Metering signal reference line establishing and using method of photoelectric metering instrument

Abstract

The invention discloses a metering signal datum line establishing method of a photoelectric metering instrument. The metering signal datum line establishing method comprises the following steps: step 1, establishing an initial datum line; 2, refreshing the reference line when the maximum or minimum sampling signal amplitude continuously changes for multiple times; and 3, establishing an upper return difference reference line and a lower return difference reference line. The invention further discloses a metering signal datum line using method of the photoelectric metering instrument, before the upper return difference datum line and the lower return difference datum line are established, 1 is output if the amplitude of a sampling signal is larger than an initial datum line, and 0 is output if the amplitude of the sampling signal is smaller than the initial datum line; after the upper return difference datum line and the lower return difference datum line are established, if Vnmax is larger than or equal to the sampling signal amplitude and larger than the upper return difference datum line, 1 is output; if the lower return difference reference line is larger than the sampling signal amplitude value and is larger than or equal to Vnmin, 0 is output.

Description

Technical Field

[0001] The invention belongs to the field of photoelectric measuring instruments, and in particular relates to a method for establishing and using a measuring signal baseline of a photoelectric measuring instrument. Background Art

[0002] Measuring instruments can be divided into electromagnetic induction, ultrasonic or photoelectric types according to their measuring principles.

[0003] Among them, the metering signal baseline in the photoelectric meter is a line used as a reference standard in the process of photoelectric signal acquisition and processing. For example, in a photoelectric detection circuit, the voltage signal corresponding to the absence of light (dark current state) is set as the baseline (generally zero level). When there is light, the photodiode generates photocurrent, and the amplitude change of the voltage signal converted by the amplifier circuit relative to this baseline represents the change in light intensity. That is, by setting such a baseline, it is easy to quantify and compare light of different intensities and output a regular digital signal of 0 or 1, thereby achieving measurement.

[0004] Then, the working conditions of photoelectric measuring instruments in actual use are more variable, such as different ambient light intensity during day and night, jitter in the installation and use environment of photoelectric measuring instruments, the installation and use environment of photoelectric measuring instruments is difficult to be in a constant temperature environment so the ambient temperature changes greatly, and the aging of photoelectric measuring instruments due to their own reflective luminescence and reflected light.

[0005] With regard to changes in operating conditions, current measuring instruments generally have poor adaptability to the operating conditions, resulting in large measurement errors.

[0006] Based on this, the applicant considered designing a method for establishing and using a metering signal baseline for a photoelectric metering instrument that can enhance adaptability to working conditions and help improve metering accuracy. Summary of the invention

[0007] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is: how to provide a method for establishing and using a metering signal baseline of a photoelectric metering instrument that can improve the adaptability to working conditions and help improve the metering accuracy.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] The method for establishing a metering signal baseline of a photoelectric meter is characterized by comprising the following steps:

[0010] Step 1: Establish an initial baseline

[0011] In the initial preset sampling cycles, when the maximum amplitude of the sampling signal is equal to each other for N consecutive times and the minimum amplitude is equal to each other for N consecutive times, the initial values ​​are obtained: the maximum amplitude V0max of the photoelectric signal and the minimum amplitude V0min of the photoelectric signal; the initial baseline is established as: (V0max+V0min) / 2;

[0012] Assume the amplitude difference threshold value D, the restriction condition of D is: D ≥ N × △e, △e is the specified error, N is a positive number;

[0013] Step 2: When the maximum or minimum sampling signal amplitude changes for multiple times in a row, refresh the baseline

[0014] Within a preset number of sampling cycles, obtain real-time acquisition values: the maximum amplitude Vrmax of the photoelectric signal and the minimum amplitude Vrmin of the photoelectric signal;

[0015] When Vrmax>V0max, reset according to the preset instruction and refresh the maximum amplitude Vnmax of the photoelectric signal according to the real-time sampling signal;

[0016] When Vrmin<V0min, reset according to the preset instruction and refresh the minimum amplitude Vnmin of the photoelectric signal according to the real-time sampling signal;

[0017] n is a positive integer greater than or equal to 1;

[0018] The refresh baseline is: (arithmetic mean of Vnmax + arithmetic mean of Vnmin) / 2;

[0019] Step 3: Establish upper and lower hysteresis baselines

[0020] When Vrmax-Vrmin≥amplitude difference threshold D, then:

[0021] The previous hysteresis baseline is: refresh baseline × (1 + 0.1 to 0.3);

[0022] The lower hysteresis baseline is: refresh baseline × (1-0.1 to 0.3).

