CN102162747A - Signal processing circuit for photoelectric sensor - Google Patents

Abstract

A signal processing circuit for a photoelectric sensor, comprising a light receiving circuit, a light signal processing circuit, a temperature sensor circuit, a pressure sensor, a single-chip microcomputer circuit, a power supply circuit and a display circuit, the single-chip microcomputer circuit is mainly composed of a single-chip microcomputer, the light-receiving circuit receives light signals, and the light-receiving The circuit is electrically connected to the optical signal processing circuit, and the optical signal processing circuit processes the optical signal received by the light receiving circuit. The signal output terminal is electrically connected with the single-chip microcomputer, and the power supply circuit supplies power for the single-chip microcomputer. The present invention is used in a photoelectric sensor signal processing circuit that can overcome the influence of sensor performance change, measured medium optical characteristic change, measured medium temperature, pressure, etc. for the photoelectric liquid level meter, and can also be used for normal pressure, normal temperature or pressure, temperature In a changing smoke environment, measure the smoke concentration, etc.

Description

A photoelectric sensor signal processing circuit

technical field

The invention belongs to the field of electronics, and in particular relates to a photoelectric signal processing circuit for signal display and processing of a photoelectric liquid level gauge.

Background technique

At present, in the liquid level measurement technology of water, oil and toxic or corrosive liquids, the method of photoelectric signal detection is used for some special occasions (such as the amount of toxic liquid loaded, the volume of liquid in a closed non-transparent container) etc.) are effective where other readings are inconvenient. In terms of photoelectric signal processing, due to the aging of components and the pollution of the sensor by the environment in the workplace, the output of the optical signal drifts, which is different from the original calibration value, which reduces the performance of the photoelectric instrument system. At the same time, the working pressure and temperature of the measured liquid The change of the measured medium affects the density of the measured medium and the precise volume of the container, resulting in inaccurate liquid level measurement, and the measured value needs to be corrected, but the existing liquid level gauge lacks such a correction function.

Contents of the invention

The purpose of the present invention is to provide a photoelectric sensor signal processing circuit that corrects the influence of the performance change of the liquid level gauge, the optical characteristic change of the measured medium, and the temperature and pressure changes of the measured medium on the liquid level measurement value.

The technical solution of the present invention to achieve the above object is a photoelectric sensor signal processing circuit. The single-chip microcomputer circuit is mainly composed of a single-chip microcomputer, the optical receiving circuit receives optical signals, the optical receiving circuit is electrically connected to the optical signal processing circuit, the optical signal processing circuit processes the optical signals received by the optical receiving circuit, and the optical receiving circuit The signal processing circuit is electrically connected to the single-chip electromechanical, the temperature sensor circuit is electrically connected to the single-chip electromechanical, the single-chip microcomputer is electrically connected to the display circuit, the signal output terminal of the pressure sensor is electrically connected to the single-chip electromechanical, and the power supply circuit supplies power to the single-chip microcomputer.

The light receiving circuit includes a P-I-N photodetector or an APD photodetector or a photoelectric tube or a photoresistor.

The temperature sensor circuit includes a temperature sensor.

The temperature sensor is a semiconductor thermometer or a thermistor.

The display circuit includes a display driving circuit and a display device, and the display driving circuit drives the display device.

The optical signal processing circuit includes a filter circuit, a signal amplifying circuit and an A/D converter, the filter circuit is electrically connected to the signal amplifying circuit, and the signal amplifying circuit is electrically connected to the A/D converter.

The display circuit includes 6 display devices.

The pressure sensor is selected from Photohelic3000SGT series pressure sensor or WWDP series pressure sensor. It also includes a serial port communication circuit, which is composed of RS232 and its peripheral circuits.

The advantage of the present invention is that: due to the use of light receiving circuit, temperature sensor circuit, pressure sensor and other devices, it can provide more accurate values from the aspects of optics, temperature, pressure, etc., so it can correct sensor performance changes and be used in photoelectric liquid level gauges. Measuring the influence of the change of the optical characteristics of the medium, the temperature and pressure of the measured medium on the measured value of the liquid level; the invention accurately displays the liquid level through the photoelectric conversion technology and the signal processing circuit with the single-chip microcomputer as the core.

