阅读说明：本技术 数字式万用表自动化校准装置 (Automatic calibrating device of digital multimeter ) 是由 何慧 李宗昆 杨水旺 于 2019-08-20 设计创作，主要内容包括：本发明涉及电学计量技术领域,公开了一种数字式万用表自动化校准装置。该装置包括：控制器,用于输出控制校准源产生标准信号的第一指令和控制切换单元在数字式万用表的不同通路之间切换的第二指令；校准源,用于根据第一指令产生对应的标准信号；切换单元,用于根据第二指令切换至对应的通路并将校准源产生的标准信号传输至所切换的通路,以便数字式万用表执行测量；图像采集单元,与控制器连接,用于采集数字式万用表的读数图像并输出读数图像至控制器；控制器还用于对读数图像进行识别得到数字式万用表的读数,根据得到的读数计算误差,并根据所计算的误差判断数字式万用表是否超差。由此,可以实现对数字万用表的全自动校准。(The invention relates to the technical field of electrical measurement and discloses an automatic calibration device of a digital multimeter. The device includes: the controller is used for outputting a first instruction for controlling the calibration source to generate the standard signal and a second instruction for controlling the switching unit to switch among different channels of the digital multimeter; the calibration source is used for generating a corresponding standard signal according to the first instruction; the switching unit is used for switching to a corresponding channel according to a second instruction and transmitting a standard signal generated by the calibration source to the switched channel so that the digital multimeter can perform measurement; the image acquisition unit is connected with the controller and is used for acquiring a reading image of the digital multimeter and outputting the reading image to the controller; the controller is also used for identifying the reading image to obtain the reading of the digital multimeter, calculating an error according to the obtained reading, and judging whether the digital multimeter is out of tolerance or not according to the calculated error. Therefore, the full-automatic calibration of the digital multimeter can be realized.)

1. An automatic calibration device of a digital multimeter, the device comprising:

the controller is used for outputting a first instruction for controlling the calibration source to generate the standard signal and a second instruction for controlling the switching unit to switch among different channels of the digital multimeter;

the calibration source is connected with the controller and used for generating a corresponding standard signal according to the first instruction;

the switching unit is connected with the calibration source and the controller and used for switching to a corresponding channel according to the second instruction and transmitting a standard signal generated by the calibration source to the switched channel so that the digital multimeter can perform measurement;

the image acquisition unit is connected with the controller and used for acquiring a reading image of the digital multimeter and outputting the reading image to the controller;

the controller is further used for identifying the reading image to obtain the reading of the digital multimeter, calculating an error according to the obtained reading, and judging whether the digital multimeter is out of tolerance or not according to the calculated error.

2. The apparatus of claim 1, wherein the controller calculates an error based on the obtained readings and determining whether the error is out of tolerance based on the calculated error comprises:

calculating an error based on the obtained reading and the generated calibration signal;

comparing the calculated error to an error threshold range;

under the condition that the calculated error is within the error threshold range, judging that the digital multimeter is not out of tolerance;

and judging that the digital multimeter is out of tolerance when the calculated error exceeds the error threshold range.

3. The apparatus of claim 2, wherein the image capture unit comprises a lens and an industrial camera.

4. The apparatus of claim 3, further comprising a pan/tilt head, wherein the image capture unit is disposed on the pan/tilt head.

5. The apparatus of claim 4, wherein the image capture unit communicates with the controller via a LAN port.

6. The apparatus of claim 1, further comprising a storage unit for storing the reading and the determination result obtained by the recognition.

7. The device according to any one of claims 1-6, wherein the switching unit is a relay.

8. The device of any one of claims 1-6, further comprising a multimeter calibration fixture for setting up the digital multimeter.

9. The device of any one of claims 1-6, further comprising a human-machine interface.

Technical Field

The invention relates to the technical field of electrical measurement, in particular to an automatic calibration device for a digital multimeter.

Background

The digital multimeter is widely applied to various fields of scientific research and production due to low price and simple use. In order to ensure that the quantity value transmission is accurate and reliable, the digital multimeter must be regularly calibrated according to the requirements of national and industrial regulation specifications.

