Communication device for gas appliances

Abstract

In a communication device for a gas appliance using a control device having input terminals, control terminals, and output terminals, the present invention provides a technology that enables the output of an output signal corresponding to an input signal without independently providing a control signal to the control terminal. [Solution] The hot water heater 1 comprises a hot water supply circuit 2 and a control device 92 having a control terminal DE to which a control signal consisting of a high-level transmit permission signal or a low-level transmit disallowance signal is input. The control device 92 comprises a voltage conversion circuit 91 connected between the input terminal DI and the control terminal DE. The voltage conversion circuit 91 converts the control signal input to the control terminal DE to a low level when the input signal input to the input terminal DI is high level, and converts the control signal input to the control terminal DE to a high level when the input signal input to the input terminal DI is low level. The device also comprises a pull-up resistor RPU connected between the power line BL and the output line LO.

Description

Technical Field

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[0001] The present disclosure relates to a communication device for a gas appliance.

Background Art

[0002] Patent Document 1 includes a water heater device as a water heater main body installed outside the bathroom and a remote control device installed on the wall surface inside the bathroom. The water heater device includes an operation control unit as operation control means for controlling the operation state. The operation control unit is composed of a program control type controller equipped with a microcomputer and is configured to be able to communicate with the remote control device. The remote control device is provided with an operation switch for instructing the start and stop of the operation and the like. Inside the remote control device, a remote control circuit board is provided. The remote control circuit board is composed of a printed wiring board composed of various ICs, electronic components, and the like. The operation control unit of the water heater device and the remote control circuit board are connected via a pair of two-wire remote control wirings, and two-way communication is possible in a half-duplex system.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, as a configuration for performing two-way communication in a half-duplex system between the gas appliance main body and the remote control device, for example, an IC having an input terminal, a control terminal, and an output terminal is used, an input signal can be input to the input terminal of the IC, a control signal for transmission permission or non-transmission permission can be input to the control terminal, and when a non-transmission permission signal is input to the control terminal, the output terminal is set to a high impedance state, and when an input signal is input to the input terminal in a state where a transmission permission signal is input to the control terminal, a method of outputting an output signal corresponding to the input signal from the output terminal can be considered.

[0005] However, there are cases where communication methods other than this one are desired. For example, it may be desirable to apply the aforementioned IC to a communication method that does not use independent control signals. However, the aforementioned IC cannot be applied to a communication method that does not use control signals as is, so some kind of countermeasure is required.

[0006] One of the purposes of this disclosure is to provide a technology for a communication device for a gas appliance that uses a control device having input terminals, control terminals, and output terminals, which enables the output of an output signal corresponding to an input signal without independently providing a control signal to the control terminal. [Means for solving the problem]

[0007] One of the disclosures is a communication device for gas appliances, A control device having an input terminal into which an input signal is input, a control terminal into which a control signal is input which is a signal that switches between a high-level signal, which is a transmit permission signal, and a low-level signal, which is a transmit disallowance signal, and an output terminal into which an output signal is output, wherein when the transmit permission signal is input to the control terminal, the output signal corresponding to the input signal is output, and when the transmit disallowance signal is input to the control terminal, the output terminal becomes high impedance, A voltage conversion circuit connected to the input terminal and the control terminal, A power line from which a predetermined voltage is supplied from the power supply circuit, The output line connected to the aforementioned output terminal, A pull-up resistor connected between the power line and the output line, Equipped with, The voltage conversion circuit converts the control signal input to the control terminal to the transmission disable signal when the input signal input to the input terminal is a high-level signal, and converts the control signal input to the control terminal to the transmission enable signal when the input signal input to the input terminal is a low-level signal. When the output terminal is in a high impedance state, the output line becomes high level. When the output terminal is in a low-level state, the output line is in a low-level state. [Effects of the Invention]

[0008] According to the technology disclosed herein, in a communication device for a gas appliance using a control device having an input terminal, a control terminal, and an output terminal, an output signal corresponding to an input signal can be output without independently providing a control signal to the control terminal. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a front view illustrating the external appearance of a water heater equipped with a communication device for a gas appliance according to the first embodiment. [Figure 2] Figure 2 is a schematic circuit diagram that conceptually illustrates the internal configuration of the hot water supply system shown in Figure 1. [Figure 3] Figure 3 is a block diagram illustrating the schematic electrical configuration of the controller and remote controller that make up the hot water supply system shown in Figures 1 and 2. [Figure 4] Figure 4 is a circuit diagram illustrating a communication device for a gas appliance according to the first embodiment. [Figure 5] Figure 5 shows the relationship between the input signal, transmission permission signal, and output signal in the gas appliance communication device shown in Figure 4. [Figure 6] Figure 6 is a circuit diagram illustrating the circuits on the circuit board of a comparative example of a hot water supply device. [Figure 7] Figure 7 is an explanatory diagram illustrating the relationship between the input signal, transmission permission signal, and output signal in a comparative example of a hot water supply system. [Figure 8] This diagram illustrates a circuit that enables bidirectional communication between two control devices. [Modes for carrying out the invention]