Description of drawings

Fig. 1 is the schematic diagram of circuit structure of the present invention;

Fig. 2 is the schematic diagram of the circuit structure of the optical receiving circuit 1 of the present invention;

Fig. 3 is the circuit diagram of filter circuit 2-1 of the present invention;

Fig. 4 is the circuit diagram of signal amplifying circuit 2-2 of the present invention;

Fig. 5 is the schematic circuit diagram of A/D converter 2-3 of the present invention;

6 is a schematic diagram of the circuit connection of the light receiving circuit 1, the filter circuit 2-1 and the signal amplifying circuit 2-2 of the present invention;

FIG. 7 is a schematic circuit diagram of a display circuit 5 of the present invention;

Fig. 8 is the schematic circuit diagram of single-chip microcomputer circuit 7 of the present invention;

Fig. 9 is a schematic circuit diagram of the temperature sensor circuit 3 of the present invention;

Fig. 10 is a schematic circuit diagram of the pressure sensor 6 of the present invention;

FIG. 11 is a schematic circuit diagram of a power supply circuit 4 of the present invention;

FIG. 12 is a schematic circuit diagram of the serial port communication circuit 8 of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in Figures 1 to 12, a photoelectric sensor signal processing circuit includes a light receiving circuit 1, an optical signal processing circuit 2, a temperature sensor circuit 3, a pressure sensor 6, a single-chip microcomputer circuit 7, a power supply circuit 4 and a display circuit 5. The single-chip microcomputer circuit 7 is mainly composed of a single-chip microcomputer U1, the light receiving circuit 1 receives an optical signal, the light receiving circuit 1 is electrically connected to the light signal processing circuit 2, and the light signal processing circuit 2 processes the light signal received by the light receiving circuit 1. The optical signal, the optical signal processing circuit 2 is electrically connected to the single-chip microcomputer U1, the temperature sensor circuit 3 is electrically connected to the single-chip microcomputer U1, the single-chip microcomputer U1 is electrically connected to the display circuit 5, and the signal output terminal of the pressure sensor 6 is connected to the single-chip microcomputer U1. The single-chip microcomputer U1 is electrically connected, and the power supply circuit 4 supplies power for the single-chip microcomputer U1.

As shown in Figures 1 and 2, the light receiving circuit 1 includes a photoelectric sensor or a photoresistor or a P-I-N photodetector or an APD photodetector, and can also be connected to other photoelectric signal conversion sensors. As shown in FIG. 9 , the temperature sensor circuit 3 includes a temperature sensor. The temperature sensor is a semiconductor thermometer, a thermistor or a thermocouple.

As shown in FIGS. 1 and 7, the display circuit 5 includes a display driving circuit 5-1 and a display device 5-2, and the display driving circuit 5-1 drives the display device 5-2.

As shown in Figures 1, 3, 4, 5, and 6, the optical signal processing circuit 2 includes a filter circuit 2-1, a signal amplification circuit 2-2 and an A/D converter 2-3, and the filter circuit 2- 1 is electrically connected to the signal amplifying circuit 2-2, and the signal amplifying circuit 2-2 is electrically connected to the A/D converter 2-3. A/D converter 2-3 selects AD7890 for use. The filter circuit 2-1 includes a capacitor C01, a capacitor C02, a capacitor C03, a capacitor C04, a capacitor C05, and a capacitor C06, the capacitor C01 and the capacitor C02 are connected in parallel, the capacitor C03 is connected in parallel with the capacitor C04, and the capacitor C05 and the capacitor C06 is connected in parallel, one end of the capacitor C01 and the capacitor C02 is connected to the power supply VCC, one end of the capacitor C03 and the capacitor C04 is connected to -12V, one end of the capacitor C05 and the capacitor C06 is connected to +12V, the capacitor C01, the capacitor C02, the capacitor C03, the capacitor The other ends of C04, capacitor C05 and capacitor C06 are all grounded. The signal amplifying circuit 2-2 includes an amplifier, a resistor, a capacitor and a resistor.

