Matrix key circuit of ultrasonic liquid level sensor

Abstract

The utility model discloses a matrix keying circuit of an ultrasonic liquid level sensor, which comprises a microcontroller, a row signal line, a column signal line, an isolation power supply circuit, an anti-interference module, a signal processing and control unit and a collaborative module interface, and the row signal line and the column signal line are both electrically connected with the microcontroller and the anti-interference module. The anti-interference module is electrically connected with the isolation power supply circuit and the signal processing and control unit, and the signal processing and control unit is electrically connected with the cooperation module interface. According to the utility model, the isolation power supply circuit is separated from a system line, so that ground loop interference can be effectively avoided, and through cooperation of the filter circuit and the isolation circuit, high-frequency noise can be effectively filtered, power supply ripples can be reduced, signal conduction interference can be effectively blocked, and the stability of the matrix key circuit in the using process can be improved; therefore, the stability of the ultrasonic liquid level sensor is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to ultrasonic liquid level sensor technical field especially relates to a kind of matrix key circuit of ultrasonic liquid level sensor. BACKGROUND

[0002] The matrix key circuit of ultrasonic liquid level sensor is mainly used to realize the interactive control between user and sensor, and its core function is to complete parameter setting, mode switching and system debugging by key operation, the anti-interference effect of matrix key circuit is not ideal in use process, when long distance or high-density wiring, row and column signal lines of matrix key are prone to capacitive coupling or inductive coupling between adjacent wires, leading to signal crosstalk, and further it can cause the situation of key false triggering (such as when pressing down "1" key, false triggering "4" key), in addition, affected by system long power line, there is ground loop interference, thereby affecting the stable use of ultrasonic liquid level sensor, according to the above situation, the present application proposes a kind of matrix key circuit of ultrasonic liquid level sensor. SUMMARY

[0003] The utility model discloses a kind of matrix key circuit of ultrasonic liquid level sensor to solve the shortcomings in prior art.

[0004] To achieve the above object, the utility model adopts the following technical scheme:

[0005] A kind of matrix key circuit of ultrasonic liquid level sensor, including microcontroller, row signal line, column signal line, isolation power supply circuit, anti-interference module, signal processing and control unit and collaborative module interface, the row signal line and column signal line are all electrically connected with microcontroller and anti-interference module, anti-interference module and isolation power supply circuit and signal processing and control unit are electrically connected, signal processing and control unit and collaborative module interface are electrically connected;

[0006] The isolation power supply circuit and microcontroller, signal processing and control unit and collaborative module interface are electrically connected;

[0007] The anti-interference module includes filter circuit and isolation circuit.

[0008] Preferably, the isolation power supply circuit comprises chip U1 and transformer T1, one end of resistor R3 and one end of resistor R1 are electrically connected to pin 1 of chip U1, one end of resistor R2 and negative electrode of diode D1 are electrically connected to pin 5 of chip U1, positive electrode of diode D3 is electrically connected to pin 4 of chip U1, negative electrode of diode D3 is electrically connected to negative electrode of diode D2, pin 4 of chip U1 is electrically connected to pin 2 of transformer T1, positive electrode of diode D2, positive electrode of diode D1, the other end of resistor R1 and the other end of resistor R2 are all electrically connected to pin 1 of transformer T1, one end of capacitor C1 and one end of capacitor C2 are electrically connected to pin 1 of transformer T1, the other end of capacitor C1, the other end of capacitor C2, the other end of resistor R3 and pin 2 of chip U1 are all grounded, one end of resistor R4 and one end of resistor R5 are electrically connected to pin 3 of chip U1, the other end of resistor R4 is electrically connected to pin 2 of transformer T1, positive electrode of diode D4 is electrically connected to pin 4 of transformer T1, pin 3 of transformer T1 is electrically connected to the other end of resistor R5, one end of capacitor C3 and one end of capacitor C4 are electrically connected to pin 3 of transformer T1, the other end of capacitor C3 and the other end of capacitor C4 are both electrically connected to negative electrode of diode D4, negative electrode of diode D5 is electrically connected to pin 3 of transformer T1, one end of resistor R6 is electrically connected to positive electrode of diode D5, negative electrode of diode D5 and pin 3 of transformer T1 are both grounded, pin 2 of chip U1 and pin 1 of transformer T1 are both electrically connected to the input end of the power supply, pin 3 and pin 4 of transformer T1 are both electrically connected to the input end of the microcontroller.

