CN105699009B - Based on difference comparsion technology capacitance pressure transducer, fault diagnosis system and method - Google Patents
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Abstract
The present invention relates to based on difference comparsion technology capacitance pressure transducer, fault diagnosis system, including the capacitance pressure transducer, switching circuit, data acquisition circuit and the microprocessor that are linked in sequence, the switching circuit are connect with microprocessor；Method includes：By switching circuit difference, control pressure the first cavity of sensor is connected microprocessor with Acquisition Circuit, the second cavity is connected with Acquisition Circuit, and the first cavity of acquisition pressure sensor, the second cavity corresponding pressure value respectively；The difference of two cavitys of calculation pressure sensor, and be compared with given threshold；If difference is within the set threshold range, pressure sensor is normal；Otherwise it is pressure sensor failure.The present invention has simple in structure, reliable and stable, highly practical, real-time diagnosis, reduces the labor intensity that pressure sensor irregularly detects.
Description
Technical Field
The invention relates to a fault diagnosis method for a capacitive pressure sensor, and belongs to the field of industrial process control.
Background
The pressure sensor is the most common sensor in industrial practice, is widely applied to various industrial automatic control environments, relates to various industries such as water conservancy and hydropower, aerospace, petrifaction, oil wells, electric power, ships, pipelines and the like, has more and more problems in the production process, and can not be quickly solved due to the conditions of installation, use, maintenance personnel and the like, so that the normal production is influenced, and even production safety accidents are caused.
Because the pressure sensor may break down after working for a long time, in order to ensure that the pressure sensor can accurately reflect the real condition of a detected object, the pressure sensor can be regularly detected, and the precision of the pressure sensor can be effectively ensured. The traditional pressure sensor detection mode is completed through manual operation, so that the working efficiency is low, human errors are easily introduced, more inconvenience is brought to the evaluation of the quality of the pressure sensor, and the personnel cost is increased. The manual detection mode usually adopts an irregular detection mode, so that the fault of the pressure sensor cannot be found in time, and certain potential safety hazard exists.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a method for diagnosing the fault of the capacitive pressure sensor based on the difference comparison technology, which is used as an important component for data acquisition of the pressure transmitter and provides important guarantee for the normal work of the pressure transmitter.
The technical scheme adopted by the invention for realizing the purpose is as follows: the capacitive pressure sensor fault diagnosis system based on the difference comparison technology comprises a capacitive pressure sensor, a switching circuit, a data acquisition circuit and a microprocessor which are sequentially connected, wherein the switching circuit is connected with the microprocessor; wherein,
the capacitance type pressure sensor is used for measuring pressure and outputting a capacitance value, and the output end of the capacitance type pressure sensor is connected with the switching circuit;
the switching circuit is used for receiving signals of the microprocessor to switch the output end of the capacitive pressure sensor and is connected with the data acquisition circuit and the microprocessor;
the data acquisition circuit converts the capacitance value output by the pressure sensor into pulse output with corresponding frequency, and an output pulse pin of the data acquisition circuit is connected with the microprocessor;
and the microprocessor calculates the pulse frequency of the two cavities of the pressure sensor by utilizing the capturing function of the timer and converts the pulse frequency into a corresponding pressure value.
And the two cavity output ends of the capacitive pressure sensor are respectively connected with the two input ends of the switching circuit.
The switching circuit adopts an analog switch chip.
The capacitive pressure sensor fault diagnosis method based on the difference comparison technology comprises the following steps of:
firstly, the microprocessor controls the first cavity of the pressure sensor to be connected with the acquisition circuit through the switching circuit, and acquires a pressure value corresponding to the first cavity of the pressure sensor;
secondly, the microprocessor controls the second cavity of the pressure sensor to be connected with the acquisition circuit through the switching circuit, and acquires a pressure value corresponding to the second cavity of the pressure sensor;
finally, the microprocessor calculates the difference value of the two cavities of the pressure sensor and compares the difference value with a set threshold value; if the difference value is within the set threshold value range, the pressure sensor is normal; otherwise, the pressure sensor fails.
The microprocessor controls the first cavity of the pressure sensor to be connected with the acquisition circuit through the switching circuit, and the method specifically comprises the following steps: the microcontroller controls the enable pin of the switching circuit to be at a low level, the first selection pin to be at a high level, the second selection pin to be at a high level, and the first channel is communicated with the output channel.