[0010] The following [1] and [2] are examples of communication devices for gas appliances included in this disclosure. [1] A control device having an input terminal into which an input signal is input, a control terminal into which a control signal is input which is a signal that switches between a high-level signal, which is a transmit permission signal, and a low-level signal, which is a transmit disallowance signal, and an output terminal into which an output signal is output, wherein when the transmit permission signal is input to the control terminal, the output signal corresponding to the input signal is output, and when the transmit disallowance signal is input to the control terminal, the output terminal is in a high impedance state, A voltage conversion circuit connected to the input terminal and the control terminal, A power line from which a predetermined voltage is supplied from the power supply circuit, The output line connected to the aforementioned output terminal, A pull-up resistor connected between the power line and the output line, Equipped with, The voltage conversion circuit converts the control signal input to the control terminal to the transmission disable signal when the input signal input to the input terminal is a high-level signal, and converts the control signal input to the control terminal to the transmission enable signal when the input signal input to the input terminal is a low-level signal. When the output terminal is in a high impedance state, the output line becomes high level. When the output terminal is in a low-level state, the output line is in a low-level state. A communication device for gas appliances.

[0011] When the input signal input to the input terminal is a high-level signal, the voltage conversion circuit converts the control signal input to the control terminal into a transmission-disabled signal. In this case, the output terminal of the control device becomes high impedance, and due to the presence of the pull-up resistor, the output line becomes a high-level state. Therefore, a high-level signal corresponding to the input signal is output. On the other hand, when the input signal input to the input terminal is a low-level signal, the voltage conversion circuit converts the control signal input to the control terminal into a transmission-permitted signal. In this case, the control device outputs an output signal (low-level signal) corresponding to the input signal from the output terminal, and the output line becomes a low-level state. Thus, even when the communication device of [1] above uses "a control device such that when a transmission-permitted signal is input to the control terminal, an output signal corresponding to the input signal is output, and when a transmission-disabled signal is input to the control terminal, the output terminal becomes a high-impedance state", without independently applying a control signal to the control terminal, an output signal corresponding to the input signal can be output.

[0012] (2) The control device is capable of communicating with a remote controller for operating the gas appliance. The communication device for a gas appliance according to [1].

[0013] The communication device of [1] above can be used for communication between a gas appliance and a remote controller.

[0014] <First Embodiment> The following description relates to the first embodiment. (Basic Configuration) The hot water supply device 1 shown in Figures 1 and 2 corresponds to an example of a gas appliance and is a device that at least performs the operation of supplying water heated by heat exchangers 6, 56 to the bathtub 60. It is configured as a bath and hot water supply system that has the function of supplying hot water to the bathtub 60 and the function of heating the water in the bathtub 60 while circulating it. The hot water supply device 1 has the appearance shown in Figure 1. The hot water supply device 1 has the configuration shown in Figure 2 and mainly comprises a hot water supply side circuit 2 and a bath side circuit 3. As shown in Figures 1 and 2, the hot water supply device 1 has a housing 5, a hot water supply side circuit 2 including a heat exchanger 6, and a bath side circuit 3 having piping (drop-in pipe 70) branched from the hot water supply side circuit 2. As shown in Figures 1 and 2, the hot water supply side circuit 2 and the bath side circuit 3 are housed in the housing 5 of the hot water supply device 1.

[0015] As shown in Figure 2, the hot water supply circuit 2 includes a hot water supply channel, a gas burner 4, a heat exchanger 6, etc. The hot water supply circuit 2 functions as a circuit that heats tap water supplied from an external source and dispenses it as hot water. The bath side circuit 3 includes a bath side channel, a gas burner 54, a heat exchanger 56, a circulation pump 62, thermistors 64, 65, etc. The bath side circuit 3 is used for circulating heat when filling the bathtub, reheating the bathwater, etc.

[0016] In the hot water supply circuit 2, the pipeline consisting of the inlet pipe 12, heat transfer pipe 8a, piping 20, heat transfer pipe 7a, and outlet pipe 10 functions as the hot water supply water passage described above. The inlet pipe 12 is the passage (pipe) through which water flows in from the water inlet 16. The outlet pipe 10 is the passage (pipe) through which hot water is sent to the hot water outlet 18. The gas burner 4 functions as the hot water supply burner, burning combustion gases to generate combustion exhaust.