[0023] The method for using the metering signal baseline of a photoelectric meter is characterized in that:

[0024] Before the upper hysteresis baseline and the lower hysteresis baseline are established, if the sampling signal amplitude is greater than the initial baseline, 1 is output, and if it is less than the initial baseline, 0 is output;

[0025] After the upper hysteresis baseline and the lower hysteresis baseline are established, if Vnmax≥sampling signal amplitude>upper hysteresis baseline, then output 1; if lower hysteresis baseline>sampling signal amplitude≥Vnmin, then output 0;

[0026] When the sampling amplitude is between the upper hysteresis baseline and the lower hysteresis baseline, the output remains unchanged.

[0027] The use and working principle of the method for establishing the measurement signal baseline of the photoelectric measuring instrument in this technical solution:

[0028] First of all, when the photoelectric measuring instrument is in use, due to changes in working conditions (such as different ambient light intensity during the day and at night, jitter in the installation and use environment of the photoelectric measuring instrument, the installation and use environment of the photoelectric measuring instrument is difficult to be in a constant temperature environment so the ambient temperature changes greatly, and the photoelectric measuring instrument's own reflectors, light emitting tubes, light receiving tubes and other components aging, etc.), the maximum or minimum amplitude of the collected signal will change.

[0029] After adopting this technical solution, when the maximum or minimum amplitude of the collected signal changes, the changed maximum or minimum amplitude will be refreshed, and the baseline will be refreshed according to the new maximum or minimum amplitude, and the refreshed baseline will be used as the basis for collecting and measuring signals, so as to better adapt to changes in working conditions and ensure accurate measurement under different working conditions.

[0030] At the same time, the technical solution is provided with the above third step, in which the conditional judgment of "Vrmax-Vrmin≥amplitude difference threshold value D" can avoid the situation where the metering instrument outputs the metering signal incorrectly under the condition of frequent jitter, and better ensure the accuracy of measurement under this working condition. Furthermore, the effective establishment of the upper hysteresis baseline and the lower hysteresis baseline can accurately make it possible to output signal 1 only when the amplitude of the sampling signal is in the "upper hysteresis baseline and the maximum amplitude interval", and output signal 0 only when the amplitude of the sampling signal is in the "lower hysteresis baseline and the minimum amplitude interval". It has better anti-jitter interference and ensures the reliability of instrument measurement for a long time.

[0031] From the above, compared with the prior art, the method for establishing the measurement signal baseline of the photoelectric measuring instrument of the technical scheme has the following advantages:

[0032] 1. The baseline has dynamic adaptive characteristics, which can dynamically adjust the baseline of the metering signal according to the various working conditions of the instrument, so as to better ensure that the photoelectric metering instrument has high measurement accuracy under various working conditions.

[0033] 2. Better anti-interference and anti-jitter performance.

[0034] 3. This method has low hardware requirements and can be implemented with low-configuration hardware. It also has small calculation amount and low power consumption, which can better help control the manufacturing cost of photoelectric measuring instruments and improve product competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1Logical flow chart of the method for establishing the measurement signal baseline of the photoelectric measuring instrument

[0036] Figure 2 Flow chart of the offline judgment steps in the method for establishing the measurement signal baseline of the photoelectric measuring instrument

[0037] Figure 3 Schematic diagram of sampling signal and baseline in the method of establishing the measurement signal baseline of photoelectric measuring instrument

[0038] Figure 4 This is a schematic diagram of the structure of the photoelectric metering instrument measurement signal acquisition structure (top view)

[0039] Figure 5 This is a schematic diagram of the structure of the electronic metering module in the metering signal acquisition structure of the photoelectric metering instrument (viewed from above)

[0040] Figure 6 for Figure 5 Exploded view of the electronic metering module

[0041] Figure 7 This is a structural diagram of the electronic metering module in the metering signal acquisition structure of the photoelectric metering instrument (looking up)