The microprocessor controls the pressure sensor second cavity to be connected with the acquisition circuit through the switching circuit, and the method specifically comprises the following steps: the invention relates to a microcontroller for controlling the switching circuit to make the enable pin be low level, the first selection pin be high level, the second selection pin be low level, the second channel is communicated with the output channel, the invention uses the switching circuit to connect the high and low pressure two cavities of the pressure sensor with the data acquisition circuit, the microprocessor converts the data acquired by the two cavities of the pressure sensor into pressure values, compares the difference value of the pressure values with the set threshold value, and diagnoses the working state of the pressure sensor according to the comparison result, which provides important guarantee for the normal work of the pressure transmitter and improves the safety and reliability, and has the following advantages:
1. the realization circuit is simple and the hardware cost is low. The capacitance type pressure sensor fault diagnosis circuit based on the difference comparison technology is simple in structure, mainly comprises a capacitance type pressure sensor, a switching circuit, a data acquisition circuit and a microprocessor, is basically consistent with a pressure transmitter acquisition circuit, does not need to increase hardware, and can realize pressure sensor fault diagnosis only by adding a sensor fault diagnosis program to a traditional pressure transmitter.
2. The real-time performance is strong. The fault diagnosis method of the capacitive pressure sensor requires that the pressure transmitter not only needs to calculate the measured environmental pressure value, but also needs to calculate the environmental pressure value by using the data acquired by the high-pressure cavity and the low-pressure cavity in the process of each data acquisition cycle, and carries out fault diagnosis on the pressure sensor according to the measured pressure values of the high-pressure cavity and the low-pressure cavity, thereby carrying out real-time diagnosis on the pressure sensor and improving the reliability of the pressure transmitter.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2a is a first schematic diagram of a fault diagnosis circuit according to an embodiment of the present invention;
FIG. 2b is a second schematic diagram of a fault diagnosis circuit in an embodiment of the present invention;
fig. 3 is a flowchart of the operation of the pressure sensor fault diagnosis method of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Functionally, the invention utilizes a capacitance type pressure sensor fault diagnosis method based on a difference value comparison technology to connect a high-voltage cavity and a low-voltage cavity of a capacitance type pressure sensor with a pressure acquisition circuit respectively, calculates the environmental pressure value according to the acquired values of the two cavities of the pressure sensor, and compares the two measured pressure values. If the difference value of the two measured pressures exceeds a set threshold value, the pressure sensor is indicated to be in fault; if the difference value is within the set threshold value range, the pressure sensor works normally. In terms of system structure, the pressure sensor comprises a capacitive pressure sensor, a switching circuit, a data acquisition circuit and a microprocessor, wherein the pressure sensor is connected with the data acquisition circuit through the switching circuit, the data acquisition circuit transmits acquired data to the microprocessor, and the microprocessor judges the working state of the pressure sensor according to the acquired data of a high-pressure cavity and a low-pressure cavity.
The invention relates to the following two key technologies:
1) cavity measurement switching techniques. The capacitive pressure sensor described by the invention comprises a high-voltage cavity and a low-voltage cavity, and the high-voltage cavity and the low-voltage cavity are respectively connected with a data acquisition circuit by utilizing a switching circuit, so that the data acquisition of the two cavities of the pressure sensor is realized.
2) Pressure sensor fault diagnosis techniques. The microprocessor of the capacitive pressure sensor fault diagnosis circuit converts data of two cavities of the acquired pressure sensor into pressure values, compares the difference value of the two pressure values with a set threshold value, and indicates that the pressure sensor has a fault if the difference value is greater than the set threshold value; if the difference value of the two cavities of the pressure sensor is within the set threshold value range, the pressure sensor works normally. The pressure sensor diagnosis technology effectively avoids error collection when the pressure sensor breaks down, provides powerful guarantee for normal work of the pressure transmitter, and improves the safety and reliability of the pressure transmitter.
