Wireless programmed switch for digital multimeter

Abstract

The utility model discloses a wireless programmed switch for a digital multimeter, which is characterized by comprising a control circuit, a multi-path output circuit, a multi-path input circuit and a multi-path switch circuit, the input end of the multi-path output circuit is correspondingly connected with a plurality of first output ends on the control circuit, the output end of the multi-path output circuit is correspondingly connected with a plurality of input ends on the calibrator, and the input end of the multi-path input circuit is correspondingly connected with the output end of the multi-path output circuit. The output end of the multi-path input circuit is correspondingly connected with a plurality of first input ends on the control circuit, the output end of the multi-path output circuit is further correspondingly connected with the control end of the multi-path switching circuit, and a plurality of output ends of the calibrator are correspondingly connected with the input end of the multi-path switching circuit. And the output end of the multi-way switch circuit is correspondingly connected with a plurality of input ends of the digital multimeter. According to the utility model, the trouble of manual wire changing can be saved, and the calibration work efficiency of the digital multimeter is greatly improved.

Description

Technical Field

[0001] The utility model belongs to the field of program-controlled switches, in particular to a wireless program-controlled switch for a digital multimeter. Background Art

[0002] When using a multi-product calibrator (referred to as calibrator) to automatically calibrate a handheld digital multimeter (referred to as digital multimeter), it is necessary to connect the standard signal output by the calibrator to the corresponding input terminal of the digital multimeter through a signal line.

[0003] The calibrator has 5 output terminals. During the automated calibration process, the output connection terminals need to be switched according to different functional requirements, and 2 of the terminals need to be selected to correspond to the input terminals of the digital multimeter. In the absence of a programmable switch, only manual line replacement can be used, which has low work efficiency. Summary of the invention

[0004] The utility model aims to provide a wireless thread-controlled switch for a digital multimeter, which can realize rapid switching between working conditions and save the trouble of manual line changing.

[0005] The technical solutions to achieve the above objectives include the following:

[0006] A wireless thread-controlled switch for a digital multimeter, comprising: a control circuit, a multi-channel output circuit, a multi-channel input circuit, a communication circuit and a multi-channel switch circuit;

[0007] The input ends of the multi-way output circuit are respectively connected to the multiple first output ends on the control circuit, the output ends of the multi-way output circuit are respectively connected to the multiple input ends on the calibrator, the input ends of the multi-way input circuit are respectively connected to the output ends of the multi-way output circuit, the output ends of the multi-way input circuit are respectively connected to the multiple first input ends on the control circuit, the communication circuit is connected to the control circuit, the output ends of the multi-way output circuit are also respectively connected to the control end of the multi-way switch circuit, the multiple output ends of the calibrator are correspondingly connected to the input ends of the multi-way switch circuit, and the output ends of the multi-way switch circuit are correspondingly connected to the multiple input ends of the digital multimeter.

[0008] In some embodiments, the multi-channel output circuit is a five-channel output circuit, and each of the five-channel output circuits includes: a first photocoupler and a first resistor;

[0009] The first end of the first photoelectric coupler is connected to the first voltage end through the first resistor, the second end of the first photoelectric coupler is connected to the first output end of the control circuit as the input end of the corresponding output circuit, the third end of the first photoelectric coupler is connected to the corresponding input end of the calibrator as the output end of the corresponding output circuit, and the fourth end of the first photoelectric coupler is connected to the second voltage end.

[0010] In some embodiments, the multi-input circuit is a five-input circuit, and each of the five-input circuits includes: a second photocoupler, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a first diode;

[0011] The first end of the second photoelectric coupler is connected to the third voltage end through the second resistor and the third resistor in sequence, the first end of the second photoelectric coupler is connected to the second end of the second photoelectric coupler through the fourth resistor, the third end of the second photoelectric coupler is connected to the ground end, the fourth end of the second photoelectric coupler is connected to the first input end corresponding to the control circuit as the output end of the corresponding input circuit, the fourth end of the second photoelectric coupler is connected to the first voltage end through the fifth resistor, the anode of the first diode is connected to the second end of the second photoelectric coupler, and the cathode of the first diode is connected to the corresponding output end of the five-way output circuit as the input end of the corresponding input circuit.

