Vibrating wire sensor fault diagnosis system

Abstract

The utility model provides a vibrating wire sensor fault diagnosis system, which comprises an excitation power supply control circuit, a signal chain switching circuit, a detection circuit and an isolation circuit, the signal chain switching circuit comprises a first relay and a switching control module, the switching control module is connected with a microcontroller, and the detection circuit comprises a first resistor, a second resistor and a switch module. A voltage measuring end is arranged between the first resistor and the second resistor, the first resistor and the second resistor are connected with a switch module, the switch module is connected with a microcontroller, the first resistor and the second resistor are also connected with an isolation circuit, and the isolation circuit is connected with a vibrating wire sensor. By arranging the signal chain switching circuit and the detection circuit, whether a fault exists or not can be judged in advance before the vibrating wire sensor is measured, the phenomenon of inaccurate measurement is prevented, and the risk that an excitation circuit in acquisition equipment is damaged due to the fault is completely eradicated.

Description

Technical Field

[0001] The utility model relates to the technical field of vibrating string sensors, in particular to a fault diagnosis system for vibrating string sensors. Background Art

[0002] The vibrating string sensor contains a sensitive element, and the size of the external load on the sensor can be characterized by measuring the change in its vibration frequency.

[0003] Usually, an acquisition device is required to measure a vibrating string sensor. The acquisition device sends out a high voltage excitation signal to excite the vibrating string sensor to generate an induction signal, and the measurement result is obtained through the induction signal.

[0004] However, if a fault occurs inside the vibrating string sensor or in the circuit connecting the vibrating string sensor, the acquisition device cannot determine whether the sensor is successfully excited. The fault is usually an open circuit or a short circuit. When a short circuit fault occurs, there is a greater risk that the acquisition device is directly connected to the sensor and sends a high-voltage excitation signal, which can easily cause damage to the excitation circuit inside the acquisition device and reduce the service life of the sensor. Utility Model Content

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a vibrating string sensor fault diagnosis system, aiming to solve the problem in the prior art that when measuring a vibrating string sensor, it is impossible to determine whether there is a fault inside the vibrating string sensor and in the connecting circuit.

[0006] In order to achieve the above purpose, the utility model is implemented through the following technical solutions:

[0007] A vibrating string sensor fault diagnosis system, comprising an excitation power supply control circuit, a signal chain switching circuit, a detection circuit and an isolation circuit, wherein the excitation power supply control circuit is used to excite the vibrating string sensor, the signal chain switching circuit comprises a first relay and a switching control module, the first relay comprises a first port, a second port, a third port, a fourth port, a fifth port, a sixth port, a seventh port and an eighth port, the first port is connected to a first signal line of the vibrating string sensor, the second port is connected to a second signal line of the vibrating string sensor, the third port is connected to the excitation power supply control circuit, the fourth port and the fifth port are both connected to the detection circuit, the seventh port and the eighth port are both connected to the switching control module A control module is provided, wherein the switching control module is connected to a microcontroller to control the vibrating string sensor to be electrically connected to the excitation power supply control circuit or the detection circuit, wherein the detection circuit comprises a first resistor, a second resistor and a switch module, a voltage measuring end is arranged between the first resistor and the second resistor, an end of the first resistor away from the voltage measuring end and an end of the second resistor away from the voltage measuring end are both connected to the switch module, the switch module is connected to the microcontroller to control the detection circuit to detect the vibrating string sensor, an end of the first resistor away from the voltage measuring end and an end of the second resistor away from the voltage measuring end are also connected to the isolation circuit, and the isolation circuit is connected to the vibrating string sensor.

[0008] Compared with the prior art, the beneficial effect of the utility model lies in: by setting the signal chain switching circuit and the detection circuit, the switching control module is driven by the microcontroller before using the acquisition equipment to measure the vibrating string sensor, so that the signal chain switching circuit connects the signal line of the vibrating string sensor with the detection circuit, and then the switch module is driven by the microcontroller, so that the detection circuit detects the inside and signal line of the vibrating string sensor, and diagnoses whether the circuit has a fault based on the voltage measured by the voltage measuring end, so that before measuring the vibrating string sensor, it can be pre-judged whether there is a fault, preventing inaccurate measurement, eliminating the risk of damage to the excitation circuit in the acquisition equipment due to the fault, and at the same time ensuring the service life of the vibrating string sensor, and the reliability of subsequent use of the sensor is greatly improved.

