resistors with different resistance values ​​connected in series. Each time the excitation is performed, the system needs to measure the equivalent resistance respectively. This system only takes 13 of the resistance values ​​and does not consider the two resistance values ​​of adjacent excitation electrodes.

[0049] For the measurement circuit, the differential amplifier circuit is as shown in the attached Figure 3 As shown, the voltage signals at both ends of the measured resistor are input from V_ME1 and V_ME2 respectively, first pass through the RC amplifier circuit to filter out the DC component in the signal; then pass through the limiting protection circuit to enter the positive / reverse input terminal of the differential amplifier, and change the differential gain by adjusting the ratio of resistor R29 to resistor R30.

[0050] The system is equipped with redundant double-row electrodes for mutual backup, thus improving the reliability of the device.

[0051] This system adopts a single-electrode voltage excitation method, which effectively avoids the problem of low small signal-to-noise ratio in the case of high conductivity targets.

[0052] This system will communicate with the host computer after collecting and processing the data. The host computer processor will reconstruct the data and then display it in real time on the PC.

[0053] The excitation signal generating unit is composed of an FPGA, a D / A converter and a power supply circuit.

[0054] Among them: The FPGA program design of this system is based on the internal integrated IP core module and adopts modular design. Figure 2 As shown in the figure, it mainly includes DCM module, DDS module, digital and analog conversion module, phase-sensitive modulation, asynchronous FIFO module, EMIF interface module and microprocessor. These modules are combined together to gate, amplify and filter the original signal of the sensor to form a usable measurement value, and transmit the measurement value to the host computer.

[0055] The signal acquisition and processing unit includes an electrode state selection circuit, a filtering circuit, an excitation circuit, a measurement circuit, a control circuit, and a communication circuit.

[0056] The measuring circuit comprises a differential amplifier and an adjusting resistor for controlling the gain of the differential amplifier; the differential amplifier is respectively connected to two ends of the resistor to be measured through two RC amplification circuits.

[0057] The model of the differential amplifier is AD8129AR.

[0058] The control unit is composed of a main processor and a coprocessor FPGA.

[0059] The image reconstruction unit is composed of a host computer processor and an imaging PC.

[0060] This system uses a microprocessor to complete logic control such as switching of excitation / measurement electrodes, PGA gain adjustment, reset and start of phase-sensitive demodulation, asynchronous reset and start, and interrupt request to the host computer (DSP). The control flow is shown in the attached figure. Figure 5 The controller sets the excitation electrode and the measuring electrode, and then the excitation electrode performs field excitation, and the measuring electrode receives the signal. The excitation electrode and the measuring electrode are set in a continuous cycle, and then the signal is sent to the host computer after being gated, amplified, and filtered.

[0061] The resistance information between electrodes is converted into voltage information by using R / V conversion circuit, and the voltage information reflecting the resistance information is extracted by phase-sensitive modulation unit. This system is completed by orthogonal sequence demodulation implemented by FPGA.

[0062] The specific working principle of this preferred embodiment is:

[0063] The steps include:

[0064] S1. The excitation signal generating unit generates an excitation signal source.

[0065] S2, the signal acquisition processing unit receives the digital signal from the excitation signal generating unit, uses the AD8129AR differential to single-ended amplifier, which has a very high common mode rejection ratio at high frequencies, converts the differential signal into a single-ended signal, and performs gating, amplification, filtering, and signal conversion processing on the digital signal;

[0066] S3, the control unit receives the output signal of the signal acquisition processing unit, and performs programming control on the output signal, the control module realizes the timing control of the excitation circuit and the measurement circuit, and controls the magnitude of the excitation current value to realize the accurate measurement of each channel under various working conditions;

[0067] S4, the control module sends a measurement value data frame to the image reconstruction unit;

[0068] S5. The image reconstruction unit receives the information from the control unit and reconstructs the information.

[0069] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A method for processing signals of an electrical chromatography mud concentration meter, characterized in that: The signal of the electrical chromatography mud concentration meter is processed by using the electrical chromatography mud concentration meter signal processing system, wherein the electrical chromatography mud concentration meter signal processing system is composed of a sensor electrode, an excitation signal generating unit, a signal acquisition processing unit, an image reconstruction unit and a control unit; wherein: The sensor electrode is a sensor electrode for obtaining electrical chromatography mud concentration information; The excitation signal generating unit receives information output by the sensor electrode and performs analog-to-digital conversion on the information; The signal acquisition processing unit receives the digital signal from the excitation signal generating unit, and performs gating, amplification, filtering and signal conversion processing on the digital signal; The control unit receives the output signal of the signal acquisition processing unit, and performs programming control on the output signal, realizes the timing control of the excitation circuit and the measurement circuit through the control unit, controls the magnitude of the excitation current value to realize the accurate measurement of each channel under various working conditions, and sends the measurement value data frame to the upper computer through the control unit; The image reconstruction unit receives information from the control unit and reconstructs the information; The method comprises the following steps: S1, an excitation signal generating unit generates an excitation signal source; S2, the signal acquisition processing unit receives the digital signal from the excitation signal generating unit, uses the AD8129AR differential amplifier to convert the differential signal into a single-ended signal, and performs gating, amplification, filtering and signal conversion processing on the digital signal; S3, the control unit receives the output signal of the signal acquisition processing unit, and performs programming control on the output signal, the control unit realizes the timing control of the excitation circuit and the measurement circuit, and controls the magnitude of the excitation current value to realize the accurate measurement of each channel under various working conditions; S4, the control unit sends a measurement value data frame to the image reconstruction unit; S5. The image reconstruction unit receives the information from the control unit and reconstructs the information.

2. The signal processing method of the electrical chromatography mud concentration meter according to claim 1, characterized in that: The excitation signal generating unit is composed of FPGA, D / A converter and power supply circuit.

3. The signal processing method of the electrical chromatography mud concentration meter according to claim 2, characterized in that: The FPGA includes a DCM module, a DDS module, a digital and analog quantity mutual conversion module, a phase-sensitive modulation, an asynchronous FIFO module, an EMIF interface module and a microprocessor.

4. The signal processing method of the electrical chromatography mud concentration meter according to claim 1, characterized in that: The signal acquisition and processing unit comprises an electrode state selection circuit, a filtering circuit, an excitation circuit, a measurement circuit, a control circuit and a communication circuit.

5. The signal processing method of the electrical chromatography mud concentration meter according to claim 4, characterized in that: The measuring circuit comprises a differential amplifier and an adjusting resistor for controlling the gain of the differential amplifier; the differential amplifier is respectively connected to two ends of the resistor to be measured through two RC amplification circuits.

6. The signal processing method of the electrical chromatography mud concentration meter according to claim 1, characterized in that: The control unit is composed of a main processor and a coprocessor FPGA.

7. The signal processing method of the electrical chromatography mud concentration meter according to claim 1, characterized in that: The image reconstruction unit is composed of a host computer processor and an imaging PC.

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