[0012] In some embodiments, the multi-way switching circuit is a five-way switching circuit, and each of the five-way switching circuits includes: a contactor, the control end of the contactor is connected to the output end of the corresponding five output circuits, the input end of the contactor is connected to the corresponding output end on the calibrator, and the output end of the contactor is connected to the corresponding input end on the digital multimeter.

[0013] In some embodiments, it also includes: a switching power supply chip and a voltage conversion circuit; the input end of the switching power supply chip is connected to the AC power supply end, the first output end of the switching power supply chip is connected to the input end of the voltage conversion circuit, the output end of the voltage conversion circuit is connected to five output circuits, five input circuits, a control circuit and a communication circuit, and the second output end of the switching power supply chip is connected to the five output circuits.

[0014] In some embodiments, the voltage conversion circuit includes: a first conversion circuit, a second conversion circuit, and a third conversion circuit;

[0015] The input end of the first conversion circuit is connected to the first output end of the switching power supply chip, the output end of the first conversion circuit is connected to the input end of the second conversion circuit, the output end of the second conversion circuit is connected to the input end of the third conversion circuit, and the output end of the third conversion circuit is connected to five output circuits and five input circuits.

[0016] In some embodiments, the first conversion circuit includes: a first conversion chip, a first capacitor, a second capacitor, and a third capacitor;

[0017] The first end of the first conversion chip is connected to the first output end of the switching power supply chip as the input end of the first conversion circuit, the first end of the first conversion chip is connected to the ground end through the first capacitor and the second capacitor respectively, the second end of the first conversion chip is grounded, the third end of the first conversion chip is connected to the input end of the second conversion circuit as the output end of the first conversion circuit, and the third end of the first conversion chip is also grounded through the third capacitor.

[0018] In some embodiments, the second conversion circuit includes: a second conversion chip, a fourth capacitor, a fifth capacitor, and a sixth capacitor;

[0019] The first end of the second conversion chip is connected to the output end of the first conversion circuit as the input end of the second conversion circuit, the first end of the second conversion chip is connected to the ground end through the fourth capacitor, the second end of the second conversion chip is grounded, the third end of the second conversion chip is connected to the input end of the third conversion circuit as the output end of the second conversion circuit, and the third end of the second conversion chip is also grounded through the fifth capacitor and the sixth capacitor respectively.

[0020] In some embodiments, the third conversion circuit includes: a third conversion chip, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a sixth resistor and a second diode;

[0021] The third end of the third conversion chip is connected to the output end of the second conversion circuit as the input end of the third conversion circuit, the third end of the third conversion chip is connected to the ground end through the seventh capacitor, the eighth capacitor and the ninth capacitor respectively, the first end of the third conversion chip is grounded, the second end of the third conversion chip is connected to the five output circuits and the five input circuits as the output end of the first conversion circuit, the second end of the third conversion chip is also grounded through the tenth capacitor, the eleventh capacitor and the twelfth capacitor respectively, the anode of the second diode is connected to the second end of the third conversion chip through the sixth resistor, and the cathode of the second diode is grounded.

[0022] In some embodiments, the communication circuit is a LoRa communication circuit.

[0023] The technical solution provided by the utility model has the following advantages and effects: the input ends of the multi-way output circuit are respectively connected with the multiple first output ends of the control circuit in a one-to-one correspondence, so that the control circuit can send corresponding signals to the multi-way output circuit, the output ends of the multi-way output circuit are respectively connected with the multiple output ends of the calibrator in a one-to-one correspondence, so as to facilitate the control of the calibrator to output standard values, the input ends of the multi-way input circuit are respectively connected with the output ends of the multi-way output circuit, the output ends of the multi-way input circuit are respectively connected with the second input ends of the control circuit, the multi-way input circuit detects the output signal of the multi-way output circuit to obtain a feedback signal, and transmits the feedback signal to the control circuit to determine whether the output signal of the calibrator is correct; the calibrator and the digital multimeter are connected through a multi-way switch circuit, and the on and off of the multi-way switch circuit are controlled in a one-to-one correspondence according to the output signal of the multi-way output circuit, so as to realize switching between working conditions, save the trouble of manual line changing, greatly improve the calibration efficiency of the digital multimeter, and greatly reduce the labor intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings herein show specific examples of the technical solutions described in the present utility model, and together with the specific implementation methods constitute a part of the specification, and are used to explain the technical solutions, principles and effects of the present utility model.

