Corrosion sensor circuit, corrosion detection sensor, corrosion diagnosis system, and air conditioner

Abstract

The corrosion sensor circuit (10) is provided with a microcomputer (101), corrosion sensors (102, 104, 106), resistors (103, 105, 107) as pull-up resistors, and a resistor (108) as a pull-down resistor. One end side of each of the corrosion sensors (102, 104, 106) is connected to a power supply terminal. One end side of each of the resistors (103, 105, 107) is connected to the other end of each of the corrosion sensors (102, 104, 106), and the other end side of each of the resistors (103, 105, 107) is connected to an input port (110) of the microcomputer (101). The resistor (108) is not connected to the corrosion sensors, one end side of the resistor (108) is connected to the input port (110), and the other end side is connected to a ground wire.

Description

Technical Field

[0001] This disclosure relates to a corrosion sensor circuit for detecting the corrosion state of equipment, a corrosion detection sensor having a corrosion sensor circuit, a corrosion diagnostic system, and an air conditioner. Background Technology

[0002] Commercial air conditioners installed in buildings or office buildings often exceed their design lifespan in most cases. Furthermore, some commercial air conditioners are used in unsuitable environments. In recent years, systems have been developed to detect the corrosion status of air conditioner components and prompt maintenance before the air conditioner malfunctions. Additionally, Patent Document 1 discloses a corrosion monitoring device for printed circuit boards used in environments containing corrosive gases.

[0003] Patent Document 1: Japanese Patent Application Publication No. 3-158748

[0004] However, current air conditioners do not incorporate corrosion detection sensors. Furthermore, in the prior art represented by Patent Document 1, it is difficult to effectively utilize the functionality of existing components. Therefore, the prior art suffers from increased circuit size and manufacturing costs. Moreover, it goes without saying that effectively utilizing the functionality of existing components to incorporate a corrosion detection sensor would be equally useful in devices other than air conditioners. Summary of the Invention

[0005] This disclosure is made in view of the above circumstances, and its purpose is to obtain a corrosion sensor circuit that can infer the corrosion state of a device while suppressing the increase in circuit size and manufacturing cost.

[0006] To address the aforementioned issues and achieve the objectives, the corrosion sensor circuit disclosed herein is a corrosion sensor circuit for detecting the corrosion state of equipment. The corrosion sensor circuit includes a microcomputer and one or more corrosion sensors connected to the microcomputer's input or output port. Furthermore, the corrosion sensor circuit includes one or more first resistors that are individually connected to each corrosion sensor and also connected to the input or output port. The corrosion sensor circuit also includes a second resistor that is not connected to the corrosion sensors but is connected to the input or output port.

[0007] The corrosion sensor circuit disclosed herein can predict the corrosion status of a device while suppressing the increase in circuit size and manufacturing cost. Attached Figure Description

[0008] Figure 1 This is a diagram illustrating a structural example of the corrosion sensor circuit according to Embodiment 1.

[0009] Figure 2This is a diagram illustrating the operation of the corrosion sensor circuit according to Embodiment 1.

[0010] Figure 3 This is a diagram illustrating a structural example of the corrosion sensor circuit according to Embodiment 2.

[0011] Figure 4 This is a diagram illustrating the operation of the corrosion sensor circuit involved in Embodiment 2.

[0012] Figure 5 This is a diagram illustrating a structural example of the corrosion sensor circuit according to Embodiment 3.

[0013] Figure 6 This is a diagram illustrating a structural example of the corrosion sensor circuit according to Embodiment 4.

[0014] Figure 7 This is a diagram illustrating the operation of the corrosion sensor circuit according to Embodiment 4.

[0015] Figure 8 This is a diagram illustrating a structural example of the air conditioner and corrosion diagnosis system according to Embodiment 5. Detailed Implementation

[0016] Hereinafter, with reference to the accompanying drawings, the corrosion sensor circuit, corrosion detection sensor, corrosion diagnostic system, and air conditioner involved in the embodiments of this disclosure will be described in detail. Furthermore, in the following description, physical connections and electrical connections will not be distinguished, and will be simply referred to as "connections." That is, the term "connection" includes both cases where the constituent elements are directly connected to each other and cases where the constituent elements are indirectly connected to each other via other constituent elements.

[0017] Implementation Method 1

[0018] Figure 1 This is a diagram illustrating an example of the structure of the corrosion sensor circuit 10 according to Embodiment 1. (See diagram below.) Figure 1 As shown, the corrosion sensor circuit 10 includes a microcomputer 101, corrosion sensors 102, 104, and 106, and resistors 103, 105, 107, and 108. These components are mounted on a printed circuit board 100. The corrosion sensor circuit 10 is mounted on a device to detect the corrosion state of that device. An example of such a device is an air conditioner. The printed circuit board 100, which houses the corrosion sensor circuit 10, can be mounted on various devices as a corrosion detection sensor.

[0019] The microcomputer 101 has an input port 110. One end of the corrosion sensor 102 is connected to the power supply terminal, and the other end is connected to the input port 110 via resistor 103. One end of the corrosion sensor 104 is connected to the power supply terminal, and the other end is connected to the input port 110 via resistor 105. One end of the corrosion sensor 106 is connected to the power supply terminal, and the other end is connected to the input port 110 via resistor 107. One end of resistor 108 is connected to the input port 110, and the other end is connected to ground. When viewed from the input port 110, the power supply terminal side is referred to as the "pull-up side," and the ground side is referred to as the "pull-down side." That is, resistors 103, 105, and 107 are pull-up resistors connected to each of the corrosion sensors 102, 104, and 106 in turn. Resistor 108 is a pull-down resistor not connected to any corrosion sensor.

