CN111624413A - Power frequency magnetic field intensity testing arrangement with infrared communication function - Google Patents
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- CN111624413A CN111624413A CN202010321398.4A CN202010321398A CN111624413A CN 111624413 A CN111624413 A CN 111624413A CN 202010321398 A CN202010321398 A CN 202010321398A CN 111624413 A CN111624413 A CN 111624413A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/08—Measuring electromagnetic field characteristics
- G01R29/0864—Measuring electromagnetic field characteristics characterised by constructional or functional features
- G01R29/0871—Complete apparatus or systems; circuits, e.g. receivers or amplifiers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
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- G—PHYSICS
- G08—SIGNALLING
- G08C—TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
- G08C23/00—Non-electrical signal transmission systems, e.g. optical systems
- G08C23/04—Non-electrical signal transmission systems, e.g. optical systems using light waves, e.g. infrared
Abstract
The invention provides a power frequency magnetic field intensity testing device with an infrared communication function, and mainly relates to the field of electromagnetic compatibility. The utility model provides a power frequency magnetic field intensity testing arrangement with infrared communication function, includes integrated control module, LCD demonstration and keyboard module, external memory module, signal acquisition module, host computer, LCD demonstration all is connected with integrated control module electricity with keyboard module, external memory module, signal acquisition module, host computer, signal acquisition module is active signal acquisition module. The invention has the beneficial effects that: the invention has the advantages of simple structure, high precision, low cost and low energy consumption, and can reliably complete the detection of the power frequency magnetic field intensity.
Description
Technical Field
The invention mainly relates to the field of electromagnetic compatibility, in particular to a power frequency magnetic field intensity testing device with an infrared communication function.
Background
The power frequency magnetic field is a low-frequency magnetic field generated by high-low voltage power transmission lines and household appliances. The operating frequency of the ac power supply in countries such as china and germany is 50Hz, while the operating frequency of the ac power supply in countries such as the united states and korea is 60 Hz. With the rapid development and popularization of high-voltage transmission lines, 10kV high-voltage transmission lines are almost everywhere in domestic residential areas. Whether the residents live in the power frequency magnetic field environment generated by the 10kV high-voltage overhead power line for a long time can influence the human health has become a social concern. Meanwhile, the biological effect of the magnetic field on the human body also becomes one of the important research directions in the field of electromagnetic compatibility research. At present, standards of HJ681-2013 electromagnetic environment detection method of alternating current transmission and transformation project and GB8702-2014 electromagnetic environment control limit issued by the state are mandatory standards, and the magnetic field intensity near a building close to an overhead transmission line must completely meet the requirements of the electromagnetic environment of the state. Therefore, it is necessary to monitor the power frequency magnetic field strength around the overhead transmission line and provide data support for society in time, and under the condition, the power frequency magnetic field testing device with simple operation, high measurement precision and wide application range is designed to serve the public, so that the civilian life is guaranteed, and the power frequency magnetic field testing device has great significance.
At present, a three-axis power frequency magnetic field intensity measuring device generally adopts a microprocessor, a Hall sensor (such as SS4968) and a passive coil; or a microprocessor plus a signal conditioning circuit (such as an AD824 amplifier) plus a passive coil to realize the measurement of the magnetic field intensity (root mean square value) required by HJ 681-2013. Both of these solutions have certain disadvantages. In the scheme of the microprocessor and the Hall sensor, the Hall sensor can finish the collection work of X, Y, Z magnetic fields in three directions, but the Hall sensor is easily influenced by temperature, and the linearity of output signals is poor, so that the measurement error is large; in the scheme of the microprocessor and the signal conditioning circuit, the signal conditioning circuit consists of an amplifier and a filter circuit, so that the signal processing circuit is complex and is easy to generate electromagnetic interference, and the measuring precision of the magnetic field intensity measuring device is low. In both schemes, wired communication is adopted to complete the data transmission process with the handheld device, and the phenomenon of abnormal communication easily occurs due to interference in a high magnetic field area because no electric isolation is carried out. Meanwhile, complex signal processing circuits need to be built in both schemes, and high precision of components and parts needs high voltage (up to 30V) to guarantee, so that the production cost is high, the energy consumption is high, and the popularization degree and the application range are limited.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a power frequency magnetic field intensity testing device with an infrared communication function, which has the advantages of simple structure, high precision, low cost and low energy consumption, and can reliably complete the detection of the power frequency magnetic field intensity.
