CN213517279U - A semi-automatic multi-function multimeter - Google Patents
A semi-automatic multi-function multimeter Download PDFInfo
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- CN213517279U CN213517279U CN202021518246.5U CN202021518246U CN213517279U CN 213517279 U CN213517279 U CN 213517279U CN 202021518246 U CN202021518246 U CN 202021518246U CN 213517279 U CN213517279 U CN 213517279U
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Abstract
The utility model relates to a semi-automatic multifunctional multimeter, which comprises a microprocessor module, a measuring terminal, a function selection circuit, a plurality of measuring circuits, an analog-to-digital conversion circuit, a key circuit, a display circuit and a power module; the measuring terminal is electrically connected with the function selection circuit; the microprocessor module is respectively and electrically connected with the function selection circuit, the plurality of measuring circuits, the analog-to-digital conversion circuit, the key circuit, the display circuit and the power supply module; the function selection circuit is electrically connected with the plurality of measuring circuits respectively; the plurality of measuring circuits comprise a voltage measuring circuit, a current measuring circuit and a resistance measuring circuit, and the voltage measuring circuit, the current measuring circuit and the resistance measuring circuit are all electrically connected with the analog-to-digital conversion circuit so as to convert analog signals into digital signals and transmit the digital signals to the microprocessor module for processing; the key circuit is used for the user to select the working mode and controls the function selection circuit through the microprocessor module so as to change the working mode into the mode selected by the user.
Description
Technical Field
The utility model relates to an electricity measuring instrument field, concretely relates to semi-automatic multi-functional universal meter.
Background
The technological level of the society is continuously improved at present, various novel electronic products are put into the market in the aspect, but the electronic products must pass the qualified inspection and the test of the instrument before being put into the market, and meanwhile, when various electronic equipment breaks down and needs to be maintained, the instrument and the meter must be used. Meanwhile, the requirements of the industry and the market on the measuring speed, the accuracy, the function integration degree and the like of a common measuring instrument are higher and higher. And because the rapid development of various electronic technologies keeps promoting the electronic metering test technology all the time, the future prospect of the measuring instrument is wider and wider.
In the field of electronic metrology testing, multifunctional digital multimeters are widely used and are becoming indispensable test instruments. The main functions of the device are voltage measurement, resistance measurement and current measurement, and the general expanded functions are capacitance measurement, frequency measurement, diode measurement and the like. The multifunctional digital multimeter generally uses a basic principle of digital-to-analog conversion, a measured analog signal is processed to a certain degree and then converted to form a digital signal, and the digital signal is simply processed by a singlechip and then visually displayed in a simple digital form.
However, the conventional multimeter has room for improvement in precision, safety, functional diversity and the like.
SUMMERY OF THE UTILITY MODEL
To the problem in the background art, the utility model discloses a security in improving intelligent lock has designed a semi-automatic multi-functional universal meter.
In order to solve the technical problem, the utility model discloses the technical scheme who takes does:
a semi-automatic multifunctional multimeter comprises a microprocessor module, a measuring terminal, a function selection circuit, a plurality of measuring circuits, an analog-to-digital conversion circuit, a key circuit, a display circuit and a power module;
the measuring terminal is electrically connected with the function selection circuit;
the microprocessor module is respectively and electrically connected with the function selection circuit, the plurality of measuring circuits, the analog-to-digital conversion circuit, the key circuit, the display circuit and the power supply module;
the function selection circuit is electrically connected with the plurality of measuring circuits respectively;
the plurality of measuring circuits comprise a voltage measuring circuit, a current measuring circuit and a resistance measuring circuit, and the voltage measuring circuit, the current measuring circuit and the resistance measuring circuit are all connected with an analog-to-digital conversion circuit so as to convert analog signals into digital signals and transmit the digital signals to the microprocessor module for processing;
the key circuit is used for the user to select the working mode and controls the function selection circuit through the microprocessor module so as to change the working mode into the mode selected by the user;
the display circuit is used for displaying the data obtained by current detection;
the power module is used for supplying power for the multimeter.
In some embodiments, an STM32F103C8T6 chip is used in the microprocessor module; an ADS122C04 chip is adopted in the analog-to-digital conversion circuit; an INA260 chip is adopted in the current measuring circuit; the resistance measuring circuit measures the access resistance by a voltage division method; an OLED display screen is adopted in the display circuit.
In some embodiments, the voltage measurement circuit includes a voltage range switching circuit and a true effective value conversion circuit;
the voltage gear switching circuit is connected with the function selection circuit, and the true effective value conversion circuit is arranged between the voltage gear switching circuit and the analog-to-digital conversion circuit;
the voltage gear switching circuit is used for selecting the current voltage gear under the control of the key circuit and the microprocessor module;
the true effective value conversion circuit is used for processing the voltage signal, converting the alternating current signal into a direct current signal and then transmitting the analog quantity of the direct current signal to the analog-to-digital conversion circuit for processing.
