A voltage load measuring device and a measuring method

Abstract

The application provides a voltage load measuring device and a measuring method. The measuring device comprises a standard current source and a standard resistance; the standard current source and the standard resistance are connected through a wire to form a series loop; the measuring device is used for measuring the voltage load of a current measuring instrument; when the measuring device is connected with the current measuring instrument, another series loop is formed between the standard current source and the current measuring instrument, and the standard resistance and the current measuring instrument form a parallel loop. The measuring device and the measuring method can effectively restore the actual working condition of the current measuring instrument, so that the accurate value of the voltage load of the current measuring instrument is obtained, and the current measuring result is effectively corrected.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of current and voltage measurement, in particular to a voltage burden measurement device and method. BACKGROUND

[0002] Current is one of the seven basic physical quantities in the International System of Units, and the measurement technology of current is widely used in industrial production and scientific research. For example, the testing of chip parameters in the semiconductor industry, the calibration of satellite power controller parameters in the aerospace industry, the measurement of proton accelerator power performance in the medical industry, the measurement of ion channel current based on patch clamp technology in life science research, and the precise control of particle position through current measurement in high-energy physics research. With the development of industry and the progress of scientific research, the accuracy of current measurement is increasingly required. There are many instruments for measuring current, including shunts, clamp ammeters, current sensors, current transformers, current probes, and digital multimeters. The above instruments use different principles, each with advantages and disadvantages and focuses.

[0003] In general, "accuracy" and "convenience" are the key factors to consider when measuring current. Currently, the current measurement instrument that best fits these two factors and is widely used is the digital multimeter. Inside the digital multimeter, the measurement of current is realized through units such as analog-to-digital conversion, and is displayed in decimal digits. It has a history of several decades. With the development of integrated circuits and the continuous emergence of new technologies and techniques, the best uncertainty of the eight-bit and a half digital multimeter current measurement can reach 10 -5 Of course, to achieve a smaller measurement uncertainty, there are strict requirements for temperature and humidity, connection wires, and surrounding environment.

[0004] In addition to measurement uncertainty and maximum allowable error, there is another key technical indicator for current measurement: voltage burden. Voltage burden refers to the voltage across the current measurement instrument when measuring current. Voltage burden causes the measurement result to be smaller than the actual result. In a constant current measurement circuit, the influence of voltage burden on the measurement result is small; but in a constant voltage measurement circuit, the influence of voltage burden on the measurement result is large. When the measurement circuit cannot be changed, for example, in an industrial site, the accurate value of voltage burden is needed to correct the measurement result in order to achieve the goal of high-accuracy measurement. For example, if the voltage burden of a current measurement instrument with a 1A range is 0.1V, then in a circuit with a voltage of 1V and a resistance of 1Ω, the current value measured by the current measurement instrument may be 0.9A, but the actual current should be 1A. When correcting the measurement result, 0.1V / 1Ω = 0.1A needs to be added to 0.9A to get the corrected measurement result of 1A.

[0005] At present, the voltage load of the current measuring instrument is mainly obtained by referring to the use manual of the current measuring instrument, or the voltage load across the current measuring instrument is measured by using a low-range voltmeter with high internal resistance. However, the use manual usually only gives a rough value or range, for example, the voltage load value given in the use manual of the existing digital multimeter has only 2 significant digits, and the range of the voltage load is only given as a range. If the measurement result is directly corrected by using the voltage load provided in the use manual, the measurement result will be inaccurate. If the voltage load is directly measured by using a low-range voltmeter with high internal resistance, the voltmeter may be damaged due to the excessive current. SUMMARY

[0006] The present application provides a voltage load measuring device and a measuring method to solve the technical problem that the accurate value of the voltage load of the current measuring instrument cannot be obtained.

[0007] To solve the above technical problem, the present application provides a voltage load measuring device, which comprises a standard current source and a standard resistance; the standard current source and the standard resistance are connected by a wire to form a series circuit.

[0008] The measuring device is used to measure the voltage load of the current measuring instrument. When the measuring device is connected to the current measuring instrument, another series circuit is formed between the standard current source and the current measuring instrument, and a parallel circuit is formed by the standard resistance and the current measuring instrument.

[0009] Optionally, the standard current source is a continuous adjustable power source.

