CN216082903U - True effective value alternating-current millivolt measuring voltmeter for teaching experiment - Google Patents
True effective value alternating-current millivolt measuring voltmeter for teaching experiment Download PDFInfo
- Publication number
- CN216082903U CN216082903U CN202122293869.8U CN202122293869U CN216082903U CN 216082903 U CN216082903 U CN 216082903U CN 202122293869 U CN202122293869 U CN 202122293869U CN 216082903 U CN216082903 U CN 216082903U
- Authority
- CN
- China
- Prior art keywords
- circuit
- signal
- voltage
- main control
- control circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Measurement Of Current Or Voltage (AREA)
Abstract
The utility model provides a true virtual value exchanges millivolt and measures voltmeter for teaching experiment, including master control circuit, master control circuit is connected with AD converting circuit, master control circuit's output is connected with the display button circuit, AD converting circuit is connected with the alternating current-direct current converting circuit, master control circuit still is connected with input/output communication isolating circuit and does contact output protection circuit, input/output communication isolating circuit is used for carrying out input protection and communication isolation protection to the voltmeter, do contact output protection circuit and be used for protecting the dry contact output in the voltmeter circuit. The utility model converts the collected AC voltage signal into DC signal through AC/DC conversion circuit, and then the AD conversion circuit performs analog-to-digital conversion, the main control circuit reads the digital signal of the voltage value and judges whether the voltage value exceeds the measuring range, if the voltage value exceeds the measuring range, the main control circuit switches the suitable measuring range or directly outputs the signal exceeding the measuring range, and the manual gear shifting or the changing of the measuring range is not needed, and the measuring speed is improved.
Description
Technical Field
The utility model relates to the technical field of voltage measurement, in particular to a true effective value alternating-current millivolt measurement voltmeter for teaching experiments.
Background
An AC voltmeter is an instrument for measuring the effective value of AC voltage, in the field of strong electricity, the AC voltmeter is commonly used for measuring the voltage of a monitoring line, the commonly used AC voltmeter is generally selected to ensure that the indication value is about two thirds of the full scale of a dial, an appropriate measuring range can be selected according to different measured voltage values during the use and measurement of the AC voltmeter so as to ensure that the measured voltage value is more accurate, most of the measuring ranges of the AC voltmeter have specific measuring ranges, if the voltage value exceeding the measuring range is measured during the actual measurement or the teaching experiment, the voltmeter with larger measuring range can be manually replaced, if the voltage range of the predicted quantity is not clear, the accurate range can be determined only by sequentially detecting from the voltmeter with large measuring range to the voltmeter with small measuring range, and the actual voltage detection speed is reduced due to the manual replacement of the measuring range, the development of teaching work is not facilitated, most of voltmeter lacks protective measures, and when the faults occur, the voltmeter can not feed back timely, so that the measuring work is hindered.
SUMMERY OF THE UTILITY MODEL
The utility model aims to overcome the defects of the prior art and provides an alternating current measuring voltmeter which comprises multiple protection measures such as input signal protection, TVS protection, dry contact over-range output protection and the like and can measure various waveform signals.
The technical problem to be solved by the utility model is realized by adopting the following technical scheme:
a true-value ac millivolt measurement voltmeter for teaching experiments, comprising:
the main control circuit is used for processing the data signals input by the voltmeter and outputting measured data information;
the AD conversion circuit is used for converting an input analog signal into a digital signal and transmitting the digital signal to the main control circuit;
the AC-DC conversion circuit is used for sampling and amplifying an input AC signal, converting a true effective value into a DC signal and transmitting the DC signal to the input end of the AD conversion circuit;
the input and output communication isolation circuit is used for performing input protection and communication isolation protection on a circuit of the voltmeter;
the dry contact output protection circuit is used for protecting the dry contact output in the voltmeter circuit;
the alternating current measuring voltmeter also comprises a resistance voltage division circuit, wherein the resistance voltage division circuit switches a voltage measuring range in a resistance voltage division mode on the aspect of 30V power supply, and the measuring range reaches 0.01 mV-1000V;
the input end of the alternating current-direct current conversion circuit is connected with a signal acquisition port, the output end of the alternating current-direct current conversion circuit is connected with a main control circuit through the AD conversion circuit, the input-output communication isolation circuit and the dry contact output protection circuit are connected with the main control circuit, an analog signal of alternating current voltage is transmitted to the alternating current-direct current conversion circuit through the signal acquisition port, the alternating current-direct current voltage is converted into a direct current signal through the true effective value of the alternating current-direct current conversion circuit and transmitted to the AD conversion circuit for analog-digital conversion, the analog signal is converted into a digital signal through the analog-digital conversion and transmitted to the main control circuit, the main control circuit processes a measured voltage value and outputs the digital signal to a terminal for display, the AD conversion circuit reads the voltage signal and judges whether the voltage signal exceeds the range or not through the main control circuit during the analog-digital conversion, and if the voltage exceeds the range, the main control circuit switches gears or outputs the over-range signal.