[0009] Further, the switch module includes a second relay and a third resistor, the second relay includes a first control port, a second control port, a third control port, a ground port, a fourth control port, a fifth control port, a sixth control port and a seventh control port, the first control port is connected to the third resistor, an end of the third resistor away from the second relay is connected to a reference voltage port, the second control port is connected to an end of the first resistor away from the voltage measurement end, and the third control port is connected to an end of the second resistor away from the voltage measurement end.

[0010] Furthermore, the fifth control port and the seventh control port are both connected to the microcontroller.

[0011] Furthermore, the fourth control port, the fifth control port, the sixth control port and the seventh control port are connected to a digital power supply through a driving resistor respectively.

[0012] Furthermore, a diode is connected between the seventh port and the eighth port, and the sixth port is used for grounding.

[0013] Furthermore, the excitation power supply control circuit is connected to the excitation power supply and the excitation signal terminal of the microcontroller.

[0014] Furthermore, the isolation circuit includes a first capacitor and a second capacitor, an end of the first resistor away from the voltage measuring end is connected to the first capacitor, an end of the first capacitor away from the first resistor is connected to the first signal line, an end of the second resistor away from the voltage measuring end is connected to the second capacitor, and an end of the second capacitor away from the second resistor is connected to the second signal line.

[0015] Furthermore, the resistance value of the first resistor is equal to the resistance value of the second resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a vibrating-wire sensor fault diagnosis system in an embodiment of the utility model;

[0017] Figure 2 This is a schematic diagram of the structure of a switch module in a vibrating-wire sensor fault diagnosis system in an embodiment of the utility model;

[0018] Description of main component symbols:

[0019] First relay 100 First Port 101 Second Port 102 Third Port 103 Fourth port 104 Sixth Port 105 Excitation signal terminal 106 Switching signal terminal 107 Switch module 200 First resistor 201 Second resistor 202 Voltage measurement terminal 203 The third resistor 204 Second relay 210 The first switch signal terminal 211 The second switch signal terminal 212 Drive resistance 213

[0020] The following specific implementation manner will further illustrate the present utility model in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0024] See also Figure 1 and Figure 2The vibrating string sensor fault diagnosis system in the embodiment of the utility model includes an excitation power supply control circuit, a signal chain switching circuit, a detection circuit and an isolation circuit. The excitation power supply control circuit is used to excite the vibrating string sensor. The excitation power supply control circuit is connected to the excitation power supply and the excitation signal terminal 106 of the microcontroller. The signal chain switching circuit includes a first relay 100 and a switching control module. The first relay 100 includes a first port 101, a second port 102, a third port 103, a fourth port 104, a fifth port, a sixth port 105, a seventh port and an eighth port. The first The first port 101 is connected to the first signal line of the vibrating string sensor, the second port 102 is connected to the second signal line of the vibrating string sensor, the third port 103 is connected to the excitation power supply control circuit, the fourth port 104 and the fifth port are both connected to the detection circuit, the seventh port and the eighth port are both connected to the switching control module, the switching control module is connected to a microcontroller to control the vibrating string sensor to be electrically connected to the excitation power supply control circuit or the detection circuit, a diode is connected between the seventh port and the eighth port, and the sixth port 105 is used for grounding. Preferably, the excitation power supply control circuit includes a plurality of resistors and two transistors, specifically, it is composed of resistors R1, R2, R3, R4, R5 and transistors Q1, Q2, PS is an excitation signal from the microcontroller, the excitation signal is a set of periodic square wave signals of a specific frequency, used to excite the vibrating string sensor, the excitation signal is expanded through the transistor Q2, the excitation current is increased, and enters the base of the transistor Q1, specifically, the emitter of the transistor Q1 is connected to a constant voltage power supply HVCC with a relatively high voltage, and the collector of the transistor Q1 is connected to the third port 103.