[0009] Preferably, the filter circuit comprises operational amplifier U2, positive electrode of diode D6 is electrically connected to pin 1 of operational amplifier U2, one end of capacitor C6 is electrically connected to pin 2 of operational amplifier U2, one end of capacitor C5 and one end of resistor R7 are electrically connected to the other end of capacitor C6, one end of capacitor C7 is electrically connected to the other end of resistor R7, the other end of capacitor C7 and negative electrode of diode D6 are both electrically connected to pin 3 of operational amplifier U2, one end of capacitor C8 is electrically connected to pin 5 of operational amplifier U2, one end of resistor R8 is electrically connected to the other end of capacitor C8, the other end of resistor R8 is grounded, the other end of capacitor C5 is electrically connected to the column signal line, pin 3 of operational amplifier U2 is electrically connected to the row signal line.

[0010] Preferably, the isolation circuit comprises an opto-isolator chip U3, one end of a capacitor C9, a negative electrode of a diode D7 and one end of a resistor R9 are electrically connected to a pin 1 of the opto-isolator chip U3, the positive electrode of the diode D7 and the other end of the capacitor C9 are electrically connected to a pin 2 of the opto-isolator chip U3, one end of a resistor R11 is electrically connected to the pin 2 of the opto-isolator chip U3, the other end of the resistor R11 is electrically connected to a column signal line, one end of a capacitor C11 is electrically connected to a pin 5 of the opto-isolator chip U3, the other end of the capacitor C11 is electrically connected to the pin 1 of the opto-isolator chip U3, one end of a capacitor C10 is electrically connected to a pin 3 of the opto-isolator chip U3, the other end of the capacitor C10 is electrically connected to one end of a resistor R10, one end of the resistor R10 is electrically connected to a pin 4 of the opto-isolator chip U3, the other end of the capacitor C10 and the pin 3 of the opto-isolator chip U3 are grounded, and the pin 4 of the opto-isolator chip U3 is electrically connected to a row signal line.

[0011] Preferably, the row signal line is connected to an I / O interface of a microcontroller, and is used for outputting low-level signals row by row to activate key scanning; and the column signal line is connected to an input pin of the microcontroller, and is used for detecting the level change of the corresponding column signal line when the row signal line is activated, so as to locate the position of the key.

[0012] Preferably, the cooperation module interface is connected to a master control chip through a bus SPI communication, and the master control chip is used for triggering device control or alarm functions.

[0013] Preferably, the filter circuit is used for filtering high-frequency interference and reducing power supply ripple.

[0014] Compared with the prior art, the utility model has the advantages that:

[0015] The utility model discloses through setting up isolation power supply circuit and system circuit separation, can effectively avoid ground loop interference, through filter circuit and isolation circuit cooperation, can effectively filter high -frequency noise, reduce power supply ripple, block signal conduction interference, improve the stability in the use process of matrix key circuit, and then improve the stability of ultrasonic liquid level sensor. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A connection block diagram of the matrix key circuit of the ultrasonic liquid level sensor is provided for the utility model;

[0017] Figure 2 A circuit diagram of the isolation power supply circuit in the matrix key circuit of the ultrasonic liquid level sensor is provided for the utility model;

[0018] Figure 3The utility model provides a kind of matrix key circuit's circuit diagram of filter circuit of ultrasonic liquid level sensor.

[0019] Figure 4 The utility model provides a kind of matrix key circuit's circuit diagram of isolation circuit of ultrasonic liquid level sensor. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments.

