CN214380867U - Digital quantity and analog quantity mixed input interface circuit - Google Patents
Digital quantity and analog quantity mixed input interface circuit Download PDFInfo
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- CN214380867U CN214380867U CN202120536360.9U CN202120536360U CN214380867U CN 214380867 U CN214380867 U CN 214380867U CN 202120536360 U CN202120536360 U CN 202120536360U CN 214380867 U CN214380867 U CN 214380867U
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Abstract
The application relates to a digital-analog hybrid input interface circuit, which comprises: analog voltage processing unit circuit, digital input unit circuit, mixed input terminal; the digital input unit circuit comprises a diode D1, an optocoupler U1, resistors R1 and R2; the cathode end of the D1 is connected with the first terminal of the hybrid input terminal, the anode end of the D1 is connected with the output end of the U1 diode side through R1, the collector end of the U1 triode side is connected with a digital power supply, and the emitter end of the U1 triode side is grounded through R2; the input end of the U1 diode side is used for connecting a switching signal end, and the emitter end is also used for connecting the digital input end of a post-stage circuit; the second terminal of the mixed input terminal is grounded, the first terminal of the mixed input terminal is also connected with the input end of the analog voltage processing unit circuit, and the output end of the analog voltage processing unit circuit is used for being connected with the analog input end of the subsequent circuit. The method and the device help to improve the flexibility and the fault tolerance of the application system, and facilitate later-stage rectification and maintenance.
Description
Technical Field
The application belongs to the technical field of circuit application, and particularly relates to a digital quantity and analog quantity mixed input interface circuit.
Background
A circuit that performs arithmetic operations and logical operations on digital quantities using digital signals is called a digital circuit. It is also called digital logic circuit because it has logic operation and logic processing functions. Modern digital circuits are constructed from several digitally integrated devices made by semiconductor processes. Logic gates are the basic units of digital logic circuits. A memory is a digital circuit used to store binary data. In general, digital circuits can be classified into combinational logic circuits and sequential logic circuits. A major problem studied in digital circuits is the logical relationship between the state of the output signal ("0" or "1") and the input signal ("0" or "1"), i.e. the logical function of the circuit. The present application relates primarily to the switch state
Analog circuitry refers to circuitry used to transmit, transform, process, amplify, measure, and display analog signals. Analog signals refer to continuously varying electrical signals. The analog circuit is the basis of an electronic circuit and mainly comprises an amplifying circuit, a signal operation and processing circuit, an oscillating circuit, a modulation and demodulation circuit, a power supply and the like. The present application relates generally to computing and measurement.
In the prior art, digital input and analog input are usually separated, and corresponding actual common products are a digital quantity input module and an analog quantity input module. In these modules, the same terminal in the input port can only be digital input or analog input, and the type of the butt-joint signal can be determined under the condition that the number and specification of the ports are determined. The technology is realized, and in the face of uncertainty of a complex industrial field environment, the flexibility is lacked, the fault tolerance is low, and the maintenance and replacement cost is high if the subsequent change is needed.
The above is only for the purpose of assisting understanding of the technical solutions of the present invention, and does not represent an admission that the above is the prior art.
SUMMERY OF THE UTILITY MODEL
In order to overcome the problems in the related technology to a certain extent at least, the application provides a digital quantity and analog quantity mixed input interface circuit, which can realize that the same port can be connected with digital quantity input and analog quantity input, thereby being beneficial to improving the flexibility and fault tolerance of related application systems and facilitating later-stage rectification and maintenance.
In order to achieve the purpose, the following technical scheme is adopted in the application:
the application provides a digital quantity analog quantity mixed input interface circuit, this interface circuit includes: the circuit comprises an analog voltage processing unit circuit, a digital input unit circuit and a mixed input terminal for accessing an external input signal;
the digital input unit circuit comprises a diode D1, an optocoupler U1, resistors R1 and R2; in the digital input unit circuit, a digital input unit circuit is provided,
the cathode end of the diode D1 is connected with the first terminal of the hybrid input terminal, the anode end of the diode D1 is connected with the output end of the optocoupler U1 diode side through a resistor R1, the collector end of the optocoupler U1 triode side is connected with a digital power supply, and the emitter end of the optocoupler U1 triode side is grounded through a resistor R2;
the input end of the diode side of the optical coupler U1 is used for connecting a switching signal end, and the emitter end of the triode side of the optical coupler U1 is also used for connecting the digital input end of a post-stage circuit;
the second terminal of the hybrid input terminal is grounded, the first terminal of the hybrid input terminal is also connected with the input end of the analog voltage processing unit circuit, and the output end of the analog voltage processing unit circuit is used for being connected with the analog input end of the post-stage circuit.
