JP2023157652A - Combustion apparatus and water heater - Google Patents

Abstract

To prevent unintended opening of a gas solenoid valve of a combustion apparatus.SOLUTION: A combustion apparatus includes: a memory that stores first and second software for controlling an operation; a microcomputer that executes the first or second software; a load operated by receiving electric power supply; a drive circuit that drives the load on the basis of output from the microcomputer; and a resistor. One end of the resistor is connected to between an input/output port of the microcomputer and a control terminal of the drive circuit. When a first voltage value corresponding to a first logical level output from the microcomputer is applied to the drive circuit, the drive circuit is driven. When a second voltage value corresponding to a second logical level output from the microcomputer is applied to the drive circuit, the drive circuit is stopped. During updating of the second software by using the first software, the input/output port is set to be an input port (S420). An electric potential of the other one end of the resistor is maintained at a second voltage value.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD This disclosure relates to combustion devices, and more particularly to water heaters that control software used in combustion devices.

The functionality of water heaters can be improved by updating the built-in software. Regarding software updates, for example, Japanese Patent Application Laid-Open No. 2020-112303 (Patent Document 1) describes a combustion engine with a software update function that can reliably prevent fuel from being supplied to the combustion section when updating software. "Equipment" technology is disclosed. The technique is as follows: “The control device 20 of the combustion equipment 1 includes a first control unit 21 that executes control processing based on first software, and a second control unit 22 that executes control processing based on second software. The second software is configured to cause the second control unit 22 to execute a process of updating the first software to new software, and during the execution of the first software update process, The second control unit 22 is configured to execute a control process for maintaining the control valve 4, which opens and closes the fuel supply path 3 to the combustion unit 2, in a closed state” (see [Summary]). .

Japanese Patent Application Publication No. 2020-112303

It is required that the combustion device not operate while the software is updated. On the other hand, there is also a risk that an unintended signal may be output from the microcomputer of the water heater, causing the water heater to operate. For example, a water heater's solenoid valve, fan, igniter or pump may suddenly turn on. Therefore, there is a need for techniques to prevent unintended operation of combustion devices.

The present disclosure has been made in view of the above-mentioned background, and according to a certain embodiment, a technique for preventing unintended operation of a combustion device when updating software is disclosed.

A combustion device according to an embodiment operates by receiving power from a memory that stores first software and second software that control the operation of the combustion device, and a microcomputer that executes the first software or the second software. It includes a load, a drive circuit that drives the load based on the output from the microcomputer, and a resistor. One end of the resistor is connected between the input/output port of the microcomputer and the control terminal of the drive circuit. The drive circuit drives when the first voltage value corresponding to the first logic level output from the microcomputer is applied to the drive circuit. The drive circuit stops when the second voltage value corresponding to the second logic level output from the microcomputer is applied to the drive circuit. The input/output port is set to an input port while the first software updates the second software. The potential at the other end of the resistor is maintained at the second voltage value.

In one aspect, the potential of the second voltage value is ground.
In one aspect, the potential of the second voltage value is a power supply voltage.

In one aspect, the fuel cell further includes a combustion section and a fuel valve for supplying fuel to the combustion section. The load includes a fuel valve.

According to another embodiment, a water heater including any of the above combustion devices is provided.
These and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the invention, taken in conjunction with the accompanying drawings.

1 is a schematic diagram showing a configuration example of a communication system to which a water heater 100 is applied. 2 is a block diagram showing an example of a hardware configuration of a communication adapter 150. FIG. 1 is a block diagram showing an example of a hardware configuration of a water heater 110. FIG. 7 is a flowchart illustrating an example of processing performed when rewriting the firmware of the main microcomputer 10 while maintaining the gas solenoid valve 51 in a closed state. 5 is a diagram schematically showing a part of a circuit block diagram for controlling opening and closing of a gas electromagnetic valve 51. FIG. 5 is a diagram schematically showing a part of a circuit block diagram for controlling opening and closing of a gas electromagnetic valve 51. FIG.

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

<Overall configuration>
With reference to FIG. 1, a configuration for implementing software updates in water heater 100 according to the present embodiment will be described. FIG. 1 is a schematic diagram showing a configuration example of a communication system to which a water heater 100 including a combustion device is applied.

Communication system 200 includes water heater 100 , communication equipment 3 , external communication network 4 , server 5 , router 6 , base station 7 , and mobile terminal device 8 . In the communication system 200 , the water heater 100 and the server 5 are communicably connected via the communication device 3 and the external communication network 4 in order for the server 5 to remotely manage and remotely control the water heater 100 .

