JP2005037070A - Control device for combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device especially suitable for control of multi-functional types, capable of securely executing a combustion stopping process when a microcomputer has abnormality. <P>SOLUTION: This control device comprises a main microcomputer 51 to control opening and closing of gas solenoid valves in respective combustion parts for supply of hot water and bathwater through solenoid valve drive circuits 2a and 2b, and a subsidiary microcomputer 52 to disconnect supply of power to the solenoid valve drive circuits 2a and 2b through a power disconnecting circuit 3 for fuel for closing both gas solenoid valves for supply of hot water and bathwater. The combustion stopping process in normal operation is alternately conducted by the main microcomputer 51 and the subsidiary microcomputer 52. For stopping either combustion under a state that additional heating for supply of hot water or bathwater is simultaneously conducted, the combustion stopping process is executed through the solenoid valve drive circuit 2 by the microcomputer 51 regardless of rules. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control apparatus for a combustion apparatus, and more particularly to a control apparatus suitable for use in a so-called multifunctional hot water supply apparatus.

  A recent combustion apparatus typified by a gas hot-water supply apparatus includes a control device equipped with a microcomputer (hereinafter referred to as a microcomputer) in its control center, and a gas for switching supply / stop of fuel gas by the microcomputer. Operation control of various actuators such as an electromagnetic valve, a proportional valve for adjusting the amount of fuel gas supplied, and a fan motor for adjusting the amount of air blown for combustion is performed.

  When such microcomputer control is used, the microcomputer may cause a malfunction of the hot water supply system. Therefore, as a countermeasure, a microcomputer monitoring circuit (watchdog timer IC) is also provided. (WD pulse) is output and this pulse is monitored by a microcomputer monitoring circuit. However, in the case of a hot water supply device, in addition to such a configuration for safety measures, leakage of unburned fuel and emptying are prevented. For this purpose, a safety circuit called a fail-safe circuit is incorporated (see Patent Document 1 and FIG. 3).

  However, in the configuration including such a safety circuit, a dedicated IC such as a microcomputer monitoring circuit (watchdog timer IC) b and a fail safe circuit (fail safe IC) g in addition to the microcomputer a for controlling the operation of each part of the hot water supply device. Therefore, there is a problem that the number of parts increases and the manufacturing cost increases.

  For this reason, the applicant of the present application uses a main microcomputer that controls the operation of each part of the hot water supply device and a sub-microcomputer that monitors the operation of the main microcomputer to cause the control means to monitor each other's operation through communication between the microcomputers. If the main microcomputer that controls the hot water supply system becomes abnormal, the sub-microcomputer that monitors this shuts off the power supply to the solenoid valve drive circuit through the power shut-off circuit. Has proposed a control device having a configuration in which combustion is stopped by closing a gas solenoid valve (see Patent Document 2).

JP-A-8-233258 JP 2002-318003 A

  However, if a configuration is adopted in which the power supply to the solenoid valve drive circuit is shut off by the sub-microcomputer when the main microcomputer is abnormal in this way, the combustion stop process by the sub-microcomputer is not performed as long as the main microcomputer is operating normally. Therefore, even if an abnormality occurs in the circuit related to the combustion stop process on the sub-microcomputer side, the discovery is delayed. That is, in such a configuration, there is a possibility that combustion stop processing by the sub-microcomputer may not be performed normally when an abnormality occurs in the main microcomputer, and there is room for improvement in terms of safety measures.

  In order to solve such a problem, the applicant of the present application allows the main microcomputer and the sub-microcomputer to alternately perform the combustion stop process during the normal combustion operation, so that the combustion stop process by the sub-microcomputer functions normally. A control device that can confirm whether or not to do so has been invented, but the present invention provides an improved invention.

  That is, in the hot water supply apparatus, there are multi-function models having functions other than hot water supply (for example, a water heater having a hot water supply function and a bath reheating function, a hot water supply function and a hot water generating function for heating). In the case of such a multifunctional model, a combustion part (burner unit) may be provided for each function. Thus, in a hot water supply apparatus provided with a burner unit for each function, one or more gas solenoid valves (that is, solenoid valve drive circuits) are provided for each burner unit, and the power cutoff circuit is common to these solenoid valve drive circuits. Therefore, if the sub-microcomputer is assigned to share the combustion stop process in normal combustion operation, the power supply to all solenoid valve drive circuits will be cut off at the same time if the sub-microcomputer side performs the combustion stop process. However, there is a problem that the fuel supply is stopped even for the burner unit that does not require the combustion stop. On the other hand, providing a power cut-off circuit for each solenoid valve drive circuit is not preferable because the circuit configuration becomes complicated (increase in the number of parts) and the manufacturing cost increases.