[0010] Optionally, the output of the standard current source comprises an industrial frequency current and a direct current; the output range of the industrial frequency current is 0.01 μA-20.5 A, and the 90-day absolute uncertainty is (0.1%×the output of the industrial frequency current+0.1 μA)-(0.1%×the output of the industrial frequency current+5 mA); the output range of the direct current is 0 A-20.5 A, and the 90-day absolute uncertainty is (0.012%×the output of the direct current+0.02 μA)-(0.08%×the output of the direct current+750 μA).

[0011] Optionally, the standard resistance is a continuous adjustable resistance.

[0012] Optionally, the resistance range of the standard resistance is 0.1 Ω-1 kΩ, and the accuracy level is 0.01 level.

[0013] Optionally, the wire is a shielded wire.

[0014] Optionally, the shielded wire has a coaxial structure.

[0015] The application further provides a voltage load measuring method, which comprises the following steps:

[0016] S1, connecting a current measuring instrument with the voltage load measuring device, wherein the standard current source and the current measuring instrument form a series circuit, and the standard resistance and the current measuring instrument form a parallel circuit;

[0017] S2, adjusting the output current value of the standard current source and the resistance value of the standard resistance according to the voltage load value range of each range of the current scale of the current measuring instrument, so that the current flowing through the standard resistance is greater than zero and not greater than the rated current of the standard resistance, and the current flowing through the current measuring instrument is greater than zero and not greater than the maximum value of the current scale of the current measuring instrument;

[0018] S3, multiplying the difference between the output current value of the standard current source and the measured value of the current measuring instrument by the resistance value of the standard resistance to obtain the voltage load.

[0019] Optionally, the step S2 specifically comprises: adjusting the output current value of the standard current source so that the output current value of the standard current source is equal to the maximum value of the current scale of the current measuring instrument.

[0020] Optionally, the step S2 specifically comprises: adjusting the resistance value of the standard resistance so that the resistance value of the standard resistance is equal to 10 n Ω, and n is an integer.

[0021] The voltage load measuring device and the measuring method provided by the application can effectively restore the actual working condition of the current scale of the current measuring instrument, so as to obtain the accurate value of the voltage load of the current measuring instrument, and effectively correct the current measurement result. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic view of the voltage load measuring device provided by an embodiment of the application when connected with the current measuring instrument.

[0023] Figure 2 is a flow chart of the voltage load measuring method provided by an embodiment of the application.

[0024] [The following signs are explained as follows]:

[0025] standard current source-1, standard resistance-2, wire-3, current measuring instrument-4. DETAILED DESCRIPTION

[0026] In order to make the purposes, advantages and features of the present application clearer, the following further describes a voltage load measuring device and a measuring method according to the present application in detail with reference to the accompanying drawings. It should be noted that the drawings are very simplified and use non-precise proportions, and are only used to facilitate and clarify the purposes of the embodiments of the present application.

[0027] As shown in Figure 1 , the present embodiment provides a voltage load measuring device, which comprises a standard current source 1 and a standard resistance 2; the standard current source 1 and the standard resistance 2 are connected through a wire 3 to form a series loop; the measuring device is used to measure the voltage load of a current measuring instrument 4, when the measuring device is connected with the current measuring instrument 4, another series loop is formed between the standard current source 1 and the current measuring instrument 4, and the standard resistance 2 and the current measuring instrument 4 form a parallel loop. Wherein, the current measuring instrument 4 can be a digital multimeter, an electrometer or a low-range ammeter, etc.

[0028] The voltage load measuring device provided by the present embodiment can effectively restore the actual working condition of the current range of the current measuring instrument 4, so as to obtain the accurate value of the voltage load of the current measuring instrument 4, and further effectively correct the current measurement result.

[0029] Optionally, as shown in Figure 1 , the standard current source 1 is a continuously adjustable power supply. Wherein, the resolution of the continuously adjustable power supply can be determined according to the values of each range of the current range of the current measuring instrument 4, and the output current of the continuously adjustable power supply is preferably the values covering each range of the current range of the current measuring instrument 4, so that the same continuously adjustable power supply can be used to measure the voltage load corresponding to each range of the current range of the current measuring instrument 4.

