Air blowing control device and ventilation device

Abstract

In this air blowing control device, a first circuit board controls an airflow formed inside an air blowing unit. A second circuit board is communicably connected to the first circuit board via a first communication line. An air quality measurement unit for measuring the state of the air quality in the airflow is communicably connected to the second circuit board via a second communication line. Communication between the first circuit board and the second circuit board is performed according to a first communication standard. Communication between the second circuit board and the air quality measurement unit is performed according to a second communication standard.

Description

Air flow control device and ventilation device

[0001] The present disclosure relates to an air blowing control device and a ventilation device.

[0002] In Patent Document 1, a CO 2 gas is introduced into each of an intake air duct and an exhaust air duct formed inside a housing. ２ A sensor is installed and each CO ２ CO detected by the sensor ２ The present invention discloses a ventilation system in which a controller controls a ventilation section based on the concentration of each CO ２ The sensors are individually connected to the control device via communication lines. ２ The sensor is located in the exhaust air duct. ２ The position is farther from the control device than the position of the sensor.

[0003] Patent No. 7237177

[0004] Generally, CO ２ The I2C (Inter-Integrated Circuit) communication standard is used as a communication standard for environmental sensors such as sensors. Communications conforming to the I2C communication standard have the characteristic that the longer the communication distance, the more susceptible they are to external noise and other influences. In addition, communications conforming to the I2C communication standard also have the characteristic that the longer the communication distance, the slower the rise time of the communication waveform, making the communication more likely to decrease in reliability.

[0005] In the conventional ventilation system disclosed in Patent Document 1, a CO 2 supply unit is installed in the air supply duct. ２ The sensor is located in the exhaust air duct. ２ The position is farther from the control device than the sensor position. ２ When the I2C communication standard is used as the sensor communication standard, ２ This may reduce the reliability of communication between the sensor and the control device.

[0006] The present disclosure is intended to solve the above-mentioned problems, and aims to provide an air blowing control device and a ventilation device that can suppress a decrease in the reliability of communication between an air quality measurement unit and a control unit.

[0007] The air blowing control device of the present disclosure comprises a control unit having a first circuit board that controls the airflow flowing through an air path formed inside the air blowing unit by controlling the air blowing unit, a second circuit board that is communicatively connected to the first circuit board via a first communication line, and an air quality measurement unit that is communicatively connected to the second circuit board via a second communication line and measures the air quality state of the airflow, wherein the first circuit board receives the measurement results of the air quality measurement unit as measurement information via the second circuit board, and controls the air blowing unit based on the measurement information, and communication between the first circuit board and the second circuit board is performed in accordance with a first communication standard, and communication between the second circuit board and the air quality measurement unit is performed in accordance with a second communication standard.

[0008] According to the present disclosure, it is possible to suppress a decrease in the reliability of communication between an air quality measuring unit and a control unit.

[0009] 1 is a configuration diagram showing a ventilation device according to a first embodiment. It is a functional block diagram showing the ventilation device of FIG. 1. It is a configuration diagram showing the hardware configuration of the master-side microcomputer used in each of the first and second microcomputers of FIG. 2 and the hardware configuration of the slave-side microcomputer used in each of the third microcomputers. It is a time chart showing the relationship between a clock signal SCL output from the master-side microcomputer of FIG. 3 and a data signal SDA output from the master-side microcomputer in synchronization with the clock signal SCL. It is a configuration diagram showing the hardware configuration realizing the function of the first board communication unit in the first microcomputer of FIG. 2 and the hardware configuration realizing the function of the second board communication unit in the second microcomputer. It is a time chart showing the relationship between data output from the transmission port of the first microcomputer of FIG. 5 and data input to the reception port of the first microcomputer. It is a timing chart showing the relationship between external noise synchronized with the switching period of the inverter circuit, a signal when the UART communication speed is 100 kbps, and a signal when the UART communication speed is 10 kbps.

[0010] The following describes embodiments of the subject matter of the present disclosure with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant explanations are appropriately simplified or omitted. Note that the subject matter of the present disclosure is not limited to the following embodiments, and any component of the embodiments may be modified or omitted within the scope of the gist of the present disclosure.

[0011] Embodiment 1. Fig. 1 is a configuration diagram showing a ventilation device according to embodiment 1. The ventilation device is a device that exchanges outdoor air with indoor air. The ventilation device has an air blowing unit 1 and an air blowing control device 2. The air blowing unit 1 is installed, for example, above the ceiling.

[0012] The blower unit 1 has a housing 3, an intake fan 4, an exhaust fan 5, and a heat exchanger 6. The intake fan 4, the exhaust fan 5, and the heat exchanger 6 are arranged inside the housing 3.

[0013] The housing 3 has a first side surface 3a and a second side surface 3b that face each other. An outside air intake port 31 and an exhaust air outlet 32 ​​are provided on the first side surface 3a of the housing 3. An intake air outlet 33 and an indoor air intake port 34 are provided on the second side surface 3b of the housing 3. In the housing 3, the outside air intake port 31 and the indoor air intake port 34 face each other, and the exhaust air outlet 32 ​​and the intake air outlet 33 face each other.

[0014] Two air passages, an air supply passage 35 and an air exhaust passage 36, are formed inside the housing 3, i.e., inside the blower unit 1. The air supply passage 35 is an air passage that guides outdoor air from the outside air inlet 31 to the air supply outlet 33 inside the housing 3. The air supply passage 35 runs from the outside air inlet 31 through the heat exchanger 6 to reach the air supply outlet 33.

[0015] The section of the supply air duct 35 between the outside air inlet 31 and the heat exchanger 6 is the supply air intake-side air duct 35a. The section of the supply air duct 35 that passes through the heat exchanger 6 is the supply air heat exchange-side air duct 35b. The section of the supply air duct 35 between the heat exchanger 6 and the supply air outlet 33 is the supply air outlet-side air duct 35c.

[0016] The exhaust air duct 36 is an air duct that guides indoor air from the indoor air inlet 34 to the exhaust air outlet 32 ​​inside the housing 3. The exhaust air duct 36 extends from the indoor air inlet 34 through the heat exchanger 6 to the exhaust air outlet 32.

[0017] The section of the exhaust air duct 36 between the indoor air inlet 34 and the heat exchanger 6 is an exhaust intake-side air duct 36a. The section of the exhaust air duct 36 that passes through the heat exchanger 6 is an exhaust heat exchange air duct 36b. The section of the exhaust air duct 36 between the heat exchanger 6 and the exhaust outlet 32 ​​is an exhaust outlet-side air duct 36c.

[0018] The housing 3 is provided with a first partition wall 37a, a second partition wall 37b, a third partition wall 37c, and a fourth partition wall 37d inside. The first partition wall 37a separates the exhaust air intake-side air duct 36a from the supply air blow-side air duct 35c. The second partition wall 37b separates the supply air intake-side air duct 35a from the exhaust air intake-side air duct 36a. The third partition wall 37c separates the supply air intake-side air duct 35a from the exhaust air blow-side air duct 36c. The fourth partition wall 37d separates the exhaust air blow-side air duct 36c from the supply air blow-side air duct 35c.

[0019] The supply air blower 4 is disposed in the supply air duct 35. In this embodiment, the supply air blower 4 is disposed in the supply air outlet-side duct 35c. The supply air blower 4 generates an intake air flow that flows from the outdoors to the indoors. A duct pipe (not shown) that reaches the outdoors is connected to the outside air inlet 31. A duct pipe (not shown) that reaches the indoors is connected to the supply air outlet 33.

[0020] The intake air blower 4 has an intake impeller 41 and an intake motor 42. The intake motor 42 rotates the intake impeller 41. When the intake impeller 41 rotates, an intake airflow flows through the intake air duct 35 from the outside air inlet 31 to the intake air outlet 33. As a result, outdoor air, i.e., outside air OA (outdoor air), is drawn from the outdoors through the duct piping and the outside air inlet 31 into the intake air duct 35. The outside air OA drawn into the intake air duct 35 flows through the intake air duct 35 as an intake airflow, and is then supplied to the room as supply air SA from the intake air outlet 33 through a duct piping (not shown). As a result, when the air supply impeller 41 rotates inside the blower unit 1, the air supply flow flows through the air supply duct 35 from the outdoors toward the indoors.