[0025] Preferably, the first relay 100 adopts a double-pole double-throw signal relay LS, the diode D is a Schottky diode, the diode D is used for freewheeling, and can absorb the reverse current of the relay coil, the first port 101 is connected to the first signal line of the vibrating string sensor through the FR+ terminal, and the second port 102 is connected to the second signal line of the vibrating string sensor through the FR- terminal, the switching control module includes resistors R8, R9 and a transistor Q3, the collector of the transistor Q3 is connected to the eighth port and one end of the diode D, and the other end of the diode D is connected to the seventh port and an external conventional digital power supply DVCC, specifically, DVCC is 5V, the transistor Q3 is connected to the switching signal terminal 107 through R8, and the switching signal terminal 107 is connected to the microcontroller, for Transmit SW signal. When the SW signal is at a high level, the first relay 100 can be driven to make the first port 101 electrically connected to the third port 103 and the second port 102 electrically connected to the sixth port 105. When the SW signal is at a low level, the first port 101 is electrically connected to the fourth port 104 and the fifth port. The SW signal in the vibrating string sensor fault diagnosis system is at a low level by default. It can be understood that the signal chain switching circuit can be controlled by the microcontroller sending a SW signal to connect the vibrating string sensor to the excitation power supply control circuit or the detection circuit. Before the acquisition device performs measurement, that is, before the vibrating string sensor is excited, the vibrating string sensor is first connected to the detection circuit for detection, and the switching is completed by the microcontroller, which is convenient and efficient.

[0026] The detection circuit includes a first resistor 201, a second resistor 202 and a switch module 200. The resistance of the first resistor 201 is equal to the resistance of the second resistor 202. A voltage measuring terminal 203 is set between the first resistor 201 and the second resistor 202. One end of the first resistor 201 away from the voltage measuring terminal 203 and one end of the second resistor 202 away from the voltage measuring terminal 203 are both connected to the switch module 200. The switch module 200 is connected to the microcontroller to control the detection circuit to detect the vibrating string sensor. The switch module 200 includes a second relay 210 and a third resistor 204. The second relay 210 includes a first control port, a second control port, and a second control port. The first control port is connected to the third resistor 204, and the end of the third resistor 204 away from the second relay 210 is connected to the reference voltage port, the second control port is connected to the end of the first resistor 201 away from the voltage measuring end 203, the third control port is connected to the end of the second resistor 202 away from the voltage measuring end 203, the fifth control port and the seventh control port are both connected to the microcontroller, and the fourth control port, the fifth control port, the sixth control port and the seventh control port are respectively connected to the digital power supply through the driving resistor 213.Preferably, the detection circuit is connected to the VP terminal and the VN terminal, the fourth port 104 is connected to the VP terminal, the fifth port is connected to the VN terminal, the first resistor 201 is connected to the VP terminal, the second resistor 202 is connected to the VN terminal, and the VP terminal is also connected to the second control port, and the VN terminal is also connected to the third control port. The second relay 210 is an optical coupler relay, and the fifth control port is connected to the microcontroller through the first switch signal terminal 211 to transmit a Vscm+ signal. The seventh control port is connected to the microcontroller through the second switch signal terminal 212 to transmit a Vscm- signal. Resistors R11, R12, R13 and R14 are all driving resistors, and the digital power supply adopts a conventional digital power supply. The voltage is 5V, the vibrating string sensor and the connecting circuit are the circuit to be tested, and its equivalent resistance is the resistance to be tested. The first resistor 201 and the second resistor 202 are both voltage-dividing resistors, which form a voltage drop in the circuit. The equivalent circuit of the detection circuit and the circuit to be tested is that the resistance to be tested is connected in parallel with two voltage-dividing resistors, and then connected in series with the third resistor 204. It can be understood that by measuring the V signal voltage at the voltage measuring end 203, the value of the equivalent resistance can be calculated. If the equivalent resistance is 0, a short circuit fault occurs. If the equivalent resistance is infinite, an open circuit fault occurs. The resistance value of the equivalent resistance can also be calculated based on the voltage value at the voltage measuring end 203, and the resistance value of the internal resistance of the vibrating string sensor and the resistance of its connecting circuit can be calculated.

[0027] It can be understood that by sending a signal through the microcontroller, the switch module 200 can be driven to switch to an open or disconnected state. When the switch module 200 is in the open state, the reference voltage is connected to the two signal lines of the vibrating string sensor through the reference voltage port, that is, the two signal lines connected through the S+ signal port and the S- signal port. When the switch module 200 is in the disconnected state, it is in a high-impedance state, which can prevent the reference voltage from affecting the vibrating string sensor. After turning on the switch module 200, by measuring the voltage at the voltage measuring end 203, it can be determined whether there is a fault, thereby preventing inaccurate measurement, eliminating the risk of damage to the excitation circuit in the acquisition equipment due to a fault, and at the same time ensuring the service life of the vibrating string sensor, and the reliability of subsequent use of the sensor is also greatly improved.

