CN109991295B - Intelligent pH composite electrode with temperature drift self-adjustment function and implementation method thereof - Google Patents
Intelligent pH composite electrode with temperature drift self-adjustment function and implementation method thereof Download PDFInfo
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- 239000002131 composite material Substances 0.000 title claims abstract description 62
- 238000000034 method Methods 0.000 title claims abstract description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 47
- 238000006243 chemical reaction Methods 0.000 claims abstract description 37
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- 239000000919 ceramic Substances 0.000 description 3
- 238000007667 floating Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 230000005856 abnormality Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 2
- 238000009360 aquaculture Methods 0.000 description 2
- 244000144974 aquaculture Species 0.000 description 2
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- 238000001139 pH measurement Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
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Abstract
The invention provides an intelligent pH composite electrode with temperature drift self-adjustment and a realization method thereof, wherein the pH composite electrode is provided with a temperature measuring groove, and an intelligent control part and an electrode shell part with a pH electrode body are arranged inside the pH composite electrode; the intelligent control part comprises a central control unit, an RTD resistance unit, a precision resistance unit, a signal processing unit, an A/D conversion unit and a switching unit. According to the invention, the built-in hardware circuit and the electrodes are arranged as a whole and are arranged in the water body, so that the drift condition of the hardware circuit can be greatly reduced; the high-precision resistor capable of being acquired in a switching mode is used for comparing and contrasting different temperatures or different times, drift coefficients of the hardware circuit are obtained, the drift coefficients are used for self-adjusting correction, and errors of measurement results are smaller. The invention has certain economical efficiency and practicability and is worth popularizing and using.
Description
Technical Field
The invention relates to the technical field of water quality monitoring equipment, in particular to an intelligent pH composite electrode with temperature drift self-adjustment function.
Background
The method can be applied to the pH parameter measurement of the water quality in the fields of intelligent fishery water quality monitoring, sewage environment-friendly monitoring and the like in modern aquaculture.
In the prior art, many of the pH values are detected by a handheld pH meter, so that the current pH value is obtained, obviously, the single-point detection at a single time point has reference significance only limited to the current time, and in the subsequent production operation, if the measurement is not continued, the reference value of the last measured value to the current water quality condition is not great, because the water quality is a dynamic change process, particularly in the field of aquaculture, and is more obvious.
In the implementation means in the prior art, there is also an online detector, for example, an acquisition module is set to cooperate with a pH electrode, the pH electrode is placed in a water body, the acquisition module is placed on the water body or on the shore through a floating ball or other modes, and a remote communication module such as GPRS is generally combined to realize data transmission.
In addition to the large power consumption of remote communication such as GPRS, the implementation of this type of implementation has a significant disadvantage in that the entire circuit is located in an outdoor environment in the field and, in general, may be continuously exposed to the sun for a long period of time. The output signal of the pH electrode is weak, and the hardware such as an operational amplifier and an A/D chip is generally required to be arranged, so that the hardware circuit can generate larger temperature drift or time drift after long-time solar irradiation, and the measured value is not very accurate. If the matched electrode is not provided with a device for collecting the temperature of the water body, the temperature compensation of the pH value is carried out, the measured value of the electrode has deviation, and the measured value of the electrode is possibly greatly different from the actual value due to temperature drift or time drift of a hardware circuit, so that a user can be misled to make a correct judgment by detection.
Disclosure of Invention
The invention aims at improving the technical problems, namely the technical problems to be solved by the invention are to provide the low-power-consumption intelligent pH composite electrode with the temperature drift self-regulating function, the drift condition of a built-in hardware circuit is lightened by arranging the built-in hardware circuit in a water body in a sealing way, and the antenna is arranged in a connected cable and above the water surface, so that wireless data transmission based on NB-IoT remote communication is realized.
In order to solve the technical problems, one technical scheme of the invention is as follows: an intelligent pH composite electrode with temperature drift self-adjustment is placed in a water body and used for measuring the pH value of the water body, and an intelligent control part and an electrode shell part are arranged in a main shell of the intelligent pH composite electrode;
the intelligent control part is provided with a temperature measuring groove;
the electrode shell comprises a pH electrode body with a built-in measuring electrode and a reference electrode;
the intelligent control part is internally provided with a central control unit, and an RTD resistance unit, a precision resistance unit, a signal processing unit, an A/D conversion unit and a switching unit which are connected with the central control unit;
the signal processing unit is connected with the A/D conversion unit;
one end of the RTD resistance unit and one end of the precision resistance unit are simultaneously connected with the same constant current source signal, and the other ends of the RTD resistance unit and the precision resistance unit are respectively connected with the switching unit; the switching unit is used for switching the RTD resistance unit or the precision resistance unit which are collected currently; the signal processing unit is connected with the switching unit and the pH electrode body;
and measuring signals of the pH electrode body, the RTD resistance unit or the precision resistance unit are processed by the signal processing unit, sent to the A/D conversion unit for AD conversion, and finally calculated by the central control unit to obtain a measured value.
