Adaptive analog quantity signal acquisition circuit

Abstract

The utility model provides a self-adaptive analog quantity signal acquisition circuit, which comprises a signal input terminal, a voltage / current self-adaptive circuit and an MCU (Microprogrammed Control Unit) end ADC (Analog to Digital Converter) acquisition module, and is characterized in that the signal input terminal is used for inputting a voltage or current signal of a sensor; the voltage / current self-adaptive circuit is used for converting and judging voltage or current signals input by the signal input terminal, the input end of the voltage / current self-adaptive circuit is connected with the output end of the input end protection circuit, the voltage / current self-adaptive circuit comprises an analog switch U1 and a resistor R, the U1 comprises independent switches K1, K2, K3 and K4, the resistor comprises R1, R2, R3 and R4, the U1 is provided with four independent channels A, B, C and D, control circuits for controlling the independent switches K1, K2, K3 and K4 are respectively arranged in the control circuit; and the MCU end ADC acquisition module is used for acquiring a voltage value or a current value in the voltage / current self-adaptive circuit. Adaptation can be performed according to the type of the sensor, so that the hardware cost of the device is effectively reduced, and the working efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the field of sensor signal acquisition, in particular to an acquisition circuit for adaptive analog signals. Background Art

[0002] With the increasing demand for sensor signal acquisition, the output signals of analog sensors are currently divided into two types: current type 4-20mA or voltage type 0-5V. Due to the internal circuit characteristics of the sensor, the two types of sensors have different requirements for the resistance of the output load; the current type transformer load circuit requirements are generally at the level of several hundred ohms, and the voltage type transformer load resistance requirements are generally at the level of tens of K ohms. Therefore, in practical applications, sensor signal acquisition can only be a single analog current acquisition circuit or a single analog voltage acquisition circuit, which has poor compatibility and cannot be automatically adapted. There are also on-site methods of manually adjusting the hardware load resistance to adapt to the sensor type, which is cumbersome on-site construction. Utility Model Content

[0003] In order to solve the above technical problems, the utility model proposes an adaptive analog signal acquisition circuit, which can be adapted according to the sensor type, effectively reducing the hardware cost of the device and improving work efficiency.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0005] An adaptive analog signal acquisition circuit, characterized in that it includes a signal input terminal, a voltage / current adaptive circuit and an MCU-side ADC acquisition module.

[0006] Signal input terminal, used to input voltage or current signal of sensor;

[0007] A voltage / current adaptive circuit is used to convert and judge the voltage or current signal input by the signal input terminal, the input end of the voltage / current adaptive circuit is connected to the output end of the input end protection circuit, the voltage / current adaptive circuit includes an analog switch U1 and a resistor R, the U1 includes independent switches K1, K2, K3, K4, the resistors include R1, R2, R3, R4, the U1 has four independent channels A, B, C, D, which are respectively provided with control circuits for controlling the independent switches K1, K2, K3, K4, the independent switches The independent switch K1 and the resistor R1 are connected in series, the independent switch K1 and the resistor R1 are connected in parallel to the signal input terminal and the ADC acquisition module on the MCU end, the independent switch K2 is connected in series to the resistor R2, the independent switch K2 and the resistor R2 are connected in parallel to the resistor R1, the independent switch K3 and the resistor R4 are connected in series, the independent switch K3 and R4 are connected in parallel to the signal input terminal and the ADC acquisition module on the MCU end, the resistor R3 is connected in series to the signal input terminal and the ADC acquisition module on the MCU end, and the independent switch K4 is connected in parallel to the resistor R3,

[0008] The R1 and R2 are resistors with a resistance value less than 1K, and the R3 and R4 are resistors with a resistance value greater than 10K. When the input signal is first collected, the default state of the four switches of U1 is that K1 and K4 are closed, and K2 and K3 are disconnected. When a sensor signal is input, after the ADC acquisition module on the MCU side collects the first voltage value V1, K2 is closed through the control signal in the independent channel, and the states of K1, K3, and K4 remain unchanged. The second voltage value V2 is measured, and V1 and V2 are compared. If V1=V2, it is a voltage type sensor. If V1≠V2, it is a current type sensor. If it is a current type sensor, V1 is substituted into the calculation to obtain the sensor input current I=V1 / R1. If it is a voltage type sensor, K1, K2, and K4 are disconnected and K3 is closed through the control signal in the independent channel. The voltage value V3 across R4 is measured and brought into the calculation to obtain the current sensor input voltage U=V3 / R4*(R3+R4);

[0009] The ADC acquisition module on the MCU side is used to collect the voltage value or current value in the voltage / current adaptive circuit.