[0020] Furthermore, in this document, resistors 103, 105, and 107 connected to corrosion sensors 102, 104, and 106 are sometimes collectively referred to as "the first resistor," and resistor 108 not connected to corrosion sensors 102, 104, and 106 is referred to as "the second resistor." Additionally, corrosion sensors 102, 104, and 106 are sometimes referred to as "the first corrosion sensor," "the second corrosion sensor," and "the third corrosion sensor," respectively.

[0021] Corrosion sensors 102, 104, and 106 exhibit the characteristic that their resistance gradually increases as corrosion progresses, eventually reaching an open-circuit state. Furthermore, in Figure 1 Although three corrosion sensors 102, 104, and 106 are shown in the example, this is not a limited illustration. Corrosion detection can be performed as long as one or more corrosion sensors are connected to the microcomputer 101. Alternatively, two or more corrosion sensors can be combined. In this case, by configuring multiple corrosion sensors that react with corrosive substances of different properties, it is possible to detect which substance caused the corrosion. Examples of corrosive substances include hydrogen sulfide, sulfur dioxide, and chlorine. Furthermore, corrosion sensors made of different metals that selectively react with each property can also be configured to detect which substance caused the corrosion.

[0022] Alternatively, corrosion sensors 102, 104, and 106 can also be made of the same metal, with different metal thicknesses. If the corrosion sensors 102, 104, and 106 are configured with variations in metal thickness, the microcomputer 101 can infer the degree of corrosion of the corrosion sensors 102, 104, and 106 based on the information obtained at the input port 110.

[0023] Here, R1, R2, R3, and R4 represent the resistance values ​​of resistors 103, 105, 107, and 108, respectively. While R1, R2, and R3 can be the same value, they are preferably separated by a certain degree. This allows us to determine which corrosion sensor among corrosion sensors 102, 104, and 106 has increased its resistance value by observing the voltage or voltage change at input port 110.

[0024] In addition, Figure 1 In the structure, in the series circuit of corrosion sensor 102 and resistor 103 to which a power supply voltage is applied, corrosion sensor 102 is positioned on the high potential side and resistor 103 is positioned on the low potential side, but this is not a limitation. The connection order of the series circuit can also be reversed. That is, resistor 103 can also be positioned on the high potential side and corrosion sensor 102 on the low potential side. The same applies to the series circuit of corrosion sensor 104 and resistor 105 and the series circuit of corrosion sensor 106 and resistor 107.

[0025] In addition, Figure 1 In the structure, corrosion sensors 102, 104, and 106, along with resistors 103, 105, and 107, are configured on the pull-up side, and resistor 108 is configured on the pull-down side. However, this configuration can also be reversed. That is, resistor 108 can also be configured on the pull-up side, and corrosion sensors 102, 104, and 106, along with resistors 103, 105, and 107, can be configured on the pull-down side.

[0026] Furthermore, the circuit components mounted on the printed circuit board 100 are exposed to the same or similar environment. Therefore, not only are corrosion sensors 102, 104, and 106 susceptible to corrosion, but the microcomputer 101 and resistors 103, 105, 107, and 108 are also susceptible to corrosion. Therefore, it is preferable to configure the circuit elements, i.e., the peripheral circuit components other than corrosion sensors 102, 104, and 106, with a corrosion-resistant coating applied, while the corrosion sensors 102, 104, and 106 are not coated. When configured in this way, the accuracy of corrosion detection can be improved.

[0027] Next, refer to Figure 1 as well as Figure 2 The operation of the corrosion sensor circuit 10 according to Embodiment 1 will be explained. Figure 2 This is a diagram illustrating the operation of the corrosion sensor circuit 10 according to Embodiment 1. Figure 2 The vertical axis represents port voltage, and the horizontal axis represents time. Port voltage is the voltage value input to input port 110 of microcomputer 101, which is read by microcomputer 101. Figure 2In this example, R1 = 100 kΩ, R2 = 50 kΩ, and R3 = 10 kΩ. That is, the resistance values ​​R1, R2, and R3 are set to different values. In addition, the resistance value R4 is arbitrary.

[0028] If the resistance values ​​R1, R2, and R3 are set to different values, the port voltage and its change will differ when any of the corrosion sensors 102, 104, and 106 becomes an open circuit. For example, the change in resistance of corrosion sensor 102, which has a maximum resistance value of 100 kΩ, will not be significant even when it becomes an open circuit, but the change will be larger when corrosion sensor 106, which has a minimum resistance value of 10 kΩ, becomes an open circuit.

[0029] The microcomputer 101 can identify which sensor is open-circuited by reading the change in port voltage. Figure 2 The diagram shows the changes in port voltage when the corrosion sensors 106, 104, and 102 are open-circuited, i.e., in ascending order of resistance value.

