CN213423324U - Milliohm-level precision resistance measurement module - Google Patents
Milliohm-level precision resistance measurement module Download PDFInfo
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- CN213423324U CN213423324U CN202022484305.8U CN202022484305U CN213423324U CN 213423324 U CN213423324 U CN 213423324U CN 202022484305 U CN202022484305 U CN 202022484305U CN 213423324 U CN213423324 U CN 213423324U
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Abstract
The utility model discloses a milliohm level precision resistance measuring module, which comprises a resistance to be measured, a precision constant current source circuit, a signal amplifying circuit, an output amplitude limiting protection circuit and a noise processing circuit, wherein the noise processing circuit is arranged between the signal amplifying circuit and the output amplitude limiting protection circuit; the utility model discloses voltage difference signal to the resistance to be measured both ends is amplified, is fallen noise processing and amplitude limiting output, obtains the voltage signal who satisfies the collection condition at last. The utility model discloses have extensive suitability in the aspect of the precision resistance measurement, only contain the snatching of voltage signal, enlarge and the function of filtering noise, integration in any system that can be convenient, the measuring range is 0-100m omega.
Description
Technical Field
The utility model relates to an accurate resistance measurement, concretely relates to accurate resistance measurement module of milliohm level.
Background
The existing precision resistance measuring module is integrated with the functions of storage, display and communication, and has no independent measuring module which can directly meet the requirement of an acquisition card on input signals. Moreover, the problem of noise interference is particularly prominent because the signal to be measured is very tiny. Therefore, a milliohm-level precision resistance measurement module is required to be developed according to the input signal requirement of the data acquisition card, so that the milliohm-level precision resistance measurement module can directly acquire data, and the problems are solved.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that develop a precise resistance measurement module of milliohm level, but the exclusive use just directly satisfies the acquisition card input signal requirement, this module need enlarge and filtering noise small signal, solve the problem that does not directly be used for satisfying the measurement module of acquisition card input signal requirement.
The utility model discloses a following technical scheme realizes:
a milliohm-level precision resistance measuring module comprises a resistance to be measured, a precision constant current source circuit, a signal amplification circuit and an output amplitude limiting protection circuit, and is characterized by further comprising a noise processing circuit, wherein the noise processing circuit is arranged between the signal amplification circuit and the output amplitude limiting protection circuit, one end of the noise processing circuit is connected with the signal amplification circuit, and the other end of the noise processing circuit is connected with the output amplitude limiting protection circuit; the precise constant current source circuit is connected to two ends of the resistor to be tested and used for providing constant current; the signal amplification circuit is connected to two ends of the resistor to be detected and used for amplifying voltage difference signals at two ends of the resistor to be detected to obtain amplified voltage signals; the noise processing circuit performs noise reduction processing on the amplified voltage signal to obtain a noise-reduced voltage signal; and the output amplitude limiting protection circuit carries out amplitude limiting on the voltage signal subjected to noise reduction and outputs a voltage signal meeting the acquisition condition. The high-precision constant current source circuit can still keep the output current constant when the external power grid power supply fluctuates and the impedance characteristic changes, has the characteristics of constant output current, good temperature stability, small direct current resistance, large equivalent alternating current output resistance and the like, and provides a stable current for the whole circuit to ensure the stable work of other circuit modules.
The precision resistance measuring module in the prior art is integrated with the functions of storage, display and communication, and has no independent measuring module which can directly meet the requirement of an acquisition card on input signals. And because the voltage difference signal at the resistance both ends that await measuring is very little, except the voltage difference signal of the resistance itself that awaits measuring in these small signals, the high frequency interference signal that brings because of electromagnetism and vibration in the environment in addition, these interference signal can make the collection card can't directly gather the voltage signal of resistance, for true, accurate and stable of the signal that awaits measuring that makes the collection the utility model designs a noise processing circuit for filtering high frequency interference signal has promoted the proportion of effective signal, makes the signal that data acquisition card gathered more accurate.
