Self-checking acquisition module of pressure sensor and self-checking method of pressure sensor

Abstract

This invention discloses a self-test acquisition module and a self-testing method for a pressure sensor. The first common terminal and the second common terminal of the analog switch of the self-testing unit are connected to the first signal node and the second signal node of the pressure sensor, respectively. The common terminal is selectively connected to the normally open and normally closed contacts of the output terminal. The two normally closed contacts are connected to the amplification and conversion unit circuit of the acquisition module. The first and second normally open contacts are each connected to a first branch and a second branch, respectively. The first branch connects to the voltage measurement unit circuit of the acquisition module, and the second branch has a resistor and is grounded. A self-resetting fuse is connected in series on the power supply line of the pressure sensor. By separating different fault types of the pressure sensor into different test voltages and identifying the voltage to determine the current fault type of the pressure sensor, a fast and convenient online pressure sensor fault self-testing function and remote fault diagnosis function are realized, reducing the complexity of manual processing.

Description

Technical Field

[0001] This invention belongs to the field of mold devices, specifically, it relates to a self-test acquisition module for a pressure sensor and a self-test method for the pressure sensor. Background Technology

[0002] In intelligent mold solutions, pressure sensors are typically installed within the mold to collect melt pressure during the mold production process. The accuracy of the pressure sensor data is crucial. Firstly, it provides direct data on the internal melt pressure of the mold during operation. By analyzing this pressure data, it helps determine if there are any technical defects in the products produced each time, issuing alarms for potential problems and serving as a vital basis for judging the quality of injection molded products. When monitoring the injection molding process, specific parameters such as peak pressure and integral values ​​are usually selected as criteria for judging the quality of injection molded products. If abnormal fluctuations caused by a faulty pressure sensor lead to abnormal changes in parameter values, the entire system will alarm, which is not necessary for production. Secondly, in some application scenarios, production personnel control the injection molding machine to switch operating states when specific parameters reach a threshold (e.g., peak pressure reaches a certain limit), controlling the mold production process based on pressure data. If a faulty pressure sensor causes abnormal data, this will severely disrupt the production process, making normal production impossible.

[0003] Pressure sensors installed inside large molds often have long cables. After installation, the mold may undergo assembly, disassembly, or processing operations, which can easily affect or even damage the pressure sensors and cables. Therefore, a simple method is needed to perform a self-test before using the pressure sensor, quickly determining its usability and preventing abnormal data caused by sensor damage from affecting the production process.

[0004] In existing technical solutions, production personnel need to manually measure each pressure sensor after each mold disassembly and repair, or check and measure it only after abnormal data is collected. The former method is very time-consuming, requiring constant monitoring of the mold processing status, and measuring the pressure sensors requires specialized equipment or tooling, making it difficult to operate in large-scale applications. The latter method is inherently lagging, and cannot be dealt with promptly after a failure occurs.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a self-test acquisition module for a pressure sensor that integrates a pressure self-test circuit into the self-test acquisition module. When the module is powered on, it can complete the self-test operation of the installed sensor.

[0007] The second objective of this invention is to propose a self-testing method for pressure sensors.

[0008] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows: A self-test acquisition module for a pressure sensor, wherein the analog switch of the self-test unit is provided with two common terminals and two sets of output terminals, and the first common terminal and the second common terminal are respectively connected to the first signal node and the second signal node of the pressure sensor. The first common terminal corresponds to the first normally open contact and the first normally closed contact of the first group of output terminals, which are selected to be connected; the second common terminal corresponds to the second normally open contact and the second normally closed contact of the second group of output terminals, which are selected to be connected. The two normally closed contacts are connected to the data acquisition module. The first normally open contact and the second normally open contact are each connected to the first branch and the second branch, respectively. The first branch is connected to the voltage measurement unit circuit of the acquisition module, and the second branch is equipped with a resistor and grounded. A resettable fuse is connected in series on the power line of the pressure sensor.

[0009] Furthermore, the analog switch is also equipped with a control pin, the high and low levels of which control the common terminal to be connected to the normally closed or normally open contact.

[0010] Furthermore, the power supply of the pressure sensor is connected to the power supply of the self-test acquisition module, and the ground wire of the pressure sensor is connected to the ground wire of the self-test acquisition module.