[0021] Referring to Figures 1-4 A kind of matrix key circuit of ultrasonic liquid level sensor, including microcontroller, row signal line, column signal line, isolation power supply circuit, anti-interference module, signal processing and control unit and collaborative module interface, row signal line and column signal line are electrically connected with microcontroller and anti-interference module, wherein row signal line is connected with the I / O interface of microcontroller, is used to output low-level signal row by row to activate key scanning, column signal line is connected to the input pin of microcontroller, detects the corresponding column signal line level change when row signal line activation, to locate the position of key;

[0022] Anti-interference module and isolation power supply circuit and signal processing and control unit are electrically connected, signal processing and control unit and collaborative module interface are electrically connected, wherein collaborative module interface is connected with master control chip by bus SPI communication, and device control or alarm function is triggered by master control chip;

[0023] The isolation power supply circuit, the microcontroller, the signal processing and control unit and the cooperative module are electrically connected; wherein the isolation power supply circuit comprises a chip U1 and a transformer T1, one end of a resistor R3 and one end of a resistor R1 are electrically connected to the pin 1 of the chip U1, one end of a resistor R2 and the negative electrode of a diode D1 are electrically connected to the pin 5 of the chip U1, the positive electrode of a diode D3 is electrically connected to the pin 4 of the chip U1, the negative electrode of the diode D3 is electrically connected to the negative electrode of a diode D2, the pin 4 of the chip U1 is electrically connected to the pin 2 of the transformer T1, the positive electrode of the diode D2, the positive electrode of the diode D1, the other end of the resistor R1 and the other end of the resistor R2 are electrically connected to the pin 1 of the transformer T1, one end of a capacitor C1 and one end of a capacitor C2 are electrically connected to the pin 1 of the transformer T1, the other end of the capacitor C1, the other end of the capacitor C2, the other end of the resistor R3 and the pin 2 of the chip U1 are grounded, one end of a resistor R4 and one end of a resistor R5 are electrically connected to the pin 3 of the chip U1, the other end of the resistor R4 is electrically connected to the pin 2 of the transformer T1, the positive electrode of a diode D4 is electrically connected to the pin 4 of the transformer T1, the other end of the resistor R5 is electrically connected to the pin 3 of the transformer T1, one end of a capacitor C3 and one end of a capacitor C4 are electrically connected to the pin 3 of the transformer T1, the other end of the capacitor C3 and the other end of the capacitor C4 are electrically connected to the negative electrode of the diode D4, the negative electrode of a diode D5 is electrically connected to the pin 3 of the transformer T1, one end of a resistor R6 is electrically connected to the positive electrode of the diode D5, the negative electrode of the diode D5 and the pin 3 of the transformer T1 are grounded, the pin 2 of the chip U1 and the pin 1 of the transformer T1 are electrically connected to the input end of the power supply, the pin 3 and the pin 4 of the transformer T1 are electrically connected to the input end of the microcontroller;

[0024] The anti-interference module comprises a filter circuit and an isolation circuit;

[0025] The filter circuit is used for filtering high-frequency interference and reducing power supply ripple, and the filter circuit comprises an operational amplifier U2, the positive electrode of a diode D6 is electrically connected to the pin 1 of the operational amplifier U2, one end of a capacitor C6 is electrically connected to the pin 2 of the operational amplifier U2, one end of a capacitor C5 and one end of a resistor R7 are electrically connected to the other end of the capacitor C6, one end of a capacitor C7 is electrically connected to the other end of the resistor R7, the other end of the capacitor C7 and the negative electrode of the diode D6 are electrically connected to the pin 3 of the operational amplifier U2, one end of a capacitor C8 is electrically connected to the pin 5 of the operational amplifier U2, one end of a resistor R8 is electrically connected to the other end of the capacitor C8, the other end of the resistor R8 is grounded, the other end of the capacitor C5 is electrically connected to a column signal line, the pin 3 of the operational amplifier U2 is electrically connected to a row signal line;

