JP7817551B2 - Combustion equipment and hot water supply equipment - Google Patents

Description

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

The functionality of a water heater can be improved by updating its built-in software. Regarding software updates, for example, Japanese Patent Application Laid-Open Publication No. 2020-112303 (Patent Document 1) discloses a technology for a "combustion appliance with a software update function that can reliably prevent fuel from being supplied to the combustion unit during a software update." This technology describes a "combustion appliance (1) with a control device (20) that 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 processing to update the first software to new software, and to cause the second control unit (22) to execute control processing to maintain the control valve (4) that opens and closes the fuel supply path (3) to the combustion unit (2) in a closed state during the first software update process" (see [Abstract]).

Japanese Patent Application Laid-Open No. 2020-112303

It is required that the combustion equipment not operate during software updates. However, there is a risk that the water heater's microcomputer may output an unintended signal, causing the water heater to operate. For example, the water heater's solenoid valve, fan, igniter, or pump may suddenly operate. Therefore, technology is needed to prevent the combustion equipment from operating unintendedly.

This disclosure has been made in light of the above-mentioned background, and in accordance with one embodiment, discloses a technology for preventing unintended operation of a combustion device during software updates.

A combustion device according to one embodiment includes a memory storing 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 receives power and operates, a drive circuit that drives the load based on output from the microcomputer, and a resistor. 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 operates when a first voltage value corresponding to a first logic level output from the microcomputer is applied to the drive circuit. The drive circuit stops when a second voltage value corresponding to a second logic level output from the microcomputer is applied to the drive circuit. While the first software updates the second software, the input/output port is set to an input port. The potential of the other end of the resistor is maintained at a 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 load further includes a combustion section and a fuel valve for supplying fuel to the combustion section. The load includes the fuel valve.

According to another embodiment, there is provided a water heater including any one of the combustion devices described above.
The above 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 an example of the configuration of a communication system to which a water heating apparatus 100 is applied. FIG. 2 is a block diagram showing an example of the hardware configuration of a communication adapter 150. FIG. 2 is a block diagram showing an example of a hardware configuration of a water heater 110. 10 is a flowchart showing an example of a process performed when firmware of a main microcomputer 10 is rewritten while a gas electromagnetic valve 51 is maintained in a closed state. FIG. 2 is a diagram schematically illustrating a part of a circuit block diagram that controls the opening and closing of a gas electromagnetic valve 51. FIG. 2 is a diagram schematically illustrating a part of a circuit block diagram that controls the opening and closing of a gas electromagnetic valve 51.

Embodiments of the present invention will now be described with reference to the drawings. In the following description, identical components are designated by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

<Overall structure>
A configuration for implementing a software update in water heating apparatus 100 according to the present embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an example configuration of a communication system to which water heating apparatus 100 equipped with a combustion apparatus is applied.

The communication system 200 includes a water heating apparatus 100, a communication device 3, an external communication network 4, a server 5, a router 6, a base station 7, and a mobile terminal device 8. In the communication system 200, the water heating apparatus 100 and the server 5 are communicatively connected via the communication device 3 and the external communication network 4 to enable the server 5 to remotely manage and operate the water heating apparatus 100.

The water heating apparatus 100 includes a water heater 110, a remote controller (hereinafter 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 delivered to a hot water supply destination via pipes connected to multiple hot water supply outlets 111. For example, the hot water supply destination may include a faucet and a bathtub (not shown). Alternatively, the hot water supply destination may include a heater (not shown) that uses high-temperature water as a heat source, thereby providing the water heating apparatus 100 with a heating function.

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 a solenoid valve for controlling the supply of fuel gas to the water heater 110, and an air supply fan for supplying air to be mixed with the fuel gas.

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

The communication adapter 150 has wireless communication functionality for communicating with the communication device 3 using a specified communication protocol. The communication adapter 150 may also be configured to be built into the remote control 160.

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

A wired LAN router can also be used as the communication device 3 instead of a wireless LAN router. In this case, the communication adapter 150 is configured to communicate with the wired LAN router using a specified communication protocol.

Server 5 has the function of managing remote control (e.g., remote operation and remote monitoring) of water heating apparatus 100 via external communication network 4. Communication adapter 150 is communicatively connected to communication device 3 via wireless communication, allowing communication with server 5 via external communication network 4. As a result, water heating apparatus 100 is communicatively connected to server 5 via communication adapter 150 as a relay device, enabling two-way data communication between water heating apparatus 100 and server 5.

The server 5 can also communicate with a mobile terminal device 8, such as a smartphone or tablet terminal. When the mobile terminal device 8 is within a range where it can connect to the communication device 3, it can communicate with the server 5 by connecting to the communication device 3 via wireless communication. When the mobile terminal device 8 is outside the home, for example, it can communicate with the server 5 by connecting to the external communication network 4 via a router 6 or base station 7.

In this way, in addition to operating the remote control 160, the user can use the mobile terminal device 8 to access the server 5 both inside and outside the range where the communication device 3 can be connected, thereby remotely controlling the water heating apparatus 100.