[0030] First, with all corrosion sensors 102, 104, and 106 not open-circuited, the combined resistance of the three series circuits and the voltage division ratio of the resistance R4 to the power supply voltage appear at input port 110. The port voltage at this time is represented by the flat section 202. Subsequently, as time passes and corrosion progresses at each corrosion sensor, the resistance value of each corrosion sensor gradually increases. Therefore, the port voltage decreases with the drop section 203. Based on the slope of this drop section 203 relative to time, i.e., the rate of change of the port voltage relative to time, in other words, based on the amount of change in the port voltage over time, the degree of corrosion can be estimated. Therefore, the corrosion progress can be displayed as predicted information on a display, stored in the memory of the microcomputer 101, or in an external storage device without waiting for the corrosion sensors to become open-circuited. Furthermore, in Figure 2 In the diagram, the flat section 202 is represented by a straight line parallel to the horizontal axis, but it does not necessarily have to be completely flat; it is simply represented by a straight line parallel to the horizontal axis for convenience. The same applies to the flat sections 204 and 206, which will be described later. Similarly, in the descending section 203, the decrease in port voltage is represented by a straight line, but it is not limited to a linear decrease; it is simply represented by a straight line for convenience. The same applies to the descending sections 205 and 207, which will be described later.

[0031] As corrosion progresses further in each corrosion sensor, corrosion sensor 106 becomes an open circuit. In this case, the port voltage drops to the flat portion 204. Based on the amount of voltage drop at this time, it is possible to detect that corrosion sensor 106 has become an open circuit.

[0032] As corrosion progresses further in each corrosion sensor, corrosion sensor 104 becomes an open circuit. In this case, the port voltage drops to the flat section 206 via the drop section 205. Finally, when corrosion sensor 102 becomes an open circuit, the only resistor connected to the input port is resistor 108, which acts as a pull-down resistor, so the voltage becomes 0 [V] via the drop section 207.

[0033] Furthermore, corrosion sensors 102, 104, and 106 can also be configured to be made of different metals and react with corrosive substances having different properties. In this configuration, the amount of voltage drop or the slope of the voltage drop can be used to detect which metal's corrosion affects the voltage drop. Additionally, the speed of corrosion can be determined based on the relationship between the measured voltage drop slope and the theoretical value, or the relationship between the measured voltage drop slope and past empirical values ​​of the voltage drop slope.

[0034] Alternatively, corrosion sensors 102, 104, and 106 can be configured to be made of the same metal, but with varying thicknesses. In this configuration, corrosion sensors 102, 104, and 106 sequentially become open-circuit states, starting with the thinnest. Therefore, since the port voltage reaches the flat portions 202, 204, and 206, the corrosion rate can be predicted more accurately and in stages. Furthermore, since the slopes of the descending portions 203, 205, and 207 are different, it is preferable to pre-store data related to the slopes of the descending portions 203, 205, and 207 in the memory of the microcomputer 101 or an external storage device. This allows for more accurate prediction of the corrosion rate at each stage.

[0035] As described above, the corrosion sensor circuit according to Embodiment 1 includes: a microcomputer; one or more corrosion sensors connected to the input port of the microcomputer; one or more first resistors connected to each corrosion sensor individually and also connected to the input port; and a second resistor connected to the input port but not to the corrosion sensors. The microcomputer detects the voltage at the input port and detects the corrosion state of the corrosion sensors based on the detected voltage. Alternatively, the microcomputer detects the logic value at the input port and detects the corrosion state of the corrosion sensors based on the detected logic value. When using a corrosion sensor circuit configured in this way, it is possible to predict the corrosion state of a device equipped with the corrosion sensor circuit while suppressing increases in circuit size and manufacturing costs.

[0036] When there are multiple corrosion sensors, the microcomputer can also detect the difference in resistance value in the series circuit between the corrosion sensor and the first resistor for each sensor, and based on this difference, determine the corrosion sensors connected to the series circuit where the resistance value is open. This allows for the identification of the primary causative agent of corrosion. Furthermore, the determination of the primary causative agent of corrosion can also be based on the amount of voltage change detected at the input port, or on the change in logic value detected at the input port.

[0037] Furthermore, when there are multiple corrosion sensors made of the same metal with varying thicknesses, the microcomputer calculates the change in resistance in the series circuit between the corrosion sensor and the first resistor, and infers the degree of corrosion based on the average value of the change. This improves the accuracy of corrosion inference.

[0038] Furthermore, if the order in which the resistance value of the first resistor becomes an open circuit is known in advance, and the relationship between the rate of increase of the resistance value and the rate of decrease of the detected voltage, the degree of corrosion of the corrosion sensor can be inferred based on the rate of voltage decrease. This can improve the accuracy of corrosion inference.

[0039] Implementation Method 2

[0040] Figure 3 This is a diagram illustrating an example of the structure of the corrosion sensor circuit 30 according to Embodiment 2. (See diagram below.) Figure 3 As shown, the corrosion sensor circuit 30 includes a microcomputer 301, corrosion sensors 302, 304, and 306, and resistors 303, 305, 307, and 308. These components are mounted on a printed circuit board 300. The corrosion sensor circuit 30 is mounted on a device to detect the corrosion state of the device. An example of such a device is an air conditioner. Furthermore, the names of the components of the corrosion sensor circuit 30 and the requirements for each component will only be described in terms of differences from Embodiment 1, and descriptions of common aspects will be omitted.

[0041] The microcomputer 301 has an input port 310. The input port 310 can also be either an analog-to-digital (A / D) converter port for reading voltage, or an input port for detecting "high" or "low" logic values. Furthermore, in terms of the structure of Embodiment 2, the ability to detect corrosion of each corrosion sensor in stages through logic values ​​is an advantage compared to Embodiment 1.