Preferably, the main control circuit is further connected with a display key circuit, the output end of the display key circuit is connected with a display, the input end of the display key circuit is provided with a plurality of keys, data information processed by the main control circuit is displayed through the display of the display key circuit, and the automatic range or the manual range of the voltmeter is selected through the keys of the display key circuit.
Preferably, the input/output communication isolation circuit includes a control chip U4, a VIA pin and a VOB pin of the control chip U4 are connected to a control chip U5, a transient suppression diode U6 is connected in parallel to a pin B and a pin a of the control chip U5, and two ends of the transient suppression diode U6 are connected to a series connection of a transient suppression diode U3 and a transient suppression diode U7.
Preferably, the model of the transient suppression diode U6 is SMBJ11CA, and the models of the transient suppression diode U3 and the transient suppression diode U7 are SMBJ6.5CA.
Preferably, the model of the control chip U4 is ADUM1201 for performing input/output communication isolation, and the model of the control chip U5 is MAX13487 for RS485 communication.
Preferably, the display key circuit comprises a control chip U1, the model of the control chip U1 is TM1628, and one key is respectively connected on pins KS1-KS6 in series for realizing different functions.
Preferably, the main control circuit comprises a control chip U3, the model of the control chip U3 is STM8S105K4T6C, a PB2 pin of the control chip is connected with an RLY5 pin of the dry contact output protection circuit, and PD7, PD4, PD3 and PD2 pins of the control chip are sequentially connected with CS, SCLK, PWM and DIN pins of the AD conversion circuit.
The utility model has the advantages and positive effects that:
the utility model converts the collected AC voltage signal into DC signal through AC/DC conversion circuit, then the AD conversion circuit performs analog-to-digital conversion, the main control circuit reads the digital signal of the voltage value and judges whether the voltage value exceeds the range, if the voltage value exceeds the range, the main control circuit switches the proper range or directly outputs the over-range signal, manual gear shifting or range changing is not needed, the measuring speed is improved, the measuring range can reach 0.01mV-1000V, the resolution ratio can reach 0.01mV, and the protection of 485 communication and input/output signals can be realized through the dry contact output protection circuit and the input/output communication isolation circuit, and various complex waveform signals including sine wave, square wave, triangle wave and pulse wave can be measured, thus being convenient for teaching and normal measuring work of students.