Water heater 100 includes a water heater 110, a remote controller (hereinafter also simply referred to as "remote control") 160 that accepts instructions from a user, and a communication adapter 150. Hot water from the water heater 110 is sent to a hot water supply destination via piping connected to a plurality of hot water supply ports 111. For example, the hot water supply destination includes a sink and a bathtub (not shown). Alternatively, the hot water supply device 100 has a heating function because the hot water supply destination includes a heater (not shown) that uses high temperature water as a heat source.

A circuit board 115 is installed inside the water heater 110. A controller 140 for driving and controlling the water heater 110 is mounted on the circuit board 115. The controller 140 controls an electromagnetic valve for controlling the supply of fuel gas to the water heater 110, an air supply fan for supplying air to be mixed with the fuel gas, and the like.

Water heater 110 and remote control 160 are connected to communication adapter 150 by a communication line (for example, a two-core communication line) 170. Remote control 160 has a display 161 and an input interface 162. By operating the input interface 162 according to the screen displayed on the display 161, the user can set hot water filling, hot water supply temperature setting, and the like. For example, remote control 160 is installed in the bathroom or kitchen. Note that multiple remote controllers 160 may be used. In this way, the user can use the remote controller 160 to make various settings for each function of the water heater 100.

The communication adapter 150 has a wireless communication function for communicating with the communication device 3 using a predetermined communication protocol. Note that the communication adapter 150 may be configured to be built into the remote control 160.

The communication device 3 has a function of communicatively connecting devices existing within a certain range to the server 5 via the external communication network 4. For example, the communication device 3 is configured by a wireless LAN (Local Area Network) router. Further, the external communication network 4 is typically the Internet.

As the communication device 3, a wired LAN router may be used instead of the wireless LAN router. In this case, the communication adapter 150 is configured to communicate with the wired LAN router using a predetermined communication protocol.

The server 5 has a function for managing remote control (for example, remote operation and remote monitoring) of the water heater 100 via the external communication network 4 . The communication adapter 150 can communicate with the server 5 via the external communication network 4 by being communicatively connected to the communication device 3 by wireless communication. Thereby, the water heating apparatus 100 is communicatively connected to the server 5 using the communication adapter 150 as a relay device, so that bidirectional data communication between the water heating apparatus 100 and the server 5 is performed.

The server 5 can also be communicatively connected to a mobile terminal device 8 such as a smartphone or a tablet terminal. When the mobile terminal device 8 exists within a range where it can be connected to the communication device 3, the mobile terminal device 8 can communicate with the server 5 by being connected to the communication device 3 by wireless communication. When the mobile terminal device 8 is located outside the house, the mobile terminal device 8 can communicate with the server 5 by connecting to the external communication network 4 via the router 6 or the base station 7 .

In this way, in addition to operating the remote control 160, the user uses the mobile terminal device 8 to access the server 5 both inside and outside the range connectable to the communication device 3, thereby controlling the water heater 100. Remote control is possible.

An application program for the water heater 100 can be installed on the remote control 160 and the mobile terminal device 8. For example, the application program is downloaded from the server 5 and then installed.

In addition, each of the water heater 110 (controller 140), remote controller 160, and communication adapter 150 has a program (hereinafter also referred to as "firmware (F/W)") for controlling the operation of each device. ) is memorized. When the firmware is shipped from the factory, the current version is written. Furthermore, the firmware can be rewritten to a different version by distribution from the server 5. In some aspects, multiple firmware may be stored on water heater 110, remote control 160, or communication adapter.

<Configuration of water heater>
(Communication adapter)
The configuration of communication adapter 150 will be described with reference to FIG. 2. FIG. 2 is a block diagram showing an example of the hardware configuration of the communication adapter 150. Communication adapter 150 includes a microcomputer (hereinafter also referred to as "microcomputer") 151, communication units 152 and 153, a power supply circuit 154, a memory 155, an antenna 157, and a connector 158. The communication line 170 shown in FIG. 1 is connected to the connector 158.

The microcomputer 151 includes a CPU (Central Processing Unit) 151a and an interface (I/F) 151b. Communication unit 152 bidirectionally transmits and receives data to and from water heater 110 and remote control 160 via communication line 170 connected to connector 158 . The communication unit 153 bidirectionally transmits and receives data to and from the communication device 3 by wireless communication via the antenna 157. Power supply circuit 154 receives power supply from communication line 170 connected to connector 158 and generates an operating power supply voltage for each element within communication adapter 150 .