[0042] exist Figure 3In this circuit, one end of corrosion sensor 302 is connected to the power supply terminal, and the other end is connected to input port 310 via resistor 303. One end of corrosion sensor 304 is connected to input port 310, and the other end is connected to ground via resistor 305. One end of corrosion sensor 306 is connected to the power supply terminal, and the other end is connected to input port 310 via resistor 307. One end of resistor 308 is connected to input port 310, and the other end is connected to ground. Resistors 303 and 307 are pull-up resistors connected to each corrosion sensor 302 and 306 respectively. Resistor 305 is a pull-down resistor connected to corrosion sensor 304. Resistor 308 is a pull-down resistor not connected to any corrosion sensor. Resistor 308 is configured such that even when all corrosion sensors 302, 304, and 306 are open-circuited, the logic of input port 310 will not become high impedance.

[0043] Furthermore, in this document, resistors 303, 305, and 307 connected to corrosion sensors 302, 304, and 306 are sometimes collectively referred to as "the first resistor," and resistor 308 not connected to corrosion sensors 302, 304, and 306 is referred to as "the second resistor." Additionally, resistors 303 and 307 connected to corrosion sensors 302 and 306 and connected to the pull-up side are sometimes referred to as "the first pull-up resistor" and "the second pull-up resistor," respectively. Furthermore, resistor 305 connected to corrosion sensor 304 and connected to the pull-down side is sometimes referred to as "the first pull-down resistor."

[0044] Next, refer to Figure 3 as well as Figure 4 The operation of the corrosion sensor circuit 30 according to Embodiment 2 will be explained. Figure 4 This is a diagram illustrating the operation of the corrosion sensor circuit 30 according to Embodiment 2. Figure 4 The vertical axis represents port voltage, and the horizontal axis represents time. Port voltage is the voltage value appearing at input port 310 of the microcomputer 301. The microcomputer 301 reads this voltage as a logic value. Figure 4 In the example, R1 = 100 [Ω], R2 = 1 [kΩ], R3 = 10 [kΩ], and R4 = 100 [kΩ]. Furthermore, these resistance values ​​are just examples; any resistor with a value set so that the microcomputer 301 can read a "high" or "low" logic value is acceptable. Additionally, these resistance values ​​are determined by assuming that the corrosion sensors 302, 304, and 306 become open-circuit in that order. Therefore, the corrosion sensors 302, 304, and 306 are constructed with metals whose thickness increases in that order. Furthermore, it is preferable that the corrosion sensors 302, 304, and 306 are made of the same metal, but they do not necessarily have to be the same metal.

[0045] First, with all corrosion sensors 302, 304, and 306 not open-circuited, a power supply voltage appears at input port 310 based on the voltage division ratio of the combined resistance value of the two series circuits connected to corrosion sensors 302 and 306, and the combined resistance value of the series circuit connected to corrosion sensor 304 and resistor 308. However, in Figure 4 In this example, the voltage division ratio is roughly determined by the resistance values ​​of R1 = 100 [Ω] and R2 = 1 [kΩ], and approximately 9 / 10 of the power supply voltage appears at input port 310. Therefore, even when input port 310 is used as an input port for detecting logic values, it is possible to ensure that a "high" voltage 403 can be detected.

[0046] Next, as the corrosion sensor 302 becomes an open circuit over time, a power supply voltage of approximately 1 / 11 (1 / (10+1)) of the power supply voltage appears at input port 310, based on the voltage division ratio of R3 = 10 [kΩ] and R2 = 1 [kΩ]. This voltage is determined by... Figure 4 Voltage 404 is indicated by the input port 310. Voltage 404 is a voltage sufficient to detect a "low" level even when the input port 310 is used as an input port for detecting logic values.

[0047] Furthermore, when the corrosion sensor 304 becomes an open circuit over time, a power supply voltage of 10 / 11 of the power supply voltage appears at the input port 310, based on the voltage division ratio of R3 = 10 [kΩ] and R4 = 100 [kΩ] (100 / (10+100) = 10 / 11). This voltage is generated by... Figure 4 The voltage 405 indicates that the voltage 405 is sufficient to detect a "high" level even when input port 310 is the input port for detecting logic values. Finally, with corrosion sensors 302, 304, and 306 all open circuits, only R4 = 100 [kΩ] remains, thus the logic changes to "low".

[0048] Because input port 310 changes as described above, the corrosion of each corrosion sensor can be detected in stages using logic values. Therefore, the degree of corrosion of corrosion sensors 302, 304, and 306 can be estimated in stages. Furthermore, the rate of corrosion progression can be inferred from changes in logic values.

[0049] Implementation Method 3

[0050] A general-purpose microcomputer is multifunctional and has various ports corresponding to its functions. Taking a microcomputer installed in an air conditioner as an example, it has communication ports for communicating with other printed circuit boards or devices, input ports for reading logic values ​​output by sensors, and input ports for reading the speed of motors such as fan motors. Furthermore, communication with other printed circuit boards or devices is implemented via push-pull outputs. When the connected object is a circuit whose logic does not use initial high impedance, it is configured as follows: Figure 5 With that structure, the open-circuit state of the corrosion sensor can be detected even without a dedicated port.

[0051] Figure 5 This is a diagram illustrating an example of the structure of the corrosion sensor circuit 50 according to Embodiment 3. (See diagram below.) Figure 5 As shown, the corrosion sensor circuit 50 includes a microcomputer 501, a corrosion sensor 502, and resistors 503 and 504. These components are mounted on a printed circuit board 500. The corrosion sensor circuit 50 is mounted on a device to detect the corrosion state of the device. An example of such a device is an air conditioner. Furthermore, the names of the components of the corrosion sensor circuit 50 and the requirements for each component are described only for points that differ from other embodiments, and descriptions of common aspects are omitted.

