CN114546012A - Amplifier-based adjustable voltage-current conversion circuit and signal acquisition system - Google Patents
Amplifier-based adjustable voltage-current conversion circuit and signal acquisition system Download PDFInfo
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- CN114546012A CN114546012A CN202210086993.3A CN202210086993A CN114546012A CN 114546012 A CN114546012 A CN 114546012A CN 202210086993 A CN202210086993 A CN 202210086993A CN 114546012 A CN114546012 A CN 114546012A
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/561—Voltage to current converters
Abstract
The invention relates to an amplifier-based adjustable voltage-current conversion circuit and a signal acquisition system; the adjustable voltage-current conversion circuit comprises an inverting amplifier, an inverter and an isolation transmitter which are sequentially connected, wherein the inverting amplifier comprises a first resistor, a first operational amplifier and a potentiometer, one end of the first resistor is used for being externally connected with a voltage signal input, and the other end of the first resistor is connected with an inverting input end of the first operational amplifier; one end of the potentiometer is connected with the reverse input end of the first operational amplifier, and the other end of the potentiometer is connected with the output end of the first operational amplifier; the output end of the first operational amplifier is also connected with the input of the phase inverter; the magnitude of the voltage signal output by the first operational amplifier is adjusted by changing the resistance value of the potentiometer, and the magnitude of the current output by the output signal end of the isolation transmitter is adjusted. The invention changes the resistance value of the potentiometer, correspondingly, the current signal output by the isolation transmitter is changed, the current output of 0-20mA can be realized, the output range of the current is expanded, and the adjustable voltage-current conversion function is realized.
Description
Technical Field
The invention belongs to the technical field of industrial measurement and control, and particularly relates to an amplifier-based voltage-adjustable current conversion circuit and a signal acquisition system.
Background
With the development of industrial technology, various signals need to be transmitted in industrial applications. For example, various non-electrical physical quantities measured in industry, such as speed, pressure, temperature, etc., need to be detected by sensors and converted into analog signals for remote transmission to a remote control room or display device. At present, a lot of signal transmission methods are adopted to transmit analog signals through current, because signals transmitted by using voltage are attenuated and easily interfered, and signals transmitted by current are not attenuated due to long distance.
Sensors and meters in the industrial field mostly adopt 4-20mA current to transmit analog quantity signals, and a 4-20mA current output circuit is a constant current source circuit. Generally, the input of the circuit is a voltage signal, and the output is a current signal, for example, a 4-20mA current isolation output circuit disclosed in CN112003481A, which obtains the final output current according to the set input voltage and the resistance of the current sampling resistor, and only adjusts the input voltage, the magnitude of the output current can be adjusted. However, for the single chip microcomputer, it can only output 0V or 3.3V, and for the above-mentioned 4-20mA current isolation output circuit, it is unable to adjust the output current.
Disclosure of Invention
Based on the above-mentioned shortcomings and drawbacks of the prior art, it is an object of the present invention to provide an amplifier-based adjustable voltage-to-current conversion circuit and signal acquisition system that meet the aforementioned needs.
In order to achieve the purpose, the invention adopts the following technical scheme:
the adjustable voltage-current conversion circuit based on the amplifier comprises an inverting amplifier, an inverter and an isolation transmitter which are sequentially connected, wherein the inverting amplifier comprises a first resistor, a first operational amplifier and a potentiometer, one end of the first resistor is used for inputting an external voltage signal, and the other end of the first resistor is connected with the inverting input end of the first operational amplifier; one end of the potentiometer is connected with the reverse input end of the first operational amplifier, and the other end of the potentiometer is connected with the output end of the first operational amplifier; the output end of the first operational amplifier is also connected with the input of the phase inverter;
the magnitude of the voltage signal output by the first operational amplifier is adjusted by changing the resistance value of the potentiometer, and the magnitude of the current output by the output signal end of the isolation transmitter is adjusted.
As a preferred scheme, the phase inverter comprises a second resistor, a second operational amplifier and a third resistor, wherein one end of the second resistor is connected with the output end of the first operational amplifier, and the other end of the second resistor is connected with the inverting input end of the second operational amplifier; one end of the third resistor is connected with the reverse input end of the second operational amplifier, and the other end of the third resistor is connected with the output end of the second operational amplifier; the output end of the second operational amplifier is also connected with the input signal end of the isolation transmitter;
and the resistance values of the second resistor and the third resistor are equal.