The memory 155 includes a ROM (Read Only Memory) 155a and a RAM (Random Access Memory) 155b. The ROM 155a is typically configured with an EEPROM (Electrically Erasable Programmable Read-Only Memory), and stores firmware of the communication adapter 150, data and programs used for control, and the like. During startup processing, the microcomputer 151 reads firmware stored in the ROM 155a and deploys it in the RAM 155b. The microcomputer 151 controls the operation of the communication adapter 150 by executing a program developed in the RAM 155b. Although the memory 155 and the microcomputer 151 are shown as separate elements in FIG. 2, a part or all of the memory 155 may be built into the microcomputer 151.

The communication unit 153 transmits and receives data to and from the server 5 via the communication device 3 and the external communication network 4. Thereby, the communication adapter 150 periodically transmits the operation information of the water heater 100 to the server 5. As a result, the server 5 collects and manages various information about the water heater 100 installed in a home, accommodation facility, or other place that is communicatively connected via the communication adapter 150 .

On the other hand, the server 5 transmits data to the communication adapter 150. Thereby, a remote control service for the water heater 100 can be provided. For example, from the server 5 or the mobile terminal device 8, predetermined operations of the water heater 100, such as switching the hot water supply operation switch on/off and changing the hot water supply temperature setting, are performed via the external communication network 4. be able to.

In the communication system 200, updating of the firmware of each component device constituting the water heater 100 is automatically performed by distribution from the server 5. For example, in the case of the communication adapter 150, the firmware is updated by storing the firmware downloaded from the server 5 in the ROM 155a.

<Water heater>
With reference to FIG. 3, the configuration of water heater 110 according to an embodiment will be described. FIG. 3 is a block diagram showing an example of the hardware configuration of the water heater 110. Water heater 110 includes a circuit board 115, a gas solenoid valve 51, a burner 52, and a gas supply pipe 53. The circuit board 115 includes a controller 140 , a display 31 , a drive power source 41 , a power cutoff circuit 42 , a voltage detection circuit 43 , and a solenoid valve drive circuit 44 .

The controller 140 includes a main microcomputer (hereinafter also referred to as "main microcomputer") 10 and a sub-microcomputer (hereinafter also referred to as "sub-microcomputer") 20.

The main microcomputer 10 is communicatively connected to external devices (for example, a remote control 160, a server 5, etc.) existing outside the water heater 110. For example, the main microcomputer 10 is communicatively connected to a remote control 160 via a communication line 170, and is communicatively connected to a server 5 via a communication line 170, a communication adapter 150, a communication device 3, and an external communication network 4. The main microcomputer 10, the electromagnetic valve drive circuit 44, the gas electromagnetic valve 51, and the burner 52 constitute a part of the combustion device. The combustion device further includes a combustion section (not shown). The gas solenoid valve 51 corresponds to a fuel valve that adjusts the amount of fuel (gas) supplied to the combustion section.

On the other hand, the sub microcomputer 20 is not communicatively connected to any external device, but is communicatively connected to the main microcomputer 10 . That is, the sub microcomputer 20 cannot directly communicate with the remote controller 160, the server 5, etc., and is configured to be able to communicate only with the main microcomputer 10.

The main microcomputer 10 includes a CPU 11 , an interface circuit 12 , a reset circuit 13 , a ROM 14 , a RAM 15 , and a communication unit 16 .

The CPU 11 controls the operation of the main microcomputer 10 and executes arithmetic processing according to a program. The ROM 14 is configured by, for example, an EEPROM, and stores software (ie, firmware) for controlling the operation of the water heater 110, as well as data and programs used for other controls. The CPU 11 reads firmware stored in the ROM 14, loads it in the RAM 15, and controls the hot water supply operation of the water heater 110 by executing the loaded program. Typically, the current version of the firmware is written at the time of shipment from the factory.

Communication unit 16 is a communication interface for communicating with external devices (for example, remote control 160 and server 5). The main microcomputer 10 is configured to be able to communicate with external devices using a communication unit 16. Therefore, the firmware stored in the memory (for example, ROM 14 and RAM 15) of the main microcomputer 10 can be rewritten to a different version of firmware by distribution from the server 5. For example, the firmware is updated by storing update firmware sent from the server 5 in the ROM 14. For example, the firmware may be upgraded from the initial version as appropriate for the purpose of adding functions or fixing bugs.

The interface circuit 12 communicates various data, signals, etc. with the sub-microcomputer 20, power cutoff circuit 42, voltage detection circuit 43, and electromagnetic valve drive circuit 44 according to instructions from the CPU 11. When the reset circuit 13 receives the input of the reset signal output from the sub-microcomputer 20, it stops the main microcomputer 10.