  The present invention has been made in view of such problems, and the object of the present invention is a control device that can reliably perform a combustion stop process when a microcomputer malfunctions, particularly for control of multifunctional models. The object is to provide a suitable control device at low cost.

  In order to achieve such an object, a control apparatus for a combustion apparatus according to the present invention is a control apparatus for a combustion apparatus that includes a plurality of combustion sections and includes a load for supplying fuel to each combustion section. A power shut-off means configured to be able to shut off the power supplied to the load drive means, and a control means having at least two or more microcomputers having communication means and mutually monitoring operations through communication. One of the microcomputers is a main microcomputer that controls the operation of each part of the combustion apparatus including at least the load driving means, and the other is a sub-microcomputer that controls at least the power shut-off means. In the control device configured so that the main microcomputer and the sub-microcomputer alternately perform the combustion stop process based on a predetermined rule when performing the stop process, two or more The burning part is combusting, and when the combustion of one of the burning parts is stopped, the main microcomputer is configured to execute the combustion stopping process regardless of the predetermined rule. To do.

  As a preferred embodiment, the combustion stop process by the main microcomputer is performed through load driving means.

  Further, as another preferred embodiment, as for confirmation of whether or not the combustion stop processing has been normally performed, the control device detects a fuel leakage detection means for detecting an abnormal fuel leakage from the combustion section. Or after the combustion stop process based on the predetermined rule, the main microcomputer executes a fire extinguishing determination process for confirming whether or not the fire extinguishing operation has been normally performed based on information from the fuel leakage detection means, or The fire extinguishing judgment process in which the microcomputer that has not performed the combustion stop process after the combustion stop process based on the predetermined rule confirms whether the fire extinguishing operation has been normally performed based on the information from the fuel leakage detection means. It is characterized by performing.

  As still another preferred embodiment, when it is determined that the fire extinguishing operation is not normally performed as a result of the fire extinguishing determination process, the combustion stop process is executed by the microcomputer on the side that performed the extinguishing determination process. Features. Further, when this fire extinguishing judgment process is performed only by the main microcomputer, if it is determined that the combustion stop process by the main microcomputer is not normal as a result of the fire extinguishing judgment process, the sub microcomputer is instructed to perform the combustion stop process. The

  Here, the predetermined rule is that the main microcomputer and the sub microcomputer share the combustion stop process. The sub microcomputer performs the next combustion stop process after the main microcomputer executes the combustion stop process, and the sub microcomputer stops the combustion. It is preferable that the main microcomputer and the sub-microcomputer alternately perform the combustion stop process once every time, such as the main microcomputer performs the next combustion stop process after the process is executed. It may be irregular such that the stop process is performed twice and the other is performed once.

  The abnormal fuel leakage means leakage of unburned fuel or so-called emptying when the combustion device is a hot water supply device. The leakage of the unburned fuel is caused by the presence or absence of a flame in the load monitoring means (for example, an electromagnetic valve monitoring circuit when the load is an electromagnetic valve) for monitoring the state of the load for supplying the fuel and the combustion part. With the flame detection means to detect (for example, a flame detection circuit equipped with a frame rod), it can be determined that there is leakage of unburned fuel when no flame is detected even though fuel is supplied. Regarding leakage of unburned fuel, the load monitoring means and the flame detection means constitute fuel leakage detection means. On the other hand, the empty fire is generated by the load monitoring means, the flame detection means and the water flow detection means for detecting the flow of water to the hot water supply device (for example, a water amount detection circuit using a water amount sensor or a detection circuit using a water flow switch). Since there is no water flow (or there is only water flow of a predetermined flow rate or less) even though a flame is detected, it can be determined that the air is fired. The detection means and the water flow detection means constitute a fuel leakage detection means.

  According to the control device for a combustion apparatus of the present invention, at least two or more microcomputers that mutually monitor the operation are used as the control means, and one of the parts of the combustion apparatus includes load driving means for supplying fuel. The main microcomputer controls the operation and the other is a sub-microcomputer that controls the power shut-off means. The sub-microcomputer operates the power shut-off means when an abnormal fuel leak is detected by the fuel leak detecting means. Since the power supply to the load driving means is cut off, the operation control function of the combustion device and the mutual monitoring function (watchdog function) of the microcomputer are performed by two microcomputers in the minimum structure. In addition, a fuel cutoff function (fail-safe function) at the time of abnormal fuel leakage can be realized. Therefore, the number of parts can be reduced as compared with the conventional control device, and the control device for the combustion device can be provided at low cost.

  Moreover, according to the present invention, the main microcomputer controls the operation of each part of the combustion device, and the sub-microcomputer is responsible for the watchdog function and the fail-safe function, so that only the main microcomputer is dedicated to the specifications of the combustion device. The sub-microcomputer can be a general-purpose product that does not depend on the type of the main microcomputer. Further, since the processing contents of the sub-microcomputer are simple, it is not necessary to use a high-performance microcomputer. Therefore, according to this invention, the manufacturing cost as the whole control apparatus can be held down cheaply.