[0017] The heat exchanger 6 functions as a hot water supply side heat exchanger 6. The heat exchanger 6 is the part that transfers heat generated by the gas burner 4 to the water passing through the hot water supply side water passage (a pipeline consisting of an inlet pipe 12, a heat transfer pipe 8a, a pipe 20, a heat transfer pipe 7a, and a hot water outlet pipe 10) to heat the water. The heat exchanger 6 is located in the middle of the hot water supply side water passage and transfers heat generated by combustion in the gas burner 4 to the water passing through the inside of the hot water supply side water passage. The heat exchanger 6 comprises a primary heat exchanger 7 and a secondary heat exchanger 8. The primary heat exchanger 7 is located upstream of the combustion exhaust path of the gas burner 4 within the hot water supply combustion chamber 90. The secondary heat exchanger 8 is located downstream of the combustion exhaust path within the hot water supply combustion chamber 90.

[0018] The heat exchanger 6 functions to recover sensible heat from the combustion exhaust using the primary heat exchanger 7, and then recover latent heat using the secondary heat exchanger 8. The primary heat exchanger 7 is equipped with heat transfer tubes 7a that serve as water passages within the primary heat exchanger 7, and transfers the heat of combustion contained in the combustion exhaust generated by the gas burner 4 to the water passing through the heat transfer tubes 7a, thereby exchanging heat by transferring sensible heat energy to the water. The secondary heat exchanger 8 is equipped with heat transfer tubes 8a that serve as water passages within the secondary heat exchanger 8, and transfers the heat of combustion from the combustion exhaust generated by the gas burner 4 after it has passed through the primary heat exchanger 7 to the water passing through the heat transfer tubes 8a, thereby exchanging heat by transferring latent heat energy to the water.

[0019] In the hot water supply circuit 2, an inlet pipe 12 is connected to the inlet of the secondary heat exchanger 8, with a configuration that supplies tap water. The inlet pipe 12 is equipped with an inlet thermistor 25 that detects the temperature of the water passing through the inlet pipe 12 (specifically, the water temperature at a location upstream of the heat exchanger 6 and downstream of the water inlet 16 within the water pipe) and a water flow sensor 34 that detects the amount of water flowing through the inlet pipe 12 (i.e., the amount of water flowing through the water pipe). The inlet thermistor 25 has the function of detecting the temperature of water introduced from the outside.

[0020] Downstream of the inlet pipe 12, the heat transfer tubes 8a of the secondary heat exchanger 8 are connected, and further downstream, a pipe 20 is connected that connects the heat transfer tubes 8a of the secondary heat exchanger 8 to the heat transfer tubes 7a of the primary heat exchanger 7. The heat transfer tubes 7a of the primary heat exchanger 7 are connected to this pipe 20, and the outlet pipe 10 is connected to the outlet of the primary heat exchanger 7 to discharge the hot water heated by the primary heat exchanger 7. Of these, the hot water supply side water passage consisting of the inlet pipe 12, heat transfer tubes 8a, pipe 20, heat transfer tubes 7a, and outlet pipe 10 functions as a water passage provided in the hot water supply side circuit 2.

[0021] On the other hand, the bath-side water passage, consisting of the drop-in pipe 70 and the piping 66, functions as a second water passage provided in the bath-side circuit 3. The hot water outlet pipe 10 is provided with an inner cylinder outlet thermistor 27, which is located on the primary heat exchanger 7 (heat exchanger 6) side and detects the temperature of the hot water that has been heat-exchanged in the primary heat exchanger 7, and a hot water outlet thermistor 26, which is located on the hot water outlet 18 side and detects the temperature of the hot water after mixing with water from the bypass pipe 14.

[0022] A bypass pipe 14 is provided as a water passage that bypasses the inlet pipe 12 and the outlet pipe 10, and is configured as a water passage different from that of the heat exchanger 6. The bypass pipe 14 is equipped with a bypass valve 32 that can transition between a closed state in which the water flow through the bypass pipe 14 is blocked and an open state in which the opening degree is increased compared to the closed state.

[0023] In the inlet pipe 12, a water flow control valve 33 is provided upstream of the branching point where the bypass pipe 14 is connected. The water flow control valve 33 is equipped with a motor whose rotation angle of the drive shaft is controlled by instructions from the controller 22, and is configured to continuously change the opening of the inlet pipe 12 between a closed state and a fully open state. In this configuration, the water flow control valve 33 functions to regulate the amount of water flowing through the water pipe from the water inlet 16 to the hot water outlet 18.

[0024] The gas pipe 40 that supplies gas to the gas burner 4 is equipped with a gas source solenoid valve 42, a hot water gas proportional control valve 44, and hot water switching solenoid valves 46, 46... for each branch pipe leading to each gas burner 4, starting from the upstream side. Below the hot water combustion chamber 90, a hot water fan 48 is provided to supply combustion air to each gas burner 4 and gas burner 54. A switching solenoid valve 53 is provided in the branch pipe from the gas pipe connected to the gas burner 54. The hot water gas proportional control valve 44 and the hot water switching solenoid valve 46 function to adjust the amount of gas supplied to the gas burner 4.

