Self-detecting signal acquisition circuit based on analog quantity current-voltage hybrid input

Abstract

The application provides a self-detection signal collection circuit based on analog current-voltage mixed input, which comprises a surge protection circuit, a switch selection circuit, a clamping protection circuit, a follower circuit, an impedance matching circuit and an ADC collection chip connected in sequence, and a microcontroller, wherein the microcontroller is connected with the ADC collection chip and the switch selection circuit, the microcontroller is used to acquire the output voltage of the impedance matching circuit through the ADC collection chip, periodically detect the output voltage of the impedance matching circuit, and periodically output high level or low level to the switch selection circuit based on the periodic detection result of the output voltage of the impedance matching circuit, so as to control the switch selection circuit to switch gears. The technical problem that the workload of sensor wiring work is large, the work efficiency is low and the error rate is high due to the fact that only multiple different types of analog signal input collection modules can be used to collect multiple different output signal sensors in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of signal acquisition, and in particular to a self-detection signal acquisition circuit based on analog current-voltage mixed input. BACKGROUND

[0002] In the industrial production process, various sensors such as pressure sensors and temperature and humidity sensors are used. Different sensors give different signals, some give voltage signals, and some give current signals. Therefore, the market analog signal input acquisition modules are roughly divided into voltage input type and current input type. However, for the cabinet application with many interfaces and mixed signal types, using multiple analog signal input acquisition modules of different types to collect sensor information of multiple different output signal types is extremely cumbersome in operation. Many times, it takes a lot of work to correct a line error, which is low in work efficiency and has a high error rate. The wrong connection of signal type and analog input acquisition module will cause the corresponding circuit to burn out.

[0003] Therefore, it is urgent to design a signal acquisition circuit compatible with voltage signal and current signal input. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a self-detection signal acquisition circuit based on analog current-voltage mixed input, which is used to solve the technical problems of large workload, low work efficiency and high error rate of sensor wiring work in the prior art due to the use of multiple analog signal input acquisition modules of different types to collect multiple different output signals of sensors.

[0005] To achieve the above purpose, the technical solutions adopted by the embodiments of the present application are as follows:

[0006] A self-detection signal acquisition circuit based on analog current-voltage mixed input for collecting signals of a sensor, comprising a surge protection circuit, a switch selection circuit, a clamping protection circuit, a follower circuit, an impedance matching circuit, an ADC acquisition chip and a microcontroller.

[0007] The input end of the surge protection circuit is connected with the output end of the sensor.

[0008] The input end of the switch selection circuit is connected with the output end of the surge protection circuit.

[0009] The input end of the clamping protection circuit is connected with the output end of the switch selection circuit.

[0010] The input end of the follower circuit is connected with the output end of the clamping protection circuit.

[0011] The input end of the impedance matching circuit is connected with the output end of the follower circuit, and the output end is connected with the ADC acquisition chip;

[0012] The input end of the microcontroller is connected with the ADC acquisition chip, and the output end is connected with the enable end of the switch selection circuit. The microcontroller acquires the output voltage of the impedance matching circuit through the ADC acquisition chip, and periodically detects the output voltage of the impedance matching circuit. The microcontroller periodically outputs high level or low level to the enable end of the switch selection circuit based on the periodic detection result of the output voltage, so as to control the switch selection circuit to switch gears.

[0013] In the self-detection signal acquisition circuit based on analog current-voltage hybrid input, the surge protection circuit includes a first bidirectional TVS diode, a second bidirectional TVS diode, and a third bidirectional TVS diode.

[0014] One end of the second bidirectional TVS diode is connected with the positive output end of the sensor, and the other end is connected with the negative output end of the sensor.

[0015] One end of the first bidirectional TVS diode is connected with the positive output end of the sensor, and the other end is grounded.

[0016] One end of the third bidirectional TVS diode is connected with the negative output end of the sensor, and the other end is grounded.

[0017] The second bidirectional TVS diode is connected with the switch selection circuit.