[0021] The exhaust fan 5 is disposed in the exhaust air duct 36. In this embodiment, the exhaust fan 5 is disposed in the exhaust outlet-side air duct 36c. The exhaust fan 5 generates an exhaust air flow that flows from the room to the outside. A duct pipe (not shown) that reaches the room is connected to the room air inlet 34. A duct pipe (not shown) that reaches the outside is connected to the exhaust air outlet 32.

[0022] The exhaust fan 5 includes an exhaust impeller 51 and an exhaust motor 52. The exhaust motor 52 rotates the exhaust impeller 51. When the exhaust impeller 51 rotates, an exhaust airflow flows through the exhaust air duct 36 from the indoor air inlet 34 toward the exhaust outlet 32. As a result, air recirculated in the room, i.e., return air RA, is drawn into the exhaust air duct 36 from the room through the duct piping and the indoor air inlet 34. The return air RA drawn into the exhaust air duct 36 flows through the exhaust air duct 36 as an exhaust airflow, and then passes through the exhaust outlet 32 ​​and a duct piping (not shown) to be discharged to the outdoors as exhaust air EA. As a result, when the exhaust impeller 51 rotates inside the blower unit 1, an exhaust airflow flows through the exhaust air duct 36 from the room toward the outdoors.

[0023] The heat exchanger 6 is formed with an intake heat exchange air passage 35b and an exhaust heat exchange air passage 36b. The heat exchanger 6 includes an intake air passage layer in which the intake heat exchange air passage 35b is formed and an exhaust air passage layer in which the exhaust heat exchange air passage 36b is formed. When the heat exchanger 6 is viewed along the stacking direction of the intake air passage layer and the exhaust air passage layer, the direction along the intake air heat exchange air passage 35b and the direction along the exhaust heat exchange air passage 36b are perpendicular to each other. In the heat exchanger 6, heat exchange occurs between the intake air flowing through the intake air heat exchange air passage 35b and the exhaust air flowing through the exhaust heat exchange air passage 36b. The heat exchanger 6 is formed by alternately stacking corrugated sheets and flat sheets. The intake air heat exchange air passage 35b and the exhaust air heat exchange air passage 36b are formed between the corrugated sheet and the flat sheet.

[0024] The heat exchanger 6 is provided with an intake filter 61 and an exhaust filter 62 .

[0025] The intake air filter 61 is disposed in the intake air duct 35. The intake air filter 61 is attached to a portion of the heat exchanger 6 on the intake air suction side air duct 35a side. The intake air filter 61 is a filter for removing foreign matter such as dust and dirt from the intake air flow.

[0026] The exhaust filter 62 is disposed in the exhaust air duct 36. The exhaust filter 62 is attached to a portion of the heat exchanger 6 on the exhaust air duct 36a side. The exhaust filter 62 is a filter for removing foreign matter such as dust and dirt contained in the exhaust air flow from the exhaust air flow.

[0027] 2, which will be described later, is provided in the housing 3. The damper device 38 has a first damper (not shown) that opens and closes the outside air intake port 31, a second damper (not shown) that opens and closes the exhaust outlet 32, and a third damper (not shown) that opens and closes an opening formed in the first partition wall 37a.

[0028] The air blowing control device 2 has a control unit 7 , an exhaust measuring unit 8 , an intake measuring unit 9 , a relay board 10 , and a remote controller 11 .

[0029] The control unit 7 is provided on the outer surface of the housing 3, avoiding the outside air inlet 31, the exhaust outlet 32, the supply air outlet 33, and the indoor air inlet 34. In this embodiment, the control unit 7 is provided on the outer surface of the part of the housing 3 that forms the exhaust intake-side air passage 36a.

[0030] The control unit 7 has, as a first circuit board, a control board 71 that controls the blower unit 1. The control board 71 controls the supply airflow that flows through the supply air passage 35 and the exhaust airflow that flows through the exhaust air passage 36 by controlling the blower unit 1. In other words, the control board 71 controls the airflow that flows through the air passage formed inside the blower unit 1 by controlling the blower unit 1.

[0031] The remote controller 11 is provided in a room to which the intake airflow is supplied. This allows the remote controller 11 to be operated from within the room. The remote controller 11 is communicably connected to the control board 71 via a remote control communication line 111. This allows operation signals corresponding to operations on the remote controller 11 to be sent from the remote controller 11 to the control board 71 via the remote control communication line 111. This allows the operation of the air blowing unit 1 to be set based on the operation signals from the remote controller 11.

[0032] The exhaust measurement unit 8 is an air quality measurement unit that measures the state of air quality in the exhaust flow flowing through the exhaust air duct 36. In this embodiment, the exhaust measurement unit 8 individually measures the concentrations of pollutants and particulates in the exhaust flow as the state of air quality in the exhaust flow. ２ The exhaust gas measuring unit 8 has, as a plurality of environmental sensors, a PM2.5 sensor 81, a PM2.5 sensor 82, and a formaldehyde sensor 83. Note that the exhaust gas measuring unit 8 as an air quality measuring unit may measure at least one of the temperature and humidity of the exhaust flow as the state of air quality in the exhaust flow. That is, the exhaust gas measuring unit 8 as an air quality measuring unit may have, as an environmental sensor, at least one of a temperature sensor that measures the temperature of the exhaust flow as the state of air quality in the exhaust flow, and a humidity sensor that measures the humidity of the exhaust flow as the state of air quality in the exhaust flow.

[0033] CO ２ The sensor 81 measures CO in the exhaust stream. ２ The PM2.5 sensor 82 is a sensor that measures the concentration of PM2.5 in the exhaust stream. The formaldehyde sensor 83 is a sensor that measures the concentration of formaldehyde in the exhaust stream. ２ is a pollutant that causes air pollution. PM2.5 is a fine particle that causes air pollution. Formaldehyde is a volatile organic compound found in building materials, furniture, etc., and is a pollutant that causes sick building syndrome.

[0034] The exhaust gas measuring unit 8 is disposed in the exhaust gas intake side air duct 36a. ２ , PM2.5 and formaldehyde are removed from the exhaust stream by the exhaust filter 62. ２ The concentrations of PM2.5 and formaldehyde are measured.

[0035] The intake air measuring unit 9 is an air quality measuring unit that measures the state of air quality in the intake air flowing through the intake air duct 35. The intake air measuring unit 9 is disposed at a position farther from the control unit 7 than the exhaust air measuring unit 8. In this embodiment, the intake air measuring unit 9 measures the concentrations of pollutants and particulates in the intake air flow individually as the state of air quality in the intake air flow. In addition, in this embodiment, the intake air measuring unit 9 measures the CO ２ The system has a plurality of environmental sensors, including a CO sensor 91 and a PM2.5 sensor 92. ２ The sensor 91 measures the CO ２ The PM2.5 sensor 92 is a sensor that measures the concentration of PM2.5 in the intake air flow. The intake air measurement unit 9 as an air quality measurement unit may measure at least one of the temperature and humidity of the intake air flow as the state of air quality in the intake air flow. That is, the intake air measurement unit 9 as an air quality measurement unit may have, as an environmental sensor, at least one of a temperature sensor that measures the temperature of the intake air flow as the state of air quality in the intake air flow, and a humidity sensor that measures the humidity of the intake air flow as the state of air quality in the intake air flow.

[0036] Since formaldehyde is generated from building materials, furniture, etc., the concentration of formaldehyde in the intake airflow taken into intake air duct 35 from outdoors is usually negligibly low. Therefore, in this embodiment, intake air measuring unit 9 does not include a formaldehyde sensor.

[0037] The relay board 10 is disposed in the intake-side air duct 35a as a second circuit board. Therefore, the relay board 10 is disposed closer to the intake measurement unit 9 than the control unit 7 and the exhaust measurement unit 8. The control unit 7 is also disposed closer to the exhaust measurement unit 8 than the relay board 10 and the intake measurement unit 9.

[0038] The relay board 10 is communicably connected to the control board 71 via a first communication line 12. The supply air measuring unit 9 is communicably connected to the relay board 10 via a second communication line 13. ２ The sensor 91 and the PM2.5 sensor 92 are individually connected to each other via a second communication line 13 so as to be able to communicate with each other.