[0025] In the bath-side circuit 3, the piping 66 includes piping 67 for guiding water from the bathtub 60 side to the heat exchanger 56 side, piping 68 for guiding water from the heat exchanger 56 side to the bathtub 60 side, and intermediate piping 69 connected to piping 67 and piping 68 and passing through the heat exchanger 56.

[0026] The piping 66 is configured such that one end and the other end are connected to the bathtub 60, and it also serves as a path for passing water that has come out of the bathtub 60 back into the bathtub 60. For example, during reheating or heating operations, the piping 66 guides water drawn from the bathtub 60 to the heat exchanger 56 via piping 67, and the water that has passed through the heat exchanger 56 is then guided back to the bathtub 60 via piping 68, thus creating a circulating path. The gas burner 54 functions as a bath-side burner, burning combustion gas to generate combustion exhaust. The heat exchanger 56 transfers the heat generated by the gas burner 54 to the water passing through a portion of the bath-side water pipe (specifically, the water passing through piping 66). The heat exchanger 56 comprises a primary heat exchanger 57 and a secondary heat exchanger 58, and functions to transfer the heat generated by the gas burner 54 to the water passing through piping 66.

[0027] The piping 67 is located between the bathtub 60 and the secondary heat exchanger 58, and is equipped with a circulation pump 62 and a thermistor 64 (bath thermistor) that detects the temperature of the water passing through the piping 67. The thermistor 64 functions to detect the temperature of the water discharged from the bathtub 60 (i.e., the temperature of the water inside the bathtub 60). The circulation pump 62 is a device that circulates the water in the piping 66, and functions to draw water from the bathtub 60 side and discharge the drawn water toward the heat exchanger 56 side.

[0028] The piping 68 is positioned between the primary heat exchanger 57 and the bathtub 60. A drop-in pipe 70, branched from the hot water outlet pipe 10, is connected to the piping 68, and hot water supplied from the drop-in pipe 70 flows into the piping 68. The drop-in pipe 70 is equipped with a hot water solenoid valve 72 and a drop-in water volume sensor 74. By opening the hot water solenoid valve 72 provided on the drop-in pipe 70, it is possible to supply hot water heated in the hot water supply circuit 2 to the bathtub 60. The drop-in water volume sensor 74 has the function of detecting the amount of water supplied to the bathtub 60 via the drop-in pipe 70.

[0029] The drop-in pipe 70 is the path through which hot water flows from the hot water supply side water passage of the hot water supply side circuit 2 to the piping 66 (circulation path) of the bath side circuit 3. The drop-in pipe 70 branches off from the outlet pipe 10 and connects to piping 67, and functions to guide the water heated by the heat exchanger 6 through the hot water supply side water passage to the bathtub 60.

[0030] As shown in Figure 2, the water heater 1 is equipped with a controller 22. As shown in Figure 3, the controller 22 comprises a control unit 22A configured as a known microcomputer, a memory 22B configured as a known semiconductor memory, and a communication unit 22C configured as an interface for communication with the outside. The controller 22 is configured to acquire signals from various sensors provided in the water heater circuit 2 and the bath circuit 3, and can control various actuators provided in the water heater circuit 2 and the bath circuit 3. The controller 22 controls the operation of the gas burners 4, 54 and at least a part of the supply unit. The controller 22 is connected to the power receiving unit 23. When an external power supply is connected to the power receiving unit 23 and power can be supplied from the outside, a power signal is input to the control unit 22A. The controller 22 is also configured to communicate with an external device provided outside the water heater 1 via a communication network such as the Internet, and is configured to acquire information from the external device.

[0031] As shown in Figure 3, the multiple remote controllers 80 (hereinafter referred to as remote controls 80) are arranged in a configuration that allows them to communicate with the controller 22. In the example in Figure 3, the multiple remote controls 80 include a first remote controller 81 (hereinafter referred to as the first remote control 81) installed in the bathroom and a second remote controller 82 (hereinafter referred to as the second remote control 82) installed in a location other than the bathroom (for example, the kitchen).

[0032] As shown in Figure 3, the first remote control 81 comprises a control unit 81A configured as a known microcomputer, a display unit 81B configured as a liquid crystal display device, an operation unit 81C provided with a plurality of known switches such as push buttons, an audio output unit 81D consisting of a speaker for outputting sound, and a communication unit 81E for communicating with the controller 22 and the second remote control 82. The operation unit 81C is composed of a plurality of operation units, including an operation switch. By pressing the operation switch, it is possible to switch between an operational state and an operational stop state for the hot water supply operation. The other operation units are used for input operations to instruct the filling of the bathtub 60 with hot water (input operations to instruct automatic filling and input operations to instruct energy-saving filling), input operations to reserve filling, and input operations to switch the on / off state of additional functions.