[0011] This invention also proposes a self-testing method for a pressure sensor, implemented using the aforementioned self-testing acquisition module, comprising the following steps: S1. Connect the two common terminals of the analog switch to the two normally closed contacts respectively. The acquisition module collects the pressure from the pressure sensor, compares the collected initial pressure sensor value with the reference value, and determines whether the deviation is within the set range. If the deviation is within the set range, the pressure sensor is determined to be normal and properly installed, and the self-test is exited. If the deviation is not within the set range, proceed to step S2; S2. Connect the two common terminals of the analog switch to the two normally open contacts respectively, and detect the first voltage VTEST_V of the circuit between the self-resetting fuse connected in series on the power line of the pressure sensor and the pressure sensor, the second voltage VTEST_N of the first branch connected to the first normally open contact and the third voltage VTEST_P of the first branch connected to the second normally open contact, for a total of three voltage values. The three voltage values ​​are compared with the corresponding reference voltage values. The self-test ends after the pressure sensor status and fault type are determined and reported based on the comparison results.

[0012] Further, determine the first reference voltage value V1 to satisfy , Determine the second reference voltage value V2 to satisfy , Determine the third reference voltage value V3 to satisfy ; where, VCC is the power supply voltage value, Rt is the resistance value of the second branch, and Rs is any one of the four resistances of the pressure sensor.

[0013] Further, when VTEST_V > V1 and V1 > VTEST_N > V2 and V2 > VTEST_P > V3, it is determined that the pressure sensor is normal but abnormally installed; When VTEST_V < V3, it is determined that the power supply line and the ground line of the pressure sensor are short-circuited; When VTEST_N > V1, it is determined that there is a short circuit between the power supply line of the pressure sensor and the first signal node; When VTEST_P > V1, it is determined that there is a short circuit between the power supply line of the pressure sensor and the second signal node; When VTEST_N < V3 and VTEST_P < V3, it is determined that the power supply line of the pressure sensor is short-circuited; When VTEST_N < V3 and VTEST_P > V3, it is determined that the first signal node of the pressure sensor or the first signal node and the first common end are open-circuited; When VTEST_N > V3 and VTEST_P < V3, it is determined that the second signal node of the pressure sensor or the second signal node and the second common end are open-circuited; When VTEST_N > V2 or VTEST_P > V2, it is determined that the ground line of the pressure sensor is open-circuited.

[0014] Further, when the two common ends of the analog switch are respectively connected to the two normally closed contacts, the acquisition module acquires the pressure of the pressure sensor, and when comparing the initially acquired value of the pressure sensor with the reference value, the reference value is the factory initial value of the pressure sensor.

[0015] Further, when comparing the initially acquired value of the pressure sensor with the factory initial value of the pressure sensor, multiple acquisitions and multiple comparisons are performed. When the deviations in multiple times are all within the set range, it is determined that the pressure sensor is normal and installed normally, and the self-check is exited; In any one comparison, if the deviation is not within the set range, step S2 is executed.

[0016] Further, when the control pin of the analog switch is set to a low level, the common end of the analog switch is controlled to be connected to the normally closed contact.

[0017] Furthermore, when the control pin of the analog switch is set to a high level, the common terminal of the analog switch is connected to the normally open contact.