[0025] Unless otherwise specified or defined, the same reference numerals in different drawings represent the same or similar technical features, and the same or similar technical features may also be represented by different reference numerals.

[0026] Figure 1 It is a principle diagram of a wireless thread-controlled switch for a digital multimeter provided by an embodiment of the utility model;

[0027] Figure 2 It is a wiring diagram of three working conditions provided by the embodiment of the utility model;

[0028] Figure 3 It is a schematic diagram of a five-way output circuit provided by an embodiment of the utility model;

[0029] Figure 4 It is a schematic diagram of a five-way input circuit provided by an embodiment of the utility model;

[0030] Figure 5 It is a schematic diagram of a switching power supply chip provided by an embodiment of the utility model;

[0031] Figure 6 is a schematic diagram of a first conversion circuit and a second conversion circuit provided by an embodiment of the utility model;

[0032] Figure 7 It is a schematic diagram of a third conversion circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present invention, specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0034] Unless otherwise specified or defined, the "first, second..." used in this article is merely used to distinguish names and does not represent a specific quantity or order.

[0035] Unless specifically stated or defined otherwise, the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] It should be noted that when a component is considered to be "fixed to" another component, it can be directly fixed to the other component or there can be a central component; when an component is considered to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time; when an component is considered to be "installed on" another component, it can be directly installed on the other component or there can be a central component at the same time. When an component is considered to be "set on" another component, it can be directly set on the other component or there can be a central component at the same time.

[0037] like Figure 1 As shown, the wireless thread-controlled switch for a digital multimeter provided by the embodiment of the utility model comprises: a control circuit, a multi-way output circuit, a multi-way input circuit, a communication circuit and a multi-way switch circuit;

[0038] The input ends of the multi-way output circuit are respectively connected to the multiple first output ends on the control circuit, the output ends of the multi-way output circuit are respectively connected to the multiple input ends on the calibrator, the input ends of the multi-way input circuit are respectively connected to the output ends of the multi-way output circuit, the output ends of the multi-way input circuit are respectively connected to the multiple first input ends on the control circuit, the communication circuit is connected to the control circuit, the output ends of the multi-way output circuit are also respectively connected to the control end of the multi-way switch circuit, the multiple output ends of the calibrator are correspondingly connected to the input ends of the multi-way switch circuit, and the output ends of the multi-way switch circuit are correspondingly connected to the multiple input ends of the digital multimeter.

[0039] In actual applications, the calibrator is a multi-product calibrator with five output terminals: V+, V-, I+, I-, and I20. The digital multimeter has four input terminals: V / Ω, ImA, IA, and COM. There are three actual working conditions according to the actual situation, such as Figure 2As shown, working condition 1 is the wiring condition of the DC / AC voltage and resistance functions of the digital multimeter, working condition 2 is the wiring condition of the digital multimeter under DC / AC low current, and working condition 3 is the wiring condition of the digital multimeter under DC / AC high current. In this embodiment, the multi-channel output circuit is a five-channel output circuit, the control circuit adopts a single-chip minimum system, the model of the single-chip microcomputer in the single-chip minimum system is STM32F103VCT6, the first input end, the first output end and the second output end of the control circuit are all I / O ports of the single-chip microcomputer, the input ends of the five-channel output circuit are respectively connected to the five first output ends of the control circuit in a one-to-one correspondence, so that the single-chip microcomputer can send corresponding signals to the five-channel output circuit, and the output ends of the five-channel output circuit are respectively connected to the five input ends of the calibrator. The output ends are connected one-to-one, which is convenient for controlling the calibrator to output the standard value. The input ends of the five-way input circuit are respectively connected to the output ends of the five-way output circuit, and the output ends of the five-way input circuit are respectively connected to the second input end of the control circuit. The five-way input circuit detects the output signals of the five-way output circuit to obtain feedback signals, and transmits the feedback signals to the control circuit to determine whether the output signals of the calibrator are correct. In this embodiment, the multi-way switch circuit is a five-way switch circuit, and the calibrator and the digital multimeter are connected through the five-way switch circuit. The on and off of the five-way switch circuits are controlled one-to-one according to the output signals of the five-way output circuits, so as to realize the switching of three working conditions, eliminate the trouble of manual line changing, greatly improve the calibration efficiency of the digital multimeter, and greatly reduce the labor intensity.

