TWI696151B - Circuit and method for monitoring gas concentration - Google Patents

Abstract

Conventional system for recognizing the concentration of a gas mixture exhibits shortcomings of large system framework and complicated way to process signal. Particularly, the present invention provides a circuit and a method for monitoring the gas concentration. This novel gas concentration monitoring circuit differs from the above-mentioned system and comprises: at least one gas sensor, a differentiation module and a main control circuit. In the present invention, firstly the gas sensor is used for sensing a gas concentration signal from an environment to be measured (e.g., chamber), and the differentiation module is subsequently configured to differentiate the gas concentration signal. Eventually, the main control circuit acquires an inflection point according to the differentiation result of the gas concentration signal, so as to obtain a maximum value of gas concentration.

Description

Gas concentration monitoring circuit and method

The invention relates to the technical field of monitoring gas concentration, in particular to a gas concentration monitoring circuit and a method thereof.

In today's society, the application of gas concentration monitoring is extremely wide, and its importance is seen from home medical care (such as carbon monoxide concentration alarms), industrial production (such as refrigerant leak detectors), environmental and emissions monitoring, and social security. ; Among them, it is particularly important in industry. For example, in the coating process, the gas concentration in the environment to be measured (such as the cavity) has an absolute influence on the uniformity of the coating and the quality of the coating, so the coating process must be monitored in real time. The gas concentration in the environment to be measured (for example, the cavity); in addition, with the rapid development of technology, society's requirements for the cost, performance, and stability of gas concentration monitoring have increased.

Therefore, an existing mixed gas identification system has been proposed. FIG. 1 is a block diagram showing a conventional mixed gas concentration identification system. As shown in FIG. 1, the mixed gas concentration identification system 1 ′ includes: a power module 10 ′, a gas sensing module 11 ′, a micro-processing unit 12 ′, an input unit 13 ′, and a memory unit 14', and a display unit 15', The mixed gas identification system 1'mainly uses the conversion relationship between the concentration and the analog signal of the gas sensing module 11' built in the micro-processing unit 12', and receives the output from the gas sensing module 11' An analog signal, and the analog signal is calculated by a partial pressure load circuit to produce the concentration of each gas, thereby determining whether the analog signal and the gas concentration have converged or stabilized, and thereby synchronously correct the concentration of the gas; wherein The gas sensing module 11' is composed of a plurality of gas sensors. If N kinds of gases are to be sensed, N gas sensors and at least one multiplexer 16' must be installed.

Although the mixed gas identification system 1'can identify the gas concentration, it still has the problems of cumbersome steps in processing signals and the cost of manufacturing components; therefore, how to process signals when detecting multiple gas concentrations is simple and economical The consideration of the above-mentioned cost is actually a problem that is urgently to be solved.

In view of this, the inventor of this case worked hard to create and finally developed a gas concentration monitoring circuit and method of the present invention.

Unlike the conventional mixed gas identification system, which shows a huge system architecture and complex signal processing methods in practical applications, the present invention mainly provides a gas concentration monitoring circuit and a gas concentration monitoring system with a simple structure and signal processing method Method; wherein, the gas concentration monitoring circuit is composed of at least one gas sensor, a differential processing module, and a main control circuit. In the present invention, a gas concentration signal is firstly measured from a test environment through a gas sensor, and then a differential processing module is used A differential processing is performed on the gas concentration signal; finally, the main control circuit can obtain an inverse curve data according to the result of the differential processing, and then know the maximum concentration of the gas.

In order to achieve the above main object of the present invention, the inventor of the present case provides an embodiment of the gas concentration monitoring circuit, which is applied to monitor the concentration of at least one gas in a test environment and includes: at least one gas sensing Is installed in the environment to be measured and used to sense a gas concentration signal of the gas in the environment to be measured; a differential processing module is electrically connected to the gas concentration sensor to The gas concentration signal is subjected to a differential processing; and a main control circuit is coupled to the differential processing module; wherein, the main control circuit can obtain an inverse curve data according to the result of the differential processing, and then know the The maximum concentration of one of the gases.