Further preferably, the noise processing circuit comprises a resistor R1 and a capacitor C1, and the resistor R1 and the capacitor C1 are connected in series. The reason is that high-frequency noise is generated in the amplifying circuit due to the existence of electromagnetism, vibration and the like in the amplifying process, in order to filter the high-frequency noise generated in the amplifying process, the resistor R1 and the capacitor C1 are connected in series to form a noise processing circuit, the resistor R1 has the function of current limiting, and the capacitor C1 is used for filtering high-frequency noise signals in the amplified voltage signals and keeping effective signals. After passing through the noise processing circuit, the occupation ratio of effective signals is improved, and the signals acquired by the data acquisition card are more accurate and stable.
Preferably, in order to filter the high-frequency interference signal and prevent the high-frequency interference signal from entering an amplification link, a capacitor C2 is connected, and the capacitor C2 is in short circuit between the signal amplification circuit and the resistor to be detected.
Preferably, the signal amplifying circuit comprises a differential amplifying module, a signal following module and a proportional amplifying module, wherein the differential amplifying module is used for amplifying differential mode signals in voltage difference signals at two ends of the resistor to be detected, and suppressing common mode signals therein to obtain differentially amplified voltage signals; the signal following module is used for improving the load carrying capacity of the circuit, amplifying power and keeping the voltage signal of differential amplification unchanged; the proportional amplification module is used for amplifying the voltage signal subjected to differential amplification in proportion to obtain an amplified voltage signal.
Preferably, the differential amplification module, the signal following module and the proportional amplification module in the amplification circuit are all based on an integrated operational amplifier circuit, because the input signals of the acquisition card are all low-frequency signals, when the signals are amplified, a direct coupling amplification circuit is needed for amplification, and the direct coupling connection mode has good low-frequency characteristics and is easy to manufacture into an integrated circuit. The common direct-coupled amplifying circuit has a zero drift phenomenon, while the differential amplifying circuit is a direct-coupled amplifying circuit, and the differential circuit has good electrical symmetry, so that the differential circuit has a good inhibition effect on common-mode signals and can effectively inhibit the zero drift phenomenon. The differential amplifier circuit has two basic input signals of a differential mode and a common mode, and is called as a differential mode input signal when signals connected with two input ends are equal in size and opposite in polarity due to the symmetry of the circuit; when the signals connected to the two input terminals are equal in magnitude and same in polarity, the signals are called common mode signals. The signal to be amplified is input as a differential mode signal, and the influence of environmental factors such as temperature on the circuit is input as a common mode signal, so that the differential mode signal is amplified and the common mode signal is suppressed. The signal follower circuit keeps the signal unchanged, improves the load capacity and plays a role in buffering and isolation.
Preferably, the milliohm-level precision resistance measurement module is a measurement module which is independently used and directly outputs signals meeting the requirements of an acquisition card.
Further preferably, the milliohm-level precision resistance measurement module only has the functions of amplifying the voltage signal and filtering noise in the voltage signal, so that the milliohm-level precision resistance measurement module can be applied to any data acquisition system, and the measurement range of the milliohm-level precision resistance measurement module is 0-100m omega.
Compared with the prior art, the utility model, following advantage and beneficial effect have:
the utility model relates to a milliohm level precision resistance measurement module is solitary module that can be used to resistance measurement to noise interference has been handled. The utility model discloses have extensive suitability in the aspect of the accurate resistance measurement, integration in any system that can be convenient. The milliohm-level precision resistance measurement module only has the functions of amplifying the input tiny voltage signal and filtering high-frequency noise in the tiny voltage signal, and is suitable for being directly used by any data acquisition system, and the measurement range of the measured resistance is 0-100m omega. The utility model discloses when measuring milliohm level resistance, have simulation small-signal input, enlargies, noise treatment and signal output's function. The module has perfect functions, has strong adaptability with any data acquisition system, and is convenient for users to use in any customized data acquisition system.
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 application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
fig. 1 is a schematic view of the structure of the present invention.
Detailed Description
To make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following examples and drawings, and the exemplary embodiments and descriptions thereof of the present invention are only used for explaining the present invention, and are not intended as limitations of the present invention.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that: it is not necessary to employ these specific details to practice the present invention. In other instances, well-known structures, circuits, materials, or methods have not been described in detail so as not to obscure the present invention.
Throughout the specification, reference to "one embodiment," "an embodiment," "one example," or "an example" means: the particular features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment of the invention. Thus, the appearances of the phrases "one embodiment," "an embodiment," "one example" or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and/or sub-combination in one or more embodiments or examples. Further, those of ordinary skill in the art will appreciate that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
In the description of the present invention, the terms "front", "back", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the scope of the present invention.