In order to achieve the purpose, the invention is realized by the following technical scheme:
the utility model provides a power frequency magnetic field intensity testing arrangement with infrared communication function, includes integrated control module, LCD demonstration and keyboard module, external memory module, signal acquisition module, host computer, LCD demonstration all is connected with integrated control module electricity with keyboard module, external memory module, signal acquisition module, host computer, signal acquisition module is active signal acquisition module.
The integrated control module includes microprocessor module, power module, buzzer module and infrared communication module, microprocessor module shows through integrated USART communication module and LCD and is connected with keyboard module, infrared communication module electricity, microprocessor module is connected with external memory module, buzzer electricity through integrated IO communication module, microprocessor module passing signal input part is connected with signal acquisition module electricity, power module is used for showing and keyboard module, infrared communication module, signal acquisition module power supply for microprocessor module, LCD.
The signal acquisition module comprises an active triaxial magnetic field probe and a signal detection circuit, the power supply module provides power for the active triaxial magnetic field probe and the signal detection circuit, and the active triaxial magnetic field probe is connected with the signal input end of the microprocessor module through the signal detection circuit.
The microprocessor module is an STM32F3 series STM32F303 singlechip with a built-in operational amplifier and an analog-to-digital converter.
Compared with the prior art, the invention has the beneficial effects that:
1. the device adopts the active triaxial magnetic field probe to replace a passive triaxial magnetic field probe to acquire signals, and is matched with the STM32F303 single chip microcomputer with the built-in operational amplifier, so that a signal conditioning circuit can be simplified, and the electromagnetic interference is reduced, thereby improving the measurement precision.
2. The device is in contact with handheld recording equipment in an infrared wireless transmission mode, so that the electrical isolation of a transmission line is realized, and the interference of a high-strength magnetic field on data transmission can be inhibited.
Drawings
FIG. 1 is a block diagram of the system structure of the power frequency magnetic field intensity testing device of the present invention;
FIG. 2 is a hardware system structure diagram of the power frequency magnetic field intensity testing device of the invention;
FIG. 3 is a circuit block diagram of an infrared serial communication interface structure according to the present invention;
FIG. 4 is a block diagram of the single axis (X-axis) signal detection circuit design of the present invention;
FIG. 5 is a block diagram of an LCD page display design according to the present invention;
FIG. 6 is a flow chart of the RMS measurement method of the present invention;
FIG. 7 is a flow chart of a power frequency magnetic field strength measurement and control program of the present invention;
Detailed Description
The invention is further described with reference to the accompanying drawings and specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and these equivalents also fall within the scope of the present application.
As shown in fig. 1 to 7, the power frequency magnetic field strength testing apparatus with infrared communication function according to the present invention is characterized in that: the device comprises an integrated control module, an LCD display and keyboard module, an external memory module, a signal acquisition module and an upper computer, wherein the LCD display and keyboard module, the external memory module, the signal acquisition module and the upper computer are all electrically connected with the integrated control module, and the signal acquisition module is an active signal acquisition module.
Wherein, microprocessor module shows through integrated USART communication module and LCD and is connected with keyboard module, infrared communication module electricity, microprocessor module is connected with external memory module, bee calling organ electricity through integrated IO communication module, microprocessor module passes through signal input part and is connected with signal acquisition module electricity.