The sub-microcomputer 20 includes a CPU 21, an interface circuit 22, a reset circuit 23, a ROM 24, and a RAM 25. The CPU 21 controls the entire sub-microcomputer 20 and executes arithmetic processing according to a program. The ROM 24 stores various data, programs, and the like. The CPU 21 reads the program stored in the ROM 24, loads it into the RAM 25, and executes the loaded program.

The interface circuit 22 communicates various data, signals, etc. with the main microcomputer 10, display 31, and power cutoff circuit 42 according to instructions from the CPU 21. The reset circuit 23 outputs a reset signal to the main microcomputer 10 according to instructions from the CPU 21.

Main microcomputer 10 and sub-microcomputer 20 output power cutoff signals via interface circuits 12 and 22, respectively. The power cutoff signal is input to the power cutoff circuit 42. The power supply cutoff circuit 42 is inserted into a circuit from the drive power supply 41 to the electromagnetic valve drive circuit 44, and cuts off the voltage supplied to the gas electromagnetic valve 51.

The solenoid valve drive circuit 44 mainly includes, for example, a relay contact (not shown) that opens and closes a power line (not shown) that supplies drive voltage to the gas solenoid valve 51, and a relay coil (not shown) that controls the relay contact. (not connected) and a switching element that switches between energizing and cutting off the current to the relay coil. As the switching element, for example, an FET (Field Effect Transistor), a bipolar transistor, or the like is used. A control signal from the main microcomputer 10 can be input to a control terminal of the switching element (for example, a gate in the case of an FET, a base in the case of a bipolar transistor).

Since the gas solenoid valve 51 is of a normally closed type, when the power cutoff circuit 42 functions and the voltage supplied to the gas solenoid valve 51 is cut off, the gas solenoid valve 51 closes and gas supply to the burner 52 is interrupted. Gas supply from pipe 53 is stopped. A voltage detection circuit 43 is provided between the power cutoff circuit 42 and the electromagnetic valve drive circuit 44, and a signal from the voltage detection circuit 43 is input to the interface circuit 12 of the main microcomputer 10.

As described above, the power cutoff signals output from the main microcomputer 10 and the sub microcomputer 20 are input to the power cutoff circuit 42. The power cutoff circuit 42 is configured to cut off the power supply from the drive power source 41 when receiving a power cutoff signal output from either the main microcomputer 10 or the sub microcomputer 20 . In this case, the voltage supplied to the gas electromagnetic valve 51 is cut off, and the supply of gas to the burner 52 is stopped.

Whether or not the power supply from the drive power source 41 has been cut off can be determined by the main microcomputer 10 checking the signal from the voltage detection circuit 43. The voltage detection circuit 43 is a circuit that determines whether or not electric power is being supplied to the electromagnetic valve drive circuit 44, and is a circuit that indirectly determines whether or not fuel is being supplied to the burner 52.

Here, as described above, since the main microcomputer 10 includes the communication unit 16 for communicating with external devices, the firmware for controlling the operation of the water heater 110 stored in the ROM 14 can be used remotely. It can be updated with.

<Control structure>
The control structure of water heater 110 according to this embodiment will be described with reference to FIG. 4. FIG. 4 is a flowchart showing an example of a process performed when the firmware of the main microcomputer 10 is rewritten while the gas solenoid valve 51 is maintained in a closed state. In the following example, a case will be shown in which two software (first software A and second software B) stored in a water heater control a combustion device. The first software A executes a firmware update (rewriting) of the second software B. The first software A is an example of the first software described in the claims. The second software B is an example of the second software described in the claims.

While the first software A is rewriting the second software B, it is necessary to keep the control valve (for example, the gas solenoid valve 51) that can open and close the fuel supply path closed (closed) for safety. Therefore, the main microcomputer 10 executes the following processing.

In step S410, the CPU 11 of the main microcomputer 10 starts the first software A stored in the ROM 14.

In step S420, the CPU 11 sets the port for controlling the opening and closing of the gas solenoid valve 51 to input mode. The port becomes high impedance, and the output of the signal that opens the gas solenoid valve 51 is prohibited.

In step S430, the CPU 11 uses the first software A to update the firmware of the second software B (update the firmware).

In step S440, when the CPU 11 detects the completion of the update of the second software B, it starts the updated second software B.

In step S450, the CPU 11 sets the port for controlling the opening and closing of the gas electromagnetic valve 51 to output mode, and initializes it with a low output.

In step S460, the CPU 11 executes the second software B to perform normal control. Thereafter, when the CPU 11 detects a combustion request, it starts combustion operation.

The operation for controlling the opening and closing of the gas solenoid valve 51 will be described with reference to FIGS. 5 and 6. 5 and 6 are diagrams each schematically showing a part of a circuit block diagram for controlling the opening and closing of the gas electromagnetic valve 51. As shown in FIG.

