阅读说明：本技术 一种防干扰的数字pH传感器 (Anti-interference digital pH sensor ) 是由 唐宾国 熊志明 张鑫 于 2019-07-25 设计创作，主要内容包括：本发明提供一种防干扰的数字pH传感器,包括pH电极、电路板、以及外壳,其中,所述外壳中含有静电屏蔽层,所述静电屏蔽层与地线连接,用于保证测量电路不受场干扰源的影响；所述电路板包括由内部测量电路组成的变送器和与外部电路连接的接口,所述变送器将pH电极获得的电压信号转换成pH测量值；所述接口包括电源隔离模块以及通信隔离模块,保证测量电路不受直接接触的干扰源的影响。本发明的有益效果：能够有效避免在实际工程应用中所遇到的各种干扰源的影响,从而很大程度上提升了用户体验,为后续的数据分析与应用服务打下了良好基础。(the invention provides an anti-interference digital pH sensor which comprises a pH electrode, a circuit board and a shell, wherein the shell contains an electrostatic shielding layer, and the electrostatic shielding layer is connected with a ground wire and used for ensuring that a measuring circuit is not influenced by a field interference source; the circuit board comprises a transmitter consisting of an internal measuring circuit and an interface connected with an external circuit, and the transmitter converts a voltage signal obtained by the pH electrode into a pH measuring value; the interface comprises a power isolation module and a communication isolation module, and ensures that the measuring circuit is not influenced by a directly contacted interference source. The invention has the beneficial effects that: the influence of various interference sources in actual engineering application can be effectively avoided, so that the user experience is improved to a great extent, and a good foundation is laid for subsequent data analysis and application service.)

1. an interference-proof digital pH sensor, comprising a pH electrode, a circuit board, characterized in that the circuit board comprises a transmitter consisting of an internal measurement circuit and an interface connected with an external circuit, wherein:

The transmitter is connected with the pH electrode and is used for converting a voltage signal obtained by the pH electrode into a pH measurement value;

The interface comprises a 485 communication module and a power management module, the 485 communication module is used for communication between the interface and an external circuit, and the power management module is connected with an external power supply and supplies power for an internal measurement circuit in the transmitter and an interface circuit in the interface;

The interface also comprises a power isolation module and a communication isolation module, wherein the power isolation module is used for isolating the power supply of the internal measuring circuit from an external power supply, and the communication isolation module is used for isolating the communication between the interface and the internal measuring circuit and the communication between the interface and the external circuit so as to ensure that the measuring circuit is not influenced by a directly contacted interference source;

The communication isolation module comprises an integrated circuit U21, a plurality of external communication pins connected with an external circuit are arranged on the integrated circuit U21, and the external communication pins are connected with the 485 communication module to realize communication between the integrated circuit U21 and the external circuit; a plurality of internal communication pins connected with an internal measurement circuit are arranged on the integrated circuit U21, so that communication between the integrated circuit U21 and the internal measurement circuit is realized; an internal power interface pin is also arranged on the integrated circuit U21 to ensure power isolation in the communication process with the internal and external circuits;

The power isolation module includes integrated circuit U41, integrated circuit U41 is connected with external power supply to convert outside 12V operating voltage into the 5V operating voltage who keeps apart with external circuit, integrated circuit U41 still is connected with integrated circuit U42, integrated circuit U42 will the 5V operating voltage that integrated circuit U41 output converts 3.3V operating voltage into, integrated circuit U42 connects on the integrated circuit U21 the internal power source interface pin supplies power for internal measurement circuit, realizes that the power keeps apart.

2. The tamper-proof digital pH sensor according to claim 1, further comprising a housing with an electrostatic shield, the electrostatic shield being a copper film, connected to ground for securing the internal measurement circuitry from the field interference source.

3. The tamper-proof digital pH sensor according to claim 1, wherein the integrated circuit U21 is provided with a power interface pin connected to an external power source, the power interface pin is used for connecting to the integrated circuit U43, and the integrated circuit U43 converts an external 12V operating voltage into a 5V operating voltage to supply power to the integrated circuit U21.

4. The tamper-proof digital pH sensor of claim 1, wherein said transmitter comprises a microcontroller unit, and a signal conditioning circuit, a temperature compensation circuit, a memory management module, a reference voltage circuit connected to said microcontroller unit, wherein:

The signal conditioning circuit is used for processing the voltage signal obtained by the pH electrode and transmitting the processed voltage signal to the microcontroller unit;

the microcontroller unit utilizes the storage management module to calculate the voltage signal and convert the voltage signal into a corresponding pH measurement value;

the storage management module manages the memory in the operation process;

The temperature compensation circuit provides measurement of a temperature value for compensating a pH measurement value;

The reference voltage circuit provides a voltage reference for the signal conditioning circuit.

5. the tamper-proof digital pH sensor according to claim 1, wherein said internal communication pin on said integrated circuit U21 is connected to said microcontroller unit.

Technical Field

The invention relates to a pH sensor, in particular to an anti-interference digital pH sensor.

background

The pH sensor is a sensor for measuring the pH value of a water body or a solution, and the pH value of the water body or the solution is measured by the hydrogen ion concentration, so the pH sensor usually uses an ion selective electrode to measure the pH value.

The digital pH sensor generally comprises a pH electrode, a transmitter and an interface, wherein the pH electrode converts the concentration of hydrogen ions in water or solution into a voltage signal, the voltage signal is processed by a signal conditioning circuit of the transmitter, then is sent to a microcontroller unit for operation and conversion into a corresponding pH value, and finally is communicated with the outside through a 485 module. The temperature compensation circuit provides measurement of a temperature value and is used for the micro control unit to compensate the pH measurement value; the power management module is mainly responsible for providing working voltage for each unit in the system.

Because the signal output by the pH electrode is very weak, in practical engineering application, various interference factors such as fluctuation of a power supply grid, impulse voltage/current caused by starting and stopping of high-power equipment, lightning, static electricity and the like exist, and the interference factors enter a measuring circuit in a direct or indirect mode, so that the normal work of a pH sensor is influenced, the pH measurement value is obviously jumped, and data generated due to interference not only influences user experience, but also brings obstacles to analysis and interpretation of the data.

Disclosure of Invention

In view of the above, the present invention provides an anti-interference digital pH sensor scheme, which adopts a mode of adding an isolation module to completely isolate a measurement circuit from the outside for direct interference factors, and structurally adds a shielding layer for a field interference source which is not in direct contact, and connects the shielding layer with a system ground wire to ensure that the sensor is not interfered.

The invention provides an anti-interference digital pH sensor, which comprises a pH electrode and a circuit board, and is characterized in that the circuit board comprises a transmitter consisting of an internal measuring circuit and an interface connected with an external circuit, wherein:

the transmitter is connected with the pH electrode and is used for converting a voltage signal obtained by the pH electrode into a pH measurement value; the interface comprises a 485 communication module and a power management module, the 485 communication module is used for communication between the interface and an external circuit, and the power management module is connected with an external power supply and supplies power for an internal measurement circuit in the transmitter and an interface circuit in the interface; the interface also comprises a power isolation module and a communication isolation module, wherein the power isolation module is used for isolating the power supply of the internal measuring circuit from an external power supply, and the communication isolation module is used for isolating the communication between the interface and the internal measuring circuit and the communication between the interface and the external circuit so as to ensure that the measuring circuit is not influenced by a directly contacted interference source;

The communication isolation module comprises an integrated circuit U21, a plurality of external communication pins connected with an external circuit are arranged on the integrated circuit U21, and the external communication pins are connected with the 485 communication module to realize communication between the integrated circuit U21 and the external circuit; a plurality of internal communication pins connected with an internal measurement circuit are arranged on the integrated circuit U21, so that communication between the integrated circuit U21 and the internal measurement circuit is realized; an internal power interface pin is also arranged on the integrated circuit U21 to ensure power isolation in the communication process with the internal and external circuits;

The power isolation module includes integrated circuit U41, integrated circuit U41 is connected with external power supply to convert outside 12V operating voltage into the 5V operating voltage who keeps apart with external circuit, integrated circuit U41 still is connected with integrated circuit U42, integrated circuit U42 will the 5V operating voltage that integrated circuit U41 output converts 3.3V operating voltage into, integrated circuit U42 connects on the integrated circuit U21 the internal power source interface pin supplies power for internal measurement circuit, realizes that the power keeps apart.

furthermore, the sensor also comprises a shell with an electrostatic shielding layer, wherein the electrostatic shielding layer is a copper film and is connected with a ground wire, and the copper film is used for ensuring that an internal measuring circuit is not influenced by a field interference source.

Furthermore, a power interface pin connected with an external power supply is arranged on the integrated circuit U21, the power interface pin is used for connecting the integrated circuit U43, and the integrated circuit U43 converts an external 12V working voltage into a 5V working voltage to supply power to the integrated circuit U21.

Further, the transmitter comprises a microcontroller unit, and a signal conditioning circuit, a temperature compensation circuit, a storage management module and a reference voltage circuit which are connected with the microcontroller unit, wherein:

The signal conditioning circuit is used for processing the voltage signal obtained by the pH electrode and transmitting the processed voltage signal to the microcontroller unit; the microcontroller unit utilizes the storage management module to calculate the voltage signal and convert the voltage signal into a corresponding pH measurement value; the storage management module manages the memory in the operation process; the temperature compensation circuit provides measurement of a temperature value for compensating a pH measurement value; the reference voltage circuit provides a voltage reference for the signal conditioning circuit.

further, the internal communication pin on the integrated circuit U21 is connected to the microcontroller unit.

the technical scheme provided by the invention has the beneficial effects that: different processing modes are respectively adopted aiming at different types of interference sources: for directly-contacted interference sources, such as power grid fluctuation, impulse voltage/current, lightning and the like, improvement is carried out in a physical isolation mode, wherein the physical isolation comprises power isolation and communication isolation, so that an internal measurement system is completely isolated from the outside; for the interference source which is not in direct contact, such as the field interference source like static electricity, the mode of adding the shielding layer is adopted.

Drawings

FIG. 1 is a schematic diagram of the structure of a tamper-proof digital pH sensor provided in example 1 of the present invention;

FIG. 2 is a schematic diagram of an electrostatic shielding layer of the tamper-proof digital pH sensor provided in example 1 of the present invention;

FIG. 3 is a structural diagram of the interference-proof digital pH sensor provided in example 1 of the present invention;

FIG. 4 is an integrated circuit U21 in a tamper-proof digital pH sensor provided in embodiment 1 of the present invention;

FIG. 5 is an integrated circuit U43 in a tamper-proof digital pH sensor provided in embodiment 1 of the present invention;

FIG. 6 is an integrated circuit U41 in a tamper-proof digital pH sensor provided in embodiment 1 of the present invention;

FIG. 7 is an integrated circuit U42 in a tamper-proof digital pH sensor provided in embodiment 1 of the present invention;

FIG. 8 is a structural diagram of a general digital pH sensor provided in application example 1 of the present invention;

Fig. 9 is a pH measurement result of a general digital pH sensor provided in application example 1 of the present invention;

Fig. 10 is a pH measurement of the tamper-proof digital pH sensor provided in application example 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be further described with reference to the accompanying drawings.