[0039] The measurement result of the intake air measurement unit 9, i.e., CO ２ The measurement results of the sensor 91 and the PM2.5 sensor 92 are transmitted from the intake air measurement unit 9 to the relay board 10 via the second communication line 13. The measurement results of the intake air measurement unit 9 transmitted to the relay board 10 are then transmitted from the relay board 10 to the control board 71 via the first communication line 12. As a result, the control board 71 receives the measurement results of the intake air measurement unit 9 from the intake air measurement unit 9 via the relay board 10 as measurement information for the intake air, i.e., intake air measurement information. The intake air measurement information received by the control board 71 includes the CO ２ The results include measurements of the concentration of PM2.5 in the intake airflow and measurements of the concentration of CO ２ The sensor 91 and the PM2.5 sensor 92 may be referred to as "environmental sensors 91, 92."

[0040] The exhaust gas measurement unit 8 is communicably connected to the control board 71 via the third communication line 14. ２The sensor 81, the PM2.5 sensor 82, and the formaldehyde sensor 83 are individually connected to each other so as to be able to communicate with each other via a third communication line 14. The lengths of the second communication line 13 and the third communication line 14 are each shorter than the length of the first communication line 12.

[0041] The measurement result of the exhaust gas measurement unit 8, i.e., CO ２ The measurement results of the exhaust gas measurement unit 81, the PM2.5 sensor 82, and the formaldehyde sensor 83 are individually transmitted from the exhaust gas measurement unit 8 to the control board 71 via the third communication line 14. The control board 71 receives the measurement results of the exhaust gas measurement unit 8 from the exhaust gas measurement unit 8 as measurement information for the exhaust gas, i.e., exhaust gas measurement information. The exhaust gas measurement information received by the control board 71 includes the CO ２ The results include measurements of the concentration of PM2.5 in the exhaust stream, and measurements of the concentration of formaldehyde in the exhaust stream. ２ The sensor 81, the PM2.5 sensor 82, and the formaldehyde sensor 83 may be referred to as "environmental sensors 81, 82, 83."

[0042] Communication between the intake air measurement unit 9 and the relay board 10 is performed via a second communication line 13 in accordance with the I2C communication standard, which serves as a second communication standard. Communication between the exhaust measurement unit 8 and the control board 71 is performed via a third communication line 14 in accordance with the I2C communication standard, which serves as a second communication standard. On the other hand, communication between the control board 71 and the relay board 10 is performed via a first communication line 12 in accordance with the UART (Universal Asynchronous Receiver / Transmitter) communication standard, which serves as a first communication standard. Therefore, the I2C communication standard, which serves as the second communication standard, is a different type of communication standard from the UART communication standard, which serves as the first communication standard. In this embodiment, the environmental sensors 81, 82, and 83 in the exhaust measurement unit 8 and the environmental sensors 91 and 92 in the intake air measurement unit 9 each support only the I2C communication standard.

[0043] The control board 71 receives the measurement results of the exhaust measurement unit 8 and the intake air measurement unit 9 as exhaust measurement information and intake air measurement information, respectively. Based on the intake air measurement information and exhaust measurement information, the control board 71 controls the blower unit 1. The operation of the blower unit 1 is switched between intake air operation and circulation operation under the control of the control board 71.

[0044] The air supply operation of the blower unit 1 is an operation in which an air supply flow is generated from the outdoors to the indoors and an exhaust flow is generated from the indoors to the outdoors. In the air supply operation, the air supply fan 4 and the exhaust fan 5 are driven. In addition, in the air supply operation, the first damper and the second damper open the outside air intake port 31 and the exhaust outlet port 32, and the third damper closes the opening of the first partition wall 37a.

[0045] The circulation operation of the blower unit 1 circulates indoor air without drawing in outside air. During circulation operation, the supply air blower 4 is driven, while the exhaust air blower 5 is stopped. Furthermore, during circulation operation, the first and second dampers close the outside air intake port 31 and the exhaust air outlet 32, and the third damper opens the opening in the first partition wall 37a. During circulation operation, the opening in the first partition wall 37a opens, allowing the airflow generated by the supply air blower 4 to flow from the exhaust air intake-side air duct 36a to the supply air outlet-side air duct 35c. As a result, during circulation operation, indoor air drawn into the exhaust air intake-side air duct 36a from the room air intake port 34 passes through the opening in the first partition wall and the supply air outlet-side air duct 35c, and is then blown out into the room from the supply air outlet 33. In this manner, indoor air is circulated.

[0046] The control board 71 detects the CO ２ When at least one of the concentrations of PM2.5 and formaldehyde is higher than the reference value, the intake air blower 4 and the exhaust air blower 5 are controlled according to each concentration so that the amount of intake air flow and exhaust air flow during intake operation is increased.

[0047] The control board 71 detects the CO ２When at least one of the concentrations of PM2.5 and PM2.5 is higher than the reference value, the air supply operation is stopped and the air blower unit 1 is controlled to perform the circulation operation.

[0048] Usually, CO in outdoor air ２ The concentration of CO in indoor air ２ However, if the building faces a main road and large vehicles pass by the building, the CO concentration in the outside air will be lower than that of ２ The concentration of CO in indoor air ２ In this case, the control board 71 switches the operation of the blower unit 1 from the air supply operation to the circulation operation.

[0049] In addition, the concentration of PM2.5 in the outside air may become significantly higher than normal. Furthermore, if the function of the intake air filter 61 deteriorates, the concentration of PM2.5 in the exhaust flow may become less improved than the concentration of PM2.5 in the intake air flow. Therefore, the difference between the PM2.5 concentration contained in the exhaust measurement information and the PM2.5 concentration contained in the intake air measurement information may become smaller than the reference value. In such cases, the control board 71 switches the operation of the blower unit 1 from intake air operation to circulation operation.

[0050] Fig. 2 is a functional block diagram showing the ventilation device of Fig. 1. The control board 71 has an AC / DC conversion unit 72, a control power supply generation unit 73, a first measurement and communication unit 74, a remote control communication unit 75, a first board communication unit 76, an intake fan operation command unit 77, an exhaust fan operation command unit 78, and a damper device control unit 79.

[0051] The control board 71 is equipped with a first microcomputer 711 serving as a first processor. Hereinafter, the first microcomputer 711 will be referred to as the "first microcomputer 711." The first microcomputer 711 realizes the functions of a first measurement and communication unit 74, a remote control communication unit 75, a first board communication unit 76, an intake air blower operation command unit 77, an exhaust air blower operation command unit 78, and a damper device control unit 79. Therefore, the first microcomputer 711 has the first measurement and communication unit 74, the remote control communication unit 75, the first board communication unit 76, the intake air blower operation command unit 77, the exhaust air blower operation command unit 78, and the damper device control unit 79 as functional components.

[0052] The AC / DC converter 72 converts alternating current (AC) power supplied from a commercial power source 721 to the control board 71 into direct current (DC) power. The AC / DC converter 72 supplies DC power to the intake air blower 4, the exhaust air blower 5, and the control power supply generator 73.

[0053] In this embodiment, low-power-consumption DC brushless motors are used as the air intake motor 42 in the air intake blower 4 and the exhaust motor 52 in the exhaust blower 5. However, AC motors may also be used as the air intake motor 42 and the exhaust motor 52. When AC motors are used as the air intake motor 42 and the exhaust motor 52, AC power from a commercial power source 721 is supplied directly to the air intake blower 4 and the exhaust blower 5, respectively.

[0054] The control power supply generating unit 73 supplies DC power from the AC / DC converting unit 72 to the first microcomputer 711. The control power supply generating unit 73 is used as a switching power supply in the first microcomputer 711 to generate DC power for control.

[0055] The first measurement and communication unit 74 communicates with the exhaust measurement unit 8 via the third communication line 14 in accordance with the I2C communication standard. As a result, the first measurement and communication unit 74 transmits to the exhaust measurement unit 8 a command to cause the environmental sensors 81, 82, and 83 in the exhaust measurement unit 8 to perform measurements, and receives the measurement results of the environmental sensors 81, 82, and 83 from the exhaust measurement unit 8 as exhaust measurement information.