[0040] Furthermore, if Figure 3 As shown, the multi-channel output circuit is a five-channel output circuit, and each of the five-channel output circuits includes: a first photocoupler (OC1-1, OC1-2, OC1-3, OC1-4, OC1-5) and a first resistor (R1-1, R1-2, R1-3, R1-4, R1-5);

[0041] The first end of the first photoelectric coupler is connected to the first voltage end through the first resistor, the second end of the first photoelectric coupler is connected to the first output end of the control circuit as the input end of the corresponding output circuit, the third end of the first photoelectric coupler is connected to the corresponding input end of the calibrator as the output end of the corresponding output circuit, and the fourth end of the first photoelectric coupler is connected to the second voltage end.

[0042] Specifically, in the present embodiment, the output terminals Y1, Y2, Y3, Y4, and Y5 of the five-way output circuit respectively control V+, V-, I+, I-, and I20 of the calibrator, the voltage of the first voltage terminal is 3.3V, the voltage of the second voltage terminal is 24V, and the first photoelectric coupler adopts a photoelectric coupler of model TLP627. The first terminal of the first photoelectric coupler is the anode of the first photoelectric coupler, the second terminal of the first photoelectric coupler is the cathode, the third terminal of the first photoelectric coupler is the collector, and the fourth terminal of the first photoelectric coupler is the emitter. When the second terminal of the first photoelectric coupler is controlled by the single-chip microcomputer to be a low level, the third terminal of the first photoelectric coupler is also output as a low level. When the second terminal of the first photoelectric coupler is controlled by the single-chip microcomputer to be a high level, the third terminal of the first photoelectric coupler is also output as a high level, so as to facilitate the transmission of the control signal output by the control circuit to the calibrator, so as to realize the control of the output terminal of the calibrator by the control circuit.

[0043] Furthermore, if Figure 4 As shown, the multi-channel input circuit is a five-channel input circuit, and each of the five-channel input circuits includes: a second photocoupler (OC2-1, OC2-2, OC2-3, OC2-4, OC2-5), a second resistor (R2-1, R2-2, R2-3, R2-4, R2-5), a third resistor (R3-1, R3-2, R3-3, R3-4, R3-5), a fourth resistor (R4-1, R4-2, R4-3, R4-4, R4-5), a fifth resistor (R5-1, R5-2, R5-3, R5-4, R5-5) and a first diode (D1-1, D1-2, D1-3, D1-4, D1-5);

[0044] The first end of the second photoelectric coupler is connected to the third voltage end through the second resistor and the third resistor in sequence, the first end of the second photoelectric coupler is connected to the second end of the second photoelectric coupler through the fourth resistor, the third end of the second photoelectric coupler is connected to the ground end, the fourth end of the second photoelectric coupler is connected to the first input end corresponding to the control circuit as the output end of the corresponding input circuit, the fourth end of the second photoelectric coupler is connected to the first voltage end through the fifth resistor, the anode of the first diode is connected to the second end of the second photoelectric coupler, and the cathode of the first diode is connected to the corresponding output end of the five-way output circuit as the input end of the corresponding input circuit.