In daily electrical metering calibration work, multimeters (handheld digital multimeters) are the most numerous. A single multimeter generally has the functions of measuring direct-current voltage, alternating-current voltage, direct current, alternating current and resistance, and partial multimeters also have the functions of measuring frequency, capacitance and the like. The multimeter comprises a plurality of measuring ranges under each function, a plurality of calibration points under each measuring range, and the technical indexes of the measuring ranges are different. Because the universal meter does not have a program control interface, the conventional universal meter can only be used for manual metering, manual reading and counting are easy to make mistakes, the error calculation amount is large, the labor intensity of personnel is high, the calibration time is long, and the working efficiency is low.

Disclosure of Invention

The invention provides an automatic calibration device for a digital multimeter, which can solve the technical problems of large error calculation amount, easy error counting, low working efficiency and the like in the prior art.

The invention provides an automatic calibration device of a digital multimeter, wherein the device comprises:

the controller is used for outputting a first instruction for controlling the calibration source to generate the standard signal and a second instruction for controlling the switching unit to switch among different channels of the digital multimeter;

the calibration source is connected with the controller and used for generating a corresponding standard signal according to the first instruction;

a switching unit, connected to the calibration source and the controller, for switching to a corresponding path according to the second instruction and transmitting a standard signal generated by the calibration source to the switched path, so that the digital multimeter can perform measurement (i.e., the switching unit is also connected to the digital multimeter to be measured);

the image acquisition unit is connected with the controller and used for acquiring a reading image of the digital multimeter and outputting the reading image to the controller;

the controller is further used for identifying the reading image to obtain the reading of the digital multimeter, calculating an error according to the obtained reading, and judging whether the digital multimeter is out of tolerance or not according to the calculated error.

Preferably, the controller calculates an error based on the obtained readings, and determining whether the error is out of tolerance based on the calculated error comprises:

calculating an error based on the obtained reading and the generated calibration signal;

comparing the calculated error to an error threshold range;

under the condition that the calculated error is within the error threshold range, judging that the digital multimeter is not out of tolerance;

and judging that the digital multimeter is out of tolerance when the calculated error exceeds the error threshold range.

Preferably, the image acquisition unit comprises a lens and an industrial camera.

Preferably, the device further comprises a holder, and the image acquisition unit is arranged on the holder.

Preferably, the image acquisition unit communicates with the controller through a LAN port.

Preferably, the device further comprises a storage unit for storing the reading obtained by identification and the judgment result.

Preferably, the switching unit is a relay.

Preferably, the device further comprises a universal meter calibration tool used for setting the digital universal meter.

Preferably, the device further comprises a human-computer interaction interface.

Through the technical scheme, a first instruction for controlling the calibration source to generate the standard signal and a second instruction for controlling the switching unit to switch among different channels of the digital multimeter can be output through the controller, the calibration source can generate the corresponding standard signal according to the first instruction, the switching unit can switch to the corresponding channel according to the second instruction and transmit the standard signal generated by the calibration source to the switched channel so as to facilitate the digital multimeter to execute measurement, and the image acquisition unit can acquire a reading image (i.e. a measurement result image) of the digital multimeter and output the reading image to the controller, the controller can obtain the reading of the digital multimeter by identifying the reading image, and calculating an error according to the obtained reading, and judging whether the digital multimeter is out of tolerance or not according to the calculated error. Therefore, the full-automatic calibration of the digital multimeter can be realized. In addition, the device has an automatic reading function, can eliminate gross errors caused by manual reading and inaccurate counting, further ensures the calibration quality, greatly improves the working efficiency, and has the advantages of strong universality, high automation degree, strong self-adaptive capacity, high accuracy and high efficiency.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

FIG. 1 is a block diagram of an apparatus for automated calibration of a digital multimeter according to an embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. 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. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. 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 is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

FIG. 1 is a block diagram of an apparatus for automated calibration of a digital multimeter according to an embodiment of the present invention.

As shown in FIG. 1, an embodiment of the present invention provides an automatic calibration apparatus for a digital multimeter, wherein the apparatus comprises:

a controller 10 for outputting a first instruction for controlling a calibration source 12 to generate a standard signal and a second instruction for controlling a switching unit 14 to switch between different channels (channels) of the digital multimeter 16;

for example, the first instruction and the second instruction (i.e., control signals) may be output after the controller 10 receives a "start calibration" command.