[0026] The isolation circuit comprises an opto-coupler chip U3, one end of a capacitor C9, a negative electrode of a diode D7 and one end of a resistor R9 are electrically connected to a pin 1 of the opto-coupler chip U3, the positive electrode of the diode D7 and the other end of the capacitor C9 are electrically connected to a pin 2 of the opto-coupler chip U3, one end of a resistor R11 is electrically connected to the pin 2 of the opto-coupler chip U3, the other end of the resistor R11 is electrically connected to a column signal line, one end of a capacitor C11 is electrically connected to a pin 5 of the opto-coupler chip U3, the other end of the capacitor C11 is electrically connected to the other end of the resistor R9, the negative electrode of the diode D7 and the pin 1 of the opto-coupler chip U3, one end of a capacitor C10 is electrically connected to a pin 3 of the opto-coupler chip U3, the other end of the capacitor C10 is electrically connected to one end of a resistor R10, one end of the resistor R10 is electrically connected to a pin 4 of the opto-coupler chip U3, the other end of the capacitor C10 and the pin 3 of the opto-coupler chip U3 are grounded, and the pin 4 of the opto-coupler chip U3 is electrically connected to a row signal line; the isolation power supply circuit is separated from the system circuit, ground loop interference can be effectively avoided, high-frequency noise can be effectively filtered out, power supply ripple can be reduced, signal conduction interference can be blocked, the stability of the matrix key circuit during use can be improved, and the stability of the ultrasonic liquid level sensor can be improved.

[0027] Working principle: when in use, the isolation power supply circuit can be separated from the power supply of the main control system and is powered independently, ground loop interference can be avoided to affect the matrix key circuit, the isolation power supply circuit supplies power to the entire matrix key circuit, during key operation, the operational amplifier U2 in the filter circuit amplifies high-frequency noise and effectively absorbs high-frequency noise generated by mechanical jitter of the contact point through cooperation of the capacitors C5, C6 and C7, the signal after noise reduction is transmitted to the signal processing control unit, the isolation circuit blocks interference on the conduction path through the opto-coupler chip U3 during transmission, so that the stability during signal conduction is ensured, signal interference is reduced, the situation that key mis-triggering is caused by signal crosstalk can be effectively reduced, and the stability during use is improved.

[0028] The above merely describes a preferred specific implementation manner of the utility model, but the protection scope of the utility model is not limited to this, any skilled person in the art can make equivalent replacement or change according to the technical scheme and the utility model concept of the utility model within the technical range disclosed by the utility model, which should be covered in the protection scope of the utility model.

Claims

1. A matrix keying circuit for an ultrasonic liquid level sensor, characterized by The anti-interference module comprises a filter circuit and an isolation circuit. The anti-interference module comprises a filter circuit and an isolation circuit. The anti-interference module comprises a filter circuit and an isolation circuit.

2. A matrix keying circuit for an ultrasonic liquid level sensor according to claim 1, wherein The isolation power supply circuit comprises a chip U1 and a transformer T1, one end of a resistor R3 and one end of a resistor R1 are electrically connected to a pin 1 of the chip U1, one end of a resistor R2 and a negative electrode of a diode D1 are electrically connected to a pin 5 of the chip U1, a positive electrode of a diode D3 is electrically connected to a pin 4 of the chip U1, a negative electrode of the diode D3 is electrically connected to a negative electrode of a diode D2, the pin 4 of the chip U1 is electrically connected to a pin 2 of the transformer T1, a positive electrode of the diode D2, a positive electrode of the diode D1, the other end of the resistor R1 and the other end of the resistor R2 are electrically connected to a pin 1 of the transformer T1, one end of a capacitor C1 and one end of a capacitor C2 are electrically connected to the pin 1 of the transformer T1, the other end of the capacitor C1, the other end of the capacitor C2, the other end of the resistor R3 and a pin 2 of the chip U1 are grounded, one end of a resistor R4 and one end of a resistor R5 are electrically connected to a pin 3 of the chip U1, the other end of the resistor R4 is electrically connected to the pin 2 of the transformer T1, a positive electrode of a diode D4 is electrically connected to a pin 4 of the transformer T1, the other end of the resistor R5 is electrically connected to a pin 3 of the transformer T1, one end of a capacitor C3 and one end of a capacitor C4 are electrically connected to the pin 3 of the transformer T1, the other end of the capacitor C3 and the other end of the capacitor C4 are electrically connected to a negative electrode of the diode D4, a negative electrode of a diode D5 is electrically connected to the pin 3 of the transformer T1, one end of a resistor R6 is electrically connected to a positive electrode of the diode D5, the negative electrode of the diode D5 and the pin 3 of the transformer T1 are grounded, the pin 2 of the chip U1 and the pin 1 of the transformer T1 are electrically connected to an input end of a power supply, the pin 3 and the pin 4 of the transformer T1 are electrically connected to an input end of a microcontroller.