[0028] One end of the first resistor 201 away from the voltage measuring end 203 and one end of the second resistor 202 away from the voltage measuring end 203 are also connected to the isolation circuit, the isolation circuit is connected to the vibrating string sensor, the isolation circuit includes a first capacitor and a second capacitor, one end of the first resistor 201 away from the voltage measuring end 203 is connected to the first capacitor, one end of the first capacitor away from the first resistor 201 is connected to the first signal line, one end of the second resistor 202 away from the voltage measuring end 203 is connected to the second capacitor, and one end of the second capacitor away from the second resistor 202 is connected to the second signal line. Preferably, the isolation circuit is used to isolate the detection circuit to prevent the detection circuit from affecting the subsequent circuit.

[0029] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0030] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A vibrating wire sensor fault diagnosis system, characterized in that: The invention comprises an excitation power supply control circuit, a signal chain switching circuit, a detection circuit and an isolation circuit, wherein the excitation power supply control circuit is used to excite a vibrating string sensor, the signal chain switching circuit comprises a first relay and a switching control module, the first relay comprises a first port, a second port, a third port, a fourth port, a fifth port, a sixth port, a seventh port and an eighth port, the first port is connected to a first signal line of the vibrating string sensor, the second port is connected to a second signal line of the vibrating string sensor, the third port is connected to the excitation power supply control circuit, the fourth port and the fifth port are both connected to the detection circuit, the seventh port and the eighth port are both connected to the switching control module, the switching The control module is connected to the microcontroller to control the vibrating string sensor to be electrically connected to the excitation power supply control circuit or the detection circuit. The detection circuit includes a first resistor, a second resistor and a switch module. A voltage measuring end is set between the first resistor and the second resistor. An end of the first resistor away from the voltage measuring end and an end of the second resistor away from the voltage measuring end are both connected to the switch module. The switch module is connected to the microcontroller to control the detection circuit to detect the vibrating string sensor. An end of the first resistor away from the voltage measuring end and an end of the second resistor away from the voltage measuring end are also connected to the isolation circuit. The isolation circuit is connected to the vibrating string sensor.

2. The vibrating wire sensor fault diagnosis system according to claim 1, characterized in that: The switch module includes a second relay and a third resistor, the second relay includes a first control port, a second control port, a third control port, a ground port, a fourth control port, a fifth control port, a sixth control port and a seventh control port, the first control port is connected to the third resistor, an end of the third resistor away from the second relay is connected to a reference voltage port, the second control port is connected to an end of the first resistor away from the voltage measurement end, and the third control port is connected to an end of the second resistor away from the voltage measurement end.

3. The vibrating wire sensor fault diagnosis system according to claim 2, characterized in that: The fifth control port and the seventh control port are both connected to the microcontroller.

4. The vibrating wire sensor fault diagnosis system according to claim 2, characterized in that: The fourth control port, the fifth control port, the sixth control port and the seventh control port are connected to a digital power supply through a driving resistor respectively.

5. The vibrating wire sensor fault diagnosis system according to claim 1, characterized in that: A diode is connected between the seventh port and the eighth port, and the sixth port is used for grounding.

6. The vibrating wire sensor fault diagnosis system according to claim 1, characterized in that: The excitation power supply control circuit is connected to the excitation power supply and the excitation signal terminal of the microcontroller.

7. The vibrating wire sensor fault diagnosis system according to claim 6, characterized in that: The isolation circuit includes a first capacitor and a second capacitor, wherein an end of the first resistor away from the voltage measuring end is connected to the first capacitor, an end of the first capacitor away from the first resistor is connected to the first signal line, an end of the second resistor away from the voltage measuring end is connected to the second capacitor, and an end of the second capacitor away from the second resistor is connected to the second signal line.

8. The vibrating wire sensor fault diagnosis system according to claim 1, characterized in that: The resistance value of the first resistor is equal to the resistance value of the second resistor.

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