A fault diagnosis method for a capacitive pressure sensor based on a difference comparison technology comprises the capacitive pressure sensor, a switching circuit, a data acquisition circuit and a microprocessor; the capacitance type pressure sensor mainly comprises a high-voltage cavity and a low-voltage cavity (equivalent to two capacitors) which are connected with a switching circuit; the switching circuit mainly comprises a high-speed analog switch device and connects the pressure sensor with the data acquisition circuit; the data acquisition circuit converts the capacitance value of the pressure sensor into pulse output with corresponding frequency, and an output pulse pin of the data acquisition circuit is connected with the microprocessor; and the microprocessor is connected with the data acquisition circuit, and respectively calculates the pulse frequency of the two cavities of the pressure sensor by utilizing the capturing function of the timer and converts the pulse frequency into a corresponding pressure value.
The capacitive pressure sensor is connected with the acquisition circuit by utilizing the switching circuit, and is used for respectively acquiring data of the two cavities of the pressure sensor.
And the microprocessor respectively calculates the pressure values of the two cavities of the pressure sensor, compares the difference value of the two pressure values with a set threshold value, and diagnoses the pressure sensor according to the comparison result.
If the difference value of the two cavities of the pressure sensor is greater than a set threshold value, the pressure sensor is judged to be in fault, and the microprocessor diagnoses the sensor to mark the first position; if the difference value of the two cavities of the pressure sensor is within the set threshold value range, the pressure sensor works normally.
A capacitive pressure sensor diagnostic method comprising the steps of:
firstly, connecting a pressure sensor high-pressure cavity with an acquisition circuit by using a switching circuit, and acquiring a pressure value corresponding to the pressure sensor high-pressure cavity by using a microprocessor;
secondly, connecting the low-pressure cavity of the pressure sensor with an acquisition circuit by using a switching circuit, and acquiring a pressure value corresponding to the low-pressure cavity of the pressure sensor by using a microprocessor;
finally, the microprocessor calculates the difference value of the two cavities of the pressure sensor, compares the difference value with a set threshold value, and if the difference value is greater than the set threshold value, the pressure sensor is in fault; if the difference value of the two cavities of the pressure sensor is within the set threshold value range, the pressure sensor normally works
As shown in fig. 1, the capacitive pressure sensor fault diagnosis circuit based on the difference comparison technology of the present invention includes: capacitive pressure sensor, switching circuit, data acquisition circuit, microprocessor.
As shown in fig. 2a and 2b, the high-voltage cavity 1 end of the capacitive pressure sensor J1 is connected with the input end X0 of the analog switch device U1(74HC4052) of the switching circuit, the common electrode 2 end of the capacitive pressure sensor J1 is connected with GND, the low-voltage cavity 3 end of the capacitive pressure sensor J1 is connected with the input end X2 of the analog switch device U1 of the switching circuit, and the high-voltage cavity and the low-voltage cavity of the capacitive pressure sensor J1 are respectively connected with the data acquisition circuit by using the analog switch device U1(74HC 4052); an output end X of the analog switching device U1 is connected to an input end of the data acquisition circuit, a control end INH of the analog switching device U1 is connected to a pin P2.0 of the microprocessor, a control end A of the analog switching device U1 is connected to a pin P2.1 of the microprocessor, a control end B of the analog switching device U1 is connected to a pin P2.2 of the microprocessor, and the pins P2.0 and P2.1P2.2 of the microprocessor control channel switching of the analog switching device U1(74HC 4052).
The data acquisition circuit mainly comprises comparator devices U3A and U3B, NAND gate devices U4A and U4B, divider resistors R2, R3, R4 and a standard resistor R1, and converts the capacitance value of the capacitive pressure sensor into pulse output with corresponding frequency. In the embodiment, an oscillation frequency division circuit in a 'pressure digital acquisition front end' (patent number: CN200610048057.4) patent is adopted. The output end PULSE of the data acquisition circuit is connected with a pin P1.3 of the microprocessor, and the microprocessor performs data acquisition on the PULSE signal output by the data acquisition circuit by using the timer.
As shown in fig. 3, the fault diagnosis period of the capacitive pressure sensor includes data acquisition of a high-pressure cavity of the pressure sensor, data acquisition of a low-pressure cavity of the pressure sensor, and judgment of a working state of the pressure sensor.