Further, the constant current source signal is built in the a/D conversion unit.
The implementation method of the intelligent pH composite electrode with the temperature drift self-adjustment comprises the following steps:
s1: collecting and storing AD conversion values corresponding to the precision resistor;
s2: switching acquisition lines in a time-sharing manner to acquire AD conversion values of the precision resistance and the RTD resistance respectively;
s3: calculating a temperature value corresponding to the RTD resistance, comparing and analyzing AD conversion value data differences of the precision resistances acquired twice in the S1 and the S2, and calculating a drift coefficient of the whole circuit under the current condition;
s4: according to the drift coefficient, automatically adjusting and correcting the collected pH value;
s5: repeating the steps S2-S4.
Further, the constant current source signal is one or two sets of signals.
Further, the main shell of the intelligent pH composite electrode is also provided with a sealing part and a measuring bottom, and the main shell is connected with a cable part of the built-in antenna.
Further, a communication unit is arranged in the cable part or the main shell, the communication unit is connected with an antenna through an antenna feeder line, and the antenna feeder line are arranged in the cable part.
Further, the intelligent pH composite electrode is provided with an interface unit, and the interface unit is connected with the central control unit.
Further, the intelligent pH composite electrode is provided with a self-calibration key, and the self-calibration key is connected with the central control unit.
Further, the signal processing unit comprises a four-channel operational amplifier.
Further, the implementation method of the intelligent pH composite electrode with temperature drift self-adjustment further comprises the following pre-conditions:
the circuit part of the intelligent pH composite electrode is completely sealed and arranged below the water surface.
Compared with the prior art, the invention has the following beneficial effects:
(1) The built-in hardware circuit and the electrodes are arranged as a whole and are arranged in the water body, so that the drift condition of the hardware circuit can be greatly reduced;
(2) The temperature value of the water body is acquired through the combination of the RTD resistance and the constant current source, and is used for carrying out temperature compensation on the measured pH value, so that the measurement result is more accurate;
(3) The high-precision resistor capable of being acquired in a switching way is arranged in the circuit for comparison and comparison of different temperatures or different times, so that the drift coefficient of the hardware circuit is obtained, the circuit is used for self-adjustment correction, and the error of a measurement result is smaller;
(4) The resistor and the A/D are arranged in a short distance through the built-in constant current source of the A/D chip, so that the influence of the line resistor in the traditional technology is not considered, the temperature resistor is not acquired by a three-wire system, the technology is more convenient and quick to realize, and the stability and consistency are better;
(5) By setting the self-calibration key and combining the switching unit, the initial calibration parameters can be set by self-calibration of one key, and the operation mode is simple and convenient;
(6) The NB-IoT communication module with low power consumption is arranged, the power consumption is low, the data transmission is stable, the patch antenna is arranged in the cable, and the cable is arranged above the water surface, so that the cable is convenient to transmit, the whole design is ingenious, the power consumption is low, and the cable can be powered by a battery;
(7) By arranging the storage unit and the clock unit, continuous measurement parameters in a specific time period can be continuously stored for analyzing the change trend of the water body, and meanwhile, when the communication is short-time unexpected abnormality, measurement data can be temporarily stored, so that the measurement data at a certain time point is not discarded due to the communication problem;
(8) The solution adopted according to the actual problems encountered on site is reasonable in overall design, has certain economical efficiency and practicability, and is worthy of popularization and use.
Drawings
FIG. 1 is a block diagram of the hardware components of an intelligent pH composite electrode with temperature drift self-adjustment according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a shell structure of an intelligent pH composite electrode with temperature drift self-adjustment according to an embodiment of the present invention.
Fig. 3 is a schematic exploded view of a part of a structure of an intelligent pH composite electrode with temperature drift self-adjustment according to an embodiment of the present invention.