[0042] Figure 8 for Figure 7 Exploded view of the electronic metering module

[0043] Fig. 9 for Figure 8 Enlarged view of the dotted line part

[0044] Fig.10a Schematic diagram of the signal transmission piece rotating and two pairs of photoelectric transmitting and receiving components collecting signals (in state 11)

[0045] Fig.10b Schematic diagram of the signal transmission piece rotating and two pairs of photoelectric transmitting and receiving components collecting signals (in state 01)

[0046] Fig.10c Schematic diagram of the signal transmission piece rotating and two pairs of photoelectric transmitting and receiving components collecting signals (in 00 state)

[0047] Fig.10d Schematic diagram of the signal transmission piece rotating and two pairs of photoelectric transmitting and receiving components collecting signals (in state 10)

[0048] The markings in the figure are:

[0049] A base table: signal plate (A10 light reflecting surface, A11 light absorbing surface), A2 transparent cover

[0050] B Electronic metering module: B1 fitting part, B2 lens, photoelectric transmitter and receiver assembly (B30 light emitting tube, B31 light receiving tube), B4 PCB board, B5 light blocking sheet (B51 limit protrusion), B6 ​​light blocking ring DETAILED DESCRIPTION

[0051] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0052] The method for establishing a measurement signal baseline of a photoelectric measuring instrument comprises the following steps:

[0053] Step 1: Establish an initial baseline

[0054] In the initial preset sampling cycles, when the maximum amplitude of the sampling signal is equal to each other for N consecutive times and the minimum amplitude is equal to each other for N consecutive times, the initial values ​​are obtained: the maximum amplitude V0max of the photoelectric signal and the minimum amplitude V0min of the photoelectric signal; the initial baseline is established as: (V0max+V0min) / 2;

[0055] Assume the amplitude difference threshold value D, the restriction condition of D is: D ≥ N × △e, △e is the specified error, N is a positive number;

[0056] In practice, “equal” means that the sampled values ​​are within a specified error of ± △ e, are considered equal.

[0057] Step 2: When the maximum or minimum sampling signal amplitude changes for multiple times in a row, refresh the baseline

[0058] Within a preset number of sampling cycles, obtain real-time acquisition values: the maximum amplitude Vrmax of the photoelectric signal and the minimum amplitude Vrmin of the photoelectric signal;

[0059] When Vrmax>V0max, reset according to the preset instruction and refresh the maximum amplitude Vnmax of the photoelectric signal according to the real-time sampling signal;

[0060] When Vrmin<V0min, reset according to the preset instruction and refresh the minimum amplitude Vnmin of the photoelectric signal according to the real-time sampling signal;

[0061] n is a positive integer greater than or equal to 1;

[0062] The refresh baseline is: (arithmetic mean of Vnmax + arithmetic mean of Vnmin) / 2;

[0063] Step 3: Establish upper and lower hysteresis baselines

[0064] When Vrmax-Vrmin≥amplitude difference threshold D, then:

[0065] The previous hysteresis baseline is: refresh baseline × (1 + 0.1 to 0.3);

[0066] The lower hysteresis baseline is: refresh baseline × (1-0.1 to 0.3).

[0067] In the second step: the process of resetting and refreshing the maximum amplitude Vnmax of the photoelectric signal according to the sampling signal is: the initial value of Vnmax is 0, and Vnmax is refreshed from small to large.

[0068] Because the maximum values ​​of different (metering instrument) products are different, if an empirical value Vmax_c other than 0 is set as the initial maximum value, then Vmax_c is likely to be greater than the actual maximum value, and the actual maximum value cannot be found later. Therefore, the initial value is set to 0, and the maximum value can always be found by searching from small to large. This makes this step more universal.

[0069] The above Vnmax refresh method can make Vnmax change more slowly, so that the optical receiver has enough time to accurately collect signal changes and improve the collection accuracy. And refreshing Vnmax from small to large can also better suppress and reduce interference and noise, thereby obtaining a more accurate Vnmax value.

[0070] In the second step: the process of resetting and refreshing the minimum amplitude Vnmin of the photoelectric signal according to the sampling signal is: the initial value of Vnmin is (+)4096, and Vnmin is refreshed from large to small.