[0033] The second remote control 82 is similar, comprising a control unit 82A configured as a known microcomputer, a display unit 82B configured as a liquid crystal display device, an operation unit 82C provided with a plurality of known switches such as push buttons, an audio output unit 82D consisting of a speaker for outputting sound, and a communication unit 82E for transmitting signals generated by the second remote control 82 to the controller 22. The second remote control 82 has the same configuration as the first remote control 81, or a simplified configuration, and can be set in the same way as the first remote control 81. The on / off states of both remote controls 80 are linked. Settings set on one remote control 80 are reflected in the other.

[0034] (Configuration for controller 22 to communicate with other devices, etc.) Figure 4 illustrates the circuit configuration of a communication device for a water heater 1, as an example of a communication device for a gas appliance. Specifically, Figure 4 shows the circuit on a circuit board provided in the controller 22, etc. Figure 5 shows the relationship between the input signal, control signal, and output signal of the control device 92. The communication device shown in Figure 4 may be a part of the communication unit 22C shown in Figure 3, or it may be a different part.

[0035] As shown in Figure 4, the hot water supply device 1 comprises a control device 92, a voltage conversion circuit 91, a plurality of input units CN11, CN12, and a plurality of output units CN21, CN22. The control device 92 consists of, for example, an IC (Integrated Circuit) or includes an IC, and is mounted, for example, on a circuit board within the controller 22. However, the control device 92 is not limited to being mounted within the controller 22, and may be mounted on a circuit board other than the controller 22.

[0036] The control device 92 includes an input terminal DI, a control terminal DE, output terminals A / Y, an input terminal B / Z, a control terminal RE, an output terminal RO, a power supply terminal Vcc, and a ground terminal GND. The voltage of the power supply line BL is applied to the power supply terminal Vcc. The ground terminal GND is maintained at ground level voltage. In this specification, "voltage" means voltage with respect to ground level (potential difference from ground potential) unless otherwise specified.

[0037] The input section CN11 is electrically connected to the inverting circuit 95, and the inverting circuit 95 and the input terminal DI are connected by an input line LI which acts as a conductive path. A voltage conversion circuit 91 is connected between the input line LI and the control terminal DE.

[0038] The control device 92 is capable of outputting an output signal from output terminals A / Y corresponding to the input signal input to input terminal DI when a high-level (e.g., 5[V]) transmit-permit signal is input to control terminal DE. On the other hand, when a low-level (e.g., 0[V]) transmit-disable signal is input to control terminal DE, the output signal from output terminals A / Y becomes high-impedance regardless of the input signal input to input terminal DI. In the following explanation, 5[V] is used as an example of a high level, and a 5[V] voltage signal is used as an example of a high-level signal, but other voltages may also be used. Similarly, 0[V] is used as an example of a low level, and a 0[V] voltage signal is used as an example of a low-level signal, but other voltages may also be used.

[0039] The hot water heater 1 (Figure 2, etc.) is provided with a power supply circuit (not shown), which generates a predetermined power supply voltage (for example, a constant voltage of about 5[V] or about 12[V]) and applies it to the power supply line BL. The power supply line BL, which is provided in the power supply circuit and serves as a source of the predetermined voltage (constant voltage), is electrically connected to the input line LI via a resistor R11. The input line LI between the inverting circuit 95 and the input terminal DI branches to the voltage conversion circuit 91.

[0040] In the communication device shown in Figure 4, when a high-level or low-level signal is applied to the input section CN11 by an external device (such as the control unit 22A), the input signal from the input section CN11 is inverted by the inverting circuit 95 and then applied to the input line LI. For example, when a high-level signal is input to the input section CN11, the inverting circuit 95 inverts the high-level signal and outputs a low-level signal to the input line LI, and the low-level signal is input to the input terminal DI. When a low-level signal is input to the input section CN11, the inverting circuit 95 inverts the low-level signal and outputs a high-level signal to the input line LI, and the low-level signal is input to the input terminal DI.

[0041] The voltage conversion circuit 91 is electrically connected to the output side of the inverting circuit 95. The voltage conversion circuit 91 has the function of applying a voltage based on the voltage of the input terminal DI to the control terminal DE. When the input signal input to input terminal DI (input voltage of input terminal DI) is at a high level (e.g., 5[V]), it converts the control signal input to control terminal DE (input voltage of control terminal DE) to a low level. When the input signal input to input terminal DI (input voltage of input terminal D1) is at a low level (e.g., 0[V]), it converts the control signal input to control terminal DE (input voltage of control terminal DE) to a high level.