[0018] In the self-detection signal acquisition circuit based on analog current-voltage hybrid input, the surge protection circuit further includes a residual voltage discharge circuit, and the residual voltage discharge circuit includes a first high-voltage capacitor, a second high-voltage capacitor, and a third high-voltage capacitor.

[0019] One end of the first high-voltage capacitor is connected with the positive output end of the sensor, and the other end is grounded.

[0020] The second high-voltage capacitor is connected with the second positive TVS diode in parallel.

[0021] One end of the third high-voltage capacitor is connected with the negative output end of the sensor, and the other end is grounded.

[0022] In the self-detection signal acquisition circuit based on analog current-voltage hybrid input, the switch selection circuit includes a switch relay, a sampling resistor, a pull-up resistor, a first voltage dividing resistor, and a second voltage dividing resistor.

[0023] The first normally open end of the switch relay is connected with the second end of the sampling resistor, the first end of the sampling resistor is connected with the surge protection circuit and the second normally closed end of the switch relay, the first normally closed end of the switch relay is connected with the surge protection circuit, the second normally open end of the switch relay is connected with the clamping protection circuit, the second common end of the switch relay is connected with the first voltage dividing resistor, the other end of the first voltage dividing resistor is connected with the clamping protection circuit and the second voltage dividing resistor, the other end of the second voltage dividing resistor is grounded, one end of the pull-up resistor is connected with the negative pole of the coil of the switch relay, the other end is connected with the control voltage, the negative pole of the coil of the switch relay is used as the enable end of the switch selection circuit, and the positive pole of the coil of the switch relay is connected with the control voltage.

[0024] In the self-detection signal acquisition circuit based on analog current-voltage hybrid input provided in the embodiment of the application, the switch selection circuit further comprises a protection circuit, and the protection circuit comprises a diode, a first resistor and a first capacitor.

[0025] The positive pole of the diode is connected with the negative pole of the coil of the switch relay, the negative pole of the diode is connected with the positive pole of the coil of the switch relay, the first resistor is connected with the first capacitor in series, the other end of the first resistor is connected with the positive pole of the coil of the switch relay, and the other end of the first capacitor is connected with the negative pole of the coil of the switch relay.

[0026] In the self-detection signal acquisition circuit based on analog current-voltage hybrid input provided in the embodiment of the application, the switch relay is a double-pole double-throw switch relay with a model of HFD4 / 5-SR.

[0027] In the self-detection signal acquisition circuit based on analog current-voltage hybrid input provided in the embodiment of the application, the clamping protection circuit comprises a first filter capacitor, a first clamping diode and a second clamping diode.

[0028] The first end of the first filter capacitor is connected with the switch selection circuit, and the second end is grounded, the positive pole of the first clamping diode is connected with the first end of the first filter capacitor, the negative pole is connected with the positive power supply rail, the negative pole of the second clamping diode is connected with the first end of the first filter capacitor, and the positive pole is connected with the negative power supply rail.

[0029] In the self-detection signal acquisition circuit based on analog current-voltage hybrid input provided in the embodiment of the application, the follower circuit comprises an operational amplifier, a second filter capacitor and a third filter capacitor.

[0030] The positive input end of the operational amplifier is connected with the surge protection circuit, the output end of the operational amplifier is connected with the negative input end of the operational amplifier and the impedance matching circuit, the positive power supply end of the operational amplifier is connected with the positive power supply rail and the second filter capacitor, the other end of the second filter capacitor is grounded, and the negative power supply end of the operational amplifier is connected with the negative power supply rail and the third filter capacitor, and the other end of the third filter capacitor is grounded.

[0031] In the self-detection signal acquisition circuit based on analog current-voltage hybrid input provided in the embodiment of the application, the impedance matching circuit comprises a first series resistor, a second series resistor, a differential mode resistor and a fourth filter capacitor.

[0032] The first series resistor, the differential mode resistor and the second series resistor are connected in series, the fourth filter capacitor is connected in parallel with the differential mode resistor, the voltage across the differential mode resistor is used as the final output voltage, and the two ends of the differential mode resistor are connected with the ADC acquisition chip and the microcontroller.