[0052] Microcomputer 501 has port 510. Port 510 is a logic port when high impedance is not used. One end of corrosion sensor 502 is connected to the power supply terminal, and the other end is connected to port 510 via resistor 503. One end of resistor 504 is connected to port 510, and the other end is connected to ground. Furthermore, in Figure 5 In the structure, the corrosion sensor 502 and resistor 503 are configured on the pull-up side, and resistor 504 is configured on the pull-down side, but this configuration can also be reversed. That is, resistor 504 can also be configured on the pull-up side, and corrosion sensor 502 and resistor 503 can be configured on the pull-down side.

[0053] When the corrosion sensor 502 is not open-circuited, increasing the resistance value of resistor 504 and decreasing the resistance value of resistor 503 causes port 510 to become a "high" logic value. Conversely, when the corrosion sensor 502 is open-circuited, port 510 becomes a "low" logic value. Port 510 can determine whether the corrosion sensor 502 is in an open-circuit state by detecting this logic value.

[0054] Furthermore, port 510 can be either an output port or an input port. When port 510 is an input port, the voltage or logic value is read using the idle state of the operation. For example, when it is not an input port that always inputs voltage, logic value, or signal, its idle time is utilized. Taking an air conditioner as an example, this includes the output of a stepper motor driving the blades, the speed input when the fan motor is not running, and UART (Universal Asynchronous Receiver / Transmitter) communication. When port 510 is, for example, a port that inputs the speed of the fan motor, if the fan is not rotating, the logic value is constant. Therefore, by detecting changes in the logic value, changes in the state of the corrosion sensor can be detected. This method of use reduces the resources of the microcomputer 501.

[0055] Additionally, when port 510 is an output port, the function of microprocessor 501 can be used to temporarily switch the function of port 510 from an output port to an input port to detect the voltage or logic value of port 510. This usage method reduces the resource requirements of microprocessor 501.

[0056] According to the corrosion sensor circuit of Embodiment 3, the degree of corrosion of the corrosion sensor can be inferred based on the detection value of the input port when no communication signal or input signal is received. Alternatively, the degree of corrosion of the corrosion sensor can be inferred based on the detection value of the output port when no output signal is sent to other printed circuit boards or devices. These input ports or output ports do not need to be dedicated ports, but can utilize existing ports. Furthermore, even existing ports can be used for other purposes as long as they can be utilized during temporary idle time. Because the corrosion sensor circuit of Embodiment 3 can achieve such utilization, it can effectively utilize the resources of existing microcomputers.

[0057] Implementation Method 4

[0058] Figure 6 This is a diagram illustrating an example of the structure of the corrosion sensor circuit 60 according to Embodiment 4. (See diagram below.) Figure 6As shown, the corrosion sensor circuit 60 includes a microcomputer 601, corrosion sensors 608 and 609, resistors 611 and 612, switches 606 and 607, and diodes 613, 614, 615, and 616 as backflow prevention elements. These components are mounted on a printed circuit board 600. The corrosion sensor circuit 60 is mounted on a device to detect the corrosion state of the device. An example of such a device is an air conditioner. Furthermore, in the corrosion sensor circuit 60, the names of the components and the requirements for those components are described only for points that differ from other embodiments, and descriptions of common aspects are omitted.

[0059] The microcomputer 601 according to Embodiment 4 has input ports 602 and 603 and output ports 604 and 605. This microcomputer 601 is configured to detect logic values ​​output from output ports 604 and 605 at each input port 602 and 603. Such a circuit is called a "matrix circuit". Figure 6 In the matrix circuit, by using switches 606 and 607 together, it is possible to detect the combination of logic values ​​of a 2×2=4 pattern obtained by multiplying the outputs of the two output ports 604 and 605 with the inputs of the two input ports 602 and 603. Increasing the number of input and output ports allows for economies of scale brought by the matrix circuit. Therefore, when increasing the number or type of corrosion sensors to improve the prediction accuracy based on the corrosion sensor circuit 60, the required number of ports can be reduced, thus suppressing manufacturing costs.

[0060] Furthermore, printed circuit boards (PCBs) in air conditioners include those with multiple switches and those composed of matrix circuits. In any of these PCBs, a corrosion sensor can be connected to replace the switches, allowing for the detection of the PCB's corrosion level.

[0061] Next, the connection of the corrosion sensor circuit 60 according to Embodiment 4 will be described. Figure 6 In this circuit, resistor 611 is connected to input port 602, and resistor 612 is connected to input port 603. Resistors 611 and 612 are pull-down resistors. Output port 604 is connected to input port 602 via switch 606 and diode 613, and to input port 603 via switch 607 and diode 614. Output port 605 is connected to input port 602 via corrosion sensor 608 and diode 615, and to input port 603 via corrosion sensor 609 and diode 616. Furthermore, in this document, input ports 602 and 603 are sometimes referred to as "first input port" and "second input port," respectively, and output ports 604 and 605 are sometimes referred to as "first output port" and "second output port," respectively. Additionally, switches 606 and 607 are sometimes referred to as "first switch" and "second switch," respectively.