<this invention>

1: Gas concentration monitoring circuit

2: test environment

3: gas cylinder

4: Electronic device

10: Gas sensor

11: Differential processing module

12: Main control circuit

14: Database

15: Warning module

111: Analog front end unit

112: Differential circuit

121: Communication interface

S1-S4: Method steps

<Learning>

1’: Mixed gas identification system

10’: Power module

11’: Gas sensing module

12’: Microprocessing unit

13’: Input unit

14’: Memory unit

15’: Display unit

16’: Multiplexer

1 is a block diagram showing a conventional mixed gas identification system; FIG. 2 is a schematic structural diagram of a gas concentration monitoring circuit of the present invention; FIG. 3 is a flowchart showing a method of the gas concentration monitoring circuit of the present invention; FIG. 4A is A data curve showing time versus gas concentration signal; and FIG. 4B is a data curve showing time versus gas concentration signal after one differential treatment.

In order to be able to describe the gas concentration monitoring circuit and method proposed by the present invention more clearly, the preferred embodiments of the present invention will be described in detail below with reference to the drawings.

Please refer to FIG. 2, which is a schematic structural diagram of a gas concentration monitoring circuit of the present invention. As shown in the figure, the gas concentration monitoring circuit 1 is applied to monitor at least one gas concentration in an environment 2 to be measured, and includes: at least one gas sensor 10, a differential processing module 11, and a main control circuit 12; wherein, the gas sensor 10 is disposed in the environment 2 to be measured, for sensing a gas concentration signal of the gas in the environment 2 to be tested; and, the differential processing module 11 is electrically The gas sensor 10 is connected to the gas concentration signal for differential processing; the main control circuit 12 is coupled to the differential processing module 11.

In more detail, the differential processing module 11 includes an analog front-end unit 111 and a differential circuit 112, the differential circuit 112 is coupled to the analog front-end unit 111; so configured, when the gas sensor 10 senses the gas A gas concentration signal in the environment 2 to be measured is transmitted to the analog front-end unit 111; the analog front-end unit 111 performs an amplification process on the gas concentration signal; then, the differential circuit 112 is used to complete the amplification The processed gas concentration signal is subjected to the differentiation process; finally, the main control circuit 12 obtains an inverse curve data according to the result of the above-mentioned differentiation process, and then obtains a maximum concentration of the gas.

Further, the gas concentration monitoring circuit 1 further includes at least one mass flow controller (MFC) connected to a gas cylinder 3 and the ring to be measured Between environment 2 to display the flow rate of the gas into the environment 2 to be tested, and the flow rate of the gas into the environment 2 to be tested can be adjusted according to the main control circuit 12; The gas concentration monitoring circuit 1 further includes a communication interface 121 for allowing the main control circuit 12 and an electronic device 4 to communicate with each other; in addition, the gas concentration monitoring circuit 1 may further include a database 14 coupled to the main The control circuit 12 is used to store the gas concentration signal and the inflexion point data; and, the gas concentration monitoring circuit 1 further includes an alarm module 15 coupled to the main control circuit 12 for the mass flow When the controller is disabled, a warning signal is issued to warn and remind the user, so that the monitoring effect of the present invention is more stable and perfect.

In addition, the communication interface 121 may be a wired communication interface or a wireless communication interface, and the electronic device 4 may be any one of the following: display, smartphone, smart watch, smart glasses, tablet Computer, cloud server, or notebook computer; in addition, the gas sensor 10 may be one of the following: electrochemical gas sensor, infrared optical gas sensor, metal oxide semiconductor gas sensor , And combustion reactive gas sensors.

The structure of the gas concentration monitoring circuit 1 of the present invention has been described in detail above, and then the method flow of the present invention will be described. Please refer to FIG. 3, which is a flow chart showing the method of the gas concentration monitoring circuit of the present invention. At the same time, please refer to FIGS. 4A and 4B, wherein FIG. 4A is a data curve diagram showing time versus gas concentration signal, and FIG. 4B is a data curve diagram showing time versus gas concentration signal after one differential process. According to FIG. 3, it can be known that the method of the present invention mainly includes the following steps: Step (S1): At least one gas sensor 10 disposed in a test environment 2 senses a gas concentration signal of at least one gas passing into the test environment 2 (as shown in FIG. 4A); Step (S2): a differential processing module 11 receives the gas concentration signal, and performs a differential processing on the gas concentration signal (as shown in FIG. 4B); step (S3): a main control circuit 12 according to the differential As a result of the processing, an inverse curve data is obtained, and then a maximum concentration of the gas is known.

Further, the present invention further includes a step (S4): The main control circuit 12 transmits the obtained data of the maximum concentration to an electronic device 4.

In addition, the gas concentration monitoring circuit 1 of the present invention can be based on the obtained data of the maximum value of the concentration, and the main control circuit 12 controls the mass flow through at least one connected between a gas cylinder 3 and the environment 2 to be measured The device adjusts the flow rate of the gas into the environment 2 to be tested.

