1. A dust concentration sensor calibration method is characterized by specifically comprising the following steps:

s1: the dust particles act on an external physical field, and a detector is used for collecting electric signals generated by dust;

s2: calculating the actual dust concentration by weighing and sampling;

s3: determining a curve relation between the electric signal value and the dust concentration value by comparing the numerical value of the electric signal with the numerical value of the actual dust concentration;

s4: according to the curves determined in the step S3, respectively obtaining the dust concentration values to be 25mg/m³、50mg/m³、100mg/m³、200mg/m³And 1000mg/m³The corresponding electrical signal values a, b, c, d and e;

s5: respectively to 0-25 mg/m³、25～50mg/m³、50～100mg/m³、100～200mg/m³And 200 to 1000mg/m³The five segmented curves were calibrated.

2. The dust concentration sensor calibration method according to claim 1, wherein in step S5, 0-25 mg/m is calibrated³The piecewise curve uses a quadratic curve equation.

3. The dust concentration sensor calibration method according to claim 2, wherein in step S5, 0-25 mg/m is calibrated³The quadratic curve equation adopted by the piecewise curve is as follows: k is₀x²，x≤a。

4. The dust concentration sensor calibration method according to claim 1, wherein in step S5, 25-50 mg/m of calibration is performed³、50～100mg/m³、100～200mg/m³And 200 to 1000mg/m³The piecewise curve uses a linear equation.

5. The dust concentration sensor calibration method according to claim 4, wherein in step S5, 25-50 mg/m is calibrated³、50～100mg/m³、100～200mg/m³And 200 to 1000mg/m³The linear equations adopted by the piecewise curves are respectively as follows:

wherein the content of the first and second substances,

Background

The dust concentration sensor can realize the on-line monitoring of the dust concentration, the monitoring result is transmitted to a monitoring center or terminal equipment in real time, and the monitoring result of the dust sensor is an important basis for evaluating the sanitation of the operation environment, so that the dust sensor is generally applied to dust pollution places of coal mines, metal mines and the ground. The dust sensor is used for indirectly measuring the dust concentration, the principle of the dust concentration sensor is that dust particles act on an external physical field, an electric signal is generated on a detector, the strength of the electric signal and the dust concentration present a positive correlation, then the curve relationship between the electric signal and the dust concentration value is determined by comparing the numerical value of the electric signal with the actual dust concentration value (the actual dust concentration value is obtained by weighing, sampling and calculating), the electric signal is converted into the dust concentration value through the curve relationship, the dust concentration is monitored on line in real time, the conversion process is a calibration process, the curve is a calibration curve, the calibration curve is usually not a straight line and is a multi-term curve, the intercept of the curve is the background value of the sensor, and the calibration process needs to be subtracted. As shown in fig. 1, the parabolic curve is a curve relationship between actual dust concentration and an electrical signal (regarded as a curve to be calibrated), a z point is a base value of the sensor, the base value is caused by noise in the signal and is unavoidable, the curve to be calibrated is calibrated through a broken line, the broken line can be divided into n sections, the segmented proportionality coefficients are (k1, k2, k3, …, kn), the more segments are, the higher the monitoring calibration precision is, the more complicated the calculation is, and the segmented coefficient is the calibration coefficient of the sensor.

In the field application process of the dust sensor, due to factors such as the difference of dust types and the change of an external physical field, the calibration coefficient of the sensor needs to be modified, the calibration coefficient is directly modified in the conventional method, but the monitoring value of the sensor is discontinuous, and the problems of instability and large error of the monitoring result exist.

On the other hand, local values of the sensors are changed due to differences of field direct-current power supply stability, surrounding electromagnetic field interference conditions, field grounding conditions and the like, and the background value is not a fixed value but a fluctuation value in a certain range, and the fluctuation of the background value has a large influence on the low-concentration monitoring precision. At present, aiming at the background value of a sensor, the background value is directly modified, namely, the fixed background value is directly subtracted from an electric signal of the sensor, and then the calibration is carried out according to a calibration coefficient, the problems that frequent calibration is needed, the background value is continuously modified, and the maintenance work of a field sensor is increased exist; and the low concentration monitoring result of the sensor has large fluctuation and large error.

Therefore, a convenient, accurate and fast calibration method for the dust concentration sensor is needed.

Disclosure of Invention

In view of this, the present invention aims to provide a calibration method for a dust concentration sensor, which realizes fast calibration of the dust concentration sensor, does not generate discontinuity of a calibration curve, and reduces the influence of a background value on a low concentration detection result; the dust concentration sensor can be calibrated quickly and conveniently, and the calibration result is stable and accurate.