[0062] Corrosion sensors 608 and 609 are configured in the same positions as switches 606 and 607. Diodes 613 and 615, placed before switch 606 and corrosion sensor 608, prevent short circuits between the output terminals when the outputs of output port 604 and output port 605 have different logic values. Diodes 614 and 616 serve the same purpose. As described above, resistors 611 and 612, acting as pull-down resistors, are placed before diodes 613, 614, 615, and 616. Although it also depends on the operating voltage, when output ports 604 and 605 are "high", the voltage resulting from the voltage drop of Vf generated by each diode is input to input ports 602 and 603. This structure can detect "high" and "low" when input ports 602 and 603 fall within the voltage range for detecting "high" and "low". On the other hand, if the operating voltage is low and the voltage drop of Vf is insufficient for determining a "high" logic value, a transistor can be inserted instead of a diode. Transistors are another example of backflow prevention devices. Because transistors have a low turn-on voltage, it is easier to determine "high" logic values ​​than with diodes. Furthermore, in this document, diodes 613, 614, 615, 616, and the transistors that replace them are sometimes referred to as "first backflow prevention device," "second backflow prevention device," "third backflow prevention device," and "fourth backflow prevention device," respectively.

[0063] Next, the operation of the corrosion sensor circuit 60 according to Embodiment 4 will be explained. First, when the logic value of output port 604 is "low" regardless of the states of switches 606 and 607, if the microcomputer 601 sets the logic value of output port 605 to "high", the logic value on the corrosion sensor 608 side appears at input port 602, and the logic value on the corrosion sensor 609 side appears at input port 603. Here, when the voltage of output port 604 is set to "high" and the voltage of output port 605 is set to "low" at staggered times, the logic states of switches 606 and 607 appear at input ports 602 and 603, respectively. For example, when the logic value of output port 605 is "low" and the logic value of output port 604 is "high", if switch 606 is on, "high" appears at input port 602; if switch 606 is off, "low" appears at input port 602. Similarly, when the logic value of output port 605 is "low" and the logic value of output port 604 is "high", if switch 607 is on, an "high" signal appears at input port 603; if switch 607 is off, an "low" signal appears at input port 603. As described above, when output ports 604 and 605 are set to "high", the on / off state of the circuits on the switch 606 and 607 sides, as well as the logic state of corrosion sensors 608 and 609, can be confirmed.

[0064] Although the above explanation applies to the case where input ports 602 and 603 are used as input ports for detecting logic values, further details are provided below. Figure 6 as well as Figure 7 The operation is explained when input ports 602 and 603 are AD conversion ports. Figure 7 This is a diagram illustrating the operation of the corrosion sensor circuit 60 according to Embodiment 4. Figure 7 The vertical axis represents the port voltage, and the horizontal axis represents time. The port voltage is the voltage value appearing at input ports 602 and 603 of the microcomputer 601, and is read by the microcomputer 601. In addition, since the operation on the input port 602 side is the same as the operation on the input port 603 side, the operation on the input port 602 side will be described here.

[0065] First, when output port 605 is "high," a voltage drop of Vf occurs due to the diode 615. Additionally, the resistance of the corrosion sensor 608 increases due to corrosion. At this time, because the voltage division ratio between the resistance of corrosion sensor 608 and the resistance of resistor 611 gradually decreases, the voltage at input port 602 also gradually decreases. The port voltage at this time is... Figure 7 The first descending section 703 indicates that as corrosion progresses in the corrosion sensor 608, the corrosion sensor 608 becomes an open circuit at a certain moment. At that moment, the port voltage is as follows: Figure 7 The second descending part 704 drops sharply and approaches 0 [V].

[0066] When input port 602 is an input port for detecting logic values, the open-circuit state of corrosion sensor 608 can be detected when it is "low". When input port 602 is an AD conversion port, the degree of corrosion of corrosion sensor 608 can be inferred based on the relationship between the voltage state of the first falling section 703 and the elapsed time.

[0067] In embodiment 4, a corrosion sensor circuit is constructed by adding a corrosion sensor to a substrate that forms a matrix circuit with the first and second input ports and the first and second output ports of a microcomputer and corresponding switches. When the first and second input ports are input ports for detecting logic values, the microcomputer can detect the corrosion progress state of the corrosion sensor by detecting changes in the logic values ​​of the first and second input ports. Therefore, the corrosion state of the substrate equipped with the corrosion sensor can be inferred.

[0068] As described above, if a corrosion sensor is added to an existing substrate equipped with a microcomputer and a switch to form a corrosion sensor circuit, the corrosion state of the substrate can be diagnosed without large-scale circuit changes and without setting up new ports in the microcomputer.

[0069] Furthermore, in the case where the first and second input ports in Embodiment 4 are analog-to-digital conversion ports, the microcomputer can detect the corrosion state based on the voltage changes of the first and second input ports. Therefore, the corrosion state of the substrate equipped with the corrosion sensor can be inferred.

[0070] Furthermore, while the embodiment 4 describes a 2×2 matrix circuit with two input ports and two output ports, it is not limited to this. The number of input ports can be three or more, and the number of output ports can also be three or more. Increasing the number of input and output ports allows for economies of scale brought by the matrix circuit, improving the diagnostic accuracy of corrosion conditions.

[0071] Implementation Method 5

[0072] Figure 8 This is a diagram illustrating a structural example of the air conditioner 801 and the corrosion diagnostic system 800 according to Embodiment 5. Figure 8In the illustration, the air conditioner 801 according to Embodiment 5 includes an indoor unit 802 and a remote control 803. The outdoor unit is omitted from the illustration. The indoor unit 802 is configured to connect to the Internet 813 via a network device 812 such as a Wi-Fi router. A cloud server 804 is built on the Internet 813. The remote control 803 is connected to the indoor unit 802 to perform operations such as cooling, heating, dehumidification, and setting the temperature of the cooling / heating space. The indoor unit 802, remote control 803, and cloud server 804 constitute a corrosion diagnostic system 800. The Internet 813 is one example; any network, whether wired or wireless, can be used. Similarly, the cloud server 804 is another example; any server device that can connect to the indoor unit 802 can be used.