[0045] Specifically, in the present embodiment, the second photoelectric coupler also adopts a photoelectric coupler of model TLP627, the first end of the second photoelectric coupler is the anode of the second photoelectric coupler, the second end of the second photoelectric coupler is the cathode, the third end of the second photoelectric coupler is the collector, and the fourth end of the second photoelectric coupler is the emitter. When the output end of the output circuit outputs a low level, the input end of the corresponding input circuit is also a low level, so that the output end of the corresponding input circuit is a high level. When the output end of the output circuit outputs a high level, the input end of the corresponding input circuit is also a high level, so that the output end of the corresponding input circuit is a low level. The input circuit feeds back the corresponding output signal to the control circuit to realize the re-inspection of the output signals of the five-way output circuits; through the setting of the first photoelectric coupler and the second photoelectric coupler, the isolation of the single-chip microcomputer and the calibrator is realized, and the linear conversion between the input and output signals is realized.

[0046] Furthermore, the multi-way switch circuit is a five-way switch circuit, and each of the five-way switch circuits includes: a contactor, the control end of the contactor serves as the control end of the corresponding switch circuit connected to the output end of the corresponding five output circuits, the input end of the contactor is connected to the corresponding output end on the calibrator, and the output end of the contactor is connected to the corresponding input end on the digital multimeter.

[0047] In practical applications, the five-way switch circuit includes: a first switch circuit, a second switch circuit, a third switch circuit, a fourth switch circuit and a fifth switch circuit. The control end of the first switch circuit is connected to the output end Y1 of the five output circuits, the control end of the second switch circuit is connected to the output end Y2 of the five output circuits, the control end of the third switch circuit is connected to the output end Y3 of the five output circuits, the control end of the fourth switch circuit is connected to the output end Y4 of the five output circuits, and the control end of the fifth switch circuit is connected to the output end Y5 of the five output circuits. The input end of the first switch circuit is connected to the V+ end of the calibrator, and the input end of the second switch circuit is connected to the V- The input end of the third switch circuit is connected to the I+ end of the calibrator, the input end of the fourth switch circuit is connected to the I- end of the calibrator, the input end of the fifth switch circuit is connected to the I20 end of the calibrator, the output end of the first switch circuit is connected to the V / Ω end of the digital multimeter, the output ends of the second switch circuit and the fourth switch circuit are both connected to the COM end of the digital multimeter, the output end of the third switch circuit is connected to the ImA end of the digital multimeter, and the output end of the fifth switch circuit is connected to the IA end of the digital multimeter. The output signals of the five output circuits are used to control the on and off of the corresponding switch circuits, so that flexible switching of the three working conditions can be achieved, eliminating the trouble of manual line changing, fast switching, and improving calibration efficiency.

[0048] Furthermore, if Figure 5-Figure 7As shown, it also includes: a switching power supply chip U1 and a voltage conversion circuit; the input end of the switching power supply chip U1 is connected to the AC power supply end, the first output end of the switching power supply chip U1 is connected to the input end of the voltage conversion circuit, the output end of the voltage conversion circuit is connected to five output circuits, five input circuits, a control circuit and a communication circuit, and the second output end of the switching power supply chip U1 is connected to the five output circuits.

[0049] In actual applications, the switching power supply chip U1 converts the AC power into different voltages and then outputs them. The first output terminal of the switching power supply chip U1 outputs a 12V voltage. The voltage conversion circuit is used to step down the 12V voltage output by the switching power supply chip U1 to obtain a 3.3V voltage. As the first voltage terminal, it can power five output circuits, five input circuits, a control circuit and a communication circuit. The second output terminal of the switching power supply chip U1 outputs a 24V voltage. As the second voltage terminal, it can be connected to the fourth terminal of the second photocoupler. Through the setting of the voltage conversion circuit, the output circuit of the switching power supply chip U1 can be converted into the required voltage output according to actual needs.

[0050] Furthermore, if Figure 6 and Figure 7 As shown, the voltage conversion circuit includes: a first conversion circuit, a second conversion circuit and a third conversion circuit;

[0051] The input end of the first conversion circuit is connected to the first output end of the switching power supply chip U1, the output end of the first conversion circuit is connected to the input end of the second conversion circuit, the output end of the second conversion circuit is connected to the input end of the third conversion circuit, and the output end of the third conversion circuit is connected to five output circuits and five input circuits.