[0071] Similarly, the minimum values ​​of different (metering instrument) products are different. If an empirical value Vmin_c other than +4096 is set as the initial minimum value, Vmin_c is likely to be smaller than the actual minimum value, and the actual minimum value cannot be found later. Therefore, the initial value is set to 4096 (the absolute maximum upper limit), and the minimum value can always be found by searching from large to small. This makes this step more universal.

[0072] The above Vnmin refresh method can make Vnmin change more slowly, so that the optical receiver has enough time to accurately collect signal changes and improve the collection accuracy. And refreshing Vnmin from large to small can better suppress and reduce interference and noise, so as to obtain a more accurate Vnmin value.

[0073] The method for establishing a metering signal baseline of a photoelectric metering instrument further includes an offline judgment step, which can be performed before or after any one of the first to third steps. The offline judgment step includes:

[0074] Step a: Collect ambient light signals

[0075] The light emitting tube is not powered, but the light receiving tube is powered and continues to collect data for time t1: When the light receiving tube collects a continuous and stable voltage, it stores the voltage and uses it as the ambient light signal: Vb;

[0076] Step b: Collect the superposition signal of ambient light and reflected light

[0077] The light emitting tube is powered on, the light receiving tube is powered on and continues to collect data for time t2: When the light receiving tube collects a continuous and stable voltage, the voltage is stored and used as a superposition signal of ambient light and reflected light: Vc;

[0078] Step c: Determine whether it is offline

[0079] The light transmitting tube and the light receiving tube are not powered; calculate the effective reflected light signal: Vr = Vc-Vb;

[0080] When Vr≤△e occurs n times, it is offline, where △e≈0, and n is a positive integer between 1 and 10; when Vr>△e, it is not offline.

[0081] At present, the structure commonly used in photoelectric metering instruments is to add a photoelectric electronic metering module to the base meter. The base meter is equivalent to an ordinary water meter. The electronic metering module is installed on the base meter. By emitting infrared light and receiving reflected light signals, measuring the rotation of the transmitter piece, electronic readings can be generated.

[0082] Under normal circumstances, the mechanical and electrical readings are consistent. However, if the base meter is disconnected from the electronic module (called offline in the industry; for example, someone maliciously operates it), at this time, the base meter is still measuring, but the electronic metering module is no longer measuring, which will cause the mechanical and electrical readings to be inconsistent, resulting in measurement disputes.

[0083] For offline detection, the general approach in the industry is to add Hall elements and magnetic steel to the base meter and the electronic metering module for detection. Therefore, the existing solution has additional hardware cost overhead for offline detection.

[0084] The offline judgment in this technical solution only uses the original hardware, and the processing method directly collects and analyzes the infrared signal through software, which can reliably judge whether the offline situation occurs, without additional hardware cost. The offline judgment effect is good.

[0085] The photoelectric signal is acquired by adopting a photoelectric metering instrument measurement signal acquisition structure including a signal transmitting piece and at least one pair of photoelectric transmitting and receiving components.

[0086] The method of using the measurement signal baseline of the photoelectric measuring instrument is that before the upper hysteresis baseline and the lower hysteresis baseline are established, if the sampling signal amplitude is greater than the initial baseline, 1 is output, and if it is less than the initial baseline, 0 is output;

[0087] After the upper hysteresis baseline and the lower hysteresis baseline are established, if Vnmax≥sampling signal amplitude>upper hysteresis baseline, then the output is 1; if the lower hysteresis baseline>sampling signal amplitude≥Vnmin, then the output is 0.

[0088] The following is the preferred photoelectric metering instrument measurement signal acquisition structure:

[0089] A photoelectric metering instrument measurement signal acquisition structure, comprising a signal transmitting piece and at least one pair of photoelectric transmitting and receiving components;

[0090] The signal transmitting piece is rotatably mounted in a transparent cover of a base meter of a metering instrument and is drivingly connected to a metering follower inside the metering instrument. A light reflecting surface and a light absorbing surface are arranged on the upper surface of the signal transmitting piece facing the transparent cover in a circumferential direction.