Fig. 4 is a schematic diagram of hardware components of a built-in wireless communication unit with a temperature drift self-adjusting intelligent pH composite electrode according to an embodiment of the present invention.
Fig. 5 is a partial area anatomic diagram of a cable portion of an intelligent pH composite electrode with temperature drift self-adjustment and a connection schematic diagram with an intelligent control portion according to an embodiment of the present invention.
Fig. 6 is a schematic diagram showing the connection of a signal processing unit and a switching unit of the intelligent pH composite electrode with temperature drift self-adjustment according to the present invention.
Fig. 7 is a schematic diagram of two embodiments of different interface connection modes of the intelligent pH composite electrode with temperature drift self-adjustment according to the present invention.
Fig. 8 is a schematic diagram of a communication unit with a temperature drift self-adjusting intelligent pH composite electrode provided in a cable portion according to an embodiment of the present invention.
In fig. 1: the circuit comprises a 101-central control unit, a 102-self-calibration key, a 103-A/D conversion unit, a 104-signal processing unit, a 105-switching unit, a 106-precision resistance unit, a 107-pH electrode body, a 108-voltage stabilizing unit, a 109-power supply unit, a 110-interface unit, a 111-clock unit, a 112-storage unit, a 113-RTD resistance unit, a 1041-four-channel operational amplifier and a 1031-constant current source.
In fig. 2: 1-main shell, 10-intelligent control portion, 20-sealing portion, 30-electrode shell portion, 40-measuring bottom portion, 50-protective cap, 60-cable portion, 100-temperature measuring groove.
In fig. 3: 10-intelligent control part, 20-sealing part, 30-electrode shell part, 40-measuring bottom, 60-cable part, 100-temperature measuring tank, 107-pH electrode body, 303-internal reference electrode, 304-internal reference solution, 301-external reference electrode, 302-external reference solution, 305-liquid adding hole and 401-glass membrane ball.
In fig. 4: 1-main housing, 503-communication unit, 1091-battery, 107-pH electrode body.
In fig. 5: 10-intelligent control portion, 60-cable line portion, 601-antenna feeder, 602-antenna, 603-rope, A0-horizontal plane.
In fig. 6: the circuit comprises a 101-central control unit, a 102-self-calibration key, a 103-A/D conversion unit, a 104-signal processing unit, a 105-switching unit, a 106-precision resistance unit, a 107-pH electrode body, a 108-voltage stabilizing unit, a 109-power supply unit, a 110-interface unit, a 111-clock unit, a 112-storage unit, a 113-RTD resistance unit, a 1042-dual-channel operational amplifier and a 1031-constant current source.
In fig. 7: 1-main shell, 107-pH electrode body, 110-interface unit, 501-transmission output module, 502-RS485 module.
In fig. 8: 10-intelligent control part, 60-cable line part, 602-antenna, 503-communication unit, A1-horizontal plane, A2-horizontal plane of another embodiment.
Detailed Description
The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.
It should be noted that the terms "coupled," "connected," and "mounted" in the description of the invention are to be construed broadly, and may be, for example, integrally connected, fixedly connected, or detachably connected, unless otherwise specifically defined and limited; either directly through mechanical structures or electronically, or indirectly through intermediaries.
The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The following disclosure provides different implementations, or examples, for implementing different structures or different methods of implementing the invention. In order to simplify the present disclosure, components and arrangements of specific embodiments are described below.
As shown in fig. 2, an intelligent pH composite electrode with temperature drift self-adjustment according to a preferred embodiment of the present invention is placed in a water body to measure pH of the water body, and an intelligent control part 10 and an electrode shell part 30 are provided inside a main casing 1 of the intelligent pH composite electrode.
As shown in fig. 3, the intelligent control unit 10 is provided with a temperature measuring tank 100; the electrode housing portion 30 includes a pH electrode body 107 with built-in measurement and reference electrodes.
As shown in fig. 1, the intelligent control unit 10 is internally provided with a central control unit 101, and an RTD resistance unit 113, a precision resistance unit 106, a signal processing unit 104, an a/D conversion unit 103 and a switching unit 105 which are connected with the central control unit 101; the signal processing unit 104 is connected to the a/D conversion unit 103; one end of the RTD resistance unit 113 and one end of the precision resistance unit 106 are simultaneously connected with the same constant current source signal, and the other ends are respectively connected with the switching unit 105; the switching unit 105 is used for switching the RTD resistance unit 113 or the precision resistance unit 106 which are currently acquired; the signal processing unit 104 is connected to the switching unit 105 and the pH electrode body 107; the measurement signals of the pH electrode body 107, the RTD resistance unit 113 or the precision resistance unit 106 are processed by the signal processing unit 104, then sent to the a/D conversion unit 103 for AD conversion, and finally calculated by the central control unit 101 to obtain a measurement value.