Preferably, the negative voltage signal output by the output terminal of the first operational amplifier is:
wherein R is1And R2The resistance values of the first resistor and the potentiometer are respectively-inverse phase, U0The voltage value is the voltage value of the external voltage signal;
the positive voltage signal output by the output end of the second operational amplifier is as follows:
wherein R is3And R4Respectively a second resistor and a third resistorThe resistance value of the resistor.
Preferably, the current output by the output signal end of the isolation transmitter is in a proportional relation with the voltage output by the input signal end of the isolation transmitter.
As a preferred scheme, the output voltage range of an input signal end of the isolation transmitter is 0-5V.
As a preferred scheme, the output current range of an output signal end of the isolation transmitter is 0-20 mA.
Preferably, the positive voltage signal output by the output end of the second operational amplifier does not exceed 5V.
Preferably, the isolation transmitter is of the type TF 6234N.
The invention also provides a signal acquisition system which comprises the single chip microcomputer, a power supply module and the voltage and current adjustable conversion circuit, wherein the power supply module is used for supplying power to the single chip microcomputer and the voltage and current adjustable conversion circuit, and the single chip microcomputer is used for providing an external voltage signal.
As a preferred scheme, the single chip microcomputer outputs 0V or 3.3V.
Compared with the prior art, the invention has the beneficial effects that:
according to the adjustable voltage-current conversion circuit, by changing the resistance value of the potentiometer, correspondingly, the negative voltage signal output by the first operational amplifier, the positive voltage signal output by the second operational amplifier and the current signal output by the isolation transmitter are changed, so that the current output of 0-20mA can be realized, the output range of the current is expanded, and the adjustable voltage-current conversion function is realized.
The signal acquisition system can select corresponding current output according to the type of the signal, and has strong applicability.
Drawings
Fig. 1 is a schematic circuit diagram of an adjustable voltage-to-current conversion circuit according to embodiment 1 of the present invention;
fig. 2 is a configuration diagram of a signal acquisition system according to embodiment 1 of the present invention.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention, the following description will explain the embodiments of the present invention with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.
Example 1:
as shown in fig. 1, the adjustable voltage-current converting circuit based on an amplifier of the present embodiment includes an inverting amplifier, an inverter and an isolation transformer, which are connected in sequence.
Specifically, the inverting amplifier comprises a resistor R1, a first operational amplifier U1 and a potentiometer R2, wherein one end of the resistor R1 is used for inputting an external voltage signal IN, and the other end of the resistor R1 is connected with an inverting input end of the first operational amplifier U1; one end of the potentiometer R2 is connected with the reverse input end of the first operational amplifier U1, and the other end of the potentiometer R2 is connected with the output end of the first operational amplifier U1; the non-inverting input terminal of the first operational amplifier U1 is grounded, and the output terminal of the first operational amplifier U1 is connected to the input of the inverter. The voltage signal output by the output end of the first operational amplifier U1 can be adjusted by changing the resistance value of the potentiometer R2, and the current output by the output signal end of the isolation transmitter U3 can be adjusted.
The voltage of the negative voltage signal a1 output by the output terminal of the first operational amplifier U1 in this embodiment is:
wherein R is1And R2The resistance values of the resistor R1 and the potentiometer R2 are respectively, the-is the inverse phase, and the U is0Is the voltage value of the external voltage signal IN.
The inverter of the embodiment comprises a resistor R3, a second operational amplifier U2 and a resistor R4, wherein one end of the resistor R3 is connected with the output end of the first operational amplifier U1, and the other end of the resistor R3 is connected with the inverting input end of the second operational amplifier U2; one end of the resistor R4 is connected with the reverse input end of the second operational amplifier U2, and the other end of the resistor R4 is connected with the output end of the second operational amplifier U2; the non-inverting input terminal of the second operational amplifier U2 is grounded, and the output terminal of the second operational amplifier U2 is also connected to the input signal terminal of the isolation transmitter U3. And the resistance values of the second resistor and the third resistor are equal, and the reverse phase is realized.