[0018] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0019] This invention discloses a self-test acquisition module and a self-testing method for a pressure sensor. The self-test acquisition module has an analog switch with two common terminals and two sets of output terminals. The first common terminal and the second common terminal are connected to the first and second signal nodes of the pressure sensor, respectively. The first common terminal selectively connects to the first normally open and first normally closed contacts of the first set of output terminals. The second common terminal selectively connects to the second normally open and second normally closed contacts of the second set of output terminals. The two normally closed contacts are connected to the amplification and conversion unit circuit of the acquisition module. Each of the first and second normally open contacts is connected to a first branch and a second branch, respectively. The first branch connects to the voltage measurement unit circuit of the acquisition module, and the second branch has a resistor connected to ground. A resettable fuse is connected in series on the power supply line of the pressure sensor. By integrating the pressure acquisition self-test circuit into the self-test acquisition module, the module can perform a self-test on the installed pressure sensor when powered on. If the self-test fails, the relevant departments are notified promptly. Furthermore, the data generated by the pressure sensor is not used as a basis for judgment to avoid affecting production and preventing losses due to pressure sensor malfunctions. Furthermore, this method adds only a small amount of cost compared to the normal module, making it highly valuable for widespread application. One self-testing method for a pressure sensor utilizes the aforementioned self-test acquisition module. The two common terminals of the analog switch are connected to two normally closed contacts. The acquisition module collects the pressure from the pressure sensor, compares the initial pressure value with a reference value, and determines if the deviation is within a set range. If the deviation is within the set range, the pressure sensor is considered normal and properly installed, and the self-test ends. If the deviation is not within the set range, the two common terminals of the analog switch are connected to two normally open contacts, and three voltage values ​​are detected: the first voltage VTEST_V between the resettable fuse and the pressure sensor, the second voltage VTEST_N of the first branch connected to the first normally open contact, and the third voltage VTEST_P of the first branch connected to the second normally open contact. These three voltage values ​​are compared with their corresponding reference voltage values. Based on the comparison results, the pressure sensor fault type is determined and reported, then the self-test ends. The system enables self-testing of the connected resistance strain gauge pressure sensor status after power-on; a self-testing method and process for the pressure sensor has been developed to achieve a quick self-testing function without affecting normal operating conditions, separate different abnormal states of the pressure sensor, form different detection voltages, and determine the fault type by detecting the detection voltage.

[0020] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram showing the connection between the self-test unit and the pressure sensor in the self-test acquisition module of the pressure sensor of the present invention. Figure 2 This is a table showing the relationship between pressure sensor fault types and the theoretical values ​​of the three test voltages: the first voltage VTEST_V at the TEST_V measurement point, the second voltage VTEST_N at the TEST_N measurement point, and the third voltage VTEST_P at the TEST_P measurement point. Among them, the row for "normal sensor status" means that the pressure sensor itself is not faulty but the fault is caused by abnormal installation, while the other 7 sensor statuses mean that the sensor itself has a fault.

[0022] Figure 3 This is a flowchart illustrating the self-testing method of the pressure sensor of the present invention.

[0023] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only to facilitate the description of this invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] This invention is only for the self-test of resistance strain gauge pressure sensors using Wheatstone bridges.

[0028] like Figure 1 As shown, the pressure sensor circuit of this invention is a Wheatstone bridge with a full-bridge structure, consisting of four strain gauges, each with a resistance of Rs, forming four nodes. These four nodes form two pairs of nodes, with two nodes in each pair facing each other. One pair of nodes is connected to the power supply and ground wire respectively, while the other pair of nodes serves as signal nodes and is connected to the signal lines respectively.

[0029] The connection relationships between each node and the external interface are as follows: The top node of the bridge is connected to the power supply line, providing the power supply voltage VCC; the bottom node of the bridge is connected to the ground line GND (short for Ground), forming the power supply circuit of the bridge and realizing the DC excitation of the entire bridge.

[0030] The left node of the bridge is the INP terminal (Input Positive), and the right node is the INN terminal (Input Negative). Both are signal nodes, forming the differential signal output port of the bridge, which is used to output the bridge imbalance voltage signal caused by strain.

[0031] In the full-bridge structure of this pressure sensor circuit, the four strain resistors are symmetrically distributed: two Rs in the upper bridge arm and two Rs in the lower bridge arm. The power supply terminals (power line-ground line) and signal output terminals (INP terminal-INN terminal) are diagonally distributed, implementing the full-bridge connection method of the Wheatstone bridge.

[0032] When the pressure sensor is subjected to pressure, the strain resistor deforms, causing a change in resistance. This breaks the bridge balance, and a differential voltage proportional to the strain is output between the INP and INN terminals, thus realizing the conversion of pressure into an electrical signal.

[0033] In this invention, the self-testing unit of the pressure sensor is integrated into the acquisition module to form a self-testing acquisition module for the pressure sensor.

[0034] The self-test unit of the pressure sensor includes an analog switch and a voltage divider resistor. After the self-test unit is connected to the resistance strain gauge pressure sensor, its electrical schematic diagram is as follows: Figure 1 As shown.

[0035] The pressure sensor's self-test acquisition module has an analog switch with two common terminals and two sets of output terminals. In this embodiment, the two common terminals of the analog switch are named the first common terminal (COM1) and the second common terminal (COM2).