[0010] Furthermore: it also includes an input protection circuit for protecting the input voltage or current signal, the input end of the input protection circuit is connected to the output end of the signal input terminal, and the output end is connected to the input end of the voltage / current adaptive circuit.

[0011] Furthermore: it also includes a signal conditioning and isolation circuit, which is used to control the voltage value or current value after conversion by the voltage / current adaptive circuit and filter the previous stage signal, and the input end of the signal conditioning and isolation circuit is connected to the output end of the voltage / current adaptive circuit.

[0012] Furthermore: it also includes an MCU acquisition protection circuit, which is used to protect the collected input signal. The input end of the MCU acquisition protection circuit is connected to the output end of the signal conditioning and isolation circuit, and the output end is connected to the MCU end ADC acquisition module.

[0013] Furthermore: it also includes a power supply module for powering the circuit, and the power supply module is respectively connected to the signal conditioning and isolation circuit, the MCU acquisition protection circuit and the MCU-side ADC acquisition module.

[0014] The utility model proposes an adaptive analog signal acquisition circuit, comprising a signal input terminal for sensor connection and signal input, a voltage / current adaptive circuit for converting and judging the sensor input signal, and an MCU-side ADC acquisition module for input signal acquisition, wherein the input end of the sensor is connected to the signal input terminal to realize signal input, the MCU-side ADC acquisition module is used to collect the voltage value or current value in the voltage / current adaptive circuit, the voltage / current adaptive circuit receives the signal transmitted by the signal input terminal, and appropriately processes the input signal to protect the subsequent circuit, and the voltage / current values ​​at both ends of the signal input terminal are converted by the voltage / current adaptive circuit to obtain the required voltage value.

[0015] The voltage / current adaptive circuit is divided into two parts, which are used to distinguish and collect voltage or current sensors. They are current sensor collection circuit and voltage sensor collection circuit. The current sensor collection circuit includes K1, K2, R1, R2, and the voltage sensor collection circuit includes K3, K4, R3, R4. The analog switch U1 has four independent channels A, B, C, and D, which are respectively provided with control circuits for controlling independent switches K1, K2, K3, and K4.

[0016] The principle of the current sensor acquisition circuit is as follows: R1 and R2 are resistors with a resistance value less than 1K. When the input signal is first collected, the default state of the four switches of U1 is K1 and K4 closed, and K2 and K3 are disconnected. When a sensor signal comes in, the ADC acquisition module on the MCU side collects the first voltage value V1, closes K2, and the states of K1, K3, and K4 remain unchanged. The second voltage value V2 is measured, and V1 and V2 are compared. If V1=V2, it is a voltage type sensor. If V1≠V2, it is a current type sensor. After confirming the sensor type, if it is a current type, V1 is substituted into the calculation to obtain the sensor input current I=V1 / R1; if the sensor is a voltage type, it is transferred to the voltage type sensor acquisition circuit.

[0017] The principle of the voltage type sensor acquisition circuit is as follows: R3 and R4 are resistors with resistance values ​​greater than 10K; after confirming that the sensor type is voltage type, K1, K2, and K4 are disconnected, K3 is closed, and the voltage value V3 measured across R4 is brought into the calculation to obtain the current sensor input voltage U=V3 / R4*(R3+R4).

[0018] The utility model is also provided with an input end protection circuit, which is used to protect the input voltage or current signal, the input end of which is connected to the output end of the signal input terminal, and the output end is connected to the input end of the voltage / current adaptive circuit.

[0019] The utility model is also provided with a signal conditioning and isolation circuit, which is used to control the voltage value or current value converted by the voltage / current adaptive circuit and filter the front-stage signal, and its input end is connected to the output end of the voltage / current adaptive circuit.

[0020] The utility model is also provided with an MCU acquisition protection circuit for protecting the collected input signal in the voltage / current adaptive circuit, wherein the input end is connected to the output end of the signal conditioning and isolation circuit, and the output end is connected to the MCU end ADC acquisition module.

[0021] The utility model is also provided with a power supply module for supplying power to the signal conditioning and isolation circuit, the MCU acquisition protection circuit and the MCU-end ADC acquisition module.

[0022] Compared with the prior art, the beneficial effects of the utility model are:

[0023] The utility model effectively solves the technical problem that the voltage or current type sensor acquisition circuit cannot realize self-adaptation, facilitates actual use on site, improves work efficiency and reduces device cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of the utility model;

[0025] Figure 2 It is a circuit diagram of the voltage / current adaptive circuit in the utility model;

[0026] Figure 3 It is a principle diagram of the utility model. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods:

[0028] like Figure 1-3 As shown, the utility model proposes an adaptive analog signal acquisition circuit, including a signal input terminal, a voltage / current adaptive circuit and an MCU-side ADC acquisition module.