[0042] The voltage conversion circuit 91 includes a transistor section TR1 having a PNP type transistor. The PNP type transistor constituting the transistor section TR1 is, for example, a bipolar transistor, but is not limited to this, and for example, an FET (field-effect transistor) may be used. In Figure 4, the base of the transistor section TR1 is electrically connected to the other end of resistor R11 (the end opposite to the power supply line BL) via resistor R1. The emitter of the transistor constituting the transistor section TR1 is electrically connected to the power supply line BL of the power supply circuit, and the collector is electrically connected to the control terminal DE via resistor R12. The conductive path between resistor R12 and the control terminal DE is connected to ground via resistor R13.

[0043] Output terminals A / Y are electrically connected to output line LO, and output terminals A / Y and output line LO are at the same potential. Output terminals A / Y are connected to output section CN22 via output line LO, which acts as a conductive path. Output line LO is connected to power supply line BL (e.g., 12[V]) of the power supply circuit via pull-up resistor RPU. In the example in Figure 4, one end of pull-up resistor RPU is short-circuited to power supply line BL, and the other end is short-circuited to output line LO.

[0044] In the circuit shown in Figure 4, as shown in Figure 5, an output signal can be output from the output terminals A / Y in response to the input signal input to the input terminal DI. Specifically, when a low-level signal is applied to the input section CN11, and this low-level signal is inverted by the inverting circuit 95 to input a high-level input signal (high-level signal) to the input terminal DI, the high-level signal (high-level voltage) of the input line LI input to the input terminal DI is converted to a low-level signal (low-level voltage) by the voltage conversion circuit 91, and this low-level voltage is input to the control terminal DE as a control signal. Specifically, the transistor section TR1 is turned off, and the control terminal DE is maintained at ground voltage (e.g., 0V). When a low-level signal is input to the control terminal DE in this way, the control device 92 maintains the output terminals A / Y in a high-impedance state. In the configuration shown in Figure 4, output terminals A / Y are electrically connected to output line LO, and output terminals A / Y are electrically connected to output terminals A / Y via pull-up resistor RPU such that one end of pull-up resistor RPU is short-circuited to power line BL and the other end is short-circuited to output line LO. Therefore, when output terminals A / Y are in a high-impedance state and no current flows to output terminals A / Y through output line LO, output line LO becomes a high-level state at the same level as the power line. In other words, a high-level signal is transmitted through output line LO.

[0045] On the other hand, when a high-level signal is applied to the input terminal CN11, and this high-level signal is inverted by the inverting circuit 95 to input a low-level input signal (low-level signal) to the input terminal DI, the low-level voltage (low-level signal) of the input line LI input to the input terminal DI is converted to a high-level voltage (high-level signal) by the voltage conversion circuit 91, and this high-level voltage (high-level signal) is input to the control terminal DE as a control signal. Specifically, the transistor TR1 turns on, current flows through resistors R12 and R13, and the voltage at one end of resistor R13 (the end on the control terminal DE side) becomes high, so that the control terminal DE is maintained at a high-level voltage. When a high-level voltage (high-level signal) is input to the control terminal DE in this way, the control device 92 outputs a low-level signal with a voltage equivalent to the input signal (low-level signal) input to the input terminal DI from the output terminals A / Y. Therefore, the output line LO electrically connected to the output terminals A / Y becomes low level, and the low-level signal is transmitted via the output line LO.

[0046] Figure 6 is a circuit diagram showing a configuration in which a control device, as a comparative example, is connected to a remote control for communication. Figure 7 is a diagram showing the relationship between input signals, control signals, and output signals, as a comparative example. Figure 8 is a diagram showing a circuit that enables bidirectional communication between control device 92 and control device 93. Note that in the examples of Figures 6 to 8, the same control device 92 as in Figure 4 is used.

[0047] As shown in Figure 8, the control device 92 (IC1) and the control device 93 (IC2) are equipped with an input terminal DI to which an input signal is input, a control terminal DE to which a control signal is input, input / output terminals A / Y to which an output signal is output, input terminals B / Z to which input / output signals are input, a control terminal RE to which a control signal is input, and an output terminal RO to which an output signal is output.

[0048] As shown in Figure 6, the input terminal DI is connected to the input section CN11 via multiple transistors TRA1 and TRA2. Specifically, the input section CN11 is connected to the base of the NPN transistor TRA1 via resistor R01, the emitter of transistor TRA1 is grounded, and the collector of transistor TRA1 is connected to the base of the PNP transistor TRA2. The emitter of transistor TR2 is connected to the power supply line BL of the power supply circuit, and the collector of transistor TR2 is connected to the input terminal DI. The connection between resistor R12 and the input terminal DI is to ground via resistor R13.