A calibration source 12 connected to the controller 10 for generating a corresponding standard signal (electrical signal) according to the first instruction;

a switching unit 14, connected to the calibration source 12 and the controller 10, for switching to a corresponding path according to the second instruction and transmitting a standard signal generated by the calibration source 12 to the switched path, so that the digital multimeter 16 performs measurement;

that is, after the switching unit 14 switches on the corresponding path through the switching operation, the standard signal may be transmitted to the corresponding path of the tested multimeter through the switching unit 14 for measurement.

An image acquisition unit 18 connected to the controller 10, for acquiring a reading image (i.e., measurement result image data) of the digital multimeter and outputting the reading image to the controller 10;

the controller 10 is further configured to identify the reading image to obtain a reading of the digital multimeter, calculate an error according to the obtained reading, and determine whether the digital multimeter is out of tolerance according to the calculated error.

Through the technical scheme, a first instruction for controlling the calibration source to generate the standard signal and a second instruction for controlling the switching unit to switch among different channels of the digital multimeter can be output through the controller, the calibration source can generate the corresponding standard signal according to the first instruction, the switching unit can switch to the corresponding channel according to the second instruction and transmit the standard signal generated by the calibration source to the switched channel so as to facilitate the digital multimeter to execute measurement, and the image acquisition unit can acquire a reading image (i.e. a measurement result image) of the digital multimeter and output the reading image to the controller, the controller can obtain the reading of the digital multimeter by identifying the reading image, and calculating an error according to the obtained reading, and judging whether the digital multimeter is out of tolerance or not according to the calculated error. Therefore, the full-automatic calibration of the digital multimeter can be realized. In addition, the device has an automatic reading function, can eliminate gross errors caused by manual reading and inaccurate counting, further ensures the calibration quality, greatly improves the working efficiency, and has the advantages of strong universality, high automation degree, strong self-adaptive capacity, high accuracy and high efficiency.

The digital multimeter can include a Liquid Crystal Display (LCD) through which the multimeter readings (measurements) can be displayed.

According to one embodiment of the present invention, the controller 10 calculates an error based on the obtained readings, and determining whether the error is out of tolerance based on the calculated error comprises:

calculating an error based on the obtained reading and the generated calibration signal;

comparing the calculated error to an error threshold range;

under the condition that the calculated error is within the error threshold range, judging that the digital multimeter is not out of tolerance;

and judging that the digital multimeter is out of tolerance when the calculated error exceeds the error threshold range.

According to one embodiment of the present invention, the image capture unit 18 may include a lens and an industrial camera.

According to an embodiment of the present invention, the apparatus further comprises a cradle head, on which the image acquisition unit 18 may be arranged.

The position of the four degrees of freedom can be adjusted through the cradle head, so that the universal meter image is in the visual field of the image lens.

According to one embodiment of the invention, the image acquisition unit communicates with the controller 10 via a LAN port.

According to an embodiment of the present invention, the apparatus further includes a storage unit for storing the reading obtained by the identification and the determination result.

In other words, the controller may output the identified readings (multimeter measurements) and calibration records (determinations) to the memory unit for storage.

According to an embodiment of the invention, the switching unit is a relay.

For example, the number of relays may be one or more. The specific number can be determined according to the model of the digital multimeter, and the invention is not limited to this.

According to one embodiment of the invention, the device further comprises a universal meter calibration tool used for setting the digital universal meter.

According to an embodiment of the invention, the device may further comprise a human-machine interface.

Through the man-machine interaction interface, information such as the model, the factory number, the manufacturer, the certificate unit, the calibration date and the calibration place of the tested multimeter can be input, then a calibration item can be selected, and the automatic calibration process of the multimeter can be started.

In the embodiment of the present invention, for example, the controller 10 may be a PXI controller, and the PXI controller may be disposed in a corresponding chassis; the tested digital multimeter model may be 189 a manufactured by FLUKE, usa, and the calibration source model may be 5520A manufactured by FLUKE, usa.

It will be appreciated by persons skilled in the art that the foregoing description of the various components is merely exemplary and not intended to limit the present invention.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and in the case of not making a reverse description, these orientation words do not indicate and imply that the device or element being referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be considered as limiting the scope of the present invention; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.