As shown in Figures 1 and 8, four photoelectric sensors are used in this embodiment. Each photoelectric sensor is connected with a signal amplifying circuit 2-2. The single-chip microcomputer circuit 7 includes a single-chip microcomputer U1, a reset circuit, a crystal oscillator circuit, and also includes a large-capacity serial E2PROM. Large-capacity serial E2PROM selects the model as AT24C512.

As shown in Figures 1 and 7, the display circuit 5 includes six display devices 5-2.

As shown in Figures 1 and 10, the pressure sensor 6 can be a Photohelic3000SGT series pressure sensor or a WWDP series pressure sensor.

As shown in Figures 1 and 12, it also includes a serial port communication circuit 8, which is composed of RS232 and its peripheral circuits.

The invention can overcome the influence of sensor performance change, measured medium optical characteristic change, measured medium temperature, pressure and the like when used in the photoelectric liquid level meter, and can correctly process and display the liquid level of the measured liquid. This application calculates the initial performance parameters and the measured performance parameters through the single-chip circuit 7, and can perform calculations on changes in temperature and pressure in real time, correct the influence of temperature and pressure changes on the measured liquid, and correct the liquid level gauge. performance degradation etc.

The invention can also be used for measuring smoke concentration and the like in normal pressure and normal temperature or in a smoke environment with pressure and temperature changes.

Claims (9)

1. A photoelectric sensor signal processing circuit, characterized in that it includes a light receiving circuit (1), an optical signal processing circuit (2), a temperature sensor circuit (3), a pressure sensor (6), a single-chip microcomputer circuit (7), a power supply circuit (4) and display circuit (5), the single-chip microcomputer circuit (7) is mainly composed of a single-chip microcomputer (U1), the optical receiving circuit (1) receives optical signals, and the optical receiving circuit (1) and optical signal processing The circuit (2) is electrically connected, the optical signal processing circuit (2) processes the optical signal received by the optical receiving circuit (1), the optical signal processing circuit (2) is electrically connected to the single chip microcomputer (U1), and the temperature The sensor circuit (3) is electrically connected to the single-chip microcomputer (U1), the single-chip microcomputer (U1) is electrically connected to the display circuit (5), the signal output terminal of the pressure sensor (6) is electrically connected to the single-chip microcomputer (U1), and the power supply The circuit (4) supplies power to the microcontroller (U1). 2. The photoelectric sensor signal processing circuit according to claim 1, characterized in that: the light receiving circuit (1) includes a P-I-N photodetector or an APD photodetector or a photoelectric tube or a photoresistor. 3. The photoelectric sensor signal processing circuit according to claim 1, characterized in that the temperature sensor circuit (3) includes a temperature sensor. 4. The photoelectric sensor signal processing circuit according to claim 3, characterized in that: the temperature sensor is a semiconductor thermometer or a thermistor. 5. The photoelectric sensor signal processing circuit according to claim 1, characterized in that: the display circuit (5) includes a display drive circuit (5-1) and a display device (5-2), and the display drive circuit ( 5-1) Driving the display device (5-2). 6. The photoelectric sensor signal processing circuit according to claim 1, characterized in that: the optical signal processing circuit (2) includes a filter circuit (2-1), a signal amplification circuit (2-2) and an A/D conversion device (2-3), the filter circuit (2-1) is electrically connected to the signal amplifying circuit (2-2), and the signal amplifying circuit (2-2) is electrically connected to the A/D converter (2-3) connect. 7. The photoelectric sensor signal processing circuit according to claim 5, characterized in that the display circuit (5) comprises 6 display devices (5-2). 8. The photoelectric sensor signal processing circuit according to claim 1, characterized in that: the pressure sensor (6) is a Photohelic3000SGT series pressure sensor or a WWDP series pressure sensor. 9. The photoelectric sensor signal processing circuit according to claim 1, characterized in that it also includes a serial communication circuit (8), and the serial communication circuit (8) is composed of RS232 and its peripheral circuits.

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