[0033] Compared with the prior art, the embodiment of the application has the following beneficial effects:

[0034] The self-detection signal acquisition circuit based on analog current-voltage hybrid input provided in the embodiment of the application has the following advantages: the surge protection circuit is arranged to inhibit and absorb surge voltage to protect the subsequent circuit, the switch selection circuit is arranged to switch gears, so that the signal acquisition circuit can switch between receiving voltage signals and current signals, the clamping protection circuit is arranged to clamp the input voltage within a safe range to protect the subsequent circuit, the follower circuit is arranged to stably transmit the input signal to the subsequent circuit, the impedance matching circuit is arranged to improve the differential mode matching degree of the input signal, so that the input signal can smoothly enter the ADC acquisition chip, the ADC acquisition chip can output the signal to the microcontroller after analog-digital conversion to complete the acquisition of the sensor signal, at the same time, the microcontroller can periodically detect the output voltage of the impedance matching resistor, and based on the periodic detection result of the output voltage, the microcontroller can periodically output a high level or a low level to the enable end of the switch selection circuit to control the switch selection circuit to switch gears, thereby solving the technical problems of large workload, low work efficiency and high error rate of sensor wiring work in the prior art, in which only multiple different types of analog signal input acquisition modules can be used to acquire multiple different output signals of sensors. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the following embodiment description will be briefly introduced, the drawings are not intended to be drawn in proportion, and in order to be clear, not every component will be marked in each drawing. The drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art. Among them:

[0036] Figure 1 The structural schematic diagram of the embodiment of the present application. DETAILED DESCRIPTION

[0037] Since the output signals of the sensors are divided into voltage signals and current signals, and the current analog signal input acquisition module can only receive voltage signals or current signals, in the process of connecting the interface of the cabinet, which has many interfaces and mixed signal types, using multiple analog signal input acquisition modules of different types to collect sensor information of multiple different output signal types is extremely cumbersome in operation, and in many cases, the error of checking a line needs to arrange the entire cabinet, which is a large workload, low work efficiency, and high error rate, and the wrong connection of signal types and analog signal input acquisition modules will cause the corresponding circuit to be burned out.

[0038] In view of this, the embodiment of the present application provides an analog current-voltage mixed input self-detection signal acquisition circuit, the idea of which is to set a surge protection circuit to suppress and absorb the surge voltage of the rear circuit, set a switch selection circuit to switch gears, so that the signal acquisition circuit switches between receiving voltage signals or current signals, set a clamping protection circuit to clamp the input voltage within a safe range to protect the rear circuit, set a follower circuit to stably transmit the input signal to the rear circuit, improve the differential mode matching degree of the input signal through the impedance matching circuit, so that the input signal smoothly enters the ADC acquisition chip, the ADC acquisition chip will output the signal to the microcontroller after analog-digital conversion to complete the acquisition of the sensor signal, at the same time, the microcontroller periodically detects the output voltage of the impedance matching resistor, and based on the periodic detection result of the output voltage, the microcontroller periodically outputs high level or low level to the enable end of the switch selection circuit to control the switch selection circuit to switch gears, which solves the technical problems of large workload, low work efficiency and high error rate of sensor wiring work caused by using multiple analog signal input acquisition modules of different types to collect multiple different output signals of the sensors in the prior art.

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0040] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0041] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0042] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For purposes of simplicity of the present disclosure, the following description will refer to specific examples of the present application. It is understood, however, that these are only examples and are not intended to limit the present application in any way. Furthermore, in an effort to simplify the present disclosure, certain terms used in the description of the specific examples have been used for only one or a limited number of examples. However, such use is for purposes of simplification and clarity and is not intended to limit the application in any manner. Also, it will be appreciated that the various embodiments of the present application can include different combinations of the features described, which can be applied to the various embodiments of the present application. Moreover, the present application contemplates that the various embodiments of the present application can include different combinations of the features described, which can be applied to the various embodiments of the present application.