Drawings
FIG. 1 is a block diagram of the module circuit connections of the present invention;
FIG. 2 is a circuit schematic of the master control circuit of the present invention;
fig. 3 is a circuit schematic diagram of an AD conversion circuit of the present invention;
FIG. 4 is a circuit schematic of the resistive divider circuit of the present invention;
FIG. 5 is a circuit schematic of the dry contact output protection circuit of the present invention;
FIG. 6 is a schematic circuit diagram of the AC to DC converter circuit of the present invention;
FIG. 7 is a circuit schematic of the input output communication isolation circuit of the present invention;
FIG. 8 is a schematic circuit diagram of the display key circuit of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the utility model herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The embodiments of the utility model will be described in further detail below with reference to the accompanying drawings:
as shown in figure 1, the true effective value AC millivolt measuring voltmeter for teaching experiments comprises a main control circuit, the main control circuit is used for processing data signals input by the voltmeter and outputting measured data information, the input end of the main control circuit is connected with an AD conversion circuit, the AD conversion circuit is used for converting input analog signals into digital signals and transmitting the digital signals to the main control circuit, the output end of the main control circuit is connected with a display key circuit, the output end of the display key circuit is connected with a display, the input end of the display key circuit is provided with a plurality of keys, the data information processed by the main control circuit is displayed through the display of the display key circuit, the automatic range or the manual range of the voltmeter is selected through the keys of the display key circuit, the input end of the AD conversion circuit is connected with the conversion circuit, the input end of the AC/DC conversion circuit is connected with a signal acquisition port, the analog signal of alternating voltage is transmitted to an alternating current-direct current conversion circuit through a signal acquisition port, the alternating current-direct current conversion circuit is used for converting a true effective value of an input alternating current signal into a direct current signal after sampling and amplifying the direct current signal and transmitting the direct current signal to an input end of an AD conversion circuit, the alternating current-direct current conversion circuit is used for converting the true effective value of the acquired alternating current voltage signal into the direct current signal and transmitting the direct current signal to the AD conversion circuit for analog-digital conversion, the analog signal is converted into a digital signal by the analog-digital conversion circuit and is transmitted to a main control circuit, the main control circuit is used for processing a measured voltage value and outputting the digital signal to a display of a display key circuit for displaying, the AD conversion circuit is used for reading the voltage signal and judging whether the voltage signal exceeds a measuring range or not by the main control circuit, and if the voltage signal exceeds the measuring range, the main control circuit is used for switching gears or outputting the over-range signal.
As shown in fig. 1, the main control circuit is further connected with an input/output communication isolation circuit and a dry contact output protection circuit, as shown in fig. 7, the input/output communication isolation circuit is used for performing input protection and communication isolation protection on a circuit of the voltmeter, and as shown in fig. 5, the dry contact output protection circuit is used for protecting a dry contact output in the circuit of the voltmeter.
In addition, the alternating current measuring voltmeter further comprises a resistance voltage division circuit, as shown in fig. 4, the resistance voltage division circuit switches a voltage measuring range in a form of resistance voltage division on the power supply of 30V, the measurement of the high-frequency circuit is realized through capacitance adjustment of the capacitor C16 and the capacitor C17, and the measuring range reaches 0.01 mV-1000V.
Further, the input/output communication isolation circuit includes a control chip U4, a VIA pin and a VOB pin of the control chip U4 are connected to a control chip U5, a transient suppression diode U6 is connected in parallel to a B pin and an a pin of the control chip U5, and both ends of the transient suppression diode U6 are connected to a series connection of a transient suppression diode U3 and a transient suppression diode U7, in this embodiment, the model of the transient suppression diode U6 is SMBJ11CA, the input protection and 485TVS protection are performed through the transient suppression diode U6, a TVS (transient Voltage super), which is a short term for the transient suppression diode, the models of the transient suppression diodes U3 and U7 are SMBJ6.5CA, the model of the control chip U4 is ADUM, and is used for input/output communication isolation, and the model of the control chip U5 is MAX13487 and is used for RS485 communication.
Further, as shown in fig. 8, the display key circuit includes a control chip U1, the model of the control chip U1 is TM1628, each of pins KS1-KS6 is provided with a key for realizing different functions, the instrument can be calibrated through the keys, an automatic range or a manual range can be selected, a display is provided with a status indicator lamp, a 1628 chip is used for driving a 6-bit LED nixie tube to display, and the display range is 299.99mV at minimum.
Further, as shown in fig. 2, 3 and 5, the main control circuit includes a control chip U3, the model of the control chip U3 is STM8S105K4T6C, a PB2 pin of the control chip is connected to an RLY5 pin of the dry contact output protection circuit, an RLY5 pin of the dry contact output protection circuit is connected to a triode Q3 through a resistor R20, a base of the triode Q3 is connected to a relay, a contact K1 is arranged on the relay, if a fault occurs, the relay directly acts to disconnect the main control circuit to protect the main control circuit, pins PD7, PD4, PD3 and PD2 of the control chip U3 are sequentially connected to CS, SCLK, PWM and DIN pins of the AD conversion circuit, and the model of the control chip U2 of the AD conversion circuit is LTC 2400I.