Data acquisition of a high-pressure cavity of the pressure sensor: the microcontroller controls an INH pin of an analog switch device U1(74HC4052) of the switching circuit to be at a low level, an A pin to be at a high level and a B pin to be at a high level, and a first channel X0 of the analog switch device is communicated with an output channel X; the high-pressure cavity of the pressure sensor is connected with a data acquisition circuit through an analog switch device, and the data acquisition circuit converts the capacitance value of the pressure sensor into corresponding frequency pulses to be output; the microprocessor calculates the frequency of the output pulse of the data acquisition circuit by utilizing the timer capture function, and converts the high-pressure cavity acquisition value of the pressure sensor into a pressure value.
Data acquisition of a low-pressure cavity of the pressure sensor: the microcontroller controls an INH pin of an analog switch device U1(74HC4052) of the switching circuit to be at a low level, a pin A to be at a high level and a pin B to be at a low level, and a second channel X2 of the analog switch device is communicated with an output channel X; the low-voltage cavity of the pressure sensor is connected with a data acquisition circuit through an analog switch device, and the data acquisition circuit converts the capacitance value of the pressure sensor into corresponding frequency pulses to be output; the microprocessor calculates the frequency of the output pulse of the data acquisition circuit by utilizing the timer capture function, and converts the acquisition value of the low-pressure cavity of the pressure sensor into a pressure value.
Judging the working state of the pressure sensor: the microprocessor calculates the difference value between the pressure value calculated by the high-pressure cavity of the pressure sensor and the pressure value calculated by the low-pressure cavity of the pressure sensor; the microprocessor compares the calculated difference value with a set threshold value; if the difference exceeds the threshold value, the pressure sensor is judged to be in fault, the corresponding diagnosis mark is located at the first position, and if the difference is smaller than the threshold value, the pressure sensor is judged to work normally, and the next working cycle of the pressure sensor is carried out.
Compared with the traditional pressure transmitter which calculates the ambient pressure value by using the ratio of the difference of the acquired data of the high-pressure cavity and the acquired data of the low-pressure cavity to the sum of the acquired data, the capacitive pressure sensor fault diagnosis method based on the difference comparison technology has the advantages that the accuracy of the measured ambient pressure of the high-pressure cavity or the low-pressure cavity is reduced by only using the high-pressure cavity or the low-pressure cavity, and the accuracy is about two percent. When the pressure sensor breaks down, the difference between the collected data of the high-pressure cavity and the low-pressure cavity of the pressure sensor is far more than two percent, and meanwhile, the threshold value set by reasonable fault diagnosis is set, so that the fault diagnosis is carried out on the pressure sensor in real time, and the reliability of the pressure transmitter is improved.
Claims (5)
1. Capacitive pressure sensor fault diagnosis system based on difference comparison technique, its characterized in that: the device comprises a capacitive pressure sensor, a switching circuit, a data acquisition circuit and a microprocessor which are connected in sequence, wherein the switching circuit is connected with the microprocessor; wherein,
the capacitance type pressure sensor is used for measuring pressure and outputting a capacitance value, and the output end of the capacitance type pressure sensor is connected with the switching circuit;
the switching circuit is used for receiving signals of the microprocessor to switch the output end of the capacitive pressure sensor and is connected with the data acquisition circuit and the microprocessor;
the data acquisition circuit converts the capacitance value output by the pressure sensor into pulse output with corresponding frequency, and an output pulse pin of the data acquisition circuit is connected with the microprocessor;
the microprocessor calculates the pulse frequency of the two cavities of the pressure sensor by utilizing the capturing function of the timer and converts the pulse frequency into corresponding pressure values;
and the two cavity output ends of the capacitive pressure sensor are respectively connected with the two input ends of the switching circuit.
2. The differential comparison technology based capacitive pressure sensor fault diagnosis system of claim 1, wherein: the switching circuit adopts an analog switch chip.
3. The differential comparison technology-based capacitive pressure sensor fault diagnosis method of the fault diagnosis system according to claim 1, wherein the fault diagnosis of the pressure sensor is performed in real time, and comprises the following steps:
firstly, the microprocessor controls the first cavity of the pressure sensor to be connected with the acquisition circuit through the switching circuit, and acquires a pressure value corresponding to the first cavity of the pressure sensor;
secondly, the microprocessor controls the second cavity of the pressure sensor to be connected with the acquisition circuit through the switching circuit, and acquires a pressure value corresponding to the second cavity of the pressure sensor;
finally, the microprocessor calculates the difference value of the two cavities of the pressure sensor and compares the difference value with a set threshold value; if the difference value is within the set threshold value range, the pressure sensor is normal; otherwise, the pressure sensor fails.