[0044] Analog current-voltage hybrid input-based self-detecting signal acquisition circuit is provided in the embodiments of the present application, as shown in the accompanying drawings. Figure 1 The analog current-voltage hybrid input-based self-detecting signal acquisition circuit is used for acquiring a voltage signal or a current signal output by a sensor, and includes a surge protection circuit, a switch selection circuit, a clamping protection circuit, a follower circuit, an impedance matching circuit, an ADC acquisition chip, and a microcontroller.

[0045] An input end of the surge protection circuit is connected to an output end of the sensor.

[0046] Specifically, the surge protection circuit includes a first bidirectional TVS diode TV1, a second bidirectional TVS diode TV2, and a third bidirectional TVS diode TV3. One end of the second bidirectional TVS diode TV2 is connected to a positive output end AIN+ of the sensor, and the other end is connected to a negative output end AIN- of the sensor. One end of the first bidirectional TVS diode TV1 is connected to the positive output end AIN+ of the sensor, and the other end is grounded. One end of the third bidirectional TVS diode TV3 is connected to the negative output end AIN- of the sensor, and the other end is grounded. The second bidirectional TVS diode TV2 is connected to the switch selection circuit.

[0047] Preferably, the surge protection circuit further includes a residual voltage discharge circuit for discharging residual voltage, which includes a first high-voltage capacitor C2, a second high-voltage capacitor C3, and a third high-voltage capacitor C5. One end of the first high-voltage capacitor C2 is connected to the positive output end AIN+ of the sensor, and the other end is grounded. The second high-voltage capacitor C3 is connected in parallel to the second bidirectional TVS diode TV2. One end of the third high-voltage capacitor C5 is connected to the negative output end AIN- of the sensor, and the other end is grounded.

[0048] The first bidirectional TVS diode TV1, the second bidirectional TVS diode TV2, and the third bidirectional TVS diode TV3 all have the model SMBJ30CA, the first high-voltage capacitor C2, the second high-voltage capacitor C3, and the third high-voltage capacitor C5 all have 4.7nF, and the surge protection circuit is used to suppress, absorb, and discharge surge voltage to protect the subsequent circuit.

[0049] The input end of the switch selection circuit is connected with the output end of the surge protection circuit.

[0050] Specifically, the switch selection circuit comprises a switch relay K1, a sampling resistor R1, a pull-up resistor R3, a first voltage dividing resistor R7, and a second voltage dividing resistor R8.

[0051] The first normally open end of the switch relay K1 is connected with the second end of the sampling resistor R1, the first end of the sampling resistor R1 is connected with the surge protection circuit and the second normally closed end of the switch relay K1, the first normally closed end of the switch relay K1 is connected with the surge protection circuit, the second normally open end of the switch relay K1 is connected with the clamping protection circuit, the second common end of the switch relay K1 is connected with the first voltage dividing resistor R7, the other end of the first voltage dividing resistor R7 is connected with the clamping protection circuit and the second voltage dividing resistor R8, the other end of the second voltage dividing resistor R8 is grounded, one end of the pull-up resistor R3 is connected with the negative electrode of the coil of the switch relay K1, and the other end is connected with a control voltage, the negative electrode of the coil of the switch relay K1 serves as the enable end of the switch selection circuit, and the positive electrode of the coil of the switch relay K1 is connected with the control voltage.

[0052] Preferably, the switch selection circuit further comprises a protection circuit, the protection circuit comprises a diode D3, a first resistor R6, and a first capacitor C8, the positive electrode of the diode D3 is connected with the negative electrode of the coil of the switch relay K1, the negative electrode of the diode D3 is connected with the positive electrode of the coil of the switch relay K1, the first resistor R6 is connected in series with the first capacitor C8, the other end of the first resistor R6 is connected with the positive electrode of the coil of the switch relay K1, the other end of the first capacitor C8 is connected with the negative electrode of the coil of the switch relay K1, and the protection circuit is used to suppress inverse peak voltage and prevent the switch relay K1 from being damaged.