[0073] The indoor unit 802 includes a printed circuit board 805. A microprocessor 806, a pull-down resistor 808, a sensor series resistor 807, and a connector 809 are mounted on the printed circuit board 805. A corrosion sensor 810 is mounted on a sensor substrate 811, which is a separate substrate from the printed circuit board 805. The corrosion sensor 810 is connected to the sensor series resistor 807 via the connector 809. That is, the corrosion sensor 810 can be connected to the connector 809 on the printed circuit board 805 and is configured to be detachable. Furthermore, in this document, the printed circuit board 805 is sometimes referred to as the "first substrate," and the sensor substrate 811 is sometimes referred to as the "second substrate."

[0074] Since the air conditioner 801 is configured as described above, a corrosion sensor 810 suitable for the installation environment can be selected. For example, to detect hydrogen sulfide in areas with a lot of garbage, a sensor that reacts with hydrogen sulfide can be installed. Furthermore, since a new corrosion sensor 810 can be installed after corrosion deteriorates, the printed circuit board 805 and the sensor board 811 can be reused. This simplifies maintenance and reduces maintenance costs.

[0075] The cloud server 804 collects corrosion information detected or determined by the corrosion sensor circuits involved in embodiments 1 to 4. The cloud server 804 diagnoses the corrosion status of the air conditioner 801 based on the corrosion information. Specifically, the cloud server 804 estimates the degree of corrosion of each corrosive substance, predicts the progress of corrosion, determines whether unit replacement or substrate replacement is needed, and determines whether corrosion sensor replacement is needed.

[0076] Diagnostic information from the cloud server 804 can be displayed on the remote control 803's screen. Furthermore, if the maintenance company has access to the diagnostic information from the cloud server 804, it can urge the user to replace units and circuit boards. Additionally, the progress of corrosion can be displayed, and the user can be notified to improve their environment. Moreover, knowing the degree of corrosion from each corrosive substance allows identification of the primary cause of corrosion, thus enabling the prediction of deterioration in components such as fan motors where corrosion is not directly monitored. This also allows for the prompt replacement of other components where corrosion is not directly monitored.

[0077] The above describes the scenario where diagnostic information from the cloud server 804 is displayed on the monitor of the remote control 803. However, the detection results from the microcomputer 806 can also be displayed on the monitor of the remote control 803. This allows for easy diagnosis of the corrosion status of the air conditioner 801 even without a network environment.

[0078] The structure shown in the above embodiments is an example and can be combined with other known technologies, or the embodiments can be combined with each other, or a part of the structure can be omitted or changed without departing from the spirit.

[0079] Explanation of reference numerals in the attached figures

[0080] 10, 30, 50, 60... Corrosion sensor circuit; 100, 300, 500, 600, 805... Printed circuit board; 101, 301, 501, 601, 806... Microcomputer; 102, 104, 106, 302, 304, 306, 502, 608, 609, 810... Corrosion sensor; 103, 105, 107, 108, 303, 305, 307, 308, 503, 504, 611, 612... Resistors; 110, 310, 602, 603... Input port; 202, 204, 206... Flat section; 203, 205, 207. ...Descent section; 403, 404, 405...Voltage; 510...Port; 604, 605...Output ports; 606, 607...Switches; 613, 614, 615, 616...Diodes; 703...First descending section; 704...Second descending section; 800...Corrosion diagnostic system; 801...Air conditioner; 802...Indoor unit; 803...Remote control; 804...Cloud server; 807...Sensor series resistor; 808...Pull-down resistor; 809...Connector; 811...Sensor substrate; 812...Network equipment; 813...Internet.

Claims

1. A corrosion sensor circuit for detecting the corrosion state of equipment, wherein, The corrosion sensor circuit includes: microcomputer; One or more corrosion sensors are connected to the input port of the microcomputer; One or more first resistors are connected to each of the corrosion sensors and to the input port or ground wire, respectively. as well as The second resistor is not connected to the corrosion sensor, but is connected to the input port. The corrosion sensor includes: a first corrosion sensor; a second corrosion sensor that reacts with a corrosive substance having characteristics different from those of the corrosive substance reacting with the first corrosion sensor; and a third corrosion sensor that reacts with a corrosive substance having characteristics different from those of the corrosive substances reacting with the first and second corrosion sensors. The first resistor includes: a first pull-up resistor, one end of which is connected to the first corrosion sensor and the other end of which is connected to the input port; a second pull-up resistor, one end of which is connected to the second corrosion sensor and the other end of which is connected to the input port; and a first pull-down resistor, one end of which is connected to the third corrosion sensor and the other end of which is connected to the ground wire.

2. The corrosion sensor circuit according to claim 1, wherein, The microcomputer detects the voltage at the input port and infers the corrosion status of the device based on the detected voltage.

3. The corrosion sensor circuit according to claim 1, wherein, The microcomputer detects the logic value of the input port and infers the corrosion state of the device based on the detected logic value.

4. The corrosion sensor circuit according to claim 1, wherein, The plurality of corrosion sensors include multiple corrosion sensors that react with corrosive substances having different properties.

5. The corrosion sensor circuit according to any one of claims 1 to 4, wherein, The multiple corrosion sensors are made of metals of different materials.

6. The corrosion sensor circuit according to any one of claims 1 to 4, wherein, Multiple corrosion sensors are made of the same metal, and the thickness of the metal varies from one another.