As shown in FIG. 5, a port (not shown) of the main microcomputer 10 is electrically connected to a gate of the electromagnetic valve drive circuit 44. A resistor 620 connected to ground 630 is connected between the port and the gate. The ground 630 is, for example, the circuit ground of the circuit board 115, and does not necessarily have to be at ground potential. In a certain situation, the main microcomputer 10 turns off (0V) the output from the port (arrow 610), turns off the FET, and closes the gas solenoid valve 51.

Referring to FIG. 6, in another situation, when main microcomputer 10 sets the port to input mode (high impedance), the gate level falls to Low, the FET is turned off, and gas solenoid valve 51 is closed. .

In this way, by setting the port for controlling the opening and closing of the gas solenoid valve 51 to the input mode instead of the output mode, the main microcomputer 10 no longer outputs a signal for controlling the opening and closing of the gas solenoid valve 51. Further, a situation in which the signal becomes High due to unintended disturbance or the like does not occur. Thereby, the gas electromagnetic valve 51 can be closed reliably, so that a situation in which fuel gas is supplied to the water heater 110 during firmware updating can be prevented from occurring.

Note that the scope of application of the disclosed technical idea is not limited to the gas solenoid valve 51. For example, the technical idea can be applied to a flow rate regulating valve that controls the supply of kerosene or other liquid fuel.

Note that the circuit configuration illustrated in FIG. 6 has a pull-down resistor, but in a circuit configuration according to another aspect, when the relevant port of the main microcomputer 10 is set to the input mode, the solenoid valve drive circuit 44 operates as a gas solenoid valve. A pull-up resistor may be used in place of the pull-down resistor as long as the closed state of the resistor 51 can be maintained.

Moreover, the technical idea can be applied to other than electromagnetic valves. For example, in other aspects, it may be applied to supply air fans, igniters, pumps, etc.

As described above, the water heater according to the present embodiment has a circuit configuration in which there is a resistor that connects the gate terminal of the FET for driving the gas electromagnetic valve 51 to the ground. The water heater sets the port of the main microcomputer 10 connected to the gas solenoid valve 51 and other drive circuits to the input mode until the software update is completed. The drive circuit becomes high impedance and no signal is output from the port to the FET, so the FET does not drive the gas solenoid valve 51. This prevents the gas solenoid valve 51 from opening unintentionally.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

3 communication equipment, 4 external communication network, 5 server, 6 router, 7 base station, 8 mobile terminal device, 10 main microcomputer, 12, 22 interface circuit, 13, 23 reset circuit, 14, 24, 155a ROM, 15, 25 , 155b RAM, 16, 152, 153 Communication unit, 20 Sub-microcomputer, 31 Display, 41 Drive power supply, 42 Power cutoff circuit, 43 Voltage detection circuit, 44 Solenoid valve drive circuit, 51 Gas solenoid valve, 52 Burner, 53 Gas Supply pipe, 100 Water heater, 110 Water heater, 111 Hot water inlet, 115 Circuit board, 140 Controller, 150 Communication adapter, 151 Microcomputer, 154 Power supply circuit, 155 Memory, 157 Antenna, 158 Connector, 160 Remote control, 161 Display, 162 Input Interface, 170 Communication line, 200 Communication system, 610 Arrow, 620, 820, 920, 1020 Resistor, 630, 830, 930, 1030 Ground, 810 Drive circuit, 910, 1010 Control circuit.

Claims (5)

A combustion device,
a memory that stores first software and second software that control the operation of the combustion device;
a microcomputer that executes the first software or the second software;
A load that operates by receiving power supply,
a drive circuit that drives the load based on the output from the microcomputer;
and a resistance;
One end of the resistor is connected between an input/output port of the microcomputer and a control terminal of the drive circuit,
The drive circuit drives when a first voltage value corresponding to a first logic level output from the microcomputer is applied to the drive circuit;
When a second voltage value corresponding to a second logic level output from the microcomputer is applied to the drive circuit, the drive circuit stops;
while the first software updates the second software, the input/output port is set to an input port;
The combustion device, wherein a potential at the other end of the resistor is maintained at the second voltage value. The combustion device according to claim 1, wherein the potential of the second voltage value is ground. The combustion device according to claim 1, wherein the potential of the second voltage value is a power supply voltage. a combustion section;
further comprising a fuel valve for supplying fuel to the combustion section,
The combustion apparatus of claim 1, wherein the load includes the fuel valve. A water heater comprising the combustion device according to any one of claims 1 to 4.

Images