As shown in fig. 6, a schematic diagram of the ac/dc conversion circuit is shown, where the control chip U7 of the ac/dc conversion circuit is of a model AD637, and the ac signal is sampled and amplified, then transmitted to the control chip U7 for true effective value conversion, and then transmitted to the AD conversion circuit for AD conversion.
In specific implementation, the utility model adopts 220V power supply, the external dimension is only 96 × 48 × 98mm long × wide × deep, the volume is small, the AC/DC conversion circuit converts the collected AC voltage signal into a DC signal, the AD conversion circuit performs analog-to-digital conversion, the main control circuit reads the digital signal of the voltage value and judges whether the voltage value exceeds the range, if the voltage value exceeds the range, the main control circuit switches the suitable range or directly outputs the over-range signal, manual gear shifting or range changing is not needed, the measuring speed is improved, the measuring speed can be controlled by the PWM signal, the conversion can be completed within 0.001s at most, the measuring range can reach 0.01mV-1000V, the resolution can reach 0.01mV, and the protection of 485 communication and input and output signals can be realized through the dry contact output protection circuit and the input and output communication isolation circuit, and the measurement can include sine waves, square waves and square waves, square waves and square waves, square waves and square waves are generated in the like, Square wave, triangular wave and pulse wave.
It should be emphasized that the embodiments described herein are illustrative rather than restrictive, and thus the present invention is not limited to the embodiments described in the detailed description, but other embodiments derived from the technical solutions of the present invention by those skilled in the art are also within the scope of the present invention.
Claims (7)
1. A true effective value exchanges millivolt measurement voltmeter for teaching experiment which characterized in that: the method comprises the following steps:
the main control circuit is used for processing the data signals input by the voltmeter and outputting measured data information;
the AD conversion circuit is used for converting an input analog signal into a digital signal and transmitting the digital signal to the main control circuit;
the AC-DC conversion circuit is used for sampling and amplifying an input AC signal, converting a true effective value into a DC signal and transmitting the DC signal to the input end of the AD conversion circuit;
the input and output communication isolation circuit is used for performing input protection and communication isolation protection on a circuit of the voltmeter;
the dry contact output protection circuit is used for protecting the dry contact output in the voltmeter circuit;
the resistance voltage division circuit switches the voltage measurement range in a resistance voltage division mode on the power supply of 30V;
the input end of the alternating current-direct current conversion circuit is connected with a signal acquisition port, the output end of the alternating current-direct current conversion circuit is connected with a main control circuit through the AD conversion circuit, the input-output communication isolation circuit and the dry contact output protection circuit are connected with the main control circuit, an analog signal of alternating current voltage is transmitted to the alternating current-direct current conversion circuit through the signal acquisition port, the alternating current-direct current voltage is converted into a direct current signal through the true effective value of the alternating current-direct current conversion circuit and transmitted to the AD conversion circuit for analog-digital conversion, the analog signal is converted into a digital signal through the analog-digital conversion and transmitted to the main control circuit, the main control circuit processes a measured voltage value and outputs the digital signal to a terminal for display, the AD conversion circuit reads the voltage signal and judges whether the voltage signal exceeds the range or not through the main control circuit during the analog-digital conversion, and if the voltage exceeds the range, the main control circuit switches gears or outputs the over-range signal.
2. The apparatus of claim 1, wherein the apparatus further comprises a voltage meter for measuring true rms a.c. millivolt, the voltage meter comprising: the automatic measuring range and manual measuring range selection device is characterized in that the main control circuit is further connected with a display key circuit, the output end of the display key circuit is connected with a display, the input end of the display key circuit is provided with a plurality of keys, data information processed by the main control circuit is displayed through the display of the display key circuit, and the keys of the display key circuit are used for selecting the automatic measuring range or manual measuring range of the voltmeter.
3. The apparatus of claim 1, wherein the apparatus further comprises a voltage meter for measuring true rms a.c. millivolt, the voltage meter comprising: the main control circuit comprises a control chip U3, the model of the control chip U3 is STM8S105K4T6C, the PB2 pin of the control chip U3 is connected with the RLY5 pin of the dry contact output protection circuit, and the PD7, PD4, PD3 and PD2 pins of the control chip U3 are sequentially connected with the CS, SCLK, PWM and DIN pins of the AD conversion circuit.