7. The corrosion sensor circuit according to claim 6, wherein, For each corrosion sensor, the microcomputer calculates the change in resistance value in the series circuit between the corrosion sensor and the first resistor, and infers the degree of corrosion based on the average value of the change.

8. The corrosion sensor circuit according to any one of claims 1 to 3, wherein, The microcomputer detects the voltage at the input port and infers the degree of corrosion of the corrosion sensor based on the detected change in the voltage over time.

9. The corrosion sensor circuit according to claim 1, wherein, The corrosion sensor and the first resistor are connected to the input port of the microcomputer. The input port is the input port of the logic when high impedance is not used. The microcomputer detects the voltage or logic value of the input port.

10. The corrosion sensor circuit according to claim 9, wherein, The microcomputer infers the degree of corrosion of the corrosion sensor based on the detection value of the input port when no communication signal or input signal is received.

11. The corrosion sensor circuit according to any one of claims 1 to 4, 7, 9, and 10, wherein, The microcomputer, the corrosion sensor, the first resistor, and the second resistor are mounted on a printed circuit board. No corrosion-resistant coating is applied to the corrosion sensor. Apply a corrosion-resistant coating to the circuit components other than the corrosion sensor.

12. The corrosion sensor circuit according to any one of claims 1 to 4, 7, 9, and 10, wherein, The microcomputer detects the voltage at the input port and determines the primary cause of corrosion based on the detected change in voltage.

13. The corrosion sensor circuit according to any one of claims 1 to 4, 7, 9, and 10, wherein, The microcomputer detects the logic value of the input port and determines the main causative agent of corrosion based on the detected changes in the logic value.

14. The corrosion sensor circuit according to any one of claims 1 to 4, 7, 9, and 10, wherein, For each corrosion sensor, the microcomputer detects the difference in resistance value in the series circuit between the corrosion sensor and the first resistor, and determines the corrosion sensor connected to the series circuit where the resistance value is open based on the difference information.

15. The corrosion sensor circuit according to claim 14, wherein, Knowing in advance the order in which the resistance value becomes an open circuit and the relationship between the rate of increase of the resistance value and the rate of decrease of the voltage detected by the microcomputer, the degree of corrosion of the corrosion sensor is inferred based on the rate of decrease of the voltage.

16. A corrosion sensor circuit for detecting the corrosion state of equipment, wherein, The corrosion sensor circuit includes: microcomputer; One or more corrosion sensors are connected to the input or output port of the microcomputer; One or more first resistors are connected to each of the corrosion sensors and to the input port or the output port, respectively. The second resistor is not connected to the corrosion sensor, but is connected to either the input port or the output port; Switch 1 and Switch 2; as well as The first backflow prevention element, the second backflow prevention element, the third backflow prevention element, and the fourth backflow prevention element, The microcomputer has a first input port and a second input port, and a first output port and a second output port. Pull-down resistors are connected to the first input port and the second input port respectively. The corrosion sensor includes a first corrosion sensor and a second corrosion sensor. The first output port is connected to the first input port via the first switch and the first backflow prevention element, and is connected to the second input port via the second switch and the second backflow prevention element. The second output port is connected to the first input port via the first corrosion sensor and the third backflow prevention element, and is also connected to the second input port via the second corrosion sensor and the fourth backflow prevention element.

17. The corrosion sensor circuit according to claim 16, wherein, The microcomputer infers the degree of corrosion of the corrosion sensor based on the changes in the logic values ​​of the first input port and the second input port.

18. The corrosion sensor circuit according to claim 16, wherein, The first input port and the second input port are analog-to-digital conversion ports. The microcomputer infers the degree of corrosion of the corrosion sensor based on the voltage changes at the first and second input ports.

19. The corrosion sensor circuit according to any one of claims 16 to 18, wherein, The first corrosion sensor and the second corrosion sensor are corrosion sensors that react with corrosive substances with different properties.

20. The corrosion sensor circuit according to any one of claims 16 to 18, wherein, The first corrosion sensor and the second corrosion sensor are made of metals of different materials.

21. The corrosion sensor circuit according to any one of claims 16 to 18, wherein, The first corrosion sensor and the second corrosion sensor are made of the same metal, but the thickness of the metal is different from that of the other.

22. A corrosion detection sensor, wherein, The corrosion sensor circuit is provided with any one of claims 1 to 21.

23. A corrosion diagnostic system, wherein, The corrosion diagnostic system includes: The device is equipped with the corrosion detection sensor as described in claim 22; The server device collects corrosion information detected or determined by the corrosion detection sensor, and diagnoses the corrosion status of the equipment based on the collected corrosion information. as well as The display receives and displays diagnostic information from the server device.

24. An air conditioner, wherein, It possesses the corrosion detection sensor as described in claim 22.

25. An air conditioner, wherein, The corrosion sensor circuit is provided with any one of claims 1 to 21.

26. The air conditioner according to claim 25, wherein, The corrosion sensor in the corrosion sensor circuit is mounted on a first substrate, and the peripheral circuit components other than the corrosion sensor are mounted on a second substrate. The first substrate and the second substrate are different substrates.

27. The air conditioner according to claim 26, wherein, A connector is mounted on the first substrate on which the peripheral circuit components are mounted, and the second substrate on which the corrosion sensor is mounted is connected to the first substrate via the connector.

28. The air conditioner according to claim 27, wherein, The corrosion sensor is configured to be mountable and detachable from the second substrate.

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