[0056] The first board communication unit 76 communicates with the relay board 10 via the first communication line 12 in accordance with the UART communication standard. As a result, the first board communication unit 76 transmits to the relay board 10 commands to cause the environmental sensors 91, 92 in the air supply measurement unit 9 to perform measurements, and receives the measurement results of the environmental sensors 91, 92 from the relay board 10 as air supply measurement information.

[0057] The remote control communication unit 75 communicates with the remote controller 11 via the remote control communication line 111. The remote control communication unit 75 communicates with the remote controller 11 information such as information on the operation mode set in the blower unit 1, and information for displaying the measurement results of the exhaust measurement unit 8 and the intake air measurement unit 9. The communication between the remote control communication unit 75 and the remote controller 11 is performed in accordance with a communication standard applicable to a communication distance corresponding to the length of the remote control communication line 111.

[0058] The intake air blower operation command unit 77 sends a control signal specifying the rotation speed of the intake air motor 42 to the intake air blower 4. The amount of intake air that the blower unit 1 takes in from outdoors is controlled according to the rotation speed of the intake air motor 42. Methods for controlling the rotation speed of the intake air motor 42 include changing the voltage value according to the rotation speed specified by the control signal and changing the duty ratio of the pulse according to the rotation speed specified by the control signal. The intake air blower operation command unit 77 receives a signal according to the current rotation speed of the intake air motor 42 from the intake air blower 4.

[0059] The exhaust fan operation command unit 78 sends a control signal specifying the rotation speed of the exhaust motor 52 to the exhaust fan 5. The amount of exhaust air that the blower unit 1 discharges outdoors is controlled according to the rotation speed of the exhaust motor 52. The rotation speed of the exhaust motor 52 can be controlled by a method similar to the method for controlling the rotation speed of the air intake motor 42. The exhaust fan operation command unit 78 receives a signal according to the current rotation speed of the exhaust motor 52 from the exhaust fan 5.

[0060] The damper device control unit 79 individually controls the first damper, the second damper, and the third damper in the damper device 38. The damper device control unit 79 switches the states of the first damper, the second damper, and the third damper in the damper device 38 in response to switching between air supply operation and air circulation operation of the blower unit 1.

[0061] The relay board 10 has a second measurement communication unit 101 and a second board communication unit 102 .

[0062] The relay board 10 is equipped with a second microcomputer 103 as a second processor. Hereinafter, the second microcomputer 103 will be referred to as the "second microcomputer 103." The second microcomputer 103 realizes the functions of the second measurement and communication unit 101 and the second board communication unit 102. Therefore, the second microcomputer 103 has the second measurement and communication unit 101 and the second board communication unit 102 as functional components.

[0063] The second measurement and communication unit 101 communicates with the air supply measurement unit 9 via the second communication line 13 in accordance with the I2C communication standard. That is, the air supply measurement unit 9 and the second measurement and communication unit 101 communicate with each other via the second communication line 13 in accordance with the I2C communication standard. As a result, the second measurement and communication unit 101 receives the measurement results of each environmental sensor 91, 92 from the air supply measurement unit 9 as air supply measurement information.

[0064] The second board communication unit 102 communicates with the first board communication unit 76 of the control board 71 via the first communication line 12 in accordance with the UART communication standard. That is, the first board communication unit 76 and the second board communication unit 102 communicate with each other via the first communication line 12 in accordance with the UART communication standard. As a result, the second board communication unit 102 receives commands from the control board 71 to cause the environmental sensors 91, 92 in the air supply measurement unit 9 to perform measurements. The second measurement and communication unit 101 transmits the commands that the second board communication unit 102 received from the control board 71 to the air supply measurement unit 9. In addition, the second board communication unit 102 transmits the air supply measurement information that the second measurement and communication unit 101 received from the air supply measurement unit 9 to the first board communication unit 76 of the control board 71.

[0065] The functions realized by the second microcomputer 103 are fewer than the functions realized by the first microcomputer 711 of the control board 71. Therefore, the second microcomputer 103 is a cheaper microcomputer with a smaller package size than the first microcomputer 711. As a result, the relay board 10 is a smaller and cheaper board than the control board 71.

[0066] A third microcomputer serving as a third processor is mounted on each of the environmental sensors 81, 82, 83 in the exhaust measuring section 8 and each of the environmental sensors 91, 92 in the intake air measuring section 9. Hereinafter, the third microcomputer will be referred to as a "third microcomputer."

[0067] The third microcomputers mounted on the environmental sensors 81, 82, and 83 in the exhaust measurement unit 8 communicate with the first measurement and communication unit 74 of the first microcomputer 711 in accordance with the I2C communication standard. The third microcomputers mounted on the environmental sensors 91 and 92 in the intake air measurement unit 9 communicate with the second measurement and communication unit 101 of the second microcomputer 103 in accordance with the I2C communication standard.

[0068] Next, the hardware configurations of the master-side microcomputer and the slave-side microcomputer that communicate with each other according to the I2C communication standard will be described. The hardware configuration of the master-side microcomputer is used in the hardware configuration of the first microcomputer 711 that realizes the function of the first measurement and communication unit 74 and the hardware configuration of the second microcomputer 103 that realizes the function of the second measurement and communication unit 101. The hardware configuration of the slave-side microcomputer is used in each of the third microcomputers mounted on each of the environmental sensors 81, 82, 83, 91, and 92.

[0069] 3 is a block diagram showing the hardware configuration of the master microcomputer used in each of the first microcomputer 711 and second microcomputer 103 in FIG. 2, and the hardware configuration of the slave microcomputer used in each of the third microcomputers. The master microcomputer 200 is provided with a clock output port 210 and a data input / output port 211. The slave microcomputer 300 is provided with a clock input port 310 and a data input / output port 311. Two slave microcomputers 300 are shown in FIG. 3.

[0070] The clock output port 210 is connected to the clock input port 310 of each slave microcomputer 300 via a clock signal line 400. The data input / output port 211 is connected to the data input / output port 311 of each slave microcomputer 300 via a data signal line 401. Each of the second communication line 13 and the third communication line 14 shown in FIG. 1 is a communication line having a clock signal line 400 and a data signal line 401.

[0071] As a result, each slave-side microcomputer 300 is electrically connected in parallel to the master-side microcomputer 200. That is, each third microcomputer mounted on each environmental sensor 81, 82, 83 is electrically connected in parallel to the first microcomputer 711 via the third communication line 14. Furthermore, each third microcomputer mounted on each environmental sensor 91, 92 is electrically connected in parallel to the second microcomputer 103 via the second communication line 13.

[0072] The master microcomputer 200 has a clock output unit 201, a data output unit 202, and a data input unit 203. Each slave microcomputer 300 has a clock input unit 301, a data output unit 302, and a data input unit 303. N-channel MOSFETs 15 are used as the clock output unit 201, the data output unit 202, and the data output unit 302. Buffer elements are used as the data input units 203 and 303.

[0073] The master microcomputer 200 outputs a clock signal SCL (SCL: Serial Clock) generated in a clock output unit 201 from a clock output port 210. The clock signal SCL output from the clock output port 210 is input to a clock input port 310 of the slave microcomputer 300 via a clock signal line 400. The clock signal SCL input to the clock input port 310 is recognized by a clock input unit 301 of the slave microcomputer 300.

[0074] The master microcomputer 200 outputs a data signal SDA (SDA: Serial Data) generated in the data output unit 202 from the data input / output port 211. The data signal SDA output from the data input / output port 211 is a signal synchronized with the clock signal SCL. The data signal SDA output from the data input / output port 211 is input to the data input / output port 311 of the slave microcomputer 300 via a data signal line 401. The data signal SDA input to the data input / output port 311 is recognized by the data input unit 303 of the slave microcomputer 300.

[0075] A unique identification number is assigned as a communication address to each of the environmental sensors 81, 82, 83, 91, and 92. The data signal SDA output from the data input / output port 211 contains information about the identification number of the environmental sensor with which communication is being made. Of the environmental sensors 81, 82, 83, 91, and 92, the slave microcomputer 300 of the environmental sensor whose identification number matches the identification number output from the master microcomputer 200 communicates with the master microcomputer 200.