[0052] Specifically, the input end of the first conversion circuit is also the input end of the voltage conversion circuit, and the output end of the third conversion circuit is also the output end of the voltage conversion circuit. In this embodiment, the voltage output from the first output end of the switching power supply chip U1 is first converted by the first conversion circuit, and then the output voltage of the first conversion circuit is converted by the second conversion circuit and the third conversion circuit in sequence to obtain a 3.3V voltage.

[0053] Furthermore, if Figure 6 As shown, the first conversion circuit includes: a first conversion chip U2, a first capacitor C1, a second capacitor C2 and a third capacitor C3;

[0054] The first end of the first conversion chip U2 is connected to the first output end of the switching power supply chip U1 as the input end of the first conversion circuit, the first end of the first conversion chip U2 is connected to the ground end through the first capacitor C1 and the second capacitor C2 respectively, the second end of the first conversion chip U2 is grounded, the third end of the first conversion chip U2 is connected to the input end of the second conversion circuit as the output end of the first conversion circuit, and the third end of the first conversion chip U2 is also grounded through the third capacitor C3.

[0055] Specifically, in this embodiment, the first conversion chip U2 adopts the LM7809 voltage regulator chip, and the first capacitor C1 and the second capacitor C2 are set to filter the input voltage. The first conversion chip U2 converts the input 12V voltage into a 9V voltage, and the third capacitor C3 filters the 9V voltage output by the first conversion chip U2.

[0056] Furthermore, if Figure 6 As shown, the second conversion circuit includes: a second conversion chip U3, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6;

[0057] The first end of the second conversion chip U3 is connected to the output end of the first conversion circuit as the input end of the second conversion circuit, the first end of the second conversion chip U3 is connected to the ground end through the fourth capacitor C4, the second end of the second conversion chip U3 is grounded, the third end of the second conversion chip U3 is connected to the input end of the third conversion circuit as the output end of the second conversion circuit, and the third end of the second conversion chip U3 is also grounded through the fifth capacitor C5 and the sixth capacitor C6 respectively.

[0058] Specifically, in this embodiment, the second conversion chip U3 adopts the LM7805 voltage regulator chip, and through the setting of the fourth capacitor C4, the input 9V voltage is further filtered. The second conversion chip U3 converts the input 9V voltage into a 5V voltage, and the fifth capacitor C5 and the sixth capacitor C6 filter the 5V voltage output by the second conversion chip U3.

[0059] Furthermore, if Figure 7 As shown, the third conversion circuit includes: a third conversion chip U4, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a sixth resistor R6 and a second diode D2;

[0060] The third end of the third conversion chip U4 is connected to the output end of the second conversion circuit as the input end of the third conversion circuit. The third end of the third conversion chip U4 is connected to the ground end through the seventh capacitor C7, the eighth capacitor C8 and the ninth capacitor C9 respectively. The first end of the third conversion chip U4 is grounded. The second end of the third conversion chip U4 is connected to the five output circuits and the five input circuits as the output end of the first conversion circuit. The second end of the third conversion chip U4 is also grounded through the tenth capacitor C10, the eleventh capacitor C11 and the twelfth capacitor C12 respectively. The anode of the second diode D2 is connected to the second end of the third conversion chip U4 through the sixth resistor R6, and the cathode of the second diode D2 is grounded.

[0061] Specifically, in the present embodiment, the third conversion chip U4 adopts the SPX1117-3.3 voltage stabilizing chip, and further filters the input 5V voltage through the setting of the seventh capacitor C7, the eighth capacitor C8 and the ninth capacitor C9. The third conversion chip U4 converts the input 5V voltage into a 3.3V voltage. The tenth capacitor C10, the eleventh capacitor C11 and the twelfth capacitor C12 filter the 3.3V voltage output by the third conversion chip U4. The second diode D2 is a light emitting diode. Through the setting of the light emitting diode, it is possible to judge whether the third conversion circuit is working normally according to the light emission of the light emitting diode.