[0049] The control terminal DE is connected to the control input section CNX via multiple transistors TRB1 and TRB2. Specifically, the control input section CNX is connected to the base of the NPN transistor TRB1 via resistor R02, the emitter of transistor TRB1 is grounded, and the collector of transistor TRB1 is connected to the base of the PNP transistor TRB2. The emitter of transistor TRB2 is connected to the power supply line BL of the power supply circuit, and the collector of transistor TRB2 is connected to the control terminal DE via resistor R12. The connection between resistor R12 and the control terminal DE is to ground via resistor R13.

[0050] The input / output terminals A / Y are connected to the output section CN22 via the output line LO, which acts as a conductive path. The output line LO is connected to the power supply line BL of the power supply circuit via resistor RB. Resistor RB consists of multiple resistors RA and R15 connected in series. The voltage of the power supply line BL of the power supply circuit is divided across the multiple resistors RA, RB, and R15 connected in series, and the voltage between resistor RA and resistor RB is applied to the input / output terminals A / Y.

[0051] In the circuit shown in Figure 6, the signal input to the control terminal DE is controlled by a signal on a separate path (the signal input to the control input unit CNX) from the signal input to the input unit CN11. Specifically, as shown in Figure 7, when a high-level input signal is input to the input terminal DI by the input signal from the input unit CN11, and a low-level control signal is input to the control terminal DE by the control signal from the control input unit CNX, a high-impedance output signal is output from the input / output terminals A / Y. When a low-level input signal is input to the input terminal DI by the input signal from the input unit CN11, and a low-level control signal is input to the control terminal DE by the control signal from the control input unit CNX, a high-impedance output signal is output from the input / output terminals A / Y.

[0052] When a high-level input signal is input to input terminal DI by an input signal from input unit CN11, and a high-level control signal is input to control terminal DE by a control signal from control input unit CNX, a high-level output signal is output from input / output terminals A / Y. When a low-level input signal is input to input terminal DI by an input signal from input unit CN11, and a high-level control signal is input to control terminal DE by a control signal from control input unit CNX, a low-level output signal is output from input / output terminals A / Y.

[0053] In the comparative example configuration, as shown in Figure 6, the input / output terminals A / Y are connected to both the power supply line BL and the ground side of the power supply circuit via resistors RB, RA, and R15. Therefore, when a low-level control signal (transmission disallow signal) is input to the control terminal DE, causing the input / output terminals A / Y to enter a high-impedance state, it is not possible to reliably output an output signal corresponding to the input signal at input terminal DI to the line connected to input / output terminals A / Y. In contrast, this problem can be resolved in Figure 4 of this embodiment.

[0054] The following explanation concerns an example of the effects of this configuration. The communication device shown in Figure 4 is a communication device for a gas appliance used in a water heater 1 (gas appliance) equipped with a water heater circuit 2 (hot water supply circuit) that heats water supplied from an external source to supply hot water. In this communication device, the control device 92 has an input terminal DI to which an input signal is input, a control terminal DE to which a control signal is input that switches between a high-level signal, which is a transmit permission signal, and a low-level signal, which is a transmit disallowance signal, is input, and an output terminal A / Y to which an output signal is output. Furthermore, the control device 92 outputs an output signal corresponding to the input signal when a transmit permission signal is input to the control terminal DE, and operates so that the output terminal A / Y becomes high impedance when a transmit disallowance signal is input to the control terminal DE. Furthermore, the communication device in Figure 4 includes a voltage conversion circuit 91 connected to the input terminal DI and the control terminal DE, a power line BL to which a predetermined voltage is supplied from the power supply circuit, an output line LO connected to the output terminal A / Y, and a pull-up resistor RPU connected between the power line BL and the output line LO.

[0055] In this configured communication device, when a low-level signal is input to input terminal DI, the voltage conversion circuit 91 connected to input terminal DI and control terminal DE operates to input a high-level signal, which becomes a transmit-permit signal, to control terminal DE. When a transmit-permit signal is input to control terminal DE in this way, the control device 92 outputs a low-level output signal from output terminals A / Y corresponding to the low-level input signal input to input terminal DI. When the output terminal is in a low-level state in this way, the output line is also in a low-level state. In other words, when a low-level signal is input to input terminal DI, the output terminal can also be put into a low-level state, and the output line can also be put into a low-level state. Therefore, the output line can be put into a low-level state without independently inputting a control signal to control terminal DE, or without separately controlling the signal to control terminal DE.