[0076] Each slave microcomputer 300 outputs a data signal SDA generated in the data output unit 302 from the data input / output port 311. The data signal SDA output from the data input / output port 311 includes information related to the measurement results of the environmental sensor. The data signal SDA output from the data input / output port 311 is input to the data input / output port 211 of the master microcomputer 200 via a data signal line 401. The data signal SDA input to the data input / output port 211 is recognized by the data input unit 203 of the master microcomputer 200. The clock signal SCL and the data signal SDA are each a square wave digital signal that specifies information by switching between a high level H and a low level L.

[0077] The I2C communication standard specifies that the output of the clock signal SCL from the clock output port 210 and the output of the data signal SDA from the data input / output port 211 should each be an open-drain output of an N-channel MOSFET 15. For this reason, a pull-up resistor 501 connected to a power supply voltage 500 is connected to each of the clock signal line 400 and the data signal line 401 as the output stage of the clock output port 210 and the data input / output port 211, respectively. This enables the clock output port 210 to output a high-level clock signal SCL, and the data input / output ports 211 and 311 to output a high-level data signal SDA.

[0078] The clock signal SCL and the data signal SDA output from the master microcomputer 200 each suffer from waveform rounding due to the influence of the time constant for charging the capacitance of each pull-up resistor 501 and the signal lines 400, 401 from the power supply voltage 500. Waveform rounding is a phenomenon in which the rise time of a square wave signal becomes slower when a high-level H signal is output. Since the capacitance of the signal lines 400, 401 increases as the distance between the signal lines 400, 401 increases, waveform rounding tends to become greater as the distance between the signal lines 400, 401 increases.

[0079] The time constant when a high-level H signal is output from the master microcomputer 200 decreases as the resistance value of the pull-up resistor 501 decreases. Therefore, the waveform rounding of the clock signal SCL and the data signal SDA output from the master microcomputer 200 decreases as the resistance value of the pull-up resistor 501 decreases. However, when a low-level L clock signal SCL is output from the master microcomputer 200, a current determined by the resistance value of the pull-up resistor 501 connected to the clock signal line 400 and the power supply voltage 500 flows through the clock output unit 201. Furthermore, when a low-level L data signal SDA is output from the master microcomputer 200, a current determined by the resistance value of the pull-up resistor 501 connected to the data signal line 401 and the power supply voltage 500 flows through the data output unit 202. Because there is a limit to the allowable current of the N-channel MOSFET 15 in each of the clock output unit 201 and the data output unit 202, the resistance value of each pull-up resistor 501 cannot be made smaller than necessary.

[0080] A capacitor 502 is connected to the clock input port 310 of the slave microcomputer 300 in order to remove external noise from the clock signal SCL input to the clock input port 310. In addition, a capacitor 502 is connected to the data input / output port 311 of the slave microcomputer 300 in order to remove external noise from the data signal SDA input to the data input / output port 311.

[0081] If the number of capacitors 502 increases due to an increase in the number of environmental sensors, the rise time of each signal waveform of the clock signal SCL and the data signal SDA will be further delayed. As a result, in some cases, a high-level signal may not reach the power supply voltage 500, and the buffer element of the data input unit 303 may not be able to correctly recognize the logical value of the signal. This may result in a phenomenon in which communication between the master microcomputer 200 and the slave microcomputer 300 is not established.

[0082] 4 is a time chart showing the relationship between the clock signal SCL output from the master microcomputer 200 in FIG. 3 and the data signal SDA output from the master microcomputer 200 in synchronization with the clock signal SCL. The data signal SDA output from the master microcomputer 200 is switched between high level H and low level L when the clock signal SCL is at low level L. The data signal SDA output from the slave microcomputer 300 is switched between high level H and low level L in a similar manner.

[0083] The fall times of the low-level clock signal SCL and low-level data signal SDA output from the master microcomputer 200 depend substantially on the on-resistances of the N-channel MOSFETs 15 in the clock output unit 201 and the data output unit 202. Therefore, the clock signal SCL and the data signal SDA each switch from high level H to low level L in a time shorter than their rise times. The clock signal line 400 and the data signal line 401 are adjacent to each other. Therefore, noise 20 generated when one of the signals on the clock signal line 400 and the data signal line 401 switches from high level H to low level L may cause electromagnetic interference to the other signal. Therefore, the longer the communication line including the clock signal line 400 and the data signal line 401, the more likely the clock signal SCL and the data signal SDA will electromagnetically interfere with each other, making it more likely that noise 20 will be superimposed on the communication data. Furthermore, the longer the communication line including the clock signal line 400 and the data signal line 401, the more susceptible the clock signal SCL and the data signal SDA are to the adverse effects of external noise.

[0084] As described above, in communication conforming to the I2C communication standard, i.e., I2C communication, the longer the communication line, the more likely the signal waveform distortion occurs, which may cause interference between the clock signal SCL and the data signal SDA. As a result, the longer the communication line, the more likely it is that I2C communication will not be performed properly. In other words, the reliability of I2C communication decreases as the communication line length increases. In contrast, in this embodiment, the length of the second communication line 13, which communicatively connects the environmental sensors 91, 92 in the intake air measurement unit 9 to the relay board 10, is shorter than the length of the first communication line 12. Furthermore, in this embodiment, the length of the third communication line 14, which communicatively connects the environmental sensors 81, 82, and 83 in the exhaust measurement unit 8 to the control board 71, is shorter than the length of the first communication line 12. As a result, even when I2C communication is performed between the intake air measurement unit 9 and the relay board 10, and between the exhaust air measurement unit 8 and the control board 71, communication problems due to the superposition of noise 20, the influence of external noise, etc. are suppressed.

[0085] 5 is a configuration diagram showing the hardware configuration that realizes the function of the first board communication unit 76 in the first microcomputer 711 of FIG. 2 and the hardware configuration that realizes the function of the second board communication unit 102 in the second microcomputer 103. The first microcomputer 711 is provided with a transmission port 701 and a reception port 702. The second microcomputer 103 is provided with a reception port 104 and a transmission port 105. In FIG. 5, each of the transmission ports 701 and 105 is marked with "TxD," and each of the reception ports 702 and 104 is marked with "RxD."

[0086] The transmission port 701 of the first microcomputer 711 is communicatively connected to the reception port 104 of the second microcomputer 103 via a transmission line 402. The reception port 702 of the first microcomputer 711 is communicatively connected to the transmission port 105 of the second microcomputer 103 via a reception line 403. The first communication line 12 shown in FIG. 1 is a communication line having the transmission line 402 and the reception line 403.

[0087] The first microcomputer 711 has a data output unit 712 and a data input unit 713. The second microcomputer 103 has a data input unit 106 and a data output unit 107.

[0088] Each of the data output units 712, 107 uses a CMOS (Complementary Metal-Oxide-Semiconductor) configured by combining an N-channel MOSFET 15 and a P-channel MOSFET 16. In the CMOS, the P-channel MOSFET 16 is connected to a power supply voltage 500. In this embodiment, the first microcomputer 711 and the second microcomputer 103 are microcomputers of the same series. Therefore, the same power supply voltage 500 is supplied to each of the data output units 712, 107. Each of the data input units 713, 106 uses a buffer element.

[0089] Communication according to the UART communication standard, i.e., UART communication, exchanges data by generating clocks of the same frequency inside each of the first microcomputer 711 and the second microcomputer 103. For this reason, UART communication does not require the clock signal used in the I2C communication standard.

[0090] In UART communication, a data signal generated in a data output unit 712 of a first microcomputer 711 is output from a transmission port 701. The data signal output from the transmission port 701 is input to a reception port 104 via a transmission line 402. The data signal input to the reception port 104 is recognized by a data input unit 106 of a second microcomputer 103.

[0091] Furthermore, a data signal generated in the data output unit 107 of the second microcomputer 103 is output from the transmission port 105. The data signal output from the transmission port 105 is input to the reception port 702 via the reception line 403. The data signal input to the reception port 702 is recognized by the data input unit 713 of the first microcomputer 711.

[0092] In UART communication, communication begins when a one-bit low-level L signal called a start bit is sent in the normal high-level H state. For example, if the transmitting microcomputer is initializing at power-on, and the transmitting port goes into a low-level L state for a certain period of time at an unspecified time, the receiving microcomputer may mistakenly recognize this as a start bit. Therefore, each receiving port 702, 104 is individually connected to a pull-up resistor 501 connected to the power supply voltage 500.