[0062] Furthermore, the communication circuit is a LoRa communication circuit. In this embodiment, the LoRa communication circuit adopts the LoRa chip of the WH-L101-L model, and the operating frequency band is: 398 to 525Mhz (default frequency 470MHz). The serial port is used for data transmission and reception, which lowers the threshold of wireless applications and can realize one-to-one or one-to-many communication.

[0063] The utility model discloses a wireless thread-controlled switch for a digital multimeter, wherein the input ends of the five-way output circuit are respectively connected to the five first output ends of the control circuit in a one-to-one correspondence, so that the single-chip microcomputer can send corresponding signals to the five-way output circuit, and the output ends of the five-way output circuit are respectively connected to the five output ends of the calibrator in a one-to-one correspondence, so as to facilitate the control of the calibrator to output a standard value, the input ends of the five-way input circuit are respectively connected to the output ends of the five-way output circuit, and the output ends of the five-way input circuit are respectively connected to the second input end of the control circuit, and the five-way input circuit detects the output signals of the five-way output circuit to obtain feedback signals, and transmits the feedback signals to the control circuit, so as to judge whether the output signals of the calibrator are correct; in this embodiment, the multi-way switch circuit is a five-way switch circuit, and the calibrator and the digital multimeter are connected through the five-way switch circuit, and the on and off of the five-way switch circuit are controlled in a one-to-one correspondence according to the output signals of the five-way output circuit, so as to realize the switching of three working conditions, save the trouble of manual line changing, greatly improve the calibration work efficiency of the digital multimeter, and greatly reduce the labor intensity.

[0064] When quoting drawing descriptions, new features that appear are described; in order to avoid repeated quotations of drawings resulting in less concise descriptions, features that have been described clearly will not be quoted in the drawings one by one.

[0065] The purpose of the above embodiments is to exemplarily reproduce and deduce the technical solution of the utility model, and to fully describe the technical solution, purpose and effect of the utility model. Its purpose is to make the public understand the disclosed content of the utility model more thoroughly and comprehensively, and it does not limit the protection scope of the utility model.

[0066] The above embodiments are not exhaustive enumerations based on the present invention, and there may be multiple other implementations not listed. Any replacement and improvement made without violating the concept of the present invention shall fall within the protection scope of the present invention.

Claims

1. A wireless thread controlled switch for a digital multimeter, characterized in that: include: Control circuit, multi-channel output circuit, multi-channel input circuit, communication circuit and multi-channel switch circuit; The input ends of the multi-way output circuit are respectively connected to the multiple first output ends on the control circuit, the output ends of the multi-way output circuit are respectively connected to the multiple input ends on the calibrator, the input ends of the multi-way input circuit are respectively connected to the output ends of the multi-way output circuit, the output ends of the multi-way input circuit are respectively connected to the multiple first input ends on the control circuit, the communication circuit is connected to the control circuit, the output ends of the multi-way output circuit are also respectively connected to the control end of the multi-way switch circuit, the multiple output ends of the calibrator are correspondingly connected to the input ends of the multi-way switch circuit, and the output ends of the multi-way switch circuit are correspondingly connected to the multiple input ends of the digital multimeter.

2. The wireless thread-controlled switch for a digital multimeter as claimed in claim 1, characterized in that: The multi-channel output circuit is a five-channel output circuit, and each of the five-channel output circuits includes: a first photoelectric coupler and a first resistor; The first end of the first photoelectric coupler is connected to the first voltage end through the first resistor, the second end of the first photoelectric coupler is connected to the first output end of the control circuit as the input end of the corresponding output circuit, the third end of the first photoelectric coupler is connected to the corresponding input end of the calibrator as the output end of the corresponding output circuit, and the fourth end of the first photoelectric coupler is connected to the second voltage end.