[0036] The first set of output terminals is provided with a first normally open contact and a first normally closed contact, and the second set of output terminals is provided with a second normally open contact and a second normally closed contact. In this embodiment, the first normally closed contact is named NC1 terminal, the first normally open contact is named NO1 terminal, the second normally closed contact is named NC2 terminal, and the second normally open contact is named NO2 terminal.

[0037] The first common terminal is connected to the first signal node INN terminal of the pressure sensor via a signal line, and the second common terminal is connected to the second signal node INP terminal of the pressure sensor via a signal line.

[0038] The analog switch is a double-pole double-throw analog switch, with a first normally closed contact (NC1) and a first normally open contact (NO1) corresponding to the first common terminal (COM1), and a second normally closed contact (NC2) and a second normally open contact (NO2) corresponding to the second common terminal (COM2).

[0039] The first common terminal COM1 is selected to be connected to the first normally open contact NO1 and the first normally closed contact NC1 of the first group of output terminals; the second common terminal COM2 is selected to be connected to the second normally open contact NO2 and the second normally closed contact NC2 of the second group of output terminals; the first normally closed contact NC1 is connected to the amplification and conversion unit circuit of the acquisition module through the lead IN_N, and the second normally closed contact NC2 is connected to the amplification and conversion unit circuit of the acquisition module through the lead IN_P.

[0040] like Figure 1 As shown, the first normally open contact, namely NO1, is connected to two branches, namely the first branch and the second branch. In this embodiment, the first branch is named TEST_N. The first branch is connected to the voltage measurement unit circuit of the acquisition module and is used to measure the voltage of the first branch, namely the second voltage VTEST_N. A resistor Rt is provided on the second branch and grounded.

[0041] The second normally open contact, NO2, is also connected to two branches, namely the first branch and the second branch. In this embodiment, the first branch is named TEST_P. The first branch is connected to the voltage measurement unit circuit of the acquisition module to measure the voltage of this first branch, namely the third voltage VTEST_P. A resistor Rt is provided on the second branch and grounded.

[0042] The self-test unit also includes a resettable fuse Fv, which is connected in series on the power line of the pressure sensor. A detection terminal TEST_V is set in the circuit between the resettable fuse and the pressure sensor and connected to the voltage measurement unit circuit of the acquisition module to detect the first voltage VTEST_V of the circuit between the resettable fuse and the pressure sensor.

[0043] The analog switch also has a control pin, which is named the TEST pin in this embodiment. The high or low level of the control pin controls whether the common terminal is connected to a normally closed or normally open contact. When the control pin of the analog switch is set to a low level, the common terminal of the analog switch is connected to the normally closed contact. When the control pin of the analog switch is set to a high level, the common terminal of the analog switch is connected to the normally open contact.

[0044] The power supply of the pressure sensor is connected to the power supply of the self-test acquisition module, and the ground wire of the pressure sensor is connected to the ground wire of the self-test acquisition module.

[0045] During normal operation, the power and ground wires of the pressure sensor are connected to the power and ground wires of the self-test acquisition module. A resettable fuse Fv is connected in series on the power line. The two signal lines are connected to the common terminal of the corresponding channel of the analog switch. The analog switch is configured so that the common terminal is connected to the normally closed contact. The output signal of the pressure sensor is sent to the subsequent acquisition module for signal amplification and conversion through the normally closed contact of the analog switch. Typically, the on-resistance of the analog switch is only a few ohms, or even lower, so the addition of the analog switch will not affect the normal operation of the subsequent acquisition module circuit.

[0046] This invention also proposes a self-testing method for a pressure sensor, implemented using the aforementioned self-testing acquisition module, comprising the following steps: S1. Connect the two common terminals of the analog switch to the two normally closed contacts respectively. The acquisition module collects the pressure from the pressure sensor, compares the collected initial pressure sensor value with the reference value, and determines whether the deviation is within the set range. If the deviation is within the set range, the pressure sensor is considered to be normal, and the self-test is exited. If the deviation is not within the set range, proceed to step S2; S2. Connect the two common terminals of the analog switch to the two normally open contacts respectively, and detect the first voltage VTEST_V of the circuit between the self-resetting fuse and the pressure sensor, the second voltage VTEST_N of the first branch connected to the first normally open contact, and the third voltage VTEST_P of the first branch connected to the second normally open contact, for a total of three voltage values. The three voltage values ​​are compared with their corresponding reference voltage values. The self-test ends after the fault type of the pressure sensor is determined and reported based on the comparison results.