[0093] In UART communication, when a high-level H signal is output from each transmission port 701, 105, the P-channel MOSFET 16 in the CMOS is turned on and a signal is output from the power supply voltage 500 inside the microcomputer. Therefore, compared to I2C communication, which transmits a signal to the receiving side from the power supply voltage 500 outside the microcomputer via a pull-up resistor 501 connected in series, the rise time of the signal is shorter in UART communication. This suppresses the occurrence of waveform distortion in the signal in UART communication.

[0094] 6 is a time chart showing the relationship between data output from the transmission port 701 of the first microcomputer 711 in FIG. 5 and data input to the reception port 702 of the first microcomputer 711. When the first microcomputer 711 transmits data to the second microcomputer 103, as shown in time chart (a), the first microcomputer 711 outputs a start bit 601, then a data bit 602, and finally a stop bit 603. The start bit 601 is a one-bit low-level L signal indicating the start of data transmission. The stop bit 603 is a one-bit high-level H signal indicating the end of data transmission. The second microcomputer 103 recognizes the start of data transmission when the start bit 601 is input to the reception port 104. The second microcomputer 103 also recognizes the end of data transmission when the stop bit 603 is input to the reception port (RxD) 104.

[0095] After receiving the data from the first microcomputer 711 , the second microcomputer 103 returns the data to the first microcomputer 711 and waits until the next data is sent from the first microcomputer 711 .

[0096] As shown in time chart (b), the first microcomputer 711 receives data returned from the second microcomputer 103 and inputs it to the receiving port 702 as received data. Comparing time charts (a) and (b) reveals that in UART communication, data signals do not simultaneously appear on the adjacent transmission line 402 and reception line 403. Therefore, in UART communication, electromagnetic interference is unlikely to occur to data signals on either the transmission line 402 or the reception line 403. This prevents communication problems in UART communication even if the length of the first communication line 12, which communicatively connects the control board 71 and the relay board 10, is longer than the lengths of the second communication line 13 and the third communication line 14. In other words, the reliability of UART communication is less likely to decrease with the length of the communication line than that of I2C communication.

[0097] Next, we will explain an example of suppressing communication problems caused by external noise in UART communication. To reduce power consumption, DC brushless motors are often used as the intake motor 42 of the intake fan 4 and the exhaust motor 52 of the exhaust fan 5 in the air blower unit 1. DC brushless motors rotate by generating an AC rotating magnetic field from a DC power source using an inverter circuit. The inverter circuit switches power semiconductor elements at high speed, generating a large amount of noise, such as electromagnetic waves. The noise generated by the inverter circuit easily acts as external noise on the first communication line 12 via the wiring supplying DC power from the AC / DC converter 72 (see FIG. 2 ) to the intake fan 4 and the exhaust fan 5. The switching frequency of the inverter circuit of a DC brushless motor is typically set to 20 kHz to prevent audible noise. That is, the switching period of the inverter circuit of a DC brushless motor is often set to 50 microseconds.

[0098] Here, when the first microcomputer 711 performs I2C communication with each of the environmental sensors 81, 82, and 83, it is necessary to set a clock frequency, i.e., a communication speed, in accordance with the specification range of each of the environmental sensors 81, 82, and 83. Similarly, when the second microcomputer 103 performs I2C communication with each of the environmental sensors 91 and 92, it is necessary to set a clock frequency, i.e., a communication speed, in accordance with the specification range of each of the environmental sensors 91 and 92. In contrast, the communication speed of the UART communication performed between the first microcomputer 711 and the second microcomputer 103 can be set independently.

[0099] The communication speed of UART communication is called the baud rate and is expressed as the maximum number of bits transferred per second. Therefore, the unit of communication speed is "bps," or "bits per second." The communication speed of UART communication is generally set to 9600 bps. However, the communication speed of UART communication may also be set to a specific baud rate other than 9600 bps.

[0100] 7 is a timing chart showing the relationship between external noise synchronized with the switching period of the inverter circuit, a signal when the UART communication speed is 100 kbps, and a signal when the UART communication speed is 10 kbps. In FIG. 7, the waveform of the noise synchronized with the switching period of the inverter circuit is shown as timing chart (i). Also in FIG. 7, the waveform of the signal when the UART communication speed is 100 kbps is shown as timing chart (ii). Furthermore, in FIG. 7, the waveform of the signal when the UART communication speed is 10 kbps is shown as timing chart (iii). As shown in timing chart (i) in FIG. 7, the switching period is 50 microseconds, and the time width of one noise is 5 microseconds.

[0101] When the communication speed of UART communication is 100 kbps, the time width of a 1-bit signal is 10 microseconds, as shown in timing chart (ii). Therefore, when the communication speed of UART communication is 10 kbps, the signal waveform alternates between high level H and low level L every 10 microseconds.

[0102] In UART communication, to avoid erroneously recognizing the actual logical value of the communication data due to the influence of noise, etc., the receiving microcomputer determines the theoretical value multiple times within the time width of a 1-bit signal and recognizes the larger theoretical value as the theoretical value of the communication data. When the communication speed of UART communication is 100 kbps, as shown in timing chart (ii), external noise accounts for 50% of the time width of a 1-bit signal. Therefore, in this case, if external noise is superimposed on the communication data and appears in the communication data as a logical value opposite to the actual logical value of the communication data, the receiving microcomputer may erroneously recognize the communication data as a logical value opposite to the actual logical value of the communication data.

[0103] On the other hand, when the communication speed of UART communication is 10 kbps, which is slower than 100 kbps, the time width of a 1-bit signal is 100 microseconds, as shown in time chart (iii). Therefore, when the communication speed of UART communication is 10 kbps, the time width of a 1-bit signal is longer than when the communication speed of UART communication is 100 kbps. When the communication speed of UART communication is 10 kbps, the signal waveform alternates between a high level H and a low level L every 100 microseconds.

[0104] When the communication speed of UART communication is 10 kbps, as is clear from the relationship between time chart (i) and time chart (iii), external noise is applied to the signal twice in the time width of the signal per bit. In this case, since the time width of one external noise is 5 microseconds, the total time width of the external noise accounts for 10% of the time width of the 1-bit signal. This reduces the proportion of time that external noise appears in the 1-bit signal, preventing the receiving microcomputer from erroneously recognizing the actual theoretical value of the communication data.

[0105] In this embodiment, the communication speed of the UART communication between the control board 71 and the relay board 10 is set to a communication speed at which the time width of a 1-bit signal is longer than twice the maximum time width of the exogenous noise expected on the first communication line 12. Therefore, if the time width of the exogenous noise from the inverter circuit is 5 microseconds, which is the maximum time width of the exogenous noise expected on the first communication line 12, the communication speed at which the time width of a 1-bit signal is longer than 10 microseconds is set to the communication speed of the UART communication.

[0106] This reduces the ratio of the maximum time width of external noise to the time width of a 1-bit signal to less than 50%, making it less likely that the actual theoretical value of the communication data will be mistakenly recognized by the receiving microcomputer, thereby suppressing malfunctions in UART communication caused by external noise.

[0107] The communication speed of communications conforming to the UART communication standard becomes slower as the time width of a 1-bit signal becomes longer. However, as long as it does not interfere with the operation of the ventilation system, immediate responsiveness is not required for controlling the blower unit 1 in response to the measurement results of each environmental sensor 81, 82, 83, 91, and 92. Therefore, as long as it is within an allowable range that does not interfere with the operation of the ventilation system, it is not a problem if the communication speed of communications conforming to the UART communication standard becomes slower. In other words, as long as it is within an allowable range that does not interfere with the operation of the ventilation system, it is not a problem if the time it takes for the measurement results of each environmental sensor 81, 82, 83, 91, and 92 to reach the control board 71 from each environmental sensor 81, 82, 83, 91, and 92 to reach the control board 71 becomes longer.

[0108] In such an air supply control device 2 and ventilation device, the control board 71 is communicatively connected to the relay board 10 via a first communication line 12. The relay board 10 is communicatively connected to the air supply measurement unit 9 via a second communication line 13. The control board 71 relays the measurement results of the air supply measurement unit 9 from the air supply measurement unit 9 via the relay board 10 and receives them as air supply measurement information. Communication between the control board 71 and the relay board 10 is carried out in accordance with a first communication standard. Communication between the relay board 10 and the air supply measurement unit 9 is carried out in accordance with a second communication standard.