[0029] Signal input terminal, used to input voltage or current signal of sensor;

[0030] A voltage / current adaptive circuit is used to convert and judge the voltage or current signal input by the signal input terminal. The input end of the voltage / current adaptive circuit is connected to the output end of the input end protection circuit. The voltage / current adaptive circuit includes an analog switch U1 and a resistor R. The U1 includes independent switches K1, K2, K3, and K4. The resistors include R1, R2, R3, and R4. The U1 has four independent channels A, B, C, and D, which are respectively provided with control circuits for controlling the independent switches K1, K2, K3, and K4. The independent switch K1 is connected in series with the resistor R1. The independent switch K1 and the resistor R1 are connected in parallel to the signal input terminal and the ADC acquisition module at the MCU end. The independent switch K2 is connected in series with the resistor R2. The independent switch K2 and the resistor R2 are connected in parallel to the resistor R1. The independent switch K3 and the resistor R4 are connected in series. The independent switch K3 and R4 are connected in parallel to the signal input terminal and the ADC acquisition module at the MCU end. The resistor R3 is connected in series to the signal input terminal. The independent switch K4 is connected in parallel to the resistor R3 on the ADC acquisition module at the MCU end. The R1 and R2 are resistors with a resistance value less than 1K, and the R3 and R4 are resistors with a resistance value greater than 10K. When the input signal is first collected, the default state of the four switches U1 is that K1 and K4 are closed, and K2 and K3 are disconnected. When there is a sensor signal input, after the ADC acquisition module at the MCU end collects the first voltage value V1, K2 is closed through the control signal in the independent channel, and the states of K1, K3, and K4 remain unchanged. Change, measure the second voltage value V2, compare V1 and V2, if V1=V2, it is a voltage type sensor, if V1≠V2, it is a current type sensor, if it is a current type sensor, substitute V1 into the calculation, and get the sensor input current I=V1 / R1, if it is a voltage type sensor, then through the control signal in the independent channel, disconnect K1, K2, K4, close K3, measure the voltage value V3 across R4 into the calculation, and get the current sensor input voltage U=V3 / R4*(R3+R4);

[0031] The ADC acquisition module on the MCU side is used to collect the voltage value or current value in the voltage / current adaptive circuit.

[0032] It also includes an input protection circuit for protecting the input voltage or current signal. The input end of the input protection circuit is connected to the output end of the signal input terminal, and the output end is connected to the input end of the voltage / current adaptive circuit.

[0033] It also includes a signal conditioning and isolation circuit for controlling the voltage value or current value converted by the voltage / current adaptive circuit and filtering the front-stage signal. The input end of the signal conditioning and isolation circuit is connected to the output end of the voltage / current adaptive circuit.

[0034] It also includes an MCU acquisition protection circuit for protecting the collected input signal. The input end of the MCU acquisition protection circuit is connected to the output end of the signal conditioning and isolation circuit, and the output end is connected to the MCU end ADC acquisition module.

[0035] It also includes a power supply module for powering the circuit, and the power supply module is respectively connected to the signal conditioning and isolation circuit, the MCU acquisition protection circuit and the MCU-side ADC acquisition module.

[0036] The utility model proposes an adaptive analog signal acquisition circuit, comprising a signal input terminal for sensor connection and signal input, a voltage / current adaptive circuit for converting and judging the sensor input signal, and an MCU-side ADC acquisition module for input signal acquisition, wherein the input end of the sensor is connected to the signal input terminal to realize signal input, the MCU-side ADC acquisition module is used to collect the voltage value or current value in the voltage / current adaptive circuit, the voltage / current adaptive circuit receives the signal transmitted by the signal input terminal, and appropriately processes the input signal to protect the subsequent circuit, and the voltage / current values ​​at both ends of the signal input terminal are converted by the voltage / current adaptive circuit to obtain the required voltage value.

[0037] The voltage / current adaptive circuit is divided into two parts, which are used to distinguish and collect voltage or current sensors. They are current sensor collection circuit and voltage sensor collection circuit. The current sensor collection circuit includes K1, K2, R1, R2, and the voltage sensor collection circuit includes K3, K4, R3, R4. The analog switch U1 has four independent channels A, B, C, and D, which are respectively provided with control circuits for controlling independent switches K1, K2, K3, and K4.