[0053] The switch relay K1 is a double-pole double-throw switch relay, the model of which is HFD4 / 5-SR, the first end of the sampling resistor R1 is connected with the positive output end AIN+ of the sensor, the first normally closed end of the switch relay K1 is connected with the negative output end AIN- of the sensor, the negative pole of the coil of the switch relay K1 is used as the enable end EN of the switch relay K1, that is, the enable end of the switch selection circuit, in the embodiment, the sampling resistor R1 is 250R, the pull-up resistor R3 is 4.7K, the first voltage dividing resistor R7 and the second voltage dividing resistor R8 are 100K and 500K respectively, the first resistor R6 is 1K, the first capacitor C8 is 100pF, the model of the diode D3 is 1N4148W, the control voltage is 5V, and the switch selection circuit is used for receiving the high and low level control signals of the microcontroller to switch gears, so that the signal acquisition circuit of the embodiment switches between receiving voltage signals or current signals.

[0054] The input end of the clamping protection circuit is connected with the output end of the switch selection circuit.

[0055] Specifically, the clamping protection circuit comprises a first filter capacitor C4, a first clamping diode D1 and a second clamping diode D2, the first end of the first filter capacitor C4 is connected with the switch selection circuit, and the second end is grounded, the positive pole of the first clamping diode D1 is connected with the first end of the first filter capacitor C4, and the negative pole is connected with the positive power supply rail, and the negative pole of the second clamping diode D2 is connected with the first end of the first filter capacitor C4, and the positive pole is connected with the negative power supply rail.

[0056] The clamping protection circuit is used for clamping the input voltage of the clamping protection circuit in a safe range to protect the subsequent circuit, the first end of the first filter capacitor C4 is connected with the other end of the first voltage dividing resistor R7, the first filter capacitor C4 is 100nF, the models of the first clamping diode D1 and the second clamping diode D2 are both FHLL4148-XE, the positive power supply rail is +15V, and the negative power supply rail is -15V.

[0057] The input end of the follower circuit is connected with the output end of the clamping protection circuit.

[0058] Specifically, the follower circuit comprises an operational amplifier U1, a second filter capacitor C1 and a third filter capacitor C6, the positive input end of the operational amplifier U1 is connected with the clamping protection circuit, the output end of the operational amplifier U1 is connected with the negative input end of the operational amplifier U1 and the impedance matching circuit, the positive power supply end of the operational amplifier U1 is connected with the positive power supply rail and the second filter capacitor C1, the other end of the second filter capacitor C1 is grounded, the negative power supply end of the operational amplifier U1 is connected with the negative power supply rail and the third filter capacitor C6, and the other end of the third filter capacitor C6 is grounded.

[0059] The model of the operational amplifier U1 is OPA188AIDR, the positive input end is connected with the anode of the first clamping diode D1, the second filter capacitor C1 and the third filter capacitor C6 are both 100nF, the positive power supply rail is +15V, the negative power supply rail is -15V, and the follower circuit is used for stably transmitting the input signal of the follower circuit to the subsequent circuit.

[0060] The input end of the impedance matching circuit is connected with the output end of the follower circuit, the output end of the impedance matching circuit is connected with the ADC acquisition chip, the input end of the microcontroller is connected with the ADC acquisition chip, and the output end of the microcontroller is connected with the enable end of the switch selection circuit, the microcontroller acquires the output voltage of the impedance matching circuit through the ADC acquisition chip, periodically detects the output voltage of the impedance matching circuit, and periodically outputs high level or low level to the enable end of the switch selection circuit based on the periodic detection result of the output voltage, so as to control the switch selection circuit to switch gears.

[0061] Specifically, the impedance matching circuit comprises a first series resistor R2, a second series resistor R5, a differential mode resistor R4 and a fourth filter capacitor C7, the first series resistor R2, the differential mode resistor R4 and the second series resistor R5 are connected in series, the fourth filter capacitor C7 is connected with the differential mode resistor R4 in parallel, the output voltage between the differential mode resistor R4 is used as the final output voltage, and the two ends of the differential mode resistor R4 are connected with the ADC acquisition chip.