The comprehensive control module is a comprehensive control system taking a high-performance microprocessor as a core and comprises a microprocessor module, a power supply module, a buzzer module and an infrared communication module. The microprocessor module uses STM32F3 series STM32F303 single chip microcomputer with built-in operational amplifier and analog-to-digital converter, and the microprocessor module processes the magnetic field intensity into root mean square value meeting HJ681-2013 standard requirement. The device adopts a 9V alkaline dry battery to supply power, and the power module converts the voltage of the battery into +/-3.6V, +5V and +2.5V to respectively supply power for the microprocessor module, the LCD display and keyboard module, the infrared communication module and the signal detection circuit. The buzzer module is used for giving an alarm when the device is in an abnormal condition and reminding a user of checking the condition in time. The infrared communication module is used for realizing remote transmission of measurement data. The external memory module is used for storing the measured data. The upper computer (PC) can carry out software programming debugging and program burning on the microprocessor through the debugging module. The LCD display and keyboard module communicates with the microprocessor module through an RS485 serial interface in a USART communication module integrated with the microprocessor module, on one hand, data can be displayed and processed by the microprocessor to obtain a real-time root mean square value or a peak value thereof, on the other hand, a relevant instruction can be sent to the microprocessor module, a measurement range is set, and a numerical value is displayed through the root mean square value or the peak value thereof. The signal acquisition module comprises an active triaxial magnetic field probe and a signal detection circuit, wherein the active triaxial magnetic field probe consists of three mutually orthogonal active induction coils wound on the same cube framework and is used for receiving magnetic field signals.
Preferably, the side length of the square framework is 10cm, and each coil is formed by winding 1000 turns of copper wires with the diameter of 0.21 mm; the signal detection circuit is mainly used for filtering voltage signals induced by 3 shafts and then sending the voltage signals to the STM32F303 single chip microcomputer.
The STM32F303 single chip microcomputer is internally integrated with USART, JTAG, IO and other communication modules to complete communication work with peripheral circuits. It is worth noting that the STM32F303 single chip microcomputer is internally provided with four paths of operational amplifiers, so that small signals can be captured. The 9V battery of main power festival series connection provides operating power for whole device. The upper computer (PC) can complete debugging and program burning work of the system through the JTAG. The external memory is a ROM27128, and can store and record data. The LCD display and keyboard module sends a setting instruction to the STM32F303 to complete the range, detection mode and numerical value zero clearing action and displays the returned numerical value; the infrared communication module realizes the communication process between the STM32F303 single chip microcomputer and the handheld device, completes remote operation and remote data transmission work, and realizes electrical isolation of a transmission line, so that the interference of a high-strength magnetic field on data transmission can be inhibited. The signal detection circuit corresponds to the triaxial probe, completes X, Y, Z signal acquisition work in three directions by matching with the probe, simultaneously respectively sends the signals to three paths of operational amplifiers built in the STM32F303 single chip microcomputer, and supplies the STM32F303 single chip microcomputer to perform root mean square processing on the data according to programs after analog-to-digital conversion. The buzzer module can alarm and prompt a user to switch the measuring range after the test value exceeds the set safe measuring range so as to measure the high magnetic field intensity, and simultaneously remind the user to enable the infrared communication module through the LCD display and the keyboard module, so that the test of the high magnetic field intensity and the data remote transmission work are completed, and a tester is prevented from being in the high magnetic field environment for a long time.
Design of infrared communication module:
in order to prevent data distortion caused by electromagnetic interference on long-distance wired transmission data, the invention creatively designs an infrared serial communication interface by means of an STM32F303 singlechip serial interface and a receiving circuit. The infrared communication interface transmits data by adopting infrared rays with 950nm near infrared wavelength, the transmission distance reaches 10 meters, and the safety distance of the 10kV overhead power line completely meets the requirement of power facility protection regulations on 5 m. The infrared communication module mainly comprises an infrared receiving tube and an infrared transmitting tube, wherein the receiving tube receives infrared rays, and the transmitting tube transmits the infrared rays.
As shown in FIG. 3, VCC voltage is +5V, which supplies power to the infrared communication interface circuit. RTX and TXD are STM32F303 singlechip serial ports receiving port and transmitting port respectively. Q1 and Q2 are an infrared ray receiving tube and an infrared ray emitting tube, respectively. The STM32F303 singlechip sends instructions to be driven by RTX and TXD ports to work, and meanwhile, working state indicator lamps D1 and D2 are lightened. The infrared receiving tube QI is used for receiving the instruction sent by the handheld device, and the infrared transmitting tube Q2 is used for sending data to the handheld recording device. The two are respectively corresponding to the transmitting end and the receiving end of the handheld device, so that the remote transmission work of the test data is completed.