The voltage of the positive voltage signal a2 output by the output terminal of the second operational amplifier U2 in this embodiment is:
wherein R is3And R4Respectively, the resistance values of the resistor R3 and the resistor R4.
The type of the isolation transmitter of the embodiment is TF6234N, and the current output by the output signal terminal of the isolation transmitter is in a proportional relationship with the voltage output by the input signal terminal of the isolation transmitter:
Aout＝k*U2 (3)
where k is a scaling factor, for example, k is 4, and is specifically determined according to the actual application requirement.
The principle of the adjustable voltage-current conversion circuit of the embodiment is as follows:
the resistor R1, the first operational amplifier U1 and the potentiometer R2 form an inverting proportional amplifier (i.e. an inverting amplifier), and the relational expression between the negative voltage signal A1 output by the inverting amplifier and the external voltage signal IN is shown IN the formula (1); IN the inverting amplifier, the resistance value of the potentiometer R2 is changed arbitrarily, the resistance value of the potentiometer R2 can be changed according to the actual application requirement, and as the resistance value of the potentiometer R2 is changed, the first operational amplifier U1 can output a negative voltage signal a1 which is larger or smaller than the input external voltage signal IN;
in addition, the resistor R3, the resistor R4 and the second operational amplifier U2 form an inverter, and it can be known from the above formula (2) that the resistances of the resistor R3 and the resistor R4 need to be equal to each other to perform an inversion function, and the phase of the negative voltage signal a1 is inverted by 180 degrees to become a positive voltage signal, and the value remains unchanged, so that the resistances of the resistor R3 and the resistor R4 are equal;
the positive voltage signal A2 output by the second operational amplifier U2 is transmitted to the isolation transmitter U3, and the voltage signal is converted into a current signal to be output through the isolation transmitter U3. The output voltage range of the input signal end of the isolation transmitter U3 is 0-5V, the output current range of the output signal end is 0-20mA, the current value output by the output signal end and the voltage output by the input signal end are in a proportional relation, and the proportional relation is shown in the formula (3). In addition, it should be noted that the voltage value of the positive voltage signal a2 output by the second operational amplifier U2 does not exceed 5V.
The adjustable voltage-current conversion circuit can realize adjustable output of 0-20mA current, and the output range of the current is enlarged.
As shown in fig. 2, the present embodiment further provides a signal acquisition system, which includes a single chip, a power supply module, and the voltage-current adjustable conversion circuit of the present embodiment.
The power supply module is used for supplying power to the single chip microcomputer and the voltage-current adjustable conversion circuit; specifically, the power supply module is used for supplying power to a first operational amplifier, a second operational amplifier and an isolation transmitter in the voltage-current adjustable conversion circuit.
The singlechip is used for providing an external voltage signal; the singlechip outputs 0V or 3.3V.
The signal acquisition system of this embodiment outputs 0V or 3.3V voltage through the singlechip to carry to adjustable pressure flow converting circuit, through adjustable pressure flow converting circuit processing conversion current signal output, so that signal acquisition.
Example 2:
the difference between the adjustable voltage-current conversion circuit based on the amplifier of the present embodiment and the embodiment 1 is that:
the type of the isolation transmitter is not limited to the type disclosed in embodiment 1, and other types of isolation transmitters which are commonly used can be selected according to actual application requirements;
correspondingly, the signal acquisition system of the embodiment adopts the adjustable voltage-current conversion circuit of the embodiment;
other circuit configurations can refer to embodiment 1.
The foregoing has outlined rather broadly the preferred embodiments and principles of the present invention and it will be appreciated that those skilled in the art may devise variations of the present invention that are within the spirit and scope of the appended claims.
Claims (10)
1. The adjustable voltage-current conversion circuit based on the amplifier is characterized by comprising an inverting amplifier, an inverter and an isolation transmitter which are sequentially connected, wherein the inverting amplifier comprises a first resistor, a first operational amplifier and a potentiometer, one end of the first resistor is used for inputting an external voltage signal, and the other end of the first resistor is connected with the inverting input end of the first operational amplifier; one end of the potentiometer is connected with the reverse input end of the first operational amplifier, and the other end of the potentiometer is connected with the output end of the first operational amplifier; the output end of the first operational amplifier is also connected with the input of the phase inverter;
the magnitude of the voltage signal output by the first operational amplifier is adjusted by changing the resistance value of the potentiometer, and the magnitude of the current output by the output signal end of the isolation transmitter is adjusted.