Optionally, the analog voltage processing unit circuit includes an operational amplifier U2, resistors R3, R4, R5, R6; in the circuit of the analog voltage processing unit,
one end of the resistor R3 is used as the input end of the unit circuit, the other end of the resistor R3 is connected with the non-inverting input end of the operational amplifier U2 and is grounded through a resistor R4, the inverting input end of the operational amplifier U2 is grounded through a resistor R5 and is connected with the output end of the operational amplifier U2 through a resistor R6, and the output end of the operational amplifier U2 is also used as the output end of the unit circuit;
in the analog voltage processing unit circuit, an operational amplifier U2 is provided with an operating voltage by an analog power supply.
Optionally, the diode D1 is a general diode, and the conduction voltage drop is 1V.
Optionally, the universal diode is of type 1N 4148W.
Optionally, the operational amplifier U2 is model LM 2904.
Optionally, the optical coupler U1 is an isolation optical coupler.
Optionally, the isolating optocoupler is of a type PS 2801-1.
Optionally, the digital power supply is a 3.3V power supply, and the analog power supply is a 15V power supply.
Optionally, the subsequent circuit is a control circuit based on a single chip, a first general input/output port of the single chip is used as the switching signal terminal, a second general input/output port of the single chip is used as a digital input terminal of the circuit, and an analog-to-digital conversion port of the single chip is used as an analog input terminal of the circuit.
Optionally, the post-stage circuit further includes a display screen for displaying the working state of the interface circuit, and the display screen is electrically connected to the single chip microcomputer through a serial port.
This application adopts above technical scheme, possesses following beneficial effect at least:
the digital quantity and analog quantity mixed input interface circuit realizes the mixed input function through a specific circuit structure. By adopting the interface circuit, the same port can be connected with a digital input signal of a dry contact and an analog input signal of a corresponding voltage range, so that the application mode of a circuit system applying the interface circuit is more flexible, the fault tolerance is strong, and the later-stage rectification and maintenance are facilitated.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings are included to provide a further understanding of the technology or prior art of the present application and are incorporated in and constitute a part of this specification. The drawings expressing the embodiments of the present application are used for explaining the technical solutions of the present application, and should not be construed as limiting the technical solutions of the present application.
Fig. 1 is a schematic diagram of a digital-analog hybrid input interface circuit according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail below. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without making any creative effort, shall fall within the protection scope of the present application.
For the convenience of understanding the technical solutions of the present application, the following related knowledge related to the solutions is briefly introduced here:
a. dry contact signal: a dry contact is an electrical switch having two states, closed and open. The dry contact has no polarity between the two contacts and can be exchanged. In this application mainly the output of the sensor.
b. Industrial control input/output analog quantity: the input and output are in the same range, and the voltage type is usually 0-10V; the current mode is typically 4-20 mA.
c. Optical coupling: the optical coupler has the main advantages of unidirectional signal transmission, complete electrical isolation between the input end and the output end, strong anti-interference capability, long service life and high transmission efficiency. It is widely used in level conversion, signal isolation, interstage isolation, switch circuit, long distance signal transmission, pulse amplification, Solid State Relay (SSR), instrument and meter, communication equipment and microcomputer interface.
d. An operational amplifier: an amplifier circuit capable of performing mathematical operations on a signal by an operational amplifier (OPA). It was the basic component of an analog computer and is thus named. The operational amplifier made by adopting integrated circuit process not only retains the original characteristics of very high gain and input impedance, but also has the advantages of being exquisite, cheap and flexible to use, etc., so that it can be extensively used in the fields of active filter, switched capacitor circuit, D-A and A-D converter, D.C. signal amplification, waveform generation and conversion and signal processing, etc. Virtual short and virtual break are common operational amplifier analysis methods, and the term "virtual short" means that, under ideal conditions, the potentials of two input ends are equal, as if the two input ends are shorted together, but in fact, the two input ends are not shorted, and is called as "virtual short". The virtual open circuit is short for a false open circuit because the current flowing into the input end of the integrated operational amplifier is zero under ideal conditions.