Design of the signal detection circuit:
the signal detection circuit consists of a voltage conversion chip and an active induction coil. The X-, Y-, and Z-axis induction coils are wound on cylindrical magnetic cores, which are perpendicular to each other, so that the three axes form mutually orthogonal magnetic field probes. U1 and U2 are voltage conversion chips that convert +5V to +2.5V to power the coil. The magnetic field present around the coil generates an induced voltage in the coil, the magnitude of which is proportional to the magnitude of the magnetic field. The induced voltage is output to an OPAMP port of the STM32F303 singlechip through an OUT port, and is converted into a digital signal through an amplifier and an analog-to-digital converter to be used by a central processing unit of the singlechip, so that a signal conditioning circuit can be simplified, and electromagnetic interference is reduced, thereby improving the measurement precision.
Taking the X axis as an example, a block diagram of the design of the single axis signal detection circuit is shown in fig. 4. VCC is +5V power supply, it is +2.5V to supply power for magnetic field coil by U1, U2 voltage conversion chip, 2.5V voltage is divided by circuit composed of resistance R1, resistance R2, resistance R3, capacitance C1, capacitance C2, capacitance C3 to make two ends of X axis coil reach voltage balance, when the coil measures magnetic field, the induced voltage generated by magnetic field in coil will break original voltage balance, and the induced voltage signal is transmitted to OPAMP port of STM32F303 single chip machine by X-OUT port to complete the collection of magnetic field signal in X axis direction.
Design of an LCD display interface:
the LCD display and keyboard module can send instructions to the STM32F303 single chip microcomputer, and meanwhile, data processed by the single chip microcomputer can be received in real time and displayed on a liquid crystal screen. The communication of the two modules is realized by RS485, and meanwhile, the +5V power supply of the LCD is also transmitted by RS 485.
As shown in fig. 5, the magnetic field strength menu displays the root mean square value, peak value (root mean square value maximum value holding), unit, and range of the magnetic field strength measured by the line frequency magnetic field strength measuring device. And the running state menu can display the power supply electric quantity state of the testing device in real time. The event recording menu can record the time of the test device in abnormal starting-up, abnormal shutdown, power supply undervoltage, over-range and other conditions, thereby assisting maintenance personnel to master the operation condition of the device and facilitating the maintenance of the device. The detection, range and infrared communication setting menu can set the test range, detection mode and infrared communication so as to measure the magnetic field conditions with different strengths, when the test value exceeds the safe range, the buzzer alarms to remind the user to set the infrared communication energy, and a data remote transmission mode is adopted so as to protect the human health practically; the detection mode has root mean square value and peak value 2 modes which are selectable so as to provide different value types for users.
The root mean square value measuring method comprises the following steps:
the magnetic field of X, Y, Z three directions collected by the triaxial probe is amplified by the three-way built-in amplifier of the STM32F303 single chip microcomputer, and the analog signal is converted into a digital signal for the data processing unit of the single chip microcomputer. The specific program processing flow is three paths of digital signals BX、BY、BZAfter being processed by an amplifier arranged in an STM32F303 singlechip and analog-to-digital conversion, B is generated by filtering and squaring through a first-order filter2 X、B2 Y、B2 ZAfter the three are added and the average value is taken, the root mean square value B meeting the requirement of the HJ681-2013 standard is obtained by carrying out the squaring operationRMS. The rms value measurement method design flow chart is shown in fig. 6.
Power frequency magnetic field intensity measurement and control program design flow:
the STM32F303 single chip microcomputer measurement and control program is used for realizing processing of signal acquisition, data processing, data display and the like of a power frequency magnetic field. The measurement and control program is compiled by adopting C language and is divided into a main program, a keyboard scanning program, an LCD display program, an infrared communication enabling program and the like. After the program is written, the hex file is burned into the memory of the single chip microcomputer through the ST-LINK simulator, and the program configuration of the whole testing device is completed. The flow of the power frequency magnetic field strength measurement and control program design is shown in fig. 7.