[0030] Optionally, as shown in Figure 1 , the output of the standard current source 1 includes an industrial frequency current and a direct current; the output range of the industrial frequency current is 0.01 μA-20.5 A, and the 90-day absolute uncertainty is (0.1%×the output of the industrial frequency current+0.1 μA)-(0.1%×the output of the industrial frequency current+5 mA); the output range of the direct current is 0 A-20.5 A, and the 90-day absolute uncertainty is (0.012%×the output of the direct current+0.02 μA)-(0.08%×the output of the direct current+750 μA). The standard current source 1 provided by the present embodiment can measure the voltage load corresponding to each range of the current range of most current measuring instruments 4. In other embodiments, the output current value and the uncertainty of the standard current source 1 can be adjusted according to the actual measurement requirements.

[0031] Optionally, as shown in Figure 1As shown, the standard resistance 2 is a continuously adjustable resistance. Using a continuously adjustable resistance can measure the voltage load corresponding to each range of the current measurement instrument 4 current file respectively.

[0032] Optionally, as shown in Figure 1 As shown, the resistance range of the standard resistance 2 is 0.1Ω-1kΩ, and the accuracy level is 0.01 level. Among them, the temperature coefficient, power coefficient and annual stability of the standard resistance 2 should be as small as possible. Specifically, the temperature coefficient is 1×10 -6 , the power coefficient is 5×10 -6 , and the annual stability is 2×10 -6 The standard resistance 2 provided in this embodiment can measure the voltage load corresponding to each range of the current file of most current measurement instruments 4 respectively. In other embodiments, the parameters of the standard resistance 2 can be adjusted according to actual measurement requirements.

[0033] Optionally, as shown in Figure 1 The wire 3 is a shielded wire. The shielded wire has a shielding layer, which can reduce small current leakage.

[0034] Optionally, as shown in Figure 1 The shielded wire has a coaxial structure. Using a shielded wire with a coaxial structure can prevent small current leakage.

[0035] Optionally, as shown in Figure 1 The common connection part uses a T-shaped adapter to connect. As shown in Figure 1 The ellipse at both ends of the standard resistance 2 is the end of the T-shaped adapter. Using a T-shaped adapter facilitates wiring.

[0036] Based on the same technical concept as the above-mentioned voltage load measuring device, the present embodiment also provides a voltage load measuring method, as shown in Figure 1 and Figure 2 The measuring method comprises the following steps:

[0037] S1, connect the current measurement instrument 4 with any one of the above-mentioned voltage load measuring devices, wherein the standard current source 1 and the current measurement instrument 4 form a series circuit, and the standard resistance 2 and the current measurement instrument 4 form a parallel circuit;

[0038] S2, according to the voltage load value range of each range of the current scale of the current measuring instrument 4, adjust the output current value of the standard current source 1 and the resistance value of the standard resistance 2, so that the current flowing through the standard resistance 2 is greater than zero and not greater than the nominal current of the standard resistance 2, and the current flowing through the current measuring instrument 4 is greater than zero and not greater than the maximum value of the current scale of the current measuring instrument 4 in the current range; wherein the voltage load value range of each range of the current scale of the current measuring instrument 4 can be obtained by consulting the instrument manual;

[0039] S3, the difference between the output current value of the standard current source 1 and the measured value of the current measuring instrument 4 is multiplied by the resistance value of the standard resistance 2 to obtain the voltage load. Wherein the calculation formula of the voltage load can be expressed as U=(I-I b )×R a , U is the voltage load, I is the output current value of the standard current source 1, I b is the current value measured by the current measuring instrument 4, and R a is the resistance value of the standard resistance 2.

[0040] The voltage load measurement method provided by the embodiment can effectively restore the actual working condition of the current scale of the current measuring instrument 4, so as to obtain the accurate value of the voltage load of the current measuring instrument 4, and effectively correct the current measurement result.

[0041] Optionally, as shown in Figure 1 and Figure 2 , the step S2 specifically comprises: adjusting the output current value of the standard current source 1 so that the output current value of the standard current source is equal to the maximum value of the current scale of the current measuring instrument 4 in the current range. In the scheme provided by the embodiment, the measured value of the current measuring instrument 4 will not exceed the maximum value of the current range, so as to prevent the damage of the current measuring instrument 4.