[0109] Therefore, communication between the control board 71 and the air supply measurement unit 9 can be divided into communication between the control board 71 and the relay board 10 and communication between the relay board 10 and the air supply measurement unit 9. This shortens the communication distance between the control board 71 and the relay board 10 and the communication distance between the relay board 10 and the air supply measurement unit 9 compared to the communication distance when communication between the control board 71 and the air supply measurement unit 9 is performed without going through the relay board 10. Therefore, it is possible to suppress a decrease in the reliability of communication according to both the first communication standard and the second communication standard. This suppresses a decrease in the reliability of communication between the air supply measurement unit 9 and the control unit 7, allowing for more accurate control of the air blower unit 1 according to the measurement results of the air supply measurement unit 9.

[0110] Furthermore, the length of the second communication line 13 connecting the relay board 10 and the supply air measuring unit 9 is shorter than the length of the first communication line 12 connecting the control board 71 and the relay board 10. The first communication standard is a different type of communication standard from the second communication standard. Therefore, the communication distance of communication according to the second communication standard can be shorter than the communication distance of communication according to the first communication standard.

[0111] If the communication standard corresponding to the air supply measurement unit 9 is the I2C communication standard, the I2C communication standard is used as the second communication standard. The reliability of communication according to the I2C communication standard is more likely to decrease as the communication distance increases. Therefore, by shortening the communication distance of communication according to the I2C communication standard, it is possible to more reliably prevent a decrease in the reliability of communication between the relay board 10 and the air supply measurement unit 9. Furthermore, by using the UART communication standard, which is less likely to decrease in communication reliability than the I2C communication standard as the communication distance increases, as the first communication standard, it is possible to more reliably prevent a decrease in the reliability of communication between the control board 71 and the relay board 10. This further reliably prevents a decrease in the reliability of communication between the air supply measurement unit 9 and the control unit 7. Therefore, it is possible to more accurately control the air blower unit 1 according to the measurement results of the air supply measurement unit 9.

[0112] Furthermore, the exhaust measurement unit 8 is communicatively connected to the control board 71 via a third communication line 14. The length of the third communication line 14 is shorter than the length of the first communication line 12. This makes it possible to shorten the communication distance between the exhaust measurement unit 8 and the control board 71. As a result, when the communication standard compatible with the exhaust measurement unit 8 is the I2C communication standard, it is also possible to suppress a decrease in the reliability of communication between the exhaust measurement unit 8 and the control unit 7. Therefore, it is possible to more accurately control the blower unit 1 according to the measurement results of the exhaust measurement unit 8.

[0113] The relay board 10 is also equipped with a second microcomputer 103 that implements the functions of the second board communication unit 102 and the second measurement communication unit 101. Therefore, the functions of communicating in accordance with both the I2C communication standard and the UART communication standard can be implemented by the common second microcomputer 103. By limiting the functions of the second microcomputer 103 to communication-related functions, the relay board 10 can be made smaller, making it easier to secure installation space for the relay board 10. Furthermore, an inexpensive microcomputer with a small package size can be used as the second microcomputer 103, thereby reducing the cost of the relay board 10.

[0114] Furthermore, communication between the control board 71 and the relay board 10 is performed in accordance with the UART communication standard. Therefore, even if the communication distance between the control board 71 and the relay board 10 is longer than the communication distance between the relay board 10 and the air supply measuring unit 9, it is possible to more reliably prevent a decrease in the reliability of communication between the control board 71 and the relay board 10. This makes it possible to more reliably prevent a decrease in the reliability of communication between the air supply measuring unit 9 and the control unit 7.

[0115] Furthermore, communication between the relay board 10 and the air intake measurement unit 9 is performed in accordance with the I2C communication standard. Therefore, communication between the air intake measurement unit 9 and the relay board 10 can be easily performed using the I2C communication standard, which is a common communication standard compatible with environmental sensors. Furthermore, the shorter the communication distance between the relay board 10 and the air intake measurement unit 9, the more reliably the reduction in the reliability of communication between the relay board 10 and the air intake measurement unit 9 can be suppressed. This makes it possible to more reliably suppress the reduction in the reliability of communication between the air intake measurement unit 9 and the control unit 7.

[0116] In addition, the intake air measuring unit 9 measures the CO ２ and PM2.5 concentrations are measured separately. ２ The control board 71 has a plurality of environmental sensors, namely, a CO sensor 91 and a PM2.5 sensor 92. ２ The CO ２ The control board 71 receives the measurement results of the PM2.5 sensor 92 and the pollutant concentration sensor 91 as intake air measurement information. This allows intake air measurement information relating to the concentrations of pollutants and particulates in the intake airflow, i.e., intake air measurement information relating to multiple types of air quality conditions in the intake airflow, to be sent to the control board 71 via the common relay board 10. This makes it possible to suppress increases in costs even if the number of environmental sensors for the intake airflow increases.

[0117] Furthermore, the communication speed of the UART communication standard is set so that the duration of a 1-bit signal is longer than twice the maximum duration of external noise anticipated on the first communication line 12. Therefore, in communication conforming to the UART communication standard, the ratio of the maximum duration of external noise to the duration of a 1-bit signal can be reduced to less than 50%. This prevents the relay board 10 and the control board 71, whichever receives the signal, from misinterpreting the actual theoretical value of the communication data due to the influence of external noise. This further reliably prevents a decrease in the reliability of communication between the supply air measurement unit 9 and the control unit 7.

[0118] Furthermore, the first microcomputer 711 and the second microcomputer 103 are both microcomputers from the same series. This allows the first microcomputer 711 and the second microcomputer 103 to use the same power supply voltage 500. This allows the data output section 712 of the first microcomputer 711 and the data output section 107 of the second microcomputer 103 to use CMOS transistors, each incorporating an N-channel MOSFET 15 and a P-channel MOSFET 16, for UART communication. This reduces delays in the rise time of signal waveforms in UART communication and suppresses electromagnetic interference in UART communication. This further reduces the reliability of communication between the control board 71 and the relay board 10, and further reduces the reliability of communication between the supply air measurement unit 9 and the control unit 7.

[0119] Furthermore, the first communication line 12, which communicates in accordance with the UART communication standard, has a transmission line 402 and a reception line 403 that communicatively connect the first microcomputer 711 of the control board 71 and the second microcomputer 103 of the relay board 10. This eliminates the need to provide transmission lines and reception lines corresponding to each of the environmental sensors 91, 92 in the air supply measurement unit 9. This makes it possible to reduce the number of communication lines communicatively connecting the control board 71 and the relay board 10.

[0120] In the above embodiment, the control unit 7 is arranged in a position closer to the exhaust measurement unit 8 than the intake air measurement unit 9. However, the control unit 7 may be arranged in a position closer to the intake air measurement unit 9 than the exhaust measurement unit 8. In this case, the relay board 10 is arranged in a position closer to the exhaust measurement unit 8 than the control unit 7 and the intake air measurement unit 9. In this case, the control board 71 of the control unit 7 is communicatively connected to the relay board 10 via the first communication line 12, and is communicatively connected to the intake air measurement unit 9 via the third communication line 14. Furthermore, in this case, the relay board 10 is communicatively connected to the exhaust measurement unit 8 via the second communication line 13.

[0121] This also shortens the communication distance between the exhaust measurement unit 8 and the relay board 10. Therefore, when the communication standard corresponding to the exhaust measurement unit 8 is the I2C communication standard, it is possible to suppress a decrease in the reliability of communication between the relay board 10 and the exhaust measurement unit 8. Furthermore, by using the UART communication standard as the first communication standard, it is possible to suppress a decrease in the reliability of communication between the control board 71 and the relay board 10. This allows for more accurate control of the air blower unit 1 in accordance with the measurement results of the exhaust measurement unit 8. Furthermore, it is possible to shorten the communication distance between the air supply measurement unit 9 and the control board 71, and when the communication standard corresponding to the air supply measurement unit 9 is the I2C communication standard, it is possible to suppress a decrease in the reliability of communication between the control board 71 and the air supply measurement unit 9. This allows for more accurate control of the air blower unit 1 in accordance with the measurement results of the air supply measurement unit 9.