[0047] When the control pin of the analog switch is set to a low level, the common terminal of the analog switch is connected to the normally closed contact. When the control pin of the analog switch is set to a high level, the common terminal of the analog switch is connected to the normally open contact.

[0048] In S1, during self-test, after power-on, the control pin TEST of the analog switch is first set to low level. At this time, the common open and normally closed contacts of the analog switch chip are connected, and the self-test acquisition module normally acquires the pressure from the pressure sensor. The initial value of the pressure sensor is then acquired and compared with the recorded factory initial value (as a reference value). If the deviation between the multiple acquisition results is within the set range (less than the set threshold), the pressure sensor is judged to be normal, and the self-test ends and exits. In any comparison, if a large deviation is found between the initial value of the pressure sensor and the recorded factory initial value (i.e., the deviation is not within the set range), then the following operation S2 is executed.

[0049] For resistance strain gauge pressure sensors, the four internal strain gauges form a Wheatstone bridge. Under no external pressure, the voltage between the two signal lines should be 0V, meaning the voltage between the INP and INN output terminals should be 0V. However, due to inconsistencies in manufacturing processes, this voltage is not zero. This results in a non-zero output from the acquisition module even when the pressure sensor is not subjected to external pressure. Generally, when using this type of pressure sensor, this initial value is acquired and set as the pressure zero point. The actual pressure value is obtained by subtracting this initial value from all acquired data. The initial value varies for each pressure sensor, but generally does not change significantly. By acquiring the initial value of the pressure sensor after installation and comparing it with the value before installation (i.e., the recorded factory initial value), we can determine whether the pressure sensor was compressed during installation or mold assembly. This situation will severely affect measurement accuracy.

[0050] In step S2, the control pin of the analog switch is set to a high level, making the common terminal connected to the normally open contact. At this time, the two signal lines of the pressure sensor are disconnected from the amplification and conversion unit circuit of the subsequent acquisition module. The subsequent host will measure the voltage of the circuit between the resettable fuse and the pressure sensor, specifically the first branch TEST_N connected to the first normally open contact NO1 and the first branch TEST_P connected to the second normally open contact NO2, obtaining the first voltage VTEST_V, the second voltage VTEST_N, and the third voltage VTEST_P. The subsequent host will measure the voltage on the three pins TEST_V, TEST_N, and TEST_P. At this time, the output signal of the pressure sensor is connected to the voltage measurement unit circuit of the acquisition module. Each normally open contact of the analog switch channel is externally connected to a voltage divider resistor Rt connected to ground. At this point, the sensor excitation power supply VCC—resetting fuse Fv—pressure sensor internal resistance—analog switch common terminal (COM terminal)—analog switch normally open contact (NO terminal)—voltage divider resistor Rt—ground forms a voltage divider circuit. This causes a voltage to be generated on the TEST_N signal line connected to the first normally open contact NO1, i.e., the first branch connected to the first normally open contact, which is the second voltage VTEST_N; and causes a voltage to be generated on the TEST_P signal line connected to the second normally open contact NO2, i.e., the first branch connected to the second normally open contact NO2, which is the third voltage VTEST_P. The first voltage VTEST_V, the second voltage VTEST_N, and the third voltage VTEST_P can reflect the current status of the external pressure sensor and connecting cable of the self-test acquisition module.

[0051] Figure 2 The relationship between the pressure sensor fault type and the theoretical values ​​of the three test voltages—VTEST_V (first voltage at TEST_V measurement point), VTEST_N (second voltage at TEST_N measurement point), and VTEST_P (third voltage at TEST_P measurement point)—is shown.

[0052] When the power supply line of the pressure sensor is short-circuited to ground, the resettable fuse trips, disconnecting the power supply voltage, causing the voltage at the three measurement points TEST_V, TEST_N, and TEST_P to be 0V.

[0053] The theoretical voltage values ​​at three measurement points can be calculated under various fault conditions, such as... Figure 2 As shown, the first reference voltage value V1, the second reference voltage value V2, and the third reference voltage value V3 are determined by using the calculation result as the center value and setting a certain range of margin. The voltages at the three measurement points are detected and compared with the thresholds to determine the status of the currently connected pressure sensor.

[0054] Specifically, this is due to the existence of the following relationship: , Once the model of the acquisition module and the model of the pressure sensor are determined, the VCC value, Rs value, and Rt value are fixed values, and these are accurate values ​​in the formula.

[0055] Therefore, in VCC and Choose a point V1 between them, and and Choose a point V2 between them, and Choose a point V3 between V3 and 0.

[0056] Determine the first reference voltage value V1 to satisfy... , Determine the second reference voltage value V2 to satisfy... , Determine the third reference voltage value V3 to satisfy it. ; Where VCC is the power supply voltage, Rt is the resistance value of the second branch, and Rs is any one of the four resistors of the pressure sensor.

[0057] The self-test acquisition module host follows the instructions Figure 3 The flowchart shows the sequence of steps. Using the first reference voltage value V1, the second reference voltage value V2, and the third reference voltage value V3 as thresholds, the first voltage VTEST_V, the second voltage VTEST_N, and the third voltage VTEST_P detected on the three test pins are compared with the first reference voltage value V1, the second reference voltage value V2, and the third reference voltage value V3 to determine the pressure sensor status and confirm the fault type.

[0058] Through self-testing, if the detected first voltage VTEST_V, second voltage VTEST_N, and third voltage VTEST_P are within the normal range, that is, the first voltage VTEST_V is greater than the first reference voltage V1, and the first reference voltage V1 is greater than the second voltage VTEST_N, which is greater than the second reference voltage V2, and the second reference voltage V2 is greater than the third voltage VTEST_P, which is greater than the third reference voltage V3, this can be simplified as follows: VTEST_V>V1, and V1>VTEST_N>V2, and V2>VTEST_P>V3. If the pressure sensor itself is confirmed to be functioning correctly, then the only remaining reason for the deviation between the initial pressure value and the recorded factory default value is improper installation leading to abnormal pressure on the pressure sensor. In other words, in this case, the pressure sensor itself is functioning correctly and has not malfunctioned, but improper installation has caused it to malfunction. Figure 2 The row indicating that the sensor status is normal represents the situation.

[0059] Combined with Figure 2 the other 7 pressure sensor states and Figure 3 the detection process, the comparison results and the corresponding fault types are as follows: When VTEST_V < V3, it is considered that VTEST_V is in the state of 0, and it is judged that the power line and the ground line of the pressure sensor are short-circuited; When VTEST_N > V1, it is considered that VTEST_N is in the state of VCC, and it is judged that there is a short circuit between the power line of the pressure sensor and the first signal node of the pressure sensor; When VTEST_P > V1, it is considered that VTEST_P is in the state of VCC, and it is judged that there is a short circuit between the power line of the pressure sensor and the second signal node of the pressure sensor; When VTEST_N < V3 and VTEST_P < V3, it is considered that VTEST_N and VTEST_P are in the state of 0, and it is judged that the power line of the pressure sensor is short-circuited; When VTEST_N < V3 and VTEST_P > V3, it is considered that VTEST_N is in the state of 0, and VTEST_P is in the state of, and it is judged that there is an open circuit between the first signal node of the pressure sensor or the first signal node and the first common terminal; When VTEST_N > V3 and VTEST_P < V3, it is considered that VTEST_N is in the state of, and VTEST_P is in the state of 0, and it is judged that there is an open circuit between the second signal node of the pressure sensor or the second signal node and the second common terminal; When VTEST_N > V2 or VTEST_P > V2, it is correspondingly considered that VTEST_N is in the state of or VTEST_P is in the state of, and it is judged that the ground line of the pressure sensor is open-circuited.

[0060] In step S2, after setting the analog switch to set the control pin of the analog switch to high level and performing self-check, then execute the process of setting the control pin TEST of the analog switch to low level, so as to achieve normal operation during the next acquisition.