4. The differential comparison technology-based capacitive pressure sensor fault diagnosis method according to claim 3, wherein the microprocessor controlling the connection of the first cavity of the pressure sensor and the acquisition circuit through the switching circuit is specifically: the microcontroller controls an enable pin of the switching circuit to be at a low level, a first selection pin (A) to be at a high level, a second selection pin (B) to be at a high level, and the first channel is communicated with the output channel.
5. The differential comparison technology-based capacitive pressure sensor fault diagnosis method according to claim 3, wherein the microprocessor controlling the connection of the second cavity of the pressure sensor and the acquisition circuit through the switching circuit is specifically: the microcontroller controls the enable pin of the switching circuit to be at low level, the first selection pin (A) to be at high level, the second selection pin (B) to be at low level, and the second channel is communicated with the output channel.
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| EP3431149B1 (en) * | 2017-07-18 | 2020-11-25 | Peter Kammer | Method and device for remote monitoring of fire extinguishing devices or systems |
| CN107631828A (en) * | 2017-09-13 | 2018-01-26 | 南京航伽电子科技有限公司 | Double pressure transmitter breakdown judges and switching method |
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| JP7184698B2 (en) * | 2019-03-29 | 2022-12-06 | 株式会社レプトリノ | force sensor |
| CN110763382A (en) * | 2019-11-14 | 2020-02-07 | 上海权宥环保科技有限公司 | Pressure transmitter |
| CN111397653B (en) * | 2020-04-01 | 2021-11-19 | 中煤科工集团重庆研究院有限公司 | Fault diagnosis system and method for sensor for coal mine |
| CN111649872B (en) * | 2020-06-11 | 2022-02-15 | 武汉飞恩微电子有限公司 | Pressure sensor system with redundant diagnostics |
| CN115388854A (en) * | 2022-08-26 | 2022-11-25 | 南京高华科技股份有限公司 | Air pressure height sensor |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1079298A (en) * | 1992-05-28 | 1993-12-08 | 罗斯蒙德公司 | The bearing calibration of pressure transducer |
| CN101410703A (en) * | 2006-01-26 | 2009-04-15 | 罗斯蒙德公司 | Pressure sensor fault detection |
| CN101589947A (en) * | 2008-05-27 | 2009-12-02 | 普立思胜医疗技术（北京）有限公司 | Automatic error detection method in the pressure measxurement and electric sphygmomanometer |
| CN101680814A (en) * | 2007-05-16 | 2010-03-24 | 罗斯蒙德公司 | Electrostatic pressure sensor with porous dielectric diaphragm |
| CN202974299U (en) * | 2012-11-15 | 2013-06-05 | 航天科工惯性技术有限公司 | Self-diagnosis device of intelligent test equipment |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3178564B2 (en) * | 1993-02-23 | 2001-06-18 | 横河電機株式会社 | Differential pressure measuring device |
| US7380448B2 (en) * | 2005-06-09 | 2008-06-03 | Denso Corporation | Malfunction detection apparatus for pressure sensor |
-
2014
- 2014-11-25 CN CN201410690716.9A patent/CN105699009B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1079298A (en) * | 1992-05-28 | 1993-12-08 | 罗斯蒙德公司 | The bearing calibration of pressure transducer |
| CN101410703A (en) * | 2006-01-26 | 2009-04-15 | 罗斯蒙德公司 | Pressure sensor fault detection |
| CN101680814A (en) * | 2007-05-16 | 2010-03-24 | 罗斯蒙德公司 | Electrostatic pressure sensor with porous dielectric diaphragm |
| CN101589947A (en) * | 2008-05-27 | 2009-12-02 | 普立思胜医疗技术（北京）有限公司 | Automatic error detection method in the pressure measxurement and electric sphygmomanometer |
| CN202974299U (en) * | 2012-11-15 | 2013-06-05 | 航天科工惯性技术有限公司 | Self-diagnosis device of intelligent test equipment |
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