Example one
In this embodiment, as shown in fig. 1, the digital-analog hybrid input interface circuit proposed by the present application includes: an analog voltage processing unit circuit (a lower side dashed line frame part in fig. 1), a digital input unit circuit (an upper side dashed line frame part in fig. 1), and a hybrid input terminal P1 for accessing an external input signal;
the digital input unit circuit comprises a diode D1 (the diode is a general diode, the conduction voltage drop is 1V, and for example, a diode with the model number of 1N4148W is specifically adopted), an optocoupler U1, resistors R1 and R2; in the digital input unit circuit, the digital input unit circuit is provided with a digital input unit,
a cathode end of the diode D1 is connected with a first terminal of the hybrid input terminal, an anode end of the diode D1 is connected with an output end of a diode side of the optical coupler U1 through a resistor R1, a collector end of a triode side of the optical coupler U1 is connected with a digital power supply (for example, the digital power supply is a 3.3V power supply), and a radio electrode end of the triode side of the optical coupler U1 is grounded through a resistor R2;
the input end of the diode side of the optical coupler U1 is used for connecting a switching signal end, and the emitter end of the triode side of the optical coupler U1 is also used for connecting the digital input end of a post-stage circuit;
the second terminal of the hybrid input terminal P1 is grounded, the first terminal of the hybrid input terminal P1 is further connected to the input terminal of the analog voltage processing unit circuit, and the output terminal of the analog voltage processing unit circuit is connected to the analog input terminal of the subsequent circuit.
As a specific implementation manner, in this embodiment, as shown in fig. 1, the analog voltage processing unit circuit includes an operational amplifier U2 (for example, model LM2904 of the operational amplifier U2, available from TI corporation), resistors R3, R4, R5, R6; in the circuit of the analog voltage processing unit,
one end of the resistor R3 is used as the input end of the unit circuit, the other end of the resistor R3 is connected with the non-inverting input end of the operational amplifier U2 and is grounded through a resistor R4, the inverting input end of the operational amplifier U2 is grounded through a resistor R5 and is connected with the output end of the operational amplifier U2 through a resistor R6, and the output end of the operational amplifier U2 is also used as the output end of the unit circuit;
in the analog voltage processing unit circuit, the operational amplifier U2 is supplied with an operating voltage by an analog power supply (for example, the analog power supply is a 15V power supply).
For further understanding of the digital-analog hybrid input interface circuit in the present application, the operation principle of the interface circuit will be described below.
For example, the hybrid input terminal P1 is used to interface with external sensor outputs, where the external input signals include dry contact signals and analog 0-10V voltage input signals.
The switching signal end is connected with a low level signal, the interface circuit is in an analog input working state, and a voltage signal is input to be 0-10V. The low level signal of the switching signal end acts on the input end of the diode side of the optocoupler U1, the diode part of the optocoupler U1 is not conducted, and then the triode is not conducted, and the output of the digital input unit circuit is always at a low level, which is equivalent to no output; and the analog voltage processing unit circuit is in a working state, and the relation between the output voltage UO and the input voltage UI is as follows: the UO is R4/(R3+ R4) × UI, and the UO is output to the subsequent circuit through the output terminal of the unit circuit, thereby realizing analog input (for the subsequent circuit).
When the switching signal end is connected with a high level signal, the interface circuit is in a digital input working state; when a dry contact signal output by the external sensor is off, the diode part of the optocoupler U1 is conducted, the triode part is also conducted, and the output of the digital input unit circuit is at a high level; when a dry contact signal output by the external sensor is on, the diode part of the optocoupler U1 is disconnected and is not conducted, the triode part is also not conducted, and the output of the digital input unit circuit is pulled down by R2 and is at a low level; this corresponds to the dry contact signal being output to the subsequent circuit, thereby realizing the digital quantity input (for the subsequent circuit).
It is easily understood that the resistor R1 in the interface circuit in this embodiment functions as a current limiting; the resistor R2 functions as a voltage conversion for converting the current of the emitter into a voltage representing a high level; for example, when the digital power supply is a 3.3V power supply and the U1 specifically adopts the isolation optocoupler PS2801-1, the resistance of the resistor R1 is 1K and the resistance of the resistor R2 is 4.7K.
For matching with the voltage input signal of analog quantity 0-10V, the analog power supply can adopt 15V power supply, and the resistor R3-R5-33K and the resistor R4-R6-10K. The derivation is performed based on the virtual short and virtual break principle of operational amplifier, and it is known that Up is Un, Up is UI R4/(R3+ R4), and Un is UO R5/(R5+ R6); furthermore, when UO is equal to UI/3.3 and the UI range is 0-10V, the UI range is within 3.3V and meets the ADC input requirement of a later-stage circuit.
The digital quantity and analog quantity mixed input interface circuit realizes a mixed input function through a specific circuit structure, can realize that the same port can not only be in butt joint with a dry contact digital input signal, but also can be in butt joint with an analog quantity input signal in a corresponding voltage range, thereby enabling the application mode of a circuit system applying the interface circuit to be more flexible, having strong fault tolerance and being convenient for later-stage rectification and maintenance.