[0056] On the other hand, in the communication device configured as described above, when a high-level signal is input to the input terminal DI, the voltage conversion circuit 91 connected to the input terminal DI and the control terminal DE operates to input a low-level signal, which is a transmission disallowance signal, to the control terminal DE. When a transmission disallowance signal is input to the control terminal DE in this way, the control device 92 sets the output terminals A / Y to a high-impedance state. In the communication device of Figure 4, a pull-up resistor is connected between the output line LO, which is a conductive path connected to the output terminals A / Y, and the power line BL. The voltage of the power line BL is applied to the output terminals A / Y via the pull-up resistor RPU, and when the output terminals A / Y are in a high-impedance state, the output line LO is in a high-level state. In other words, when a high-level signal is input to the input terminal DI of the control device 92, the output line can be set to a low-level state without independently inputting a control signal to the control terminal DE, or without separately controlling the signal to the control terminal DE.

[0057] Thus, the communication device in Figure 4 uses a control device 92 having an input terminal DI, a control terminal DE, and output terminals A / Y. When the control device 92 is configured to output an output signal corresponding to the input signal when a transmit permission signal is input to the control terminal DE, and when a transmit permission signal is input to the control terminal DE, the output terminals A / Y enter a high-impedance state. In this configuration, it is possible to output an output signal corresponding to the input signal without providing a separate circuit or device to generate a control signal for the input signal input to the input terminal DI.

[0058] The control device 92 uses a bidirectional communication IC and is configured to communicate with the remote control 80, which can operate the hot water supply circuit 2. Therefore, it is possible to use the bidirectional communication 92, which has a control terminal DE that can input a transmit permission signal or a transmit disallowance signal, to communicate with the hot water supply device 1, which does not perform bidirectional communication and only performs unidirectional communication.

[0059] <Other Embodiments> This disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of the features of the embodiments described above or below is possible as long as it does not contradict each other. Furthermore, any feature of the embodiments described above or below may be omitted unless explicitly stated as essential. Moreover, the embodiments described above may be modified as follows.

[0060] In the above-described embodiment, the control device 92 was equipped with input terminal DI, control terminal DE, and output terminal A / Y, as well as input / output terminal B / Z, control terminal RE, and output terminal RO. However, the configuration is not limited to this, and for example, the control device may be configured without input / output terminal B / Z, control terminal RE, and output terminal RO, or it may be equipped with other types of terminals. Similarly, in the above-described embodiment, the control device 93 on the remote control side was equipped with input terminal DI, control terminal DE, and output terminal A / Y, as well as input / output terminal B / Z, control terminal RE, and output terminal RO. However, the configuration is not limited to this, and for example, it may be configured without input / output terminal B / Z, control terminal RE, and output terminal RO, or it may be equipped with other types of terminals.

[0061] In the above-described embodiment, the remote control 80 that can communicate with the control device 92 is not limited to one; for example, the control device 92 may be capable of communicating with multiple remote controls simultaneously. Furthermore, the devices with which the control device 92 communicates are not limited to remote controls; the control device 92 may be configured to communicate with other devices.

[0062] In the above-described embodiment, a water heater 1 is used as an example of a gas appliance, but a communication device comprising a control device, a voltage conversion circuit, a power line, an output line, a pull-up resistor, etc., may also be applied to gas appliances other than water heaters (for example, a water heater / heating system or other gas appliances).

[0063] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope set forth in the claims or equivalents thereof. [Explanation of Symbols]

[0064] 1: Water heating equipment (gas appliances) 2: Hot water supply circuit (hot water supply circuit) 80: Remote control 91: Voltage conversion circuit 92: Control device A / Y: Output terminal BL: Power line DE: Control terminal DI: Input terminal LI: Input Line LO: Output line RPU: Pull-up resistor

Claims

1. A control device having an input terminal into which an input signal is input, a control terminal into which a control signal is input which is a signal that switches between a high-level signal, which is a transmit permission signal, and a low-level signal, which is a transmit disallowance signal, and an output terminal into which an output signal is output, wherein when the transmit permission signal is input to the control terminal, the output signal corresponding to the input signal is output, and when the transmit disallowance signal is input to the control terminal, the output terminal becomes high impedance, A voltage conversion circuit connected to the input terminal and the control terminal, A power line from which a predetermined voltage is supplied from the power supply circuit, The output line connected to the aforementioned output terminal, A pull-up resistor connected between the power line and the output line, Equipped with, The voltage conversion circuit converts the control signal input to the control terminal to the transmission disable signal when the input signal input to the input terminal is a high-level signal, and converts the control signal input to the control terminal to the transmission enable signal when the input signal input to the input terminal is a low-level signal. When the output terminal is in a high impedance state, the output line becomes high level. When the output terminal is in a low-level state, the output line is in a low-level state. A communication device for gas appliances.

2. The control device is capable of communicating with a remote control for operating the gas appliance. A communication device for a gas appliance according to claim 1.

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