[0091] The pair of photoelectric transceiver components are fixedly installed in an electronic metering module matched with the base meter. The electronic metering module is fixedly installed on the base meter, and the electronic metering module has a fitting portion that is directly opposite to the signal transmitting piece and is fitted and connected to the transparent cover. The fitting portion can allow the emitted light and reflected light in each pair of photoelectric transceiver components to pass through.

[0092] During implementation, the metering follower is an impeller in a water meter, or the metering follower is an output side of a mechanical transmission group in a gas meter or an input shaft (or gear) of a wheel counter.

[0093] During implementation, the light reflecting surface on the signaling piece can be directly a metal surface (such as a gold-plated or silver-plated or metal polished surface) or a reflective film (such as a nano-silicon dioxide particle layer, a reflective ceramic layer); the light absorbing surface on the signaling piece can be directly a black coating or a black wrapping layer (such as black pigment, black rubber, black metal oxide or black semiconductor material or black plastic).

[0094] Compared with the prior art, the photoelectric metering instrument measurement signal acquisition structure of this technical solution has the following advantages:

[0095] 1. The hardware structure is simpler and the hardware cost is lower, which is more conducive to controlling the manufacturing cost of photoelectric measuring instruments and improving product competitiveness.

[0096] 2. The changes to the existing base meter and electronic metering module are small, which can better adapt to the existing metering instruments and improve practicality.

[0097] The fitting portion has a through hole which covers and faces the signal transmitting piece in the orthographic projection direction, and a lens is sealed and fixed at the through hole.

[0098] The structure of the above-mentioned bonding part can not only effectively ensure the light transmission and reception of the optoelectronic transmitting and receiving components, but also play a better role in sealing the perforations, so that the interior of the electronic metering module has better sealing, and permanently ensure that the various electronic devices inside the electronic metering module have a more suitable operating environment.

[0099] During implementation, the lens material is one of glass (quartz glass or tempered glass) and transparent plastic (acrylic or PC material).

[0100] Among them, the refractive index of glass is usually between 1.4-1.9, which enables it to effectively control the refraction of light, making the emission and reception of infrared light more accurate; at the same time, the light transmittance of glass is greater than 90%, and it is not easily affected by environmental factors (such as temperature, humidity, etc.) for a long time and the light transmittance decreases significantly. Therefore, the light transmittance can be reliable for a long time, ensuring that the optoelectronic transmitting and receiving components can be used reliably for a long time.

[0101] Among them, the light transmittance of transparent plastic can reach about 92%, and its density is about half of that of glass, so it is lighter; but the thermal stability of transparent plastic is poor, and its light transmittance is prone to change in a continuous high temperature environment.

[0102] Wherein, each pair of the optoelectronic transmitting and receiving components is fixedly mounted on the lower surface of the PCB board inside the electronic metering module.

[0103] In this way, a modular structure is formed between the optoelectronic transceiver components and the PCB board in the electronic metering module, and mature SMT patch technology can be directly used for rapid production, thereby accelerating the production efficiency of the electronic metering module.

[0104] At the same time, the optoelectronic transceiver assembly first blocks the ambient light by utilizing the outer shell of the electronic metering module, and the optoelectronic transceiver assembly is arranged on the lower surface of the PCB. The PCB board can also be used to further block the ambient light, thereby significantly reducing the signal interference of the ambient light on the reliable working process of the optoelectronic transceiver assembly.

[0105] Wherein, the upper surface of the PCB board facing away from the optoelectronic transceiver component has a thickened light shielding layer.

[0106] During implementation, the thickened light shielding layer is an electroplated thickened layer or a coated insulating material or a thickened PCB substrate.

[0107] The thickened light-shielding layer can further block ambient light and play a better role in shielding light interference.

[0108] Wherein, the photoelectric metering instrument measurement signal acquisition structure further includes a light-blocking sheet that can be fixed on the lower surface of the PCB board, and the light-blocking sheet is made of an opaque material;

[0109] The light emitting tube and the light receiving tube in each pair of optoelectronic transmitting and receiving components are independently located in a corresponding single penetrating light through hole on the light blocking sheet.

[0110] During implementation, it is preferred that the light blocking sheet is pressed as a whole between the lens and the lower surface of the PCB board.