Example 1
As shown in fig. 1, a milliohm-level precision resistor measuring module includes a resistor to be measured, a precision constant current source circuit, a signal amplification circuit, an output amplitude limiting protection circuit, and a noise processing circuit, where the noise processing circuit is disposed between the signal amplification circuit and the output amplitude limiting protection circuit, one end of the noise processing circuit is connected to the signal amplification circuit, and the other end is connected to the output amplitude limiting protection circuit; the precise constant current source circuit is connected to two ends of the resistor to be tested and used for providing constant current; the signal amplification circuit is connected to two ends of the resistor to be detected and used for amplifying voltage difference signals at two ends of the resistor to be detected to obtain amplified voltage signals; the noise processing circuit performs noise reduction processing on the amplified voltage signal to obtain a noise-reduced voltage signal; and the output amplitude limiting protection circuit carries out amplitude limiting on the voltage signal subjected to noise reduction and outputs a voltage signal meeting the acquisition condition. The high-precision constant current source circuit can still keep the output current constant when the external power grid power supply fluctuates and the impedance characteristic changes, has the characteristics of constant output current, good temperature stability, small direct current resistance, large equivalent alternating current output resistance and the like, and provides a stable current for the whole circuit to ensure the stable work of other circuit modules.
The precision resistance measuring module in the prior art is integrated with the functions of storage, display and communication, and has no independent measuring module which can directly meet the requirement of an acquisition card on input signals. And because the voltage difference signal at the resistance both ends that await measuring is very little, except the voltage difference signal of the resistance itself that awaits measuring in these small signals, the high frequency interference signal that brings because of electromagnetism and vibration in the environment in addition, these interference signal can make the collection card can't directly gather the voltage signal of resistance, for true, accurate and stable of the signal that awaits measuring that makes the collection the utility model designs a noise processing circuit for filtering high frequency interference signal has promoted the proportion of effective signal, makes the signal that data acquisition card gathered more accurate.
Specifically, the noise processing circuit comprises a resistor R1 and a capacitor C1, wherein the resistor R1 and the capacitor C1 are connected in series. The reason is that high-frequency noise is generated in the amplifying circuit due to the existence of electromagnetism, vibration and the like in the amplifying process, in order to filter the high-frequency noise generated in the amplifying process, the resistor R1 and the capacitor C1 are connected in series to form a noise processing circuit, the resistor R1 has the function of current limiting, and the capacitor C1 is used for filtering high-frequency noise signals in the amplified voltage signals and keeping effective signals. After passing through the noise processing circuit, the occupation ratio of effective signals is improved, and the signals acquired by the data acquisition card are more accurate and stable.
In order to filter out high-frequency interference signals and enable the high-frequency interference signals not to enter an amplification link, a capacitor C2 is connected into a circuit, and the capacitor C2 is in short circuit between the signal amplification circuit and a resistor to be detected.
Specifically, the differential amplification module, the signal following module and the proportional amplification module in the amplification circuit are all based on an integrated operational amplification circuit, because the input signals of the acquisition card are all low-frequency signals, when the signals are amplified, a direct coupling amplification circuit is needed for amplification, and the direct coupling connection mode has good low-frequency characteristics and is easy to manufacture into an integrated circuit. The common direct-coupled amplifying circuit has a zero drift phenomenon, while the differential amplifying circuit is a direct-coupled amplifying circuit, and the differential circuit has good electrical symmetry, so that the differential circuit has a good inhibition effect on common-mode signals and can effectively inhibit the zero drift phenomenon. The differential amplifier circuit has two basic input signals of a differential mode and a common mode, and is called as a differential mode input signal when signals connected with two input ends are equal in size and opposite in polarity due to the symmetry of the circuit; when the signals connected to the two input terminals are equal in magnitude and same in polarity, the signals are called common mode signals. The signal to be amplified is input as a differential mode signal, and the influence of environmental factors such as temperature on the circuit is input as a common mode signal, so that the differential mode signal is amplified and the common mode signal is suppressed. The signal follower circuit keeps the signal unchanged, improves the load capacity and plays a role in buffering and isolation.