  Further, the control means causes the main microcomputer and the sub-microcomputer to alternately perform this process based on a predetermined rule when performing the combustion stop process of the combustion section, and at that time, the main microcomputer or the combustion stop process is performed. Since one of the other microcomputers that has not been executed makes a fire extinguishing judgment based on information from the fuel leakage detection means, it is periodically determined whether the combustion stop process by the sub-microcomputer functions normally during normal operation of the combustion device. Can be confirmed automatically, and the normal operation of the fail-safe function can be ensured.

  In addition, when two or more combustion parts are combusting and one of the combustion parts is to be stopped, the main microcomputer performs a combustion stop process regardless of the order in accordance with the above rules. Therefore, the combustion apparatus can be smoothly controlled without causing a problem that the combustion part that needs to continue combustion is extinguished when shifting from simultaneous combustion to single combustion.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a circuit block diagram when the present invention is applied to a control apparatus for a gas water heater, and FIG. 2 shows the circuit diagram thereof. More specifically, FIGS. 1 and 2 show a case where the present invention is applied to a control device for a gas water heater (so-called multi-functional model) having a hot water supply function and a bath reheating function.

  Here, the multi-function model is a water heater that has other functions in addition to the hot water supply function (for example, a bath reheating function and a hot water generating function for hot water heating). Accordingly, it means a water heater provided with a plurality of independent combustion units (combustion units). Each combustion unit is provided with one or more gas solenoid valves called capacity switching valves, and the number of combustion tubes of the combustion tube forming the burner unit can be switched by opening and closing these gas solenoid valves. ing.

  Further, as is well known, a gas proportional valve for adjusting the thermal power and a source gas solenoid valve for switching the supply / stop of fuel gas are provided upstream of the capacity switching valve. Similar to the capacity switching valve, the gas solenoid valve can be controlled to be opened and closed by a solenoid valve drive circuit 2 described later, and is closed when the power supply is shut off by the power shut-off circuit 3. . In addition, since the basic composition of these gas proportional valves and original gas solenoid valves is well-known, detailed description is abbreviate | omitted. Further, in the following description, for convenience of explanation, it is assumed that each combustion unit for hot water supply and bath reheating is provided with one gas electromagnetic valve A (see FIG. 2) as a capacity switching valve.

  The control device 1 supplies a solenoid valve drive circuit (load drive means) 2 for driving a gas solenoid valve (load) for supplying combustion gas as fuel to a burner (not shown) and a solenoid valve drive circuit 2 The main part is composed of a power cutoff circuit (power cutoff means) 3 configured to be able to shut off the power source V1, a fuel leakage detection means 4 for detecting an abnormal leakage of fuel from the burner, and a control means 5. The

  In the present embodiment, as described above, a hot water heater having a hot water supply function and a bath reheating function (that is, provided with two combustion units) is shown. An electromagnetic valve driving circuit 2a and an electromagnetic valve driving circuit 2b for bathing are provided. Along with this, the fuel leakage detection means 4 is also provided with a hot water supply 4a and a bath replenishment 4b.

  As described above, the solenoid valve drive circuit 2 is a circuit for controlling energization to the gas solenoid valve A (see FIG. 2) for supplying the combustion gas to the burner. As shown in FIG. RL1 (more specifically, a relay coil; the same applies hereinafter) and a transistor Q1 having a collector terminal connected to one end of the relay RL1 are mainly configured. Then, when a relay drive signal, which will be described later, is applied to the base terminal of the transistor Q1, the transistor Q1 is turned on and the relay RL1 is energized, whereby a relay contact (not shown) is activated to operate the gas solenoid valve A. Is configured to open when energized. That is, when the relay RL1 is energized, the relay contact is actuated, thereby energizing the coil of the gas solenoid valve A connected in series with the relay contact to the power source for the gas solenoid valve and opening the gas solenoid valve A. To be spoken.

  The power cut-off circuit 3 is a circuit configured to be able to cut off the power supplied to the relay RL1. In the present embodiment, the power cut-off circuit 3 is interposed between the drive power supply V1 of the relay RL1 and the relay RL1. The transistor Q2 is configured as a main part. Specifically, the transistor Q2 is composed of a PNP transistor, and has an emitter terminal connected to the drive power supply V1, a collector terminal connected to the other end of the relay RL1, and a base terminal described later. When the power cut-off signal is given, the transistor Q2 is turned off and the voltage supply to the relay RL1 is cut off.

  In the present embodiment, as described above, one electromagnetic valve driving circuit 2 is provided