[0122] When the control unit 7 is located closer to the intake air measurement unit 9 than the exhaust measurement unit 8, the exhaust measurement unit 8 and relay board 10 may be provided inside the room to which the intake air flow is supplied. Even in this case, the exhaust measurement unit 8 can measure the concentrations of pollutants and particulates in the exhaust flow flowing from the room to the outside as multiple types of air quality conditions in the exhaust flow inside the room.

[0123] Furthermore, in the above embodiment, the length of second communication line 13 is shorter than the length of first communication line 12. However, as long as the length of second communication line 13 is within a range that ensures communication reliability, the length of second communication line 13 may be the same as the length of first communication line 12, or may be longer than the length of first communication line 12. Even in this case, it is possible to prevent a decrease in the reliability of communication between air supply measurement unit 9 and control unit 7, and it is possible to more accurately control air blower unit 1 in accordance with the measurement results of air supply measurement unit 9.

[0124] In the above embodiment, the UART communication standard is used as the first communication standard for communication between the control board 71 and the relay board 10, and the I2C communication standard is used as the second communication standard for communication between the relay board 10 and the air supply measurement unit 9. However, as long as the lengths of the first communication line 12 and the second communication line 13 are within a range that ensures reliable I2C communication, the I2C communication standard may be used as both the first and second communication standards. In other words, as long as the lengths of the first communication line 12 and the second communication line 13 are within a range that ensures reliable communication, the same communication standard may be used as both the first and second communication standards. In this case, the length of the first communication line 12 may be the same as the length of the second communication line 13, or the length of the first communication line 12 may be different from the length of the second communication line 13. This configuration also prevents a decrease in the reliability of communication between the air supply measurement unit 9 and the control unit 7, thereby enabling more accurate control of the air blower unit 1 according to the measurement results of the air supply measurement unit 9.

[0125] In the above embodiment, the exhaust gas measuring unit 8 measures CO ２ The exhaust gas measuring unit 8 has a CO ２ The exhaust gas measuring unit 8 may have at least one of the CO 2 sensor 81, the PM 2.5 sensor 82, and the formaldehyde sensor 83. ２ It is sufficient that the concentration of at least one of PM2.5 and formaldehyde is measured.

[0126] In the above embodiment, the supply air measuring unit 9 measures CO ２ However, the intake air measuring unit 9 has a CO ２ The intake air measuring unit 9 may have at least one of the CO sensor 91 and the PM2.5 sensor 92. ２ It is sufficient that the concentration of at least one of PM2.5 and PM3.5 is measured.

[0127] Furthermore, in the above embodiment, the concentrations of pollutants and particulates in the exhaust flow are used as the state of air quality measured by the exhaust measurement unit 8. However, this is not limiting. For example, at least one of the temperature and humidity of the exhaust flow may be used as the state of air quality measured by the exhaust measurement unit 8. In this case, the control board 71 receives the measurement results of at least one of the temperature and humidity of the exhaust flow by the exhaust measurement unit 8 as exhaust measurement information from the exhaust measurement unit 8. Furthermore, at least one of the concentration of pollutants in the exhaust flow, the concentration of particulates in the exhaust flow, the concentration of odor components in the exhaust flow, the temperature of the exhaust flow, and the humidity of the exhaust flow may be used as the state of air quality measured by the exhaust measurement unit 8.

[0128] Furthermore, in the above embodiment, the concentrations of pollutants and particulates in the intake air flow are used as the state of air quality measured by the intake air measuring unit 9. However, this is not limiting. For example, at least one of the temperature and humidity of the intake air flow may be used as the state of air quality measured by the intake air measuring unit 9. In this case, the control board 71 receives the measurement results of at least one of the temperature and humidity of the intake air flow by the intake air measuring unit 9 as intake air measurement information from the intake air measuring unit 9. Furthermore, at least one of the concentration of pollutants in the intake air flow, the concentration of particulates in the intake air flow, the concentration of odorous components in the intake air flow, the temperature of the intake air flow, and the humidity of the intake air flow may be used as the state of air quality measured by the intake air measuring unit 9.

[0129] Furthermore, in the above embodiment, the air blowing control device 2 is applied to an intake / exhaust type ventilation device in which the intake air duct 35 and the exhaust air duct 36 are formed as two air ducts inside the blower unit 1. However, this is not limited to this. The air blowing control device 2 may also be applied to an intake type ventilation device in which, of the intake air duct 35 and the exhaust air duct 36, only the intake air duct 35 is formed inside the blower unit 1. The air blowing control device 2 may also be applied to an exhaust type ventilation device in which only the exhaust air duct 36 is formed inside the blower unit 1. In other words, it is sufficient that at least one of the intake air duct 35 and the exhaust air duct 36 is formed as an air duct inside the blower unit 1.

[0130] The configurations described in the above embodiments are merely examples of the contents of the present disclosure. The embodiments can be combined with other known technologies. Part of the configuration of the embodiments can be omitted or modified without departing from the gist of the present disclosure.

[0131] REFERENCE SIGNS LIST 1 blower unit, 2 blower control device, 7 control unit, 8 exhaust measurement unit (air quality measurement unit), 9 intake measurement unit (air quality measurement unit), 10 relay board (second circuit board), 12 first communication line, 13 second communication line, 35 intake air duct (air duct), 36 exhaust air duct (air duct), 71 control board (first circuit board), 76 first board communication unit, 81 CO ２ Sensor (environmental sensor), 82 PM2.5 sensor (environmental sensor), 83 Formaldehyde sensor (environmental sensor), 91 CO ２ Sensor (environmental sensor), 92 PM2.5 sensor (environmental sensor), 101 second measurement and communication unit, 102 second board communication unit, 103 second microcomputer (second processor), 711 first microcomputer (first processor).

Claims

1. An air blowing control device comprising: a control unit having a first circuit board that controls an air blowing unit to control the airflow that flows through an air passage formed inside the air blowing unit; a second circuit board that is communicatively connected to the first circuit board via a first communication line; and an air quality measurement unit that is communicatively connected to the second circuit board via a second communication line and measures the air quality state of the airflow, wherein the first circuit board receives the measurement results of the air quality measurement unit as measurement information from the air quality measurement unit via the second circuit board, and controls the air blowing unit based on the measurement information; communication between the first circuit board and the second circuit board is performed in accordance with a first communication standard; and communication between the second circuit board and the air quality measurement unit is performed in accordance with a second communication standard.

2. The air blowing control device according to claim 1, wherein the length of the second communication line is shorter than the length of the first communication line, and the first communication standard is a different type of communication standard from the second communication standard.

3. A blower control device as described in claim 1 or claim 2, wherein the first circuit board has a first board communication unit, the second circuit board has a second board communication unit and a second measurement communication unit, the first board communication unit and the second board communication unit communicate with each other according to the first communication standard, the second measurement communication unit and the air quality measurement unit communicate with each other according to the second communication standard, the first circuit board is equipped with a first processor that realizes the functions of the first board communication unit, and the second circuit board is equipped with a second processor that realizes the functions of the second board communication unit and the second measurement communication unit.

4. A blower control device according to any one of claims 1 to 3, wherein the first communication standard is a UART communication standard.

5. The air blower control device described in claim 4, wherein the communication speed of communication conforming to the UART communication standard is a communication speed at which the time width of a 1-bit signal is longer than twice the maximum time width of external noise expected on the first communication line.

6. A blower control device according to any one of claims 1 to 5, wherein the second communication standard is the I2C communication standard.

7. A blower control device as described in any one of claims 1 to 6, wherein the air quality measurement unit has a plurality of environmental sensors that individually measure the state of the air quality in the airflow, and the first circuit board receives the measurement results of each of the environmental sensors as the measurement information by relaying them from each of the environmental sensors to the second circuit board, and controls the blower unit based on the measurement information.

8. A ventilation system comprising the air blowing unit and the air blowing control device described in any one of claims 1 to 7, wherein the air blowing unit is provided with at least one of an air supply duct through which the air flows from the outdoors toward the indoors and an air exhaust duct through which the air flows from the indoors toward the outdoors.

Images