[0062] The other end of the first series resistance R2 is connected with the output end of the operational amplifier U1, the other end of the second series resistance R5 is grounded, the first series resistance R2 and the second series resistance R5 are both 1K, the differential mode resistance R4 is 10M, the fourth filter capacitor C7 is 1nF, the connection point of the differential mode resistance R4 and the first series resistance R2 is AI+, the connection point of the differential mode resistance R4 and the second series resistance R5 is AI-, the ADC acquisition chip is used for acquiring the output voltage between AI+ and AI- and performing analog-digital conversion on the voltage signal, when the output voltage between the differential mode resistance R4 acquired by the microcontroller through the ADC acquisition chip is greater than the threshold value preset in the microcontroller, the microcontroller outputs low level to the switch relay K1, so that the sampling resistance R1 is connected to the signal acquisition circuit, so that the signal acquisition circuit of the application receives the current signal, when the output voltage between the differential mode resistance R4 acquired by the microcontroller through the ADC acquisition chip is less than the threshold value preset in the microcontroller, the microcontroller outputs high level to the switch relay K1, so that the first voltage dividing resistance R7 and the second voltage dividing resistance R8 are connected to the signal acquisition circuit, so that the signal acquisition circuit of the application receives the voltage signal.

[0063] In summary, the self-detection signal acquisition circuit based on analog current-voltage hybrid input provided by the embodiment of the application sets a surge protection circuit to suppress and absorb surge voltage to protect the subsequent circuit, sets a switch selection circuit to switch gears, so that the signal acquisition circuit switches between receiving voltage signals or current signals, sets a clamping protection circuit to clamp the input voltage within a safe range to protect the subsequent circuit, sets a follower circuit to stably transmit the input signal to the subsequent circuit, improves the differential mode matching degree of the input signal through the impedance matching circuit, so that the input signal smoothly enters the ADC acquisition chip, the ADC acquisition chip outputs the signal to the microcontroller after analog-digital conversion to complete the acquisition of the sensor signal, at the same time, the microcontroller periodically detects the output voltage of the impedance matching resistance, and based on the periodic detection result of the output voltage, periodically outputs high level or low level to the enable end of the switch selection circuit to control the switch selection circuit to switch gears, solving the technical problems of large workload, low work efficiency and high error rate of sensor wiring work in the prior art due to the use of multiple different types of analog signal input acquisition modules to acquire multiple different output signals of sensors.