2. The amplifier-based adjustable voltage-to-current conversion circuit according to claim 1, wherein the inverter comprises a second resistor, a second operational amplifier and a third resistor, one end of the second resistor is connected to the output end of the first operational amplifier, and the other end of the second resistor is connected to the inverting input end of the second operational amplifier; one end of the third resistor is connected with the reverse input end of the second operational amplifier, and the other end of the third resistor is connected with the output end of the second operational amplifier; the output end of the second operational amplifier is also connected with the input signal end of the isolation transmitter;
and the second resistor and the third resistor have the same resistance.
3. The amplifier-based adjustable voltage-to-current conversion circuit of claim 2, wherein the negative voltage signal output by the output terminal of the first operational amplifier is:
wherein R is1And R2The resistance values of the first resistor and the potentiometer are respectively-inverse phase, U0The voltage value is the voltage value of the external voltage signal;
the positive voltage signal output by the output end of the second operational amplifier is as follows:
wherein R is3And R4Respectively, the resistance values of the second resistor and the third resistor.
4. The amplifier-based adjustable voltage to current conversion circuit of claim 3, wherein the current output by the output signal terminal of the isolation transmitter is proportional to the voltage output by the input signal terminal of the isolation transmitter.
5. The amplifier-based adjustable voltage-to-current conversion circuit of claim 4, wherein the output voltage of the input signal end of the isolation transmitter ranges from 0V to 5V.
6. The amplifier-based adjustable voltage-to-current conversion circuit of claim 5, wherein the output signal end of the isolation transmitter outputs a current in the range of 0-20 mA.
7. The amplifier-based adjustable voltage-to-current conversion circuit of claim 5, wherein the positive voltage signal output by the output of the second operational amplifier does not exceed 5V.
8. The amplifier-based adjustable voltage to current conversion circuit of any one of claims 1-7, wherein the isolation transmitter is of type TF 6234N.
9. A signal acquisition system is characterized by comprising a single chip microcomputer, a power supply module and the voltage-current-adjustable conversion circuit as claimed in any one of claims 1 to 8, wherein the power supply module is used for supplying power to the single chip microcomputer and the voltage-current-adjustable conversion circuit, and the single chip microcomputer is used for providing an external voltage signal.
10. A signal acquisition system according to claim 9, wherein the single-chip outputs 0V or 3.3V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210086993.3A CN114546012A (en) | 2022-01-25 | 2022-01-25 | Amplifier-based adjustable voltage-current conversion circuit and signal acquisition system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210086993.3A CN114546012A (en) | 2022-01-25 | 2022-01-25 | Amplifier-based adjustable voltage-current conversion circuit and signal acquisition system |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6630817B1 (en) * | 1999-10-28 | 2003-10-07 | Bosch Rexroth Ag | Electrical circuit arrangement for converting an input voltage |
| CN203759575U (en) * | 2014-03-20 | 2014-08-06 | 宿州学院 | Numerical control direct current source |
| CN205725671U (en) * | 2016-04-07 | 2016-11-23 | 浙江绍兴苏泊尔生活电器有限公司 | Operational amplifier unit module |
| CN209559952U (en) * | 2018-11-20 | 2019-10-29 | 北京航天科达科技有限公司 | A kind of circuit detecting consistency problem for solving alternating voltage |
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2022
- 2022-01-25 CN CN202210086993.3A patent/CN114546012A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6630817B1 (en) * | 1999-10-28 | 2003-10-07 | Bosch Rexroth Ag | Electrical circuit arrangement for converting an input voltage |
| CN203759575U (en) * | 2014-03-20 | 2014-08-06 | 宿州学院 | Numerical control direct current source |
| CN205725671U (en) * | 2016-04-07 | 2016-11-23 | 浙江绍兴苏泊尔生活电器有限公司 | Operational amplifier unit module |
| CN209559952U (en) * | 2018-11-20 | 2019-10-29 | 北京航天科达科技有限公司 | A kind of circuit detecting consistency problem for solving alternating voltage |
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