In order to achieve the purpose, the invention provides the following technical scheme:

a dust concentration sensor calibration method specifically comprises the following steps:

s1: the dust particles act on an external physical field, and a detector is used for collecting electric signals generated by dust;

s2: calculating the actual dust concentration by weighing and sampling;

s3: determining a curve relation between the electric signal value and the dust concentration value by comparing the numerical value of the electric signal with the numerical value of the actual dust concentration;

s4: according to the curves determined in the step S3, respectively obtaining the dust concentration values to be 25mg/m³、50mg/m³、100mg/m³、200mg/m³And 1000mg/m³The corresponding electrical signal values a, b, c, d and e;

s5: respectively to 0-25 mg/m³、25～50mg/m³、50～100mg/m³、100～200mg/m³And 200 to 1000mg/m³The five segmented curves were calibrated.

Further, in step S5, the calibration is performed at 0-25 mg/m³The piecewise curve uses a quadratic curve equation.

Further, in step S5, the calibration is performed at 0-25 mg/m³The quadratic curve equation adopted by the piecewise curve is as follows: k is₀x²，x≤a。

Further, step (ii)In S5, calibrating the concentration to be 25-50 mg/m³、50～100mg/m³、100～200mg/m³And 200 to 1000mg/m³The piecewise curve uses a linear equation.

Further, in step S5, calibrating 25-50 mg/m³、50～100mg/m³、100～200mg/m³And 200 to 1000mg/m³The linear equations adopted by the piecewise curves are respectively as follows:

wherein the content of the first and second substances,

the invention has the beneficial effects that: the invention can realize the quick calibration of the dust concentration sensor, the discontinuity of a calibration curve can not occur, and the influence of a background value on a low concentration detection result is reduced; and the interference of zero point is eliminated, the zero point is not required to be set in the calibration process, and the detection precision of low concentration is improved. Overall, the invention enables the dust concentration sensor to be calibrated quickly and conveniently, and the calibration result is stable and accurate.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a graphical illustration of a conventional calibration method;

FIG. 2 is a graphical illustration of the calibration method of the present invention;

FIG. 3 is a flow chart of the calibration method of the present invention.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

Referring to fig. 2 to 3, the present invention provides a calibration method for a dust concentration sensor, which specifically includes the following steps:

s1: the dust particles act on an external physical field, and a detector is used for collecting electric signals generated by dust;

s2: calculating the actual dust concentration by weighing and sampling;

s3: determining a curve relation between the electric signal value and the dust concentration value by comparing the numerical value of the electric signal with the numerical value of the actual dust concentration;

s4: according to the curves determined in the step S3, respectively obtaining the dust concentration values to be 25mg/m³、50mg/m³、100mg/m³、200mg/m³And 1000mg/m³The corresponding electrical signal values a, b, c, d and e;

s5: respectively to 0-25 mg/m³、25～50mg/m³、50～100mg/m³、100～200mg/m³And 200 to 1000mg/m³The five segmented curves were calibrated.

Measuring range of 0-1000 mg/m of dust sensor³The calibrated test error is required to be less than or equal to 15 percent, namely (real concentration value-test concentration value)/real concentration value is 100 percent to be less than or equal to +/-15 percent, the lower the concentration is, the more difficult the calibration is, when the concentration is low, the curve is divided into more sections, the higher the concentration is, and the influence of zero point fluctuation is eliminated0～25mg/m³The calibration is carried out by adopting a quadratic curve equation, and the concentration is 25-50 mg/m³The method is calibrated by adopting a straight line with the slope of k1 and is 50-100 mg/m³The method is calibrated by adopting a straight line with the slope of k2 and is 100-200 mg/m³The method is calibrated by adopting a straight line with the slope of k3 and is 200-1000 mg/m³The calibration is carried out by using a straight line with the slope of k4, and the equation of the calibration straight line is as follows:

wherein the content of the first and second substances,

from the above formula, it can be seen that the unknown parameters a, k1, k2, k3 and k4 can be calibrated by determining a point and 4 slopes by the method of the present invention, and since each segment point is a function of a set point and 4 slopes, no break point occurs when any segment slope is adjusted. On the other hand, through the calibration of the quadratic curve, the interference of a zero point is eliminated, the zero point does not need to be set in the calibration process, and the detection precision of low concentration is improved.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.