[0064] The self-detection signal acquisition circuit based on analog current-voltage hybrid input provided by the embodiments of the present application is described in detail above, and the principles and implementation manners of the present application are described by applying specific examples. The above embodiment description is only used to help understand the technical solutions of the present application and the core ideas thereof. Those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features thereof can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A self-detecting signal acquisition circuit based on analog quantity current-voltage hybrid input, used for acquiring signals of a sensor, characterized in that, The surge protection circuit, the switch selection circuit, the clamping protection circuit, the follower circuit, the impedance matching circuit, the ADC acquisition chip and the microcontroller; The input end of the surge protection circuit is connected with the output end of the sensor; The input end of the switch selection circuit is connected with the output end of the surge protection circuit, wherein the surge protection circuit comprises a first bidirectional TVS diode, a second bidirectional TVS diode and a third bidirectional TVS diode, one end of the second bidirectional TVS diode is connected with the positive output end of the sensor, the other end is connected with the negative output end of the sensor, one end of the first bidirectional TVS diode is connected with the positive output end of the sensor, the other end is grounded, one end of the third bidirectional TVS diode is connected with the negative output end of the sensor, the other end is grounded, the second bidirectional TVS diode is connected with the switch selection circuit, the surge protection circuit further comprises a residual voltage discharge circuit, the residual voltage discharge circuit comprises a first high-voltage capacitor, a second high-voltage capacitor and a third high-voltage capacitor, one end of the first high-voltage capacitor is connected with the positive output end of the sensor, the other end is grounded, the second high-voltage capacitor is connected with the second bidirectional TVS diode in parallel, one end of the third high-voltage capacitor is connected with the negative output end of the sensor, the other end is grounded, the switch selection circuit comprises a switch relay, a sampling resistor, a pull-up resistor, a first voltage dividing resistor and a second voltage dividing resistor, the first normally open end of the switch relay is connected with the second end of the sampling resistor, the first end of the sampling resistor is connected with the surge protection circuit and the second normally closed end of the switch relay, the first normally closed end of the switch relay is connected with the surge protection circuit, the second normally open end of the switch relay is connected with the clamping protection circuit, the second common end of the switch relay is connected with the first voltage dividing resistor, the other end of the first voltage dividing resistor is connected with the clamping protection circuit and the second voltage dividing resistor, the other end of the second voltage dividing resistor is grounded, one end of the pull-up resistor is connected with the coil negative pole of the switch relay, the other end is connected with a control voltage, the coil negative pole of the switch relay serves as the enable end of the switch selection circuit, the coil positive pole of the switch relay is connected with the control voltage, the switch selection circuit further comprises a protection circuit, the protection circuit comprises a diode, a first resistor and a first capacitor, the positive pole of the diode is connected with the coil negative pole of the switch relay, the negative pole of the diode is connected with the coil positive pole of the switch relay, the first resistor is connected with the first capacitor in series, the other end of the first resistor is connected with the coil positive pole of the switch relay, the other end of the first capacitor is connected with the coil negative pole of the switch relay, the protection circuit is used for inhibiting the reverse peak voltage and preventing the switch relay from being damaged; The input end of the clamping protection circuit is connected with the output end of the switch selection circuit; The input end of the follower circuit is connected with the output end of the clamping protection circuit; The input end of the impedance matching circuit is connected with the output end of the follower circuit, and the output end is connected with the ADC acquisition chip; The input end of the microcontroller is connected with the ADC acquisition chip, and the output end is connected with the enable end of the switch selection circuit. The microcontroller acquires the output voltage of the impedance matching circuit through the ADC acquisition chip, periodically detects the output voltage of the impedance matching circuit, and periodically outputs high level or low level to the enable end of the switch selection circuit based on the periodic detection result of the output voltage, so as to control the switch selection circuit to switch gears.

2. The self-detect signal acquisition circuit based on analog quantity current-voltage hybrid input according to claim 1, characterized in that, The switch relay is a double-pole double-throw switch relay with model HFD4 / 5-SR.

3. The self-detect signal acquisition circuit based on analog quantity current-voltage hybrid input according to claim 1, characterized in that, The clamping protection circuit includes a first filter capacitor, a first clamping diode and a second clamping diode. The first end of the first filter capacitor is connected with the switch selection circuit, and the second end is grounded. The anode of the first clamping diode is connected with the first end of the first filter capacitor, and the cathode is connected with the positive power supply rail. The cathode of the second clamping diode is connected with the first end of the first filter capacitor, and the anode is connected with the negative power supply rail.

4. The self-detect signal acquisition circuit based on analog quantity current-voltage hybrid input according to claim 1, characterized in that, The follower circuit includes an operational amplifier, a second filter capacitor and a third filter capacitor. The positive input end of the operational amplifier is connected with the clamping protection circuit. The output end of the operational amplifier is connected with the negative input end of the operational amplifier and the impedance matching circuit. The positive power supply end of the operational amplifier is connected with the positive power supply rail and the second filter capacitor, and the other end of the second filter capacitor is grounded. The negative power supply end of the operational amplifier is connected with the negative power supply rail and the third filter capacitor, and the other end of the third filter capacitor is grounded.

5. The self-detect signal acquisition circuit based on analog quantity current-voltage hybrid input according to claim 1, characterized in that, The impedance matching circuit includes a first series resistor, a second series resistor, a differential mode resistor and a fourth filter capacitor. The first series resistor, the differential mode resistor and the second series resistor are connected in series. The fourth filter capacitor is connected in parallel with the differential mode resistor. The voltage across the differential mode resistor is the final output voltage. The two ends of the differential mode resistor are connected with the ADC acquisition chip and the microcontroller.

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