3. The wireless thread-controlled switch for a digital multimeter as claimed in claim 1, characterized in that: The multi-channel input circuit is a five-channel input circuit, and each of the five-channel input circuits includes: a second photocoupler, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a first diode; The first end of the second photoelectric coupler is connected to the third voltage end through the second resistor and the third resistor in sequence, the first end of the second photoelectric coupler is connected to the second end of the second photoelectric coupler through the fourth resistor, the third end of the second photoelectric coupler is connected to the ground end, the fourth end of the second photoelectric coupler is connected to the first input end corresponding to the control circuit as the output end of the corresponding input circuit, the fourth end of the second photoelectric coupler is connected to the first voltage end through the fifth resistor, the anode of the first diode is connected to the second end of the second photoelectric coupler, and the cathode of the first diode is connected to the corresponding output end of the five-way output circuit as the input end of the corresponding input circuit.

4. The wireless thread-controlled switch for a digital multimeter as claimed in claim 1, characterized in that: The multi-way switch circuit is a five-way switch circuit, and each switch circuit in the five-way switch circuit includes: a contactor, the control end of the contactor is connected to the output end of the corresponding five output circuits, the input end of the contactor is connected to the corresponding output end on the calibrator, and the output end of the contactor is connected to the corresponding input end on the digital multimeter.

5. The wireless thread-controlled switch for a digital multimeter according to any one of claims 1 to 4, characterized in that: Also includes: A switching power supply chip and a voltage conversion circuit; the input end of the switching power supply chip is connected to the mains power supply end, the first output end of the switching power supply chip is connected to the input end of the voltage conversion circuit, the output end of the voltage conversion circuit is connected to five output circuits, five input circuits, a control circuit and a communication circuit, and the second output end of the switching power supply chip is connected to the five output circuits.

6. The wireless thread-controlled switch for a digital multimeter as claimed in claim 5, characterized in that: The voltage conversion circuit includes: a first conversion circuit, a second conversion circuit and a third conversion circuit; The input end of the first conversion circuit is connected to the first output end of the switching power supply chip, the output end of the first conversion circuit is connected to the input end of the second conversion circuit, the output end of the second conversion circuit is connected to the input end of the third conversion circuit, and the output end of the third conversion circuit is connected to five output circuits and five input circuits.

7. The wireless thread-controlled switch for a digital multimeter as claimed in claim 6, characterized in that: The first conversion circuit includes: a first conversion chip, a first capacitor, a second capacitor and a third capacitor; The first end of the first conversion chip is connected to the first output end of the switching power supply chip as the input end of the first conversion circuit, the first end of the first conversion chip is connected to the ground end through the first capacitor and the second capacitor respectively, the second end of the first conversion chip is grounded, the third end of the first conversion chip is connected to the input end of the second conversion circuit as the output end of the first conversion circuit, and the third end of the first conversion chip is also grounded through the third capacitor.

8. The wireless thread-controlled switch for a digital multimeter as claimed in claim 6, characterized in that: The second conversion circuit includes: a second conversion chip, a fourth capacitor, a fifth capacitor and a sixth capacitor; The first end of the second conversion chip is connected to the output end of the first conversion circuit as the input end of the second conversion circuit, the first end of the second conversion chip is connected to the ground end through the fourth capacitor, the second end of the second conversion chip is grounded, the third end of the second conversion chip is connected to the input end of the third conversion circuit as the output end of the second conversion circuit, and the third end of the second conversion chip is also grounded through the fifth capacitor and the sixth capacitor respectively.

9. The wireless thread-controlled switch for a digital multimeter as claimed in claim 6, characterized in that: The third conversion circuit includes: a third conversion chip, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a sixth resistor and a second diode; The third end of the third conversion chip is connected to the output end of the second conversion circuit as the input end of the third conversion circuit, the third end of the third conversion chip is connected to the ground end through the seventh capacitor, the eighth capacitor and the ninth capacitor respectively, the first end of the third conversion chip is grounded, the second end of the third conversion chip is connected to the five output circuits and the five input circuits as the output end of the first conversion circuit, the second end of the third conversion chip is also grounded through the tenth capacitor, the eleventh capacitor and the twelfth capacitor respectively, the anode of the second diode is connected to the second end of the third conversion chip through the sixth resistor, and the cathode of the second diode is grounded.

10. The wireless thread-controlled switch for a digital multimeter according to any one of claims 1 to 4, characterized in that: The communication circuit is a LoRa communication circuit.

Images