[0111] The advantage of setting the above-mentioned light blocking sheet is that it can not only further shield the interference of ambient light on the light emission and reflected light of the optoelectronic transceiver component; it can also use the light blocking sheet to completely isolate the interference of the photoelectric transceiver component's own transmission and reflection light process, thereby improving the accuracy of the reflected light and non-reflected light intensity signal collection of the transmitter.

[0112] At the same time, the setting of the light blocking sheet is also conducive to ensuring the accuracy of light intensity signal collection using 2 or more pairs of optoelectronic transmitting and receiving components, thereby achieving better application effects.

[0113] Wherein, the opaque materials used to make the light-blocking sheets are all black, and the composition of the opaque materials is any one of plastic, composite material, rubber or silica gel.

[0114] During implementation, composite materials such as glass fiber or carbon fiber are processed and molded with resin.

[0115] The material of the above-mentioned light blocking sheet can be elastically deformed, and can then be placed between the lens and the PCB board and fully squeezed, so that the contact surface between the light blocking sheet and the PCB and the contact surface between the light blocking sheet and the lens are fully sealed and effectively isolate the ambient light, thereby achieving the optimal anti-light interference effect and better ensuring the accuracy of light intensity signal collection.

[0116] After testing, it was found that the metering signal acquisition structure of the photoelectric metering instrument using the above-mentioned light-blocking sheet can achieve reliable signal acquisition in an environment with a light intensity of up to 45,000 lux.

[0117] Wherein, a limiting protrusion is arranged on the upper side of the light-blocking sheet, and correspondingly, an assembly hole for the limiting protrusion to be inserted and limited is arranged on the PCB board.

[0118] During implementation, it is preferred that the limiting protrusion is a rectangular structure, or the number of the limiting protrusions is at least two.

[0119] In this way, the light blocking sheet can be quickly plugged and assembled into the corresponding assembly hole on the PCB through the structure of its own limiting protrusion, thereby simplifying and accelerating the assembly efficiency of the light blocking sheet.

[0120] The number of the optoelectronic transceiver components is two pairs arranged at 90 degree intervals in the circumferential direction;

[0121] The signaling piece is in the shape of a circular piece, and the light reflecting surface and the light absorbing surface of the signaling piece are both in the shape of half a semicircle.

[0122] The advantages of the above structure are:

[0123] 1. The setting of two pairs of photoelectric transmitting and receiving components can determine whether the transmitting chip is rotating forward or reverse by generating changes in the signal, thereby determining whether the measuring instrument is rotating forward or reverse, and can detect abnormalities in time.

[0124] 2. The two pairs of photoelectric transmitting and receiving components are closer together in the circumferential direction, so that the two pairs of photoelectric transmitting and receiving components can be more concentrated in positions of equal brightness (darkness), thereby obtaining better signal collection consistency.

[0125] 3. Two pairs of photoelectric transmitting and receiving components arranged at 90 degrees can divide the 360° circle into four equal parts, and can stay in the high and low level (the light reflection surface and light absorption surface of the transmitting piece are both half a circle (180 degrees)) signal collection area for a longer time, so whether in the high-frequency or low-frequency sampling period, the high and low levels can be collected more timely and accurately, thereby obtaining accurate measurement signals.

[0126] The housing of the electronic metering module also has a light-blocking ring sleeved on the outside of the transparent cover of the base meter and a light-blocking cover (not shown in the figure) hingedly assembled with the light-blocking ring and used to cover or open the transparent cover of the base meter.

[0127] During implementation, the housing of the electronic metering module is preferably made of black or gray plastic.

[0128] The above-mentioned arrangement of the light-blocking ring and the light-blocking cover can create a darker environment inside the space covered by the light-blocking ring and the light-blocking cover, and better avoid the interference of ambient light on the optoelectronic transmitting and receiving components.

[0129] The two pairs of optoelectronic transmitting and receiving components are located on the light-blocking sheet at the innermost side close to the center of the base surface transparent cover.

[0130] In this way, the positions of the two pairs of optoelectronic transmitting and receiving components can be placed in the darkest area, thereby achieving the best effect of resisting ambient light interference signals.

[0131] The above are only preferred implementations of the present invention. It should be pointed out that a number of modifications and improved technical solutions made by those skilled in the art without departing from the technical solution should also be regarded as falling within the scope of protection required by the claims.