In this way, the above is a complete and clear description of the structural schematic diagram and method flow of the gas concentration monitoring circuit of the present invention. Through the above, we can know that the present invention has the following advantages:

(1) Unlike the conventional mixed gas identification system 1', which has the problems of cumbersome steps in processing signals and the cost of manufacturing components, the present invention uses the differential circuit 112 to perform the differential processing on the gas concentration signal to make the main The control circuit 12 can obtain the data of the inflection point, and then know the maximum value of the concentration of the gas, and at the same time achieve the advantages of reducing production costs and simplifying the steps.

It must be emphasized that the above detailed description is a specific description of possible embodiments of the present invention, but this embodiment is not intended to limit the patent scope of the present invention, and any equivalent implementation or change without departing from the technical spirit of the present invention, Should be included in the patent scope of this case.

1‧‧‧ Gas concentration monitoring circuit

2‧‧‧ Environment to be tested

3‧‧‧ gas cylinder

4‧‧‧Electronic device

10‧‧‧ gas sensor

11‧‧‧ Differential Processing Module

12‧‧‧Master control circuit

14‧‧‧ Database

15‧‧‧Alarm module

111‧‧‧ Analog Front End Unit

112‧‧‧Differential circuit

121‧‧‧Communication interface

Claims (12)

A gas concentration monitoring circuit is used to monitor the concentration of at least one gas in a test environment, and includes: at least one gas sensor, which is disposed in the test environment and used to sense the gas in the test environment A gas concentration signal in the environment to be measured; a differential processing module, which is electrically connected to the gas sensor, to perform a differential processing on the gas concentration signal; and a main control circuit, which is coupled to the differential processing Module; wherein, the main control circuit can obtain an inverse curve data according to the result of the differential processing, and then know the maximum concentration of the gas. The gas concentration monitoring circuit as described in item 1 of the patent application scope, wherein the differential processing module includes: an analog front-end unit for performing an amplification process on the gas concentration signal; and a differential circuit, which is coupled The analog front-end unit is used to perform the differential process on the gas concentration signal that has completed the amplification process. The gas concentration monitoring circuit as described in item 1 of the scope of the patent application further includes at least one mass flow controller (MFC), which is connected between a gas cylinder and the environment to be tested to display the access The flow rate of the gas in the environment to be tested; meanwhile, the mass flow controller adjusts the flow rate of the gas into the environment to be tested according to the control of the main control circuit. The gas concentration monitoring circuit as described in item 1 of the patent application scope, wherein the main control circuit further includes a communication interface for enabling the main control circuit to communicate with an electronic device. The gas concentration monitoring circuit as described in item 1 of the patent application scope, wherein the gas sensor may be one of the following: electrochemical gas sensor, infrared optical gas sensor, metal oxide semiconductor gas sensor Sensor and combustion reactive gas sensor. The gas concentration monitoring circuit as described in item 4 of the patent application scope, wherein the electronic device may be one of the following: display, smartphone, smart watch, smart glasses, tablet computer, cloud server, or notebook computer. The gas concentration monitoring circuit as described in item 4 of the patent application scope, wherein the communication interface is a wired communication interface or a wireless communication interface. The gas concentration monitoring circuit as described in item 1 of the scope of the patent application further includes: a database, coupled to the main control circuit, for storing the gas concentration signal and the inflexion point data. The gas concentration monitoring circuit as described in item 3 of the patent application scope further includes: an alarm module, coupled to the main control circuit, for issuing an alarm signal when the mass flow controller is disabled. An operation method of a gas concentration monitoring circuit includes the following steps: (1) At least one gas sensor provided in an environment to be measured senses a gas of at least one gas passing into the environment to be measured Concentration signal; (2) a differential processing module receives the gas concentration signal and performs a differential processing on the gas concentration signal; and (3) a main control circuit obtains an inverse curve point according to the result of the differential processing Data, and then know the maximum concentration of one of the gases. The operation method of the gas concentration monitoring circuit as described in item 10 of the patent application scope further includes the following steps: (4) The main control circuit transmits the obtained data of the maximum value of the concentration to an electronic device. The operation method of the gas concentration monitoring circuit as described in item 10 of the patent application scope further includes the following steps: (4a) According to the obtained data of the maximum value of the concentration, the main control circuit is connected to the gas cylinder through the At least one mass flow controller between the environment to be measured adjusts the flow rate of the gas into the environment to be tested.

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