In this embodiment, the intelligent pH composite electrode is integrally placed in the water body, and the key point is that the circuit is built in the intelligent control part 10 and is also sealed in the water body.
The pH electrode body 107 is configured to measure a pH original signal of a water body, the RTD resistance unit 113 senses a water temperature through an exposed shell portion, the precision resistance unit 106 includes a precision resistance with high precision and low temperature drift, and the precision resistance unit is sealed inside the intelligent control portion 10 and is configured to switch and collect with the RTD resistance unit 113.
In this embodiment, the temperature measuring tank 100 is hermetically provided with the RTD resistance unit 113, and a metal casing or a metal sheet that is additionally and fixedly attached to the RTD resistance unit 113 for sensing temperature is disposed on the same surface as the outer surface of the main casing 1, so as to form a part of the area of the outer surface of the main casing 1.
Under the specified or specific temperature condition, the current AD conversion value of the precision resistor unit 106 is collected and compared with the AD conversion value which is collected and stored in advance during factory shipment or calibration, so that the integral temperature drift or time drift condition of the current signal processing circuit and the AD conversion circuit can be obtained, the temperature drift coefficient can be obtained after data analysis and operation, and the pH measured value after temperature compensation is subjected to further temperature drift coefficient adjustment and correction to obtain the final pH measured value after compensation and correction.
Unlike conventional online pH detectors, conventional online pH detector circuits are placed in a housing, above the water, which is exposed to the sun or long-term exposure, which can produce a large temperature drift. In the technical scheme, the whole circuit part of the intelligent pH composite electrode is also placed under the water surface of the water body, and the temperature change is relatively small, so that the temperature drift coefficient adjustment is actually the temperature drift coefficient fine adjustment, and the pH measurement value with higher measurement accuracy is obtained by switching and collecting and performing self-adjustment correction.
In this embodiment, the constant current source signal is built in the a/D conversion unit 103, and the constant current source signal may be one set of signals or two sets of signals.
In this embodiment, two sets of constant current source signals may be used to connect with the RTD resistance unit 113 or the precision resistance unit 106, mainly considering the resistance of the connecting wire, and performing resistance sampling by adopting a three-wire connection mode; or a group of constant current sources are directly connected in series for use without considering the problem of the line resistance of the connecting wires. In this embodiment, the signal processing unit 104, the switching unit 105, the RTD resistance unit 113 and the precision resistance unit 106 are designed on the same PCB board, and are closely spaced from each other, and are not connected by external connection wires, so that the problem of line resistance is negligible, and preferably, a set of constant current source signals is used.
As shown in fig. 2, in the present embodiment, the main housing 1 of the intelligent pH composite electrode is further provided with a sealing portion 20 and a measuring bottom portion 40, and the main housing 1 is connected to a cable portion 60 of the built-in antenna.
As shown in fig. 4, in combination with the partial cable anatomical diagram of fig. 5, a communication unit 503 is disposed in the cable portion 60 or the main housing 1, the communication unit 503 is connected with an antenna 602 through an antenna feeder 601, and the antenna 602 and the antenna feeder 601 are disposed in the cable portion 60.
In this embodiment, the cable portion 60 includes a cable, one end of the cable is connected to the main housing 1 of the intelligent pH composite electrode, and the other end of the cable extends out of the water surface, and may be fixedly installed in various manners, preferably, a floating body may be connected, and the tail end portion area of the cable portion 60 is disposed above the water surface under the buoyancy of the floating body.
Preferably, the communication unit 503 employs an NB-IoT module, and the antenna 602 employs a patch ceramic antenna. The patch ceramic antenna is placed at the tail end of the cable section 60, exposed to the water surface, and connected to the NB-IoT module via the antenna feed line 601. In an actual implementation process, the cable is a special cable, and in order to reduce the probability of tearing the antenna feeder 601 built in the cable, a holding rope 603 is further arranged in the cable.
The communication unit 503 is connected to the central control unit 101 for wirelessly transmitting the final measured pH value.
Referring to fig. 1, the intelligent pH composite electrode is provided with an interface unit 110, and the interface unit 110 is connected with the central control unit 101; in this embodiment, the interface unit 110 may be connected to the communication unit 503, as shown in fig. 4.
As one of the embodiments, the communication unit 503 may be further configured in the cable section 60, and connected in series or the like through the interface unit 110, as shown in fig. 8.
In fig. 5 and 8, reference numerals A0, A1 or A2 represent the water level of the water body, and are above A0, A1 or A2, i.e. above the water surface, and below, i.e. disposed in the water body. In fig. 8, A1 and A2 are respectively disposed, which means that the communication unit 503 may be disposed above the water surface or below the water surface.
As one of the embodiments, as shown in fig. 7, the interface unit 110 may be connected to a transmitter output module 501 or an RS485 module 502, where the transmitter output module 501 or the RS485 module 502 is connected by a cable of the cable section 60 to lead a signal out of the water, and the antenna 602 is not disposed inside the cable. The transmitting output module 501 can output a 4-20mA current signal or a 1-5V voltage signal, or a 0-20mA current signal or a 0-5V voltage signal, etc.
In this embodiment, the intelligent pH composite electrode is provided with a self-calibration key 102, and the self-calibration key 102 is connected to the central control unit 101. The self-calibration key 102 may be disposed on the intelligent control unit 10, where the self-calibration key 102 is used for factory calibration preset or field recalibration, when the self-calibration key 102 is pressed, the output of the switching unit 105 and the control signal source are controlled in a time-sharing manner, the input signals of the RTD resistance unit 113 and the precision resistance unit 106 are collected in a time-sharing manner, the current temperature value corresponding to the RTD resistance unit 113 is calculated, the current AD conversion value corresponding to the precision resistance unit 106 is recorded, and the current AD conversion value is stored in the central control unit 101 or in a storage unit 112 connected to the outside of the central control unit 101, and is recorded as a pre-calibrated parameter, and is used for data comparison and analysis in the actual operation process in the following process, and in particular, the overall circuit temperature drift coefficient including the signal processing unit 104 and the a/D conversion unit 103 is automatically calculated according to the data differences in different environments such as temperature.
In this embodiment, the signal processing unit 104 includes a four-channel op-amp 1041. Because the output resistance of the pH electrode body 107 is very large, the four-channel op-amp 1041 is preferably a four-channel op-amp chip with high impedance, low offset voltage and low current drift. The four-channel op-amp 1041 is connected to the signal of the pH electrode body 107 and the voltage signal transmitted from the switching unit 105, respectively, to form two sets of input signals. By selecting the four-channel operational amplifier chip, two signal amplification steps can be implemented for both sets of signals, wherein the low bias current is first amplified once, gain amplification is then performed once, and the amplified signals are sent to the a/D conversion unit 103.
Preferably, the four-channel operational amplifier 1041 may be an operational amplifier chip with model number ADA 4505-4.
As one of the implementation manners, as shown in fig. 6, the signal processing unit 104 selects the two-channel operation 1042, which is only used for connecting and collecting the pH electrode body 107, and the voltage signal of the switching unit 105 is directly sent to the a/D conversion unit 103.
Referring also to FIG. 6, as one of the possible embodiments, the RTD resistance unit 113 may also be built into the pH electrode body 107 as an integral part of the pH electrode body 107.
As shown in fig. 1 and 6, the intelligent pH composite electrode is provided with a clock unit 111, and the clock unit 111 is connected to the central control unit 101. In this embodiment, the clock unit 111 includes a clock chip for outputting calendar time information and recording the accurate time of measurement and acquisition, and may also be used for setting an accurate acquisition period. In combination with the storage unit 112 connected to the central control unit 101, the measured values corresponding to the specific time periods may be synchronously recorded, so as to form a trend of measured data in the specified time area.
The intelligent pH composite electrode is provided with a power supply unit 109, the power supply unit 109 is connected with a voltage stabilizing unit 108, and the voltage stabilizing unit 108 outputs low voltage to supply power for the intelligent pH composite electrode. In this embodiment, the power supply unit 109 may be further connected to the interface unit 110, and a power supply may be input from within the interface unit 110. As shown in fig. 4, a battery 1091 may also be provided, and the intelligent pH composite electrode may be powered by the battery 1091. The voltage stabilizing unit 108 supplies power to the central control unit 101, the a/D conversion unit 103, the signal processing unit 104, the switching unit 105, the clock unit 111, and the storage unit 112, respectively.
As shown in fig. 2 and 3, the intelligent pH composite electrode is provided with a protective cap 50 for sleeving the measuring bottom 40. The RTD resistance unit 113 is installed in the temperature measuring tank 100 provided in the intelligent control unit 10. The pH electrode body 107 includes the electrode casing portion 30 and the measuring bottom portion 40, and is connected to the intelligent control portion 10 through the sealing portion 20. Wherein, an internal reference electrode 303, an internal reference solution 304, an external reference electrode 301 and an external reference solution 302 are arranged in the electrode shell 30, and a ceramic plug is also arranged at the bottom of the external reference electrode 301. The outer case of the electrode housing part 30 is provided with a filling hole 305 for filling an electrolyte. The measuring bottom 40 is provided with glass membrane balls 401. Preferably, the pH electrode body 107 may be directly replaced by a conventional pH composite electrode, and then the intelligent control part 10 is sleeved to achieve the purpose.
A realization method of an intelligent pH composite electrode with temperature drift self-adjustment comprises the following steps:
s1: collecting and storing AD conversion values corresponding to the precision resistor; the AD conversion value recorded at the moment is an original value, and can be reset in the subsequent calibration;
s2: switching acquisition lines in a time-sharing manner to acquire AD conversion values of the precision resistance and the RTD resistance respectively; the RTD resistance is fixed and collected regularly, the current water temperature is obtained, the temperature compensation is carried out on the collected pH value, different collection periods are set, and the precise resistance is collected;
s3: calculating a temperature value corresponding to the RTD resistance, comparing and analyzing AD conversion value data differences of the precision resistances acquired twice in the S1 and the S2, and calculating a drift coefficient of the whole circuit under the current condition;
s4: according to the drift coefficient, automatically adjusting and correcting the collected pH value; at this time, the pH value is compensated for the water temperature, and the relatively more accurate measured value can be obtained after the drift correction of the hardware circuit.
S5: repeating the steps S2-S4. Wherein step S1 can be reset by a self-calibration key.
The implementation method also comprises the following pre-conditions: the circuit part of the intelligent pH composite electrode is completely sealed and arranged below the water surface. This precondition is because the drift correction of the circuit can achieve better effect in specific situations, if the intelligent pH composite electrode is always exposed to the sun, the self-adjusting effect is reduced, and the difficulty of coefficient correction is increased. Through the integrated arrangement of the structure, the specific arrangement of the position areas and the special design of the circuit, the temperature drift self-adjusting function is realized.
According to the intelligent pH composite electrode with the temperature drift self-adjustment function, the built-in hardware circuit and the electrode are arranged into a whole and are arranged in the water body, so that the drift condition of the hardware circuit can be greatly reduced.
According to the intelligent pH composite electrode with temperature drift self-adjustment, the RTD resistance is combined with the constant current source to acquire and obtain the temperature value of the water body, the temperature value is used for carrying out temperature compensation on the measured pH value, and the measurement result is more accurate.
According to the intelligent pH composite electrode with the temperature drift self-adjustment function, provided by the invention, the built-in switchable high-precision resistor is used for comparing and comparing different temperatures or different times to obtain the drift coefficient of a hardware circuit, the drift coefficient is used for self-adjustment and correction, and the error of a measurement result is smaller.
According to the intelligent pH composite electrode with temperature drift self-adjustment, the resistor and the A/D are arranged in a short distance through the built-in constant current source of the A/D chip, the influence of the line resistor in the traditional technology is not considered, the temperature resistor is not acquired by a three-wire system, and the technology is more convenient and rapid to realize and has better stability and consistency.
According to the intelligent pH composite electrode with temperature drift self-adjustment, the self-calibration key is arranged, and the switching unit is combined, so that initial calibration parameters can be set by self-calibration through one key, and the operation mode is simple and convenient.
According to the intelligent pH composite electrode with the temperature drift self-adjustment function, the NB-IoT communication module with low power consumption is arranged, the power consumption is low, the data transmission is stable, the patch antenna is arranged in the cable and is arranged above the water surface, the transmission is convenient, the overall design is ingenious, the power consumption is low, and the power can be supplied through the battery.
