Measuring device for eliminating thermoelectric voltage at large current gear

Abstract

The utility model discloses a measuring device for eliminating thermoelectric voltage in a large current gear. The measuring device comprises a first current input terminal, a second current input terminal, a resistor, a control switch, an amplifier, an analog-to-digital converter and a micro-control unit, the resistor is respectively connected with the first current input terminal and the second current input terminal; the control switch comprises a control end, a first connecting end, a second connecting end and a third connecting end, the control end is electrically connected with the micro-control unit, the first connecting end is electrically connected with the amplifier, the second connecting end is electrically connected with the first current input terminal, and the third connecting end is electrically connected with the second current input terminal; the amplifier is electrically connected with the analog-to-digital converter, the analog-to-digital converter is electrically connected with the micro-control unit, and the analog-to-digital converter is electrically connected with the second current input terminal. According to the utility model, the control switch is creatively added and arranged, so that the influence of generated thermoelectric voltage is effectively eliminated, and the requirement of continuously measuring current greater than 6A without time limitation is met.

Description

Technical Field

[0001] The utility model relates to the technical field of measuring devices, in particular to a measuring device for eliminating thermoelectric voltage in a large current range. Background Art

[0002] The high-current input terminals of multimeters on the market need to indicate a continuous measurement time of 30 seconds. After the measurement, it takes 15 minutes to wait for the circuit board to cool before the next measurement can be made to ensure measurement accuracy.

[0003] Existing multimeters have a problem with measurement accuracy being affected by the generation of thermoelectric voltage. When the measured current is greater than 6A and the measurement is carried out for a long time, the resistor connected to the circuit board input terminal will heat up, causing the area around the input terminal to heat up. Because the chip ADC is far away from the input terminal and is in a low-temperature zone, it causes the generation of thermoelectric voltage (thermoelectromotive force), generating additional voltage in the circuit, affecting measurement accuracy. Utility Model Content

[0004] In order to overcome the above technical problems, the utility model discloses a measuring device for eliminating thermoelectric voltage in a large current range.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0006] A measuring device for eliminating thermoelectric voltage in a high current range, comprising a first current input terminal, a second current input terminal, a resistor R1, a control switch S1, an amplifier IC1, an analog-to-digital converter IC2, and a microcontroller unit IC3;

[0007] The resistor R1 is connected to the first current input terminal and the second current input terminal respectively;

[0008] The control switch S1 includes a control end, a first connection end, a second connection end, and a third connection end. The control end is electrically connected to the micro control unit IC3, the first connection end is electrically connected to the amplifier IC1, the second connection end is electrically connected to the first current input terminal, and the third connection end is electrically connected to the second current input terminal.

[0009] The amplifier IC1 is electrically connected to the analog-to-digital converter IC2 , the analog-to-digital converter IC2 is electrically connected to the micro control unit IC3 , and the analog-to-digital converter IC2 is electrically connected to the second current input terminal.

[0010] The above-mentioned large current range is used to eliminate thermoelectric voltage measurement device, wherein the amplifier IC1 includes a first amplifier input terminal, a second amplifier input terminal and an amplifier output terminal, the first amplifier input terminal is electrically connected to the first connection terminal, the second amplifier input terminal is short-circuited with the amplifier output terminal, and the amplifier output terminal is electrically connected to the micro control unit IC3 through the analog-to-digital converter IC2.

[0011] The above-mentioned large current range is used to eliminate the thermoelectric voltage measurement device, wherein the analog-to-digital converter IC2 includes a first conversion input terminal, a second conversion input terminal and a conversion output terminal, the first conversion input terminal is electrically connected to the amplification output terminal, the second conversion input terminal is electrically connected to the second current input terminal, and the conversion output terminal is electrically connected to the micro control unit IC3.

[0012] The above-mentioned high current range uses a measuring device for eliminating thermoelectric voltage, wherein the micro control unit IC3 is electrically connected to the LCD.

[0013] In the above-mentioned measuring device for eliminating thermoelectric voltage in the large current range, the first current input terminal is a 10A terminal.

[0014] In the above-mentioned measuring device for eliminating thermoelectric voltage in the large current range, the second current input terminal is a GND terminal.

[0015] In the above-mentioned measuring device for eliminating thermoelectric voltage in the large current range, the resistance of the resistor R1 is 7 mΩ.