[0061] Based on the fault types of the pressure sensors identified through testing and comparison, targeted repairs can be carried out, serving as a basis for pressure sensor maintenance and improving efficiency. For example, if an open circuit occurs, subsequent mold design and pressure sensor design and installation should ensure that the corresponding parts of the pressure sensor are not squeezed; if a short circuit occurs, it may be due to liquid ingress into the corresponding components of the pressure sensor, so subsequent mold design and pressure sensor design and installation should ensure that the pressure sensor is waterproof. Thus, by collecting and analyzing data on pressure sensor fault types, basic data can be provided for subsequent mold and pressure sensor design and installation, avoiding untargeted maintenance after pressure sensor failure.

[0062] Each time the self-test acquisition module host is powered on, it confirms the sensor status through a self-test program before starting the acquisition operation, avoiding data anomalies caused by equipment failure or installation problems from affecting the mold production process. This invention integrates the self-test unit circuit inside the acquisition module to form a self-test acquisition module. It separates different fault types of pressure sensors into different test voltages, and determines the current sensor fault type by identifying the voltage. This achieves a fast and convenient online pressure sensor fault self-test function, greatly reducing the complexity of manual processing, and also enables remote fault diagnosis.

[0063] This invention discloses a self-test acquisition module and a self-testing method for a pressure sensor. The self-test acquisition module has an analog switch with two common terminals and two sets of output terminals. The first common terminal and the second common terminal are connected to the first and second signal nodes of the pressure sensor, respectively. The first common terminal selectively connects to the first normally open and first normally closed contacts of the first set of output terminals. The second common terminal selectively connects to the second normally open and second normally closed contacts of the second set of output terminals. The two normally closed contacts are electrically connected to the amplification and conversion unit of the acquisition module. Each of the first and second normally open contacts is connected to a first branch and a second branch, respectively. The first branch connects to the voltage measurement unit circuit of the acquisition module, and the second branch has a resistor connected to ground. A resettable fuse is connected in series on the power supply line of the pressure sensor. By integrating the pressure acquisition self-test circuit into the self-test acquisition module, the module can perform a self-test on the installed pressure sensor when powered on. If the self-test fails, the relevant departments are notified promptly. Furthermore, the data generated by the pressure sensor is not used as a basis for judgment to avoid affecting production and preventing losses due to pressure sensor malfunctions. Furthermore, this method adds only a small amount of cost compared to the normal module, making it highly valuable for widespread application. One example is a self-testing method for a pressure sensor, implemented using the aforementioned self-test acquisition module. The two common terminals of the analog switch are connected to two normally closed contacts. The acquisition module collects the pressure from the pressure sensor, compares the initial pressure value with a reference value, and determines whether the deviation is within a set range. If the deviation is within the set range, the pressure sensor is considered normal, and the self-test ends. If the deviation is not within the set range, the two common terminals of the analog switch are connected to two normally open contacts, and three voltage values ​​are detected: the first voltage VTEST_V of the circuit between the resettable fuse and the pressure sensor, the second voltage VTEST_N of the first branch connected to the first normally open contact, and the third voltage VTEST_P of the first branch connected to the second normally open contact. These three voltage values ​​are compared with their corresponding reference voltage values. Based on the comparison results, the pressure sensor fault type is determined and reported before the self-test ends. The system enables self-testing of the connected resistance strain gauge pressure sensor status after power-on; a self-testing method and process for the pressure sensor has been developed to achieve a quick self-testing function without affecting normal operating conditions, separate different abnormal states of the pressure sensor, form different detection voltages, and determine the fault type by detecting the detection voltage.

[0064] This invention integrates a self-test circuit into the self-test acquisition module, separating different fault types of pressure sensors into different test voltages. By identifying the voltage, the current fault type of the pressure sensor is determined, achieving a fast and convenient online pressure sensor fault self-test function. This greatly reduces the complexity of manual processing and also enables remote fault diagnosis.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A self-test acquisition module for a pressure sensor, characterized in that: The analog switch of its self-check unit is provided with two common terminals and two groups of output terminals. The first common terminal and the second common terminal are respectively connected to the first signal node and the second signal node of the pressure sensor; The first common terminal is correspondingly connected to the first normally open contact and the first normally closed contact of the first group of output terminals for selection; the second common terminal is correspondingly connected to the second normally open contact and the second normally closed contact of the second group of output terminals for selection; The two normally closed contacts are respectively connected to the acquisition module, Both the first normally open contact and the second normally open contact are respectively connected with a first branch and a second branch. The first branch is connected to the voltage measurement unit circuit of the acquisition module, and a resistor is arranged on the second branch and grounded.