Example two
On the basis of the first embodiment, as shown IN fig. 1, IN the first embodiment, the subsequent circuit is a control circuit based on a single chip Microcomputer (MCU), a first general purpose input/output port GPIO1 of the MCU is used as a switching signal terminal, a second general purpose input/output port GPIO2 of the MCU is used as a digital input terminal of the circuit, and an analog-to-digital conversion port ADC _ IN1 of the MCU is used as an analog input terminal of the circuit. In other words, the switching of the digital quantity input and the analog quantity input can be realized by controlling the output level of the configuration GPIO 1.
As a specific implementation manner, the post-stage circuit further includes a display screen (a lower right functional schematic block in fig. 1) for displaying the working state of the interface circuit, and the display screen is electrically connected with the MCU through a serial port. Based on the specific program configuration of the MCU, when the GPIO1 outputs a low level, the display screen displays "the digital input state is off and the analog input state is on", and when the GPIO1 outputs a high level, "the digital input state is on and the analog input state is off".
It should be noted that, the description related to the specific program configuration of the MCU in this embodiment is only for illustrating the principle of the application of the present interface circuit in a specific application scenario, and the technical solution to be protected in this application does not relate to the improvement of the related principle and method.
The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A digital-analog hybrid input interface circuit, comprising: the circuit comprises an analog voltage processing unit circuit, a digital input unit circuit and a mixed input terminal for accessing an external input signal;
the digital input unit circuit comprises a diode D1, an optocoupler U1, resistors R1 and R2; in the digital input unit circuit, a digital input unit circuit is provided,
the cathode end of the diode D1 is connected with the first terminal of the hybrid input terminal, the anode end of the diode D1 is connected with the output end of the optocoupler U1 diode side through a resistor R1, the collector end of the optocoupler U1 triode side is connected with a digital power supply, and the emitter end of the optocoupler U1 triode side is grounded through a resistor R2;
the input end of the diode side of the optical coupler U1 is used for connecting a switching signal end, and the emitter end of the triode side of the optical coupler U1 is also used for connecting the digital input end of a post-stage circuit;
the second terminal of the hybrid input terminal is grounded, the first terminal of the hybrid input terminal is also connected with the input end of the analog voltage processing unit circuit, and the output end of the analog voltage processing unit circuit is used for being connected with the analog input end of the post-stage circuit.
2. The input interface circuit of claim 1, wherein the analog voltage processing unit circuit comprises an operational amplifier U2, resistors R3, R4, R5, R6; in the circuit of the analog voltage processing unit,
one end of the resistor R3 is used as the input end of the unit circuit, the other end of the resistor R3 is connected with the non-inverting input end of the operational amplifier U2 and is grounded through a resistor R4, the inverting input end of the operational amplifier U2 is grounded through a resistor R5 and is connected with the output end of the operational amplifier U2 through a resistor R6, and the output end of the operational amplifier U2 is also used as the output end of the unit circuit;
in the analog voltage processing unit circuit, an operational amplifier U2 is provided with an operating voltage by an analog power supply.
3. The input interface circuit of claim 2, wherein the diode D1 is a general-purpose diode and has a conduction voltage drop of 1V.
4. The input interface circuit as claimed in claim 3, wherein the general purpose diode is 1N 4148W.
5. The input interface circuit according to claim 2, wherein the operational amplifier U2 is of type LM 2904.
6. The digital-to-analog hybrid input interface circuit according to claim 2, wherein the optocoupler U1 is an isolation optocoupler.
7. The digital-to-analog hybrid input interface circuit according to claim 6, wherein the isolating optocoupler is of type PS 2801-1.
8. The digital-to-analog hybrid input interface circuit according to claim 2, wherein the digital power supply is a 3.3V power supply and the analog power supply is a 15V power supply.
9. The digital-analog hybrid input interface circuit according to claim 2, wherein the subsequent circuit is a control circuit based on a single chip, a first general input/output port of the single chip is used as the switching signal terminal, a second general input/output port of the single chip is used as a digital input terminal of the circuit, and an analog-digital conversion port of the single chip is used as an analog input terminal of the circuit.
10. The digital-analog hybrid input interface circuit according to claim 9, wherein the post-stage circuit further comprises a display screen for displaying the operating state of the interface circuit, and the display screen is electrically connected to the single chip microcomputer through a serial port.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202120536360.9U CN214380867U (en) | 2021-03-15 | 2021-03-15 | Digital quantity and analog quantity mixed input interface circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202120536360.9U CN214380867U (en) | 2021-03-15 | 2021-03-15 | Digital quantity and analog quantity mixed input interface circuit |
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| CN214380867U true CN214380867U (en) | 2021-10-08 |
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| CN202120536360.9U Active CN214380867U (en) | 2021-03-15 | 2021-03-15 | Digital quantity and analog quantity mixed input interface circuit |
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