[0016] The beneficial effects of the present invention include the following:

[0017] (1) The utility model innovatively adds the control switch S1, which effectively eliminates the influence of the thermoelectric voltage generated by the current input terminal, and realizes the continuous measurement of current greater than 6A without time limit, without waiting for a long time for the circuit board to cool down before entering the next measurement, thereby improving the detection efficiency and accuracy and meeting the needs of new energy current detection;

[0018] (2) The control switch S1 is connected to the second current input terminal to obtain a GND terminal voltage value, and the GND terminal voltage value is theoretically 0V;

[0019] When the measured current is greater than 6A and is measured for a long time, the first current input terminal and the second current input terminal generate heat, resulting in a temperature difference with the analog-to-digital converter IC2, thereby generating an additional thermoelectric voltage. At this time, the thermoelectric voltage between the first current input terminal and the second current input terminal is not 0V, so the control switch S1 is connected to the second current input terminal to obtain the GND end thermoelectric voltage value V1, and then connected to the first current input terminal to obtain the voltage value V2 of the resistor R1, that is, the actual voltage value is V2-V1, thereby solving the problem of eliminating the thermoelectric voltage (thermoelectromotive force) generated by the current input terminal, and achieving the purpose of continuous and accurate measurement of large current signals;

[0020] (3) The analog-to-digital converter IC2 is connected to the microcontroller unit IC3 and connected to the amplifier IC1 to realize that the current flows through the resistor R1 to generate a voltage, and then follows the analog-to-digital converter IC2 through the amplifier IC1, converts the voltage signal into a digital signal to the microcontroller unit IC3, and is processed by the program of the microcontroller unit IC3, and the current measurement value is displayed on the LCD; wherein, when the measured current is greater than 6A and the measurement is long, the collected GND end thermoelectric voltage value V1 and the resistor R1 voltage value V2 are converted into digital signals and transmitted to the microcontroller unit IC3, and then the microcontroller unit IC3 calculates the actual voltage value, that is, calculates the voltage value generated by the resistor R1, to complete the current measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0023] The present invention will be further described below through specific embodiments to make the technical solution of the present invention easier to understand and grasp, rather than to limit the present invention.

[0024] Example: See Figure 1 This embodiment provides a high current range thermoelectric voltage elimination measuring device, characterized in that it includes a first current input terminal, a second current input terminal, a resistor R1, a control switch S1, an amplifier IC1, an analog-to-digital converter (ADC) IC2, and a microcontroller unit (MCU) IC3;

[0025] The resistor R1 is connected to the first current input terminal and the second current input terminal respectively;

[0026] The control switch S1 includes a control end, a first connection end, a second connection end, and a third connection end. The control end is electrically connected to the micro control unit IC3, the first connection end is electrically connected to the amplifier IC1, the second connection end is electrically connected to the first current input terminal, and the third connection end is electrically connected to the second current input terminal.

[0027] The amplifier IC1 is electrically connected to the analog-to-digital converter IC2 , the analog-to-digital converter IC2 is electrically connected to the micro control unit IC3 , and the analog-to-digital converter IC2 is electrically connected to the second current input terminal.

[0028] Preferably, the amplifier IC1 includes a first amplifying input terminal, a second amplifying input terminal and an amplifying output terminal, the first amplifying input terminal is electrically connected to the first connecting terminal, the second amplifying input terminal is short-circuited with the amplifying output terminal, and the amplifying output terminal is electrically connected to the microcontroller unit IC3 through the analog-to-digital converter IC2.

[0029] Preferably, the analog-to-digital converter IC2 includes a first conversion input terminal, a second conversion input terminal and a conversion output terminal, the first conversion input terminal is electrically connected to the amplification output terminal, the second conversion input terminal is electrically connected to the second current input terminal, and the conversion output terminal is electrically connected to the micro control unit IC3.

[0030] Preferably, the micro control unit IC3 is electrically connected to an LCD, and the LCD is used to display the current measurement value.

[0031] Specifically, the first current input terminal is a 10A terminal;

[0032] The second current input terminal is a GND terminal;

[0033] The resistance of the resistor R1 is 7 mΩ.

[0034] Specifically, the control switch S1 is added and set innovatively to effectively eliminate the influence of thermoelectric voltage generated by the current input terminal, and realize the continuous measurement of current greater than 6A without time limit, without having to wait for a long time for the circuit board to cool down before entering the next measurement, so as to improve the detection efficiency and accuracy and meet the needs of new energy current detection.