In some embodiments, the voltage range switching circuit divides the range into three 600mV, 6V and 100V ranges; an AD637 chip is adopted in the true effective value conversion circuit.
In some embodiments, the plurality of measurement circuits further includes a capacitance measurement circuit, an inductance measurement circuit, a diode measurement circuit, and a frequency measurement circuit.
In some embodiments, NE555 chips are used in both the capacitance measuring circuit and the inductance measuring circuit; a TLV3501 chip is adopted in the frequency measurement circuit; the diode measuring circuit adopts a constant current measuring method to calculate the forward voltage drop of the diode.
Compared with the prior art, the utility model discloses an advantage includes at least: the utility model provides a pair of semi-automatic multi-functional universal meter has characteristics such as small, measure accurate, measuring speed is fast, the removal is measured conveniently, function diversity.
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Other objects and advantages of the present invention will become apparent from the following description of the invention, which is made with reference to the accompanying drawings, and can help to provide a thorough understanding of the present invention.
FIG. 1 is a schematic diagram of module connection of a semi-automatic multi-function multimeter according to the present invention;
FIG. 2 is a circuit schematic of a microprocessor module in one embodiment;
FIG. 3 is a circuit schematic of a true significance translation circuit in one embodiment;
FIG. 4 is a circuit schematic of an analog to digital conversion circuit in an embodiment;
FIG. 5 is a circuit schematic of a capacitance measurement circuit in an exemplary embodiment;
FIG. 6 is a circuit schematic of an inductance measurement circuit in an exemplary embodiment;
FIG. 7 is a circuit schematic of a current measurement circuit in one embodiment;
FIG. 8 is a circuit schematic of a resistance and diode measurement circuit in one embodiment;
FIG. 9 is a circuit schematic of a frequency measurement circuit in one embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be obtained by a person skilled in the art without any inventive work based on the described embodiments of the present invention, belong to the protection scope of the present invention.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which the invention belongs.
Referring to fig. 1, the utility model provides a semi-automatic multifunctional multimeter, which comprises a microprocessor module 1, a measuring terminal 2, a function selection circuit 3, a plurality of measuring circuits 4, an analog-to-digital conversion circuit 5, a key circuit 6, a display circuit 7 and a power module 8; the measurement terminal 2 is electrically connected to the function selection circuit 3; the microprocessor module 1 is respectively and electrically connected with the function selection circuit 3, the plurality of measuring circuits 4, the analog-to-digital conversion circuit 5, the key circuit 6, the display circuit 7 and the power module 8; the function selection circuit 3 is electrically connected to the plurality of measurement circuits 4, respectively; the plurality of measuring circuits 4 comprise a voltage measuring circuit, a current measuring circuit and a resistance measuring circuit, and the voltage measuring circuit, the current measuring circuit and the resistance measuring circuit are all electrically connected with the analog-to-digital conversion circuit 5 so as to convert analog signals into digital signals and transmit the digital signals to the microprocessor module 1 for processing; the key circuit 6 is used for a user to select a working mode, the microprocessor module 1 controls the function selection circuit 3 to change the working mode into a mode selected by the user, and the relay in the function selection circuit 3 can be used for switching the modules; the display circuit 7 is used for displaying the data obtained by current detection; and the power supply module 8 is used for supplying power to the multimeter.
Preferably, an STM32F103C8T6 chip is adopted in the microprocessor module 1; the ADS122C04 chip is adopted in the analog-to-digital conversion circuit 5; an INA260 chip is adopted in the current measuring circuit; the resistance measuring circuit measures the access resistance by a voltage division method; an OLED display screen is used in the display circuit 7.
Furthermore, the voltage measuring circuit comprises a voltage gear switching circuit and a true effective value conversion circuit; the voltage gear switching circuit is connected with the function selection circuit 3, and the true effective value conversion circuit is arranged between the voltage gear switching circuit and the analog-to-digital conversion circuit 5; the voltage gear switching circuit is used for selecting the current voltage gear under the control of the key circuit 6 and the microprocessor module 1; the true effective value conversion circuit is used for processing the voltage signal, converting the alternating current signal into a direct current signal and then transmitting the analog quantity of the direct current signal to the analog-to-digital conversion circuit 5 for processing. The voltage gear switching circuit divides the gears into three gears of 600mV, 6V and 100V, and can adopt a divider resistor, a clamp diode and a CMOS high-speed operational amplifier to form an integral circuit, thereby mainly realizing the functions of voltage division, circuit protection and information discrimination; an AD637 chip is adopted in the true effective value conversion circuit.