3. A matrix keying circuit for an ultrasonic liquid level sensor according to claim 2, wherein The filter circuit comprises an operational amplifier U2, a positive electrode of a diode D6 is electrically connected to a pin 1 of the operational amplifier U2, one end of a capacitor C6 is electrically connected to a pin 2 of the operational amplifier U2, one end of a capacitor C5 and one end of a resistor R7 are electrically connected to the other end of the capacitor C6, one end of a capacitor C7 is electrically connected to the other end of the resistor R7, the other end of the capacitor C7 and a negative electrode of the diode D6 are electrically connected to a pin 3 of the operational amplifier U2, one end of a capacitor C8 is electrically connected to a pin 5 of the operational amplifier U2, one end of a resistor R8 is electrically connected to the other end of the capacitor C8, the other end of the resistor R8 is grounded, the other end of the capacitor C5 is electrically connected to a column signal line, the pin 3 of the operational amplifier U2 is electrically connected to a row signal line.

4. A matrix keying circuit for an ultrasonic liquid level sensor according to claim 1, wherein The isolation circuit comprises an opto-coupler chip U3, one end of a capacitor C9, a negative electrode of a diode D7 and one end of a resistor R9 are electrically connected to a pin 1 of the opto-coupler chip U3, the positive electrode of the diode D7 and the other end of the capacitor C9 are electrically connected to a pin 2 of the opto-coupler chip U3, one end of a resistor R11 is electrically connected to the pin 2 of the opto-coupler chip U3, the other end of the resistor R11 is electrically connected to a column signal line, one end of a capacitor C11 is electrically connected to a pin 5 of the opto-coupler chip U3, the other end of the capacitor C11 is electrically connected to the other end of the resistor R9, the negative electrode of the diode D7 and the pin 1 of the opto-coupler chip U3, one end of a capacitor C10 is electrically connected to a pin 3 of the opto-coupler chip U3, the other end of the capacitor C10 is electrically connected to one end of a resistor R10, one end of the resistor R10 is electrically connected to a pin 4 of the opto-coupler chip U3, the other end of the capacitor C10 and the pin 3 of the opto-coupler chip U3 are grounded, and the pin 4 of the opto-coupler chip U3 is electrically connected to a row signal line.

5. A matrix keying circuit for an ultrasonic liquid level sensor according to claim 1, wherein The row signal line is connected to an I / O interface of the microcontroller, and is used for outputting low-level signals row by row to activate key scanning; the column signal line is connected to an input pin of the microcontroller, and is used for detecting the level change of the corresponding column signal line when the row signal line is activated, so as to locate the key position.

6. A matrix keying circuit for an ultrasonic liquid level sensor according to claim 1, wherein The cooperative module interface is connected to a master control chip through a bus SPI, and the master control chip is used for triggering device control or alarm functions.

7. A matrix keying circuit for an ultrasonic liquid level sensor according to claim 1, wherein The filter circuit is used for filtering high-frequency interference and reducing power supply ripple.

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