[0035] Specifically, the control switch S1 is connected to the second current input terminal to obtain a GND terminal voltage value, and the GND terminal voltage value is theoretically 0V;

[0036] When the measured current is greater than 6A and is measured for a long time, the first current input terminal and the second current input terminal generate heat, which produces a temperature difference with the analog-to-digital converter IC2, thereby generating an additional thermoelectric voltage. At this time, the thermoelectric voltage between the first current input terminal and the second current input terminal is not 0V, so the control switch S1 is connected to the second current input terminal to obtain the thermoelectric voltage value V1 of the GND end, and then connected to the first current input terminal to obtain the voltage value V2 of the resistor R1, that is, the actual voltage value is V2-V1, thereby solving the problem of eliminating the thermoelectric voltage (thermoelectromotive force) generated by the current input terminal, and achieving the purpose of continuously and accurately measuring large current signals.

[0037] Specifically, the analog-to-digital converter IC2 is connected to the microcontroller unit IC3 and connected to the amplifier IC1 to enable current to flow through the resistor R1 to generate voltage, which follows the amplifier IC1 to the analog-to-digital converter IC2, converts the voltage signal into a digital signal to the microcontroller unit IC3, and is processed by the program of the microcontroller unit IC3, and the current measurement value is displayed on the LCD; wherein, when the measured current is greater than 6A and the measurement is long, the collected GND end thermoelectric voltage value V1 and the resistor R1 voltage value V2 are converted into digital signals and transmitted to the microcontroller unit IC3, and then the microcontroller unit IC3 calculates the actual voltage value, that is, calculates the voltage value generated by the resistor R1 to complete the current measurement.

[0038] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation on the present invention. Any person skilled in the art can, without departing from the scope of the present invention, utilize the above-disclosed technical means and technical content to make many possible variations and modifications to the present invention, or modify it into equivalent embodiments with equivalent variations. Therefore, all equivalent variations based on the shape, structure, and principle of the present invention that do not depart from the content of the present invention's technical solution should be included in the scope of protection of the present invention.

Claims

1. A measuring device for eliminating thermoelectric voltage in a high current range, characterized in that: It includes a first current input terminal, a second current input terminal, a resistor R1, a control switch S1, an amplifier IC1, an analog-to-digital converter IC2 and a micro control unit IC3; The resistor R1 is connected to the first current input terminal and the second current input terminal respectively; The control switch S1 includes a control end, a first connection end, a second connection end, and a third connection end. The control end is electrically connected to the micro control unit IC3, the first connection end is electrically connected to the amplifier IC1, the second connection end is electrically connected to the first current input terminal, and the third connection end is electrically connected to the second current input terminal. The amplifier IC1 is electrically connected to the analog-to-digital converter IC2 , the analog-to-digital converter IC2 is electrically connected to the micro control unit IC3 , and the analog-to-digital converter IC2 is electrically connected to the second current input terminal.

2. The measuring device for eliminating thermoelectric voltage in a large current range according to claim 1, characterized in that: The amplifier IC1 includes a first amplifying input terminal, a second amplifying input terminal and an amplifying output terminal. The first amplifying input terminal is electrically connected to the first connecting terminal, the second amplifying input terminal is short-circuited with the amplifying output terminal, and the amplifying output terminal is electrically connected to the micro control unit IC3 through the analog-to-digital converter IC2.

3. The measuring device for eliminating thermoelectric voltage in a large current range according to claim 2, characterized in that: The analog-to-digital converter IC2 includes a first conversion input terminal, a second conversion input terminal and a conversion output terminal, the first conversion input terminal is electrically connected to the amplification output terminal, the second conversion input terminal is electrically connected to the second current input terminal, and the conversion output terminal is electrically connected to the micro control unit IC3.

4. The measuring device for eliminating thermoelectric voltage in a large current range according to claim 3, characterized in that: The micro control unit IC3 is electrically connected to the LCD.

5. The measuring device for eliminating thermoelectric voltage in a large current range according to claim 4, characterized in that: The first current input terminal is a 10A terminal.

6. The measuring device for eliminating thermoelectric voltage in a large current range according to claim 5, characterized in that: The second current input terminal is a GND terminal.

7. The measuring device for eliminating thermoelectric voltage in a large current range according to claim 6, characterized in that: The resistance of the resistor R1 is 7 mΩ.

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