4. The apparatus of claim 1, wherein the apparatus further comprises a voltage meter for measuring true rms a.c. millivolt, the voltage meter comprising: the input and output communication isolation circuit comprises a control chip U4, a VIA pin and a VOB pin of the control chip U4 are connected with a control chip U5, a transient suppression diode U6 is connected in parallel to a pin B and a pin A of the control chip U5, and two ends of the transient suppression diode U6 are connected with a transient suppression diode U3 and a transient suppression diode U7 which are connected in series.
5. The apparatus of claim 4, wherein the apparatus further comprises a voltage meter for measuring true rms in millivolts, the voltage meter comprising: the model of the transient suppression diode U6 is SMBJ11CA, and the models of the transient suppression diode U3 and the transient suppression diode U7 are SMBJ6.5CA.
6. The apparatus of claim 4, wherein the apparatus further comprises a voltage meter for measuring true rms in millivolts, the voltage meter comprising: the model of the control chip U4 is ADUM1201 and is used for carrying out input and output communication isolation, and the model of the control chip U5 is MAX13487 and is used for RS485 communication.
7. The apparatus of claim 2, wherein the apparatus further comprises a voltage meter for measuring true rms a.c. millivolt, the voltage meter comprising: the display key circuit comprises a control chip U1, the model of the control chip U1 is TM1628, and keys are respectively connected on KS1-KS6 pins in series for realizing different functions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122293869.8U CN216082903U (en) | 2021-09-18 | 2021-09-18 | True effective value alternating-current millivolt measuring voltmeter for teaching experiment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122293869.8U CN216082903U (en) | 2021-09-18 | 2021-09-18 | True effective value alternating-current millivolt measuring voltmeter for teaching experiment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216082903U true CN216082903U (en) | 2022-03-18 |
Family
ID=80677932
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122293869.8U Active CN216082903U (en) | 2021-09-18 | 2021-09-18 | True effective value alternating-current millivolt measuring voltmeter for teaching experiment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216082903U (en) |
-
2021
- 2021-09-18 CN CN202122293869.8U patent/CN216082903U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN201589855U (en) | Detection device of relay protection testing device | |
| CN206411185U (en) | A kind of automatic switching range high-current detector | |
| CN106772208B (en) | Single three-phase meter integrated reliability test board | |
| CN110171319B (en) | Three-phase standard alternating-current charging pile capable of being used for tracing | |
| CN106646334B (en) | Method and system for calculating metering error of electric energy meter | |
| CN202600011U (en) | Automatic resistance tester | |
| CN204101671U (en) | A kind of Novel multi-core cable tester | |
| CN113064018B (en) | Direct current charging pile metering detection circuit, device and method | |
| CN103344937B (en) | Intelligent electric energy meter consumption detection equipment and detection method | |
| CN216082903U (en) | True effective value alternating-current millivolt measuring voltmeter for teaching experiment | |
| CN201392362Y (en) | Electric current measurement device | |
| CN202649455U (en) | Embedded accuracy tester for current transformer | |
| CN216082904U (en) | True effective value alternating-current measurement voltmeter for teaching experiment | |
| CN107831358A (en) | A kind of current measurement device based on MAX4373HEUA | |
| CN201926710U (en) | Programmable power supply insulation resistance and grounding resistance comprehensive test instrument | |
| CN202649312U (en) | Automatic resistor tester | |
| CN201434887Y (en) | On-line monitoring unit for secondary loop voltage drop | |
| CN201319049Y (en) | High-tension current mutual-inductor transformation ratio tester | |
| CN216082911U (en) | Direct current measuring instrument for teaching experiments | |
| CN216082912U (en) | Direct current measurement ammeter for teaching experiments | |
| CN211402698U (en) | Current gear automatic switching device | |
| CN107121659A (en) | A kind of three-phase electric energy meter on-site detection means and detection method | |
| CN216082914U (en) | Be used for teaching experiment to measure three-phase power instrument with two meters method | |
| CN2325781Y (en) | Digital voltmeler meter and galvano-meter | |
| CN213457105U (en) | Voltage displacement indicator suitable for relay protection device calibration |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |