Fault detecting and positioning method suitable for logging instrument circuit board

Abstract

The invention discloses a logging instrument circuit board fault detecting and positioning method, which comprises the following specific steps: step 1, arranging a plurality of key detection points on an intact standard circuit board, and building a logging instrument circuit board fault detecting device; and step 2, establishing a standard circuit board oscillogram library, performing real-time testing by adopting the logging instrument circuit board fault detection device in the step 1, performing comparative analysis with the standard circuit board oscillogram library, analyzing the logic sequence and the relationship of each key detection point, and establishing a logic judgment fault diagnosis table based on a truth table, so that a fault point can be effectively determined. And if the measurement points are more refined, the fault points and the fault components are accurately judged. The method solves the problems that according to an existing logging instrument circuit board fault detection method, circuit board diagnosis is difficult, and the fault recognition rate is low, operation is easy, and safety is high.

Description

Technical Field

[0001] This invention belongs to the field of well logging equipment technology, specifically relating to a method for fault detection and location of circuit boards in well logging instruments. Background Technology

[0002] Well logging instruments are mechatronic devices that use methods such as acoustic waves, resistivity, and radioactivity to measure the lithology of formations and identify oil and gas reservoirs. Well logging instruments include various controllable circuit boards. The proper functioning of these circuit boards is crucial for the accuracy and reliability of well logging data; therefore, it is essential to monitor their operational status. The structure of well logging instruments is limited by the working environment, including wellbore structure, wellbore temperature, and pressure. Well logging instruments are typically long and slender cylindrical in shape for easy movement and measurement within the well. To withstand the effects of well depth pressure and temperature, the instrument casing is a sealed cylindrical steel tube structure, using a metal frame to secure and protect the circuit boards. Due to the limitations of the instrument's shape, over 90% of the circuit boards are rectangular. With the development of integrated circuits, circuit design has become more modular, with standard connectors used to connect boards. Well logging instruments can be damaged during use. Faulty circuit boards are removed from the instrument and sent to a repair station for testing. The repair station needs to test the circuit board's functionality, locate the fault, and repair it by replacing components. The existing circuit board needs to be installed in the instrument and powered by the ground. Multimeters and oscilloscopes are used to check the voltage and waveform of the working point according to the circuit diagram. Repairing a circuit board requires a lot of equipment and instruments. In addition, it is necessary to understand the circuit diagram and the principle. The repair is difficult and time-consuming.

[0003] Current circuit board fault detection technologies for well logging instruments mainly utilize image recognition and infrared imaging to identify fault areas and improve circuit board yield. Chinese patent "Circuit Board Fault Detection Method, Device, Equipment, and Storage Medium" (Application Date: 2021.06.28; Application No.: CN202110717896.5; Publication Date: 2021.09.17; Publication No.: CN113409284A) discloses a circuit board fault detection method, device, equipment, and storage medium, relating to cloud computing and computer vision. The specific implementation scheme is as follows: acquiring a microscopic image of the circuit board; determining candidate fault areas based on the microscopic image and a pre-trained image recognition model, where the image recognition model represents the correspondence between the microscopic image and the fault areas; determining test input nodes and test output nodes based on the candidate fault areas; responding to inputting test stimuli to the test input nodes, analyzing the output signal of the test output nodes to determine fault feature vectors; and predicting circuit board fault information based on the fault feature vectors and a pre-trained fault prediction model, where the fault prediction model represents the correspondence between the feature vectors and the fault information.

[0004] Chinese patent "Circuit Board Fault Detection Method and Equipment" (Application Date: 2017.12.28; Application No.: CN201711457859.5; Publication Date: 2018.06.12; Publication No.: CN108152712A) discloses a circuit board fault detection method, comprising the following steps: setting the power-on duration and the detection duration after power failure; setting the number of cycles M for acquiring infrared energy data and / or the number of times infrared energy data is acquired in each cycle N; acquiring infrared energy data for each pixel of the test circuit board for M cycles, acquiring N peak infrared energy data during power failure and N infrared energy data during power failure in each cycle, subtracting the N peak infrared energy data and N infrared energy data during power failure in each cycle, then summing the N subtraction results for each cycle, and summing the results for M cycles to obtain the difference infrared energy data; performing the same processing on a standard circuit board to obtain the difference infrared energy data; and comparing the difference infrared energy data of each pixel of the test circuit board with the difference infrared energy data of each pixel of the standard circuit board to find the abnormal point.

[0005] In existing methods for detecting circuit board faults in well logging instruments, both image technology and infrared technology rely on fuzzy judgment. When locating fault areas, logical analysis and judgment cannot be performed, resulting in a low fault identification rate and limited assistance for component-level repairs. Well logging instruments operate in high-temperature environments, and components are selected through screening. Circuit boards are expensive and require component-level repairs. In addition, some components need to be tested under heating conditions to assess their high-temperature performance. In these situations, infrared detection technology is not applicable, and visual recognition technology is also limited. Summary of the Invention

[0006] The purpose of this invention is to provide a method for fault detection and location of circuit boards in well logging instruments, which solves the problems of difficult fault diagnosis and low recognition rate of existing well logging instrument circuit boards.

[0007] The technical solution adopted in this invention is a method for fault detection and location of circuit boards in well logging instruments, which is implemented according to the following steps: Step 1: Set up multiple key detection points on a intact standard circuit board to build a fault detection device for the logging instrument circuit board. Step 2: Establish a standard circuit board waveform library, analyze the logical sequence and relationship of each key detection point, and establish a logic judgment fault diagnosis table based on the truth table.

[0008] Step 3: Use the circuit board fault detection device of the logging instrument in Step 1 to perform real-time testing and compare it with the standard circuit board waveform library. The fault point can be effectively determined by using the fault diagnosis table. If the measurement points are increased and the logical relationship is refined, the fault point and faulty component can be determined more accurately.

[0009] The invention is further characterized by: The fault detection device for the logging instrument circuit board consists of a circuit board power supply module and an input signal source module connected to the input terminal of the circuit module at the key detection point, and several branch output signal processing units connected to the output terminal of the circuit module at the key detection point. Each branch output signal processing unit is connected to a digital acquisition unit, which is connected to the expert software, the input signal source module, and the output signal processing unit.

[0010] Step 1: Before testing the circuit board, call the standard circuit board information library, load the key test point information, operation control information and standard waveforms of the key test points, check the signal waveforms of the key test points one by one according to the loaded operation sequence and collect and record them. Compare the collected waveforms with the waveforms of the corresponding key test points on the standard board, and manually judge whether the signal waveforms of the selected key test points are normal.

[0011] Step 2: When the waveform of the key test point on the circuit board is found to be abnormal when compared with the waveform of the same point in the standard library, there is a problem with the relevant part of the circuit of the corresponding test point on the circuit board. The failure of one or more components will cause the corresponding abnormality to occur. In order to distinguish which specific component is causing the failure, screen and test multiple related components around the corresponding test point in the circuit diagram. After multi-point measurement, eliminate components or circuit bypasses that are in good working condition, and finally find the fault point or faulty component.

[0012] The power supply modules of the circuit board are mostly low-voltage power supplies, typically one or more of ±15VA, ±12VA, ±9VA, ±5VA, 5VD and 3.3VD.

[0013] The input signal source module uses a programmable signal generator, which allows for online editing of various required waveforms; the output signal processing unit modulates the signal output from the circuit board to meet the input voltage requirements of the AD acquisition module.

[0014] The digital acquisition unit uses a digital oscilloscope to digitize the waveform output from the circuit board; the expert software uses a real-time analysis system to display, record and manage the digitized signals, thus integrating the programmable signal generator, digital oscilloscope and real-time analysis system into a fault detection device for logging instrument circuit boards.

[0015] The beneficial effects of this invention are that it is applicable to the fault detection and location method of logging instrument circuit boards. Based on the working principle of each logging circuit board, the key detection points of the circuit board are designed and planned. The standard waveform diagram of each detection point is recorded using a testing device, and the correctness of electrical parameters such as amplitude and frequency is determined. A truth table of the detection points is formed, and then a truth table logic algorithm is established. Based on the results, the circuit board fault and the location of damaged components are given. This invention solves the problems of difficult circuit board diagnosis and low fault identification rate in existing logging instrument circuit board fault detection methods. This invention has strong compatibility and scalability, strong adaptability to constantly updated circuits, is easy to promote and apply, and has broad application prospects in the future. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the circuit board fault detection device for logging instruments of the present invention; Figure 2 The present invention relates to a schematic diagram of a method for detecting and locating faults in circuit boards of well logging instruments. Figure 3 Flowchart for establishing standard waveforms at circuit board measurement points in this invention; Figure 4 The schematic diagram of the acquisition and control board circuit and the schematic diagram of the detection points of the CCIT15421 inclined plane instrument of this invention; Figure 5 A schematic diagram illustrating the diagnostic conclusions of the U8 fault in this invention; Figure 6 An anomaly diagram comparing the waveform of the TX+ signal on the cable drive board detection board of this invention with that of the standard board at this point; Figure 7 A schematic diagram illustrating the fault diagnosis conclusions of the power amplifier tube in this invention. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0018] Example 1 This invention relates to a method for detecting and locating faults in the circuit boards of well logging instruments, and is carried out according to the following steps: Step 1: Set up multiple key detection points on a intact standard circuit board to build a fault detection device for the logging instrument circuit board. Step 2: Establish a standard circuit board waveform library, analyze the logical sequence and relationship of each key detection point, and establish a logic judgment fault diagnosis table based on the truth table.

[0019] Step 3: Use the circuit board fault detection device of the logging instrument in Step 1 to perform real-time testing and compare it with the standard circuit board waveform library. The fault point can be effectively determined by using the fault diagnosis table. If the measurement points are increased and the logical relationship is refined, the fault point and faulty component can be determined more accurately.

[0020] Example 2 This invention relates to a method for detecting and locating faults in the circuit boards of well logging instruments, and is carried out according to the following steps: Step 1: Set up multiple key detection points on a intact standard circuit board to build a fault detection device for the logging instrument circuit board. The structure of a well logging instrument circuit board fault detection device, such as Figure 1 As shown, the circuit board power supply module and the input signal source module are connected to the input terminal of the circuit module at the key detection point, respectively. The output terminal of the circuit module at the key detection point is connected to the output signal processing unit of several branches. The output signal processing unit of each branch is connected to the digital acquisition unit. The digital acquisition unit is connected to the expert software, the input signal source module, and the output signal processing module, respectively.

[0021] Step 2: Establish a standard circuit board waveform library, analyze the logical sequence and relationship of each key detection point, and establish a logic judgment fault diagnosis table based on the truth table.

[0022] Step 3: Use the circuit board fault detection device of the logging instrument in Step 1 to perform real-time testing and compare it with the standard circuit board waveform library. The fault point can be effectively determined by using the fault diagnosis table. If the measurement points are increased and the logical relationship is refined, the fault point and faulty component can be determined more accurately.

[0023] Before testing the circuit board, the standard circuit board information library is called to load key test point information, operation control information and standard waveforms of key test points. The signal waveforms of key test points are checked one by one according to the loaded operation sequence and collected and recorded. The collected waveforms are compared with the waveforms of the corresponding key test points on the standard board, and the signal waveforms of the selected key test points are judged manually to see if they are normal.

[0024] When the waveform of a key test point on a circuit board is abnormal compared to the waveform of that point in the standard library, there is a problem with the relevant part of the circuit of the corresponding test point on the circuit board. The failure of one or more components will cause the corresponding abnormality to occur. To distinguish which specific component is causing the failure, multiple related components around the corresponding test point in the circuit diagram are screened and tested. After multi-point measurement, components or circuit bypasses that are in good working order are eliminated, and finally the fault point or faulty component is found.

[0025] Example 3 This invention relates to a method for detecting and locating faults in the circuit boards of well logging instruments, and is carried out according to the following steps: Step 1: Set up multiple key detection points on a intact standard circuit board to build a fault detection device for the logging instrument circuit board. Taking a typical differential signal acquisition circuit as an example, such as Figure 2As shown, five key detection points are set: P1, P2, P3, P4, and P5, used to locate fault points and faulty components. Detection points P1 and P2 are connected to the differential amplifier circuit module, which in turn is connected to the filter circuit. Detection point P3 is connected between the differential amplifier circuit module and the filter circuit. The filter circuit is connected to the bias circuit, which is connected between the filter circuit and the bias circuit. Detection point P4 is connected between the bias circuit and the acquisition circuit, which is connected between the bias circuit and the acquisition circuit. By filtering and limiting the differential amplified signal, and biasing the filter circuit with the bias circuit, the final acquired signal is output.

[0026] Step 2: Establish a standard circuit board waveform library, analyze the logical sequence and relationship of each key detection point, and establish a logic judgment fault diagnosis table based on the truth table.

[0027] Step 3: Use the circuit board fault detection device of the logging instrument in Step 1 to perform real-time testing and compare it with the standard circuit board waveform library. The fault point can be effectively determined by using the fault diagnosis table. If the measurement points are increased and the logical relationship is refined, the fault point and faulty component can be determined more accurately.

[0028] Abnormalities may occur in the waveforms of the five key detection points. Fault diagnosis information requires analysis of the logical sequence and relationship of each key detection point to establish a logical judgment fault diagnosis table, as shown in Table 1. This can effectively determine the fault point. If the measurement points are further refined, the faulty component can be identified more accurately.

[0029] Table 1 is a table for diagnosing logical judgment faults.

[0030] In Table 1, abnormal waveforms are defined as logic 1, normal waveforms as logic 0, and X represents any state. According to the circuit, P1 and P2 are the positive and negative terminals of a differential signal. An abnormality in either P1 or P2 will be diagnosed as fault A, thus the logical relationship is: A = P1 + P2. When fault A does not occur (i.e., both P1 and P2 waveforms are normal), and the measured P3 is abnormal, the diagnosis is fault B. When fault A occurs, the P3 measurement point must be abnormal, therefore the logical relationship is B = P3 & A. Similarly, the logical relationships C = P4 & B and D = P5 & C are derived. From the above logical relationships, to ensure accurate fault diagnosis and avoid logical confusion, when establishing a standard circuit board waveform library, the measurement point order should be determined first, and step-by-step measurement and verification will make it easier to determine the fault point. The above example can be applied to a circuit board with N measurement points, and the more measurement points, the more accurate the fault diagnosis.

[0031] Example 4 This invention relates to a method for detecting and locating faults in the circuit boards of well logging instruments, and is carried out according to the following steps: Step 1: Set up multiple key detection points on a intact standard circuit board to build a fault detection device for the logging instrument circuit board; connect the circuit board power supply module and input signal source module to the input terminal of the circuit module of the key detection point, respectively; connect the output terminal of the circuit module of the key detection point to the output signal processing unit of several branches, and connect the output signal processing unit of each branch to the digital acquisition unit. The digital acquisition unit is connected to the expert software and the input signal source module and output signal processing module, respectively. The expert software adopts a real-time analysis system.

[0032] The circuit board's power supply module is mostly a low-voltage power supply, typically one or more of ±15VA, ±12VA, ±9VA, ±5VA, 5VD, and 3.3VD. The input signal source module uses a programmable signal generator, which can edit various required waveforms online, such as square waves, sawtooth waves, and triangular waves. The required test waveforms are designed according to the working principle of the circuit board being inspected. The output signal processing unit modulates the signal output by the circuit board to meet the input voltage requirements of the AD acquisition module. The digital acquisition unit uses a digital oscilloscope to digitize the waveform output by the circuit board. The expert software uses a real-time analysis system, which is a software program that displays, records, and manages the digitized signals. Thus, the programmable signal generator, digital oscilloscope, and real-time analysis system are integrated and connected to form a fault detection device for logging instrument circuit boards.

[0033] Step 2: Establish a standard circuit board waveform library, analyze the logical sequence and relationship of each key detection point, and establish a logic judgment fault diagnosis table based on the truth table.

[0034] Step 3: Use the circuit board fault detection device of the logging instrument in Step 1 to perform real-time testing and compare it with the standard circuit board waveform library. The fault point can be effectively determined by using the fault diagnosis table. If the measurement points are increased and the logical relationship is refined, the fault point and faulty component can be determined more accurately.

[0035] A flowchart for establishing a standard circuit board waveform library for key testing points on circuit boards, such as... Figure 3 As shown, the steps are as follows: set the standard board file directory, import the circuit board physical diagram, import the circuit schematic block diagram, add the schematic block diagram module information, import the circuit schematic diagram, configure the input waveform information, select the test point location, add the test point information, check if the test points have been added, add operation information after adding, input waveform information, configure the input and output unit signal channel information, check if the waveform operation has been added, confirm whether to create a new standard board, exit after successful creation, return to the main interface, select waveform operation, set parameters, collect standard waveforms and save, when all waveform operations are completed, click "End Detection", save the detection results, and exit the current standard board.

[0036] When the waveform of a key test point on a circuit board is abnormal compared to the waveform of that point in the standard library, there is a problem with the relevant part of the circuit of the corresponding test point on the circuit board. The failure of one or more components will cause the corresponding abnormality to occur. To distinguish which specific component is causing the failure, multiple related components around the corresponding test point in the circuit diagram are screened and tested. After multi-point measurement, components or circuit bypasses that are in good working order are eliminated, and finally the fault point or faulty component is found.

[0037] Establish the acquisition and control board circuit of the CCIT15421 inclined plane instrument, such as... Figure 4 As shown, a faulty circuit board was tested using the standard waveform library and expert diagnostic information of the CCIT15421 inclined plane instrument's acquisition and control board circuit. The preceding measurement points related to measurement point AIN0 were CXIN, CX0, CX1, CYIN, CY0, and CY1. The results of testing at each point were compared with the standard waveforms, as shown... Figure 5 As shown, it was found that only the AIN0 signal waveform was incorrect, while the waveforms of the previous measurement points were all normal. The diagnosis result was a fault in U8.

[0038] Based on the diagnostic conclusion, after replacing the multiplexer U8 on the board, the AIN0 waveform returned to normal, completing the repair of the circuit board. Similarly, a signal standard library for the TELC6306 cable driver board was established, and a faulty board was tested. When testing the TX+ signal, there was no signal output, and the waveform comparison was abnormal, such as... Figure 6 As shown, the diagnostic conclusion is that the power amplifier tube PA12H is faulty. Figure 7 As shown, the circuit board was restored after the power amplifier tube was replaced.

[0039] This invention relates to a method for fault detection and location on circuit boards of logging instruments. When establishing a standard board waveform library, the detection sequence and logical relationship of each measurement point are meticulously planned to achieve accurate fault identification. It solidifies expert maintenance experience. After the standard board waveform library is established, the board under test only needs to follow the standard board's prompts to detect the signal waveform at each measurement point and compare the waveforms to determine if they are abnormal. The operation is simple, reducing the technical requirements for on-site personnel, decreasing labor intensity, improving maintenance efficiency, requiring less equipment, and offering high maintenance timeliness. It has significant advantages for the standardization and preventative maintenance of logging instruments.

Claims

1. A method for fault detection and location of circuit boards in well logging instruments, characterized in that, The specific steps are as follows: Step 1: Set up multiple key detection points on a intact standard circuit board to build a fault detection device for the logging instrument circuit board. Step 2: Establish a standard circuit board waveform library, analyze the logical sequence and relationship of each key detection point, and establish a logic judgment fault diagnosis table based on the truth table. Step 3: Use the circuit board fault detection device of the logging instrument in Step 1 to perform real-time testing and compare it with the standard circuit board waveform library. The fault point can be effectively determined by using the fault diagnosis table. If the measurement points are increased and the logical relationship is refined, the fault point and faulty component can be determined more accurately.

2. The method for fault detection and location of circuit boards in well logging instruments according to claim 1, characterized in that, The well logging instrument circuit board fault detection device is configured such that a circuit board power supply module and an input signal source module are connected to the input terminal of the circuit module at the key detection point, and the output terminal of the circuit module at the key detection point is connected to several branch output signal processing units. Each branch output signal processing unit is connected to a digital acquisition unit, and the digital acquisition unit is connected to the expert software, the input signal source module, and the output signal processing module, respectively.

3. The method for fault detection and location of circuit boards in well logging instruments according to claim 2, characterized in that, In step 2, before testing the circuit board, the standard circuit board information library is called to load key test point information, operation control information and standard waveforms of key test points. The signal waveforms of key test points are checked one by one according to the loaded operation sequence and collected and recorded. The collected waveforms are compared with the waveforms of the corresponding key test points on the standard board, and the signal waveforms of the selected key test points are manually judged to be normal.

4. The method for fault detection and location of circuit boards in well logging instruments according to claim 3, characterized in that, When the waveform of the key test point on the circuit board in step 2 is abnormal compared with the waveform of the same point in the standard library, there is a problem with the relevant part of the circuit of the corresponding test point on the circuit board. The failure of one or more components will cause the corresponding abnormality to occur. In order to distinguish which specific component is causing the failure, multiple related components around the corresponding test point are screened and tested in conjunction with the circuit diagram. After multi-point measurement, components or circuit bypasses that are in good working condition are eliminated, and finally the fault point or faulty component is found.

5. The method for fault detection and location of circuit boards in well logging instruments according to claim 2, characterized in that, The power supply modules of the circuit board are mostly low-voltage power supplies, typically one or more of ±15VA, ±12VA, ±9VA, ±5VA, 5VD and 3.3VD.

6. The method for fault detection and location of circuit boards in well logging instruments according to claim 5, characterized in that, The input signal source module uses a programmable signal generator to edit various required waveforms online; the output signal processing unit modulates the signal output from the circuit board to meet the input voltage requirements of the AD acquisition module.

7. The method for fault detection and location of circuit boards in well logging instruments according to claim 6, characterized in that, The digital acquisition unit uses a digital oscilloscope to digitize the waveform output from the circuit board; the expert software uses a real-time analysis system to display, record and manage the digitized signals, thereby integrating the programmable signal generator, digital oscilloscope and real-time analysis system into a well logging instrument circuit board fault detection device.

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