The operation process of the invention is as follows:
(1) and 2 sections of 9V alkaline batteries are installed, a switch key is pressed down to start the device, and the LCD finishes initialization work. 2 alkaline batteries are converted by an auxiliary power supply to respectively provide power for each module of the power frequency magnetic field intensity testing device.
(2) And setting a measuring range and a detection mode such as a root mean square value or a peak value (maximum root mean square value is kept) through the LCD and the keyboard module, and sending the instructions to the STM32F303 singlechip.
(3) And holding the power frequency magnetic field intensity testing device to enable the probe to be close to the tested object, observing the real-time numerical value displayed by the LCD, and reading the real-time root mean square value or the peak value after a maximum value holding key is pressed after the numerical value to be tested is stable. After the data is read, a zero clearing key is pressed, and then the test of the next tested object is carried out. In the measuring process, if the test value exceeds the range, the buzzer can give out an alarm sound to remind a user to switch to a larger range and enable infrared communication at the same time, so that a remote test mode is provided for the user, and the human body is ensured to be in a safe test distance.
(4) And after reading the data, pressing a switch key to shut down the device, and finishing the test.
Claims (4)
1. The utility model provides a power frequency magnetic field intensity testing arrangement with infrared communication function which characterized in that: the device comprises an integrated control module, an LCD display and keyboard module, an external memory module, a signal acquisition module and an upper computer, wherein the LCD display and keyboard module, the external memory module, the signal acquisition module and the upper computer are all electrically connected with the integrated control module, and the signal acquisition module is an active signal acquisition module.
2. The power frequency magnetic field intensity testing device with the infrared communication function according to claim 1, characterized in that: the integrated control module includes microprocessor module, power module, buzzer module and infrared communication module, microprocessor module shows through integrated USART communication module and LCD and is connected with keyboard module, infrared communication module electricity, microprocessor module is connected with external memory module, buzzer electricity through integrated IO communication module, microprocessor module passing signal input part is connected with signal acquisition module electricity, power module is used for showing and keyboard module, infrared communication module, signal acquisition module power supply for microprocessor module, LCD.
3. The power frequency magnetic field intensity testing device with the infrared communication function according to claim 2, characterized in that: the signal acquisition module comprises an active triaxial magnetic field probe and a signal detection circuit, the power supply module provides power for the active triaxial magnetic field probe and the signal detection circuit, and the active triaxial magnetic field probe is connected with the signal input end of the microprocessor module through the signal detection circuit.
4. The power frequency magnetic field intensity testing device with the infrared communication function according to claim 2, characterized in that: the microprocessor module is an STM32F3 series STM32F303 singlechip with a built-in operational amplifier and an analog-to-digital converter.
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Citations (6)
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| CN101911093A (en) * | 2008-01-09 | 2010-12-08 | Nxp股份有限公司 | Evaluating an electromagnetic field strength of an electromagnetic gate apparatus |
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| CN102495381A (en) * | 2011-12-18 | 2012-06-13 | 河海大学常州校区 | Induction type electromagnetic leakage detection device and method |
| CN103149459A (en) * | 2013-03-14 | 2013-06-12 | 上海理工大学 | Electromagnetic distribution testing system and electromagnetic distribution testing method thereof |
| CN204302480U (en) * | 2015-01-06 | 2015-04-29 | 东北石油大学 | A kind of monolithic processor controlled teslameter |
| CN110610111A (en) * | 2019-09-16 | 2019-12-24 | 电子科技大学 | Remote passive wireless magnetic field quantity sensing system |
-
2020
- 2020-04-22 CN CN202010321398.4A patent/CN111624413A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101911093A (en) * | 2008-01-09 | 2010-12-08 | Nxp股份有限公司 | Evaluating an electromagnetic field strength of an electromagnetic gate apparatus |
| CN102129052A (en) * | 2010-11-30 | 2011-07-20 | 吴鹏 | Spatial three-axis magnetic sensor |
| CN102495381A (en) * | 2011-12-18 | 2012-06-13 | 河海大学常州校区 | Induction type electromagnetic leakage detection device and method |
| CN103149459A (en) * | 2013-03-14 | 2013-06-12 | 上海理工大学 | Electromagnetic distribution testing system and electromagnetic distribution testing method thereof |
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Application publication date: 20200904 |