Claims

1. A method for establishing a measurement signal baseline of a photoelectric measuring instrument, characterized in that: The following steps are involved: Step 1: Establish an initial baseline In the initial preset sampling cycles, when the maximum amplitude of the sampling signal is equal to each other for N consecutive times and the minimum amplitude is equal to each other for N consecutive times, the initial values ​​are obtained: the maximum amplitude V0max of the photoelectric signal and the minimum amplitude V0min of the photoelectric signal; the initial baseline is established as: (V0max+V0min) / 2; Assume the amplitude difference threshold value D, the restriction condition of D is: D ≥ N × △e, △e is the specified error, N is a positive number; Step 2: When the maximum or minimum sampling signal amplitude changes for multiple times in a row, refresh the baseline Within a preset number of sampling cycles, obtain real-time acquisition values: the maximum amplitude Vrmax of the photoelectric signal and the minimum amplitude Vrmin of the photoelectric signal; When Vrmax>V0max, reset according to the preset instruction and refresh the maximum amplitude Vnmax of the photoelectric signal according to the real-time sampling signal; When Vrmin<V0min, reset according to the preset instruction and refresh the minimum amplitude Vnmin of the photoelectric signal according to the real-time sampling signal; n is a positive integer greater than or equal to 1; The refresh baseline is: (arithmetic mean of Vnmax + arithmetic mean of Vnmin) / 2; Step 3: Establish upper and lower hysteresis baselines When Vrmax-Vrmin≥amplitude difference threshold D, then: The previous hysteresis baseline is: refresh baseline × (1 + 0.1 to 0.3); The lower hysteresis baseline is: refresh baseline × (1-0.1 to 0.3).

2. The method for establishing a measurement signal baseline of a photoelectric measuring instrument according to claim 1, characterized in that: In the second step: the process of resetting and refreshing the maximum amplitude Vnmax of the photoelectric signal according to the sampling signal is: the initial value of Vnmax is 0, and Vnmax is refreshed from small to large.

3. The method for establishing a measurement signal baseline of a photoelectric measuring instrument according to claim 1, characterized in that: In the second step: the process of resetting and refreshing the minimum amplitude Vnmin of the photoelectric signal according to the sampling signal is: the initial value of Vnmin is 4096, and Vnmin is refreshed from large to small.

4. The method for establishing a measurement signal baseline of a photoelectric measuring instrument according to claim 1, characterized in that: The method further includes an offline judgment step, which can be performed before or after any one of the first step to the third step. The offline judgment step includes: Step a: Collect ambient light signals The light emitting tube is not powered, but the light receiving tube is powered and continues to collect data for time t1: When the light receiving tube collects a continuous and stable voltage, it stores the voltage and uses it as the ambient light signal: Vb; Step b: Collect the superposition signal of ambient light and reflected light The light emitting tube is powered on, the light receiving tube is powered on and continues to collect data for time t2: When the light receiving tube collects a continuous and stable voltage, the voltage is stored and used as a superposition signal of ambient light and reflected light: Vc; Step c: Determine whether it is offline The light transmitting tube and the light receiving tube are not powered; calculate the effective reflected light signal: Vr = Vc-Vb; When Vr≤△e occurs n times, it is offline, where △e≈0, and n is a positive integer between 1 and 10; when Vr>△e, it is not offline.

5. The method for establishing a measurement signal baseline of a photoelectric measuring instrument according to claims 1 to 4, characterized in that: The photoelectric signal is acquired by adopting a photoelectric metering instrument measurement signal acquisition structure including a signal transmitting piece and at least one pair of photoelectric transmitting and receiving components.

6. A method for using a metering signal reference line of a photoelectric meter, characterized in that: Before the upper hysteresis baseline and the lower hysteresis baseline are established, if the sampling signal amplitude is greater than the initial baseline, 1 is output, and if it is less than the initial baseline, 0 is output; After the upper hysteresis baseline and the lower hysteresis baseline are established, if Vnmax≥sampling signal amplitude>upper hysteresis baseline, then output 1; if lower hysteresis baseline>sampling signal amplitude≥Vnmin, then output 0; When the sampling amplitude is between the upper hysteresis baseline and the lower hysteresis baseline, the output remains unchanged.

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