[0042] Optionally, as shown in Figure 1 and Figure 2 , the step S2 specifically comprises: adjusting the resistance value of the standard resistance 2 so that the resistance value of the standard resistance 2 is equal to 10 n Ω, and the n is an integer. In the scheme provided by the embodiment, since the resistance value of the standard resistance 2 is equal to 1Ω, 10Ω or 1kΩ, etc., the calculation of the voltage load is facilitated.

[0043] As a specific measurement case, the voltage load of each range of the current scale of the digital multimeter with eight and a half display digits is measured by the above-mentioned voltage load measurement device and measurement method, and the specific data is shown in the following table:

[0044]

[0045] In the measuring process, I, I b and R a values can be adjusted as appropriate, not necessarily consistent with the values in the table. The voltage load U corresponding to each range of the current range of the digital multimeter or other current measuring instrument 4 is a fixed value.

[0046] As can be seen from the above table, using the voltage load measuring device and measuring method provided by the application, the voltage load corresponding to different positions and different ranges of the current range of the digital multimeter can be measured respectively, and the measurement result is accurate.

[0047] In summary, the voltage load measuring device and measuring method provided by the application can effectively restore the actual working condition of the current range of the current measuring instrument 4, so as to obtain the accurate value of the voltage load of the current measuring instrument 4, and further effectively correct the current measurement result.

[0048] The above description is only a description of the preferred embodiments of the application, and does not limit the scope of the application in any way. Any modification or modification made by a person of ordinary skill in the art based on the above disclosure is within the protection scope of the application.

Claims

1. A voltage load measuring device, characterized by, The measuring device comprises a standard current source and a standard resistance; the standard current source and the standard resistance are connected through a wire to form a series circuit; The measuring device is used to measure the voltage load of a current measuring instrument, wherein the voltage load refers to the voltage between the two ends of the current measuring instrument when the current measuring instrument measures current; when the measuring device is connected to the current measuring instrument, another series circuit is formed between the standard current source and the current measuring instrument, and a parallel circuit is formed by the standard resistance and the current measuring instrument; The standard current source is a continuous adjustable power supply. The standard resistance is a continuous adjustable resistance.

2. A device for measuring a voltage load as claimed in claim 1, characterized in that The output of the standard current source comprises an AC current and a DC current; the output range of the AC current is 0.01 μA-20.5 A, and the 90-day absolute uncertainty is (0.1%×the output of the AC current+0.1 μA)-(0.1%×the output of the AC current+5 mA); the output range of the DC current is 0 A-20.5 A, and the 90-day absolute uncertainty is (0.012%×the output of the DC current+0.02 μA)-(0.08%×the output of the DC current+750 μA).

3. A device for measuring voltage load as claimed in claim 1, characterized in that, The resistance range of the standard resistance is 0.1 Ω-1 kΩ, and the accuracy level is 0.01 level.

4. A device for measuring voltage load as claimed in claim 1, characterized in that, The wire is a shielded wire.

5. A device for measuring a voltage load as claimed in claim 4, characterized in that, The shielded wire has a coaxial structure.

6. A method of measuring voltage load, characterized by, The measuring method comprises the following steps: S1, connecting a current measuring instrument to the voltage load measuring device of any one of claims 1-5, wherein the standard current source and the current measuring instrument form a series circuit, and the standard resistance and the current measuring instrument form a parallel circuit; S2, adjusting the output current value of the standard current source and the resistance value of the standard resistance according to the voltage load value range of each range of the current file of the current measuring instrument, so that the current flowing through the standard resistance is greater than zero and not greater than the nominal rated current of the standard resistance, and the current flowing through the current measuring instrument is greater than zero and not greater than the maximum value of the current file of the current measuring instrument in the current range; S3, multiplying the difference between the output current value of the standard current source and the measurement value of the current measuring instrument by the resistance value of the standard resistance to obtain the voltage load.

7. A method of measuring voltage load according to claim 6, characterized in that, The step S2 specifically comprises adjusting the output current value of the standard current source so that the output current value of the standard current source is equal to the maximum value of the current file of the current measuring instrument in the current range.

8. A method of measuring voltage load according to claim 7, characterized in that, The step S2 specifically comprises: adjusting the resistance value of the standard resistance so that the resistance value of the standard resistance is equal to 10 n Ω, and the n is an integer.

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