Preferably, the plurality of measurement circuits 4 further include a capacitance measurement circuit, an inductance measurement circuit, a diode measurement circuit, and a frequency measurement circuit. NE555 chips are adopted in the capacitance measuring circuit and the inductance measuring circuit; a TLV3501 chip is adopted in the frequency measurement circuit; the diode measuring circuit adopts a constant current measuring method to calculate the forward voltage drop of the diode.
In one particular embodiment, referring to FIG. 2, STM32F103C8T6 is employed as the core control chip of microprocessor module 1, thereby unrolling the design peripheral circuitry around the chip. The STM32F103C8T6 chip has low working voltage, high processing speed, large memory and low power consumption, and can effectively control each module.
Referring to fig. 3, the true effective value conversion circuit employs an AD637 true effective value conversion chip as the conversion processing of the alternating voltage signal. The AD637 can calculate the true effective value, the true root-mean-square value, the square value and the mean-square value of any complex alternating voltage input waveform, the provided integrated circuit RMS-to-DC converter has high performance which cannot be compared with a discrete analog circuit, the signal input with the highest bandwidth of 8MHz is allowed, and the inherent limitation of direct RMS calculation is overcome by using an implicit true effective value calculation method. The establishment time of the signal is not influenced by other level signals, the response time is extremely short, the output amplitude is only attenuated by 3dB, and the linearity error is only 0.02 percent. An amplification buffer area is designed in the chip to buffer and amplify the input signal, so that the measurement accuracy of the weak alternating current signal is reduced. Meanwhile, an internal protection circuit is arranged to limit the voltage and protect the rear-end kernel processing chip when the input voltage is overloaded.
Referring to fig. 4, the analog-to-digital conversion circuit 5 adopts an ADC122C04 chip, and has the characteristics of fast processing, high resolution, good stability, and the like.
Referring to fig. 5 and 6, the capacitance measuring circuit and the inductance measuring circuit both use NE555 chips. The chip can achieve a good measuring effect, and meanwhile, the circuit volume of the system is effectively saved. The capacitance is measured by a pulse counting method; the measurement of inductance adopts a capacitance three-point type oscillation circuit.
Referring to fig. 7, the current measurement circuit is centered on an INA260 chip. The INA260 is primarily used to meter current, power and voltage. The metering function of bidirectional measurement is realized, and the sampling resistor in the chip can be monitored by shunting from a high side or a low side.
Referring to fig. 8, in order to reduce the system volume, the resistance measuring circuit and the diode measuring circuit are integrated, and a small-area double-layer structure is used for building a PCB (printed circuit board) block, so that the reasonable application of space is facilitated. The resistance measuring module adopts a proportional voltage division method and is generally divided into voltage division selection of seven gears and seven different upper resistors. The diode measuring circuit adopts a constant current measuring method to calculate the forward voltage drop of the diode.
Referring to fig. 9, a TLV3501 high-speed comparator chip is used in the frequency measurement circuit, a 560 Ω resistor is connected in series with an inverting terminal of the comparator, a signal to be measured is input, and a 560 Ω resistor is connected in series with a comparison voltage obtained by dividing a power supply voltage at a non-inverting terminal of the comparator, and the comparison voltage is input to the non-inverting terminal.
To sum up, the utility model provides a pair of semi-automatic multi-functional universal meter has characteristics such as small, measure accurate, measuring speed is fast, the removal is measured conveniently, function diversity.
The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021518246.5U CN213517279U (en) | 2020-07-28 | 2020-07-28 | A semi-automatic multi-function multimeter |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202021518246.5U CN213517279U (en) | 2020-07-28 | 2020-07-28 | A semi-automatic multi-function multimeter |
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| CN213517279U true CN213517279U (en) | 2021-06-22 |
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| CN202021518246.5U Expired - Fee Related CN213517279U (en) | 2020-07-28 | 2020-07-28 | A semi-automatic multi-function multimeter |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115128323A (en) * | 2022-05-11 | 2022-09-30 | 福建福清核电有限公司 | A multimeter intelligent module with electric alarm and self-blocking function |
| CN115308464A (en) * | 2022-09-14 | 2022-11-08 | 深圳市捷创智通科技有限公司 | High-precision universal meter |
-
2020
- 2020-07-28 CN CN202021518246.5U patent/CN213517279U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115128323A (en) * | 2022-05-11 | 2022-09-30 | 福建福清核电有限公司 | A multimeter intelligent module with electric alarm and self-blocking function |
| CN115308464A (en) * | 2022-09-14 | 2022-11-08 | 深圳市捷创智通科技有限公司 | High-precision universal meter |
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Granted publication date: 20210622 |