In practical operation, the milliohm-level precision resistance measurement module is a measurement module which is independently used and directly outputs signals meeting the requirements of an acquisition card input signal.
In addition, the milliohm-level precision resistance measurement module only has the functions of amplifying the voltage signal and filtering noise in the voltage signal, so that the milliohm-level precision resistance measurement module can be applied to any data acquisition system, and the measurement range of the milliohm-level precision resistance measurement module is 0-100m omega.
It can be understood that the utility model relates to a precision resistance measurement module of milliohm level can be used for resistance measurement module alone when in actual use to handle noise interference. The method has wide applicability in the aspect of precision resistance measurement, and can be conveniently integrated in any system. Because the module only has the functions of amplifying the input tiny voltage signal and filtering noise in the tiny voltage signal, the module is suitable for any data acquisition system to be directly used, and the measuring range is 0-100m omega. The utility model discloses when measuring milliohm level resistance, have simulation small-signal input, enlarge, noise treatment and signal output's function, the module function is perfect, has very strong adaptability with any data acquisition system, and convenience of customers is used for any customization data acquisition system.
The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above description is only the embodiments of the present invention, and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. A milliohm-level precision resistance measuring module comprises a resistance to be measured, a precision constant current source circuit, a signal amplification circuit and an output amplitude limiting protection circuit, and is characterized by further comprising a noise processing circuit, wherein the noise processing circuit is arranged between the signal amplification circuit and the output amplitude limiting protection circuit, one end of the noise processing circuit is connected with the signal amplification circuit, and the other end of the noise processing circuit is connected with the output amplitude limiting protection circuit;
the precise constant current source circuit is connected to two ends of the resistor to be tested and used for providing constant current;
the signal amplification circuit is connected to two ends of the resistor to be detected and used for amplifying voltage difference signals at two ends of the resistor to be detected to obtain amplified voltage signals;
the noise processing circuit performs noise reduction processing on the amplified voltage signal to obtain a noise-reduced voltage signal;
and the output amplitude limiting protection circuit carries out amplitude limiting on the voltage signal subjected to noise reduction and outputs a voltage signal meeting the acquisition condition.
2. A milliohm-scale precision resistance measurement module as claimed in claim 1, wherein the noise processing circuit includes a resistor R1 and a capacitor C1, the resistor R1 and the capacitor C1 being connected in series.
3. A milliohm-scale precision resistance measurement module as claimed in claim 1, further comprising a capacitor C2, wherein the capacitor C2 is shorted between the signal amplification circuit and the resistor to be measured.
4. A milliohm-level precision resistance measurement module according to claim 1, wherein the signal amplification circuit includes a differential amplification module, a signal following module and a proportional amplification module, the differential amplification module is configured to amplify a differential mode signal in a voltage difference signal at two ends of the resistor to be measured, and suppress a common mode signal therein to obtain a differentially amplified voltage signal; the signal following module is used for improving the load carrying capacity of the circuit and keeping the voltage signal of differential amplification unchanged; the proportional amplification module is used for amplifying the voltage signal subjected to differential amplification in proportion to obtain an amplified voltage signal.
5. A milliohm-level precision resistance measurement module as claimed in claim 1, wherein the differential amplification module, the signal following module and the proportional amplification module in the signal amplification circuit are all based on an integrated operational amplifier circuit.
6. A milliohm-scale precision resistance measurement module as claimed in claim 1, wherein the milliohm-scale precision resistance measurement module is a measurement module that is used alone and directly outputs the input signal that meets the requirements of the acquisition card.
7. A milliohm-level precision resistance measurement module according to claim 1, wherein the milliohm-level precision resistance measurement module is applied to any data acquisition system, and the measurement range is 0-100m Ω.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202022484305.8U CN213423324U (en) | 2020-10-30 | 2020-10-30 | Milliohm-level precision resistance measurement module |
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| CN202022484305.8U CN213423324U (en) | 2020-10-30 | 2020-10-30 | Milliohm-level precision resistance measurement module |
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| CN213423324U true CN213423324U (en) | 2021-06-11 |
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| CN202022484305.8U Active CN213423324U (en) | 2020-10-30 | 2020-10-30 | Milliohm-level precision resistance measurement module |
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