According to the intelligent pH composite electrode with the temperature drift self-adjustment function, the storage unit and the clock unit are arranged, so that continuous measurement parameters in a specific time period can be continuously stored, the continuous measurement parameters are used for analyzing the change trend of the water body, meanwhile, when the communication is short-time unexpected abnormality, measurement data can be temporarily stored, and the measurement data at a certain time point is not discarded due to the communication problem.
The intelligent pH composite electrode with the temperature drift self-adjustment function provided by the invention adopts a solution according to actual problems encountered on site, is reasonable in overall design, has certain economical efficiency and practicability, and is worthy of popularization and use.
The foregoing description of the preferred embodiments of the present invention is provided for illustration and description only, and is not intended to limit the scope of the invention. All equivalent changes and modifications made according to the claims of the present invention shall fall within the scope of the present invention.
Claims (8)
1. An intelligent pH composite electrode with temperature drift self-adjustment is placed in a water body and used for measuring the pH value of the water body, and is characterized in that an intelligent control part (10) and an electrode shell part (30) are arranged in a main shell (1) of the intelligent pH composite electrode;
the intelligent control part (10) is provided with a temperature measuring groove (100);
the electrode shell (30) comprises a pH electrode body (107) with a built-in measuring electrode and a reference electrode;
a central control unit (101), an RTD resistance unit (113), a precision resistance unit (106), a signal processing unit (104), an A/D conversion unit (103) and a switching unit (105) are arranged in the intelligent control part (10);
the signal processing unit (104) is connected with the A/D conversion unit (103);
one end of the RTD resistance unit (113) and one end of the precision resistance unit (106) are simultaneously connected with the same constant current source signal, and the other ends of the RTD resistance unit and the precision resistance unit are respectively connected with the switching unit (105); the switching unit (105) is used for switching the RTD resistance unit (113) or the precision resistance unit (106) which are acquired currently;
the signal processing unit (104) is connected with the switching unit (105) and the pH electrode body (107);
the measurement signals of the pH electrode body (107), the RTD resistance unit (113) or the precision resistance unit (106) are processed by the signal processing unit (104), then are sent to the A/D conversion unit (103) for AD conversion, and finally are calculated by the central control unit (101) to obtain measurement values;
the constant current source signal is built in the A/D conversion unit (103);
the implementation method of the intelligent pH composite electrode with the temperature drift self-adjustment comprises the following steps:
s1: collecting and storing AD conversion values corresponding to the precision resistor;
s2: switching acquisition lines in a time-sharing manner to acquire AD conversion values of the precision resistance and the RTD resistance respectively;
s3: calculating a temperature value corresponding to the RTD resistance, comparing and analyzing AD conversion value data differences of the precision resistances acquired twice in the S1 and the S2, and calculating a drift coefficient of the whole circuit under the current condition;
s4: according to the drift coefficient, automatically adjusting and correcting the collected pH value;
s5: repeating the steps S2-S4.
2. The intelligent pH composite electrode with temperature drift self-adjustment according to claim 1, wherein the constant current source signal is one or two sets of signals.
3. The intelligent pH composite electrode with temperature drift self-adjustment according to claim 1, wherein the main housing (1) of the intelligent pH composite electrode is further provided with a sealing portion (20) and a measuring bottom portion (40), and the main housing (1) is connected with a cable portion (60) of an internal antenna.
4. A temperature drift self-adjusting intelligent pH composite electrode according to claim 3, characterized in that a communication unit (503) is provided in the cable section (60) or the main housing (1), the communication unit (503) is connected with an antenna (602) through an antenna feeder (601), and the antenna (602) and the antenna feeder (601) are built in the cable section (60).
5. The intelligent pH composite electrode with temperature drift self-adjustment according to claim 1, characterized in that the intelligent pH composite electrode is provided with an interface unit (110), the interface unit (110) being connected with the central control unit (101).
6. The intelligent pH composite electrode with temperature drift self-adjustment according to claim 1, characterized in that the intelligent pH composite electrode is provided with a self-calibration key (102), the self-calibration key (102) being connected with the central control unit (101).
7. The intelligent pH composite electrode with temperature drift self-adjustment according to claim 1, wherein the signal processing unit (104) comprises a four-channel op-amp (1041).
8. The intelligent pH composite electrode with temperature drift self-adjustment according to claim 1, wherein the implementation method further comprises the following pre-conditions:
the circuit part of the intelligent pH composite electrode is completely sealed and arranged below the water surface.
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