An application program for the water heating apparatus 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, the water heater 110 (controller 140), remote control 160, and communication adapter 150 each store a program (hereinafter also referred to as "firmware (F/W)") for controlling the operation of that device. The current version of firmware is written to the device when it is shipped from the factory. It is also possible to overwrite it with a different version of firmware by distribution from server 5. In certain situations, multiple firmware versions may be stored in the water heater 110, remote control 160, or communication adapter.

<Configuration of hot water supply device>
(Communication adapter)
The configuration of the 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. The 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. The communication unit 152 transmits and receives data bidirectionally to and from the water heater 110 and remote control 160 via a communication line 170 connected to a connector 158. The communication unit 153 transmits and receives data bidirectionally to and from the communication device 3 via wireless communication via an antenna 157. The power supply circuit 154 receives power from the communication line 170 connected to the connector 158 and generates the operating power supply voltage for each element within the communication adapter 150.

Memory 155 includes ROM (Read Only Memory) 155a and RAM (Random Access Memory) 155b. ROM 155a is typically configured as an EEPROM (Electrically Erasable Programmable Read-Only Memory) and stores firmware for communications adapter 150, as well as data and programs used for control. During startup, microcomputer 151 reads the firmware stored in ROM 155a and loads it into RAM 155b. Microcomputer 151 executes the programs loaded in RAM 155b to control the operation of communications adapter 150. Note that while FIG. 2 depicts memory 155 and microcomputer 151 as separate elements, some or all of memory 155 may be built into 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. As a result, the communication adapter 150 periodically transmits operating information about the water heating apparatus 100 to the server 5. As a result, the server 5 collects and manages various information about the water heating apparatus 100 installed in homes, accommodation facilities, and other facilities that are connected to the server 5 via the communication adapter 150.

Meanwhile, server 5 transmits data to communication adapter 150. This allows a remote control service for water heating apparatus 100 to be provided. For example, predetermined operations for water heating apparatus 100, such as switching the hot water operation switch on/off and changing the hot water temperature setting, can be performed from server 5 or mobile terminal device 8 via external communication network 4.

In communication system 200, firmware updates for each component device of water heating apparatus 100 are automatically performed by distribution from server 5. For example, in the case of communication adapter 150, firmware is updated by downloading firmware from server 5 and storing it in ROM 155a.

<Water heater>
The configuration of a water heater 110 according to an embodiment will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an example of the hardware configuration of the water heater 110. The 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 supply 41, a power supply 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 the "main microcomputer") 10 and a sub-microcomputer (hereinafter also referred to as the "sub-microcomputer") 20.

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

On the other hand, the sub-microcomputer 20 is not connected for communication with any external devices, but is connected for communication with the main microcomputer 10. In other words, the sub-microcomputer 20 cannot communicate directly with the remote control 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.

CPU 11 controls the operation of main microcomputer 10 and executes arithmetic processing according to a program. ROM 14 is, for example, configured as an EEPROM, and stores software (i.e., firmware) for controlling the operation of water heater 110, as well as data and programs used for other control. CPU 11 reads the firmware stored in ROM 14, expands it into RAM 15, and executes the expanded program to control the hot water supply operation of water heater 110. Typically, the current version of firmware is written when the device is shipped from the factory.

The communication unit 16 is a communication interface for communicating with external devices (e.g., the remote control 160 and the server 5). The main microcomputer 10 is configured to be able to communicate with external devices using the communication unit 16. Therefore, the firmware stored in the memory of the main microcomputer 10 (e.g., the ROM 14 and RAM 15) is configured to be rewritable with a different version of firmware distributed from the server 5. For example, the firmware is updated by storing update firmware transmitted from the server 5 in the ROM 14. For example, the firmware can be upgraded from the initial version as needed to add functions or fix bugs, etc.

In accordance with instructions from the CPU 11, the interface circuit 12 communicates various data and signals with the sub-microcomputer 20, power supply cutoff circuit 42, voltage detection circuit 43, and solenoid valve drive circuit 44. The reset circuit 13 stops the main microcomputer 10 upon receiving a reset signal output from the sub-microcomputer 20.

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 calculations according to programs. The ROM 24 stores various data, programs, etc. The CPU 21 reads out programs stored in the ROM 24, expands them in the RAM 25, and executes the expanded programs.

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

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

The solenoid valve drive circuit 44 is primarily composed of, for example, a relay contact (not shown) that opens and closes a power supply line (not shown) that supplies drive voltage to the gas solenoid valve 51, a relay coil (not shown) for controlling the relay contact, and a switching element that switches between energizing and de-energizing the relay coil. The switching element may be, for example, a field effect transistor (FET) or a bipolar transistor. A control signal from the main microcomputer 10 can be input to the control terminal of the switching element (for example, the gate in the case of an FET, or the base in the case of a bipolar transistor).