2. The self-test acquisition module for a pressure sensor according to claim 1, characterized in that: The analog switch is also provided with a control pin, and the high and low levels of the control pin are set to control the connection of the common terminal with the normally closed contact or the normally open contact.

3. The self-test acquisition module for a pressure sensor according to claim 2, characterized in that: The power supply of the pressure sensor is connected to the power supply of the self-check acquisition module, and the ground wire of the pressure sensor is connected to the ground wire of the self-check acquisition module.

4. A self-testing method for a pressure sensor, characterized in that: Implemented by using the self-check acquisition module according to any one of claims 1-3, including the following steps: S1. Connect the two common terminals of the analog switch to the two normally closed contacts respectively. The acquisition module acquires the pressure of the pressure sensor, compares the acquired initial value of the pressure sensor with the reference value, and judges whether the deviation between the two is within the set range. If the deviation is within the set range, it is judged that the pressure sensor is normal and installed normally, and the self-check is exited; If the deviation is not within the set range, step S2 is executed; S2. Connect the two common terminals of the analog switch to the two normally open contacts respectively, and detect three voltage values: the first voltage VTEST_V between the self-resetting fuse in series on the power supply line of the pressure sensor and the pressure sensor, the second voltage VTEST_N of the first branch connected to the first normally open contact, and the third voltage VTEST_P of the first branch connected to the second normally open contact; Compare the three voltage values with the corresponding reference voltage values respectively, judge the state and fault type of the pressure sensor according to the comparison results, and report them and then end the self-check.

5. A self-check method for a pressure sensor according to claim 4, characterized in that: Determine the first reference voltage value V1 to satisfy... , Determine the second reference voltage value V2 to satisfy... , Determine the third reference voltage value V3 to satisfy it. ; Wherein, VCC is the power supply voltage value, Rt is the resistance value of the second branch, and Rs is any one of the four resistances of the pressure sensor.

6. A self-check method for a pressure sensor according to claim 5, characterized in that: When VTEST_V > V1 and V1 > VTEST_N > V2 and V2 > VTEST_P > V3, it is judged that the pressure sensor is normal but installed abnormally; When VTEST_V < V3, it is judged that the power supply line and the ground wire of the pressure sensor are short-circuited; When VTEST_N > V1, it is judged that the power supply line of the pressure sensor and the first signal node are short-circuited; When VTEST_P > V1, it is judged that the power supply line of the pressure sensor and the second signal node are short-circuited; When VTEST_N < V3 and VTEST_P < V3, it is judged that the power supply line of the pressure sensor is short-circuited; When VTEST_N < V3 and VTEST_P > V3, it is judged that the first signal node of the pressure sensor or the first signal node and the first common terminal are open-circuited; When VTEST_N > V3 and VTEST_P < V3, it is determined that there is an open circuit between the second signal node of the pressure sensor or between the second signal node and the second common terminal; When VTEST_N > V2 or VTEST_P > V2, it is determined that there is an open circuit in the ground wire of the pressure sensor.

7. The self-testing method for a pressure sensor according to claim 6, characterized in that: When the two common terminals of the analog switch are respectively connected to the two normally closed contacts, and the acquisition module acquires the pressure of the pressure sensor and compares the acquired initial value of the pressure sensor with the reference value, the reference value is the factory initial value of the pressure sensor.

8. A self-testing method for a pressure sensor according to claim 7, characterized in that: When comparing the acquired initial value of the pressure sensor with the factory initial value of the pressure sensor, multiple acquisitions and multiple comparisons are performed. When the deviations in multiple comparisons are all within the set range, it is determined that the pressure sensor is normal and installed correctly, and the self-check is exited; In any comparison, if the deviation is not within the set range, step S2 is executed.

9. A self-testing method for a pressure sensor according to claim 8, characterized in that: When the control pin of the analog switch is set to a low level, the common terminal of the analog switch is controlled to be connected to the normally closed contact.

10. A self-testing method for a pressure sensor according to claim 9, characterized in that: When the control pin of the analog switch is set to a high level, the common terminal of the analog switch is controlled to be connected to the normally open contact.

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