[0038] The principle of the current sensor acquisition circuit is as follows: R1 and R2 are resistors with a resistance value less than 1K. When the input signal is first collected, the default state of the four switches of U1 is K1 and K4 closed, and K2 and K3 are disconnected. When a sensor signal comes in, the ADC acquisition module on the MCU side collects the first voltage value V1, closes K2, and the states of K1, K3, and K4 remain unchanged. The second voltage value V2 is measured, and V1 and V2 are compared. If V1=V2, it is a voltage type sensor. If V1≠V2, it is a current type sensor. After confirming the sensor type, if it is a current type, V1 is substituted into the calculation to obtain the sensor input current I=V1 / R1; if the sensor is a voltage type, it is transferred to the voltage type sensor acquisition circuit.

[0039] The principle of the voltage type sensor acquisition circuit is as follows: R3 and R4 are resistors with resistance values ​​greater than 10K; after confirming that the sensor type is voltage type, K1, K2, and K4 are disconnected, K3 is closed, and the voltage value V3 measured across R4 is brought into the calculation to obtain the current sensor input voltage U=V3 / R4*(R3+R4).

[0040] In this embodiment, an input protection circuit is also provided, which is used to protect the input voltage or current signal, and its input end is connected to the output end of the signal input terminal, and the output end is connected to the input end of the voltage / current adaptive circuit.

[0041] In this embodiment, a signal conditioning and isolation circuit is also provided, which is used to control the voltage value or current value after conversion by the voltage / current adaptive circuit and filter the previous stage signal, and its input end is connected to the output end of the voltage / current adaptive circuit.

[0042] In this embodiment, an MCU acquisition protection circuit is also provided for protecting the collected input signal in the voltage / current adaptive circuit, the input end of which is connected to the output end of the signal conditioning and isolation circuit, and the output end is connected to the ADC acquisition module at the MCU end.

[0043] In this embodiment, a power supply module is also provided to supply power to the signal conditioning and isolation circuit, the MCU acquisition protection circuit and the MCU-side ADC acquisition module.

[0044] The utility model effectively solves the technical problem that the voltage or current type sensor acquisition circuit cannot realize self-adaptation, facilitates actual use on site, improves work efficiency and reduces device cost.

[0045] The above is only a preferred embodiment of the present invention and does not constitute any other limitation on the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. An adaptive analog signal acquisition circuit, characterized in that: Including signal input terminal, voltage / current adaptive circuit and MCU end ADC acquisition module, Signal input terminal, used to input voltage or current signal of sensor; A voltage / current adaptive circuit is used to convert and judge the voltage or current signal input by the signal input terminal, the input end of the voltage / current adaptive circuit is connected to the output end of the input end protection circuit, the voltage / current adaptive circuit includes an analog switch U1 and a resistor R, the U1 includes independent switches K1, K2, K3, K4, the resistors include R1, R2, R3, R4, the U1 has four independent channels A, B, C, D, which are respectively provided with control circuits for controlling the independent switches K1, K2, K3, K4, the independent switches The independent switch K1 and the resistor R1 are connected in series, the independent switch K1 and the resistor R1 are connected in parallel to the signal input terminal and the ADC acquisition module on the MCU end, the independent switch K2 is connected in series to the resistor R2, the independent switch K2 and the resistor R2 are connected in parallel to the resistor R1, the independent switch K3 and the resistor R4 are connected in series, the independent switch K3 and R4 are connected in parallel to the signal input terminal and the ADC acquisition module on the MCU end, the resistor R3 is connected in series to the signal input terminal and the ADC acquisition module on the MCU end, and the independent switch K4 is connected in parallel to the resistor R3, The R1 and R2 are resistors with a resistance value less than 1K, and the R3 and R4 are resistors with a resistance value greater than 10K. The ADC acquisition module on the MCU side is used to collect the voltage value or current value in the voltage / current adaptive circuit.

2. The adaptive analog signal acquisition circuit according to claim 1, characterized in that: It also includes an input protection circuit for protecting the input voltage or current signal. The input end of the input protection circuit is connected to the output end of the signal input terminal, and the output end is connected to the input end of the voltage / current adaptive circuit.

3. The adaptive analog signal acquisition circuit according to claim 1, characterized in that: It also includes a signal conditioning and isolation circuit for controlling the voltage value or current value converted by the voltage / current adaptive circuit and filtering the front-stage signal. The input end of the signal conditioning and isolation circuit is connected to the output end of the voltage / current adaptive circuit.

4. The adaptive analog signal acquisition circuit according to claim 3, characterized in that: It also includes an MCU acquisition protection circuit for protecting the collected input signal. The input end of the MCU acquisition protection circuit is connected to the output end of the signal conditioning and isolation circuit, and the output end is connected to the MCU end ADC acquisition module.

5. The adaptive analog signal acquisition circuit according to claim 3 or 4, characterized in that: It also includes a power supply module for powering the circuit, and the power supply module is respectively connected to the signal conditioning and isolation circuit, the MCU acquisition protection circuit and the MCU-side ADC acquisition module.

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