The gas solenoid valve 51 is normally closed, so when the power cutoff circuit 42 functions and cuts off the voltage supplied to the gas solenoid valve 51, the gas solenoid valve 51 closes, stopping the supply of gas from the gas supply pipe 53 to the burner 52. A voltage detection circuit 43 is provided between the power cutoff circuit 42 and the solenoid valve drive circuit 44, and the 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 supply 41 when it receives 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 solenoid valve 51 is cut off, and the supply of gas to the burner 52 is stopped.

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

As mentioned above, the main microcomputer 10 includes a communication unit 16 for communicating with external devices, so the firmware for controlling the operation of the water heater 110, which is stored in the ROM 14, can be updated remotely.

<Control structure>
The control structure of water heater 110 according to this embodiment will be described with reference to Figure 4. Figure 4 is a flowchart showing an example of processing performed when rewriting the firmware of main microcomputer 10 while maintaining gas solenoid valve 51 in a closed state. The following example shows a case where two pieces of software (first software A and second software B) stored in the water heater control a combustion appliance. First software A performs firmware upgrade (rewriting) of second software B. First software A is an example of the first software described in the claims. 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, the control valve (for example, the gas solenoid valve 51) that can open and close the fuel supply path must be closed for safety reasons. Therefore, the main microcomputer 10 executes the following process.

In step S410, the CPU 11 of the main microcomputer 10 launches 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 a signal to open the gas solenoid valve 51 is prohibited.

In step S430, the CPU 11 performs a firmware update of the second software B using the first software A.

In step S440, when the CPU 11 detects that the update of second software B has been completed, it launches the updated second software B.

In step S450, the CPU 11 sets the port for controlling the opening and closing of the gas solenoid valve 51 to output mode and initializes it with 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 of controlling the opening and closing of the gas solenoid valve 51 will be described with reference to Figures 5 and 6. Figures 5 and 6 are each a schematic representation of a portion of the circuit block diagram that controls the opening and closing of the gas solenoid valve 51.

As shown in FIG. 5, a port (not shown) of the main microcontroller 10 is electrically connected to the gate of the solenoid valve drive circuit 44. A resistor 620 connected to ground 630 is connected between the port and the gate. Ground 630 is, for example, the circuit ground of the circuit board 115 and does not necessarily have to be at earth potential. At a certain stage, the main microcontroller 10 turns off (0 V) the output (arrow 610) from the port, thereby turning off the FET and closing the gas solenoid valve 51.

Referring to Figure 6, in another phase, when the main microcontroller 10 sets the port to input mode (high impedance), the gate level falls to low, the FET turns off, and the gas solenoid valve 51 closes.

In this way, by setting the port for controlling the opening and closing of the gas solenoid valve 51 to input mode instead of output mode, the signal for controlling the opening and closing of the gas solenoid valve 51 is no longer output from the main microcomputer 10, and the signal will not go high due to unintended disturbances, etc. This ensures that the gas solenoid valve 51 is reliably closed, preventing situations such as fuel gas being supplied to the water heater 110 during a firmware update.

Note that the scope of application of the disclosed technical concept is not limited to the gas solenoid valve 51. For example, the technical concept may also be applied to a flow control valve that controls the supply of kerosene or other liquid fuels.

The circuit configuration illustrated in Figure 6 includes a pull-down resistor, but other circuit configurations may include a pull-up resistor instead of a pull-down resistor, as long as the solenoid valve drive circuit 44 can maintain the gas solenoid valve 51 in a closed state when the corresponding port of the main microcontroller 10 is set to input mode.

Furthermore, this technical concept can be applied to devices other than solenoid valves. For example, it can also be applied in other aspects to air intake fans, igniters, pumps, etc.

As described above, the water heater according to this embodiment has a circuit configuration in which a resistor is present that connects the gate terminal of the FET for driving the gas solenoid valve 51 to ground. Until the software update is complete, the water heater sets the port of the main microcomputer 10 connected to the gas solenoid valve 51 and other drive circuits to input mode. The drive circuit becomes high impedance and signals are no longer 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 herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims, not the above description, and is intended to include all modifications that are equivalent in meaning to and within the scope of the claims.

3 Communication equipment, 4 External communication network, 5 Server, 6 Router, 7 Base station, 8 Portable 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 supply cut-off 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 outlet, 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 resistors, 630, 830, 930, 1030 ground, 810 drive circuit, 910, 1010 control circuit.

Claims (5)

A combustion device comprising:
a memory for storing first software and second software for controlling 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 an 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 is driven when a first voltage value corresponding to a first logic level output from the microcomputer is applied to the drive circuit;
the drive circuit is stopped when a second voltage value corresponding to a second logic level output from the microcomputer is applied to the drive circuit;
While the first software updates the second software, the input/output port is set to an input port;
The potential of the other end of the resistor is maintained at the second voltage value. The combustion device described in claim 1, wherein the potential of the second voltage value is ground. The combustion device described in claim 1, wherein the second voltage value is a power supply voltage. A combustion section;
a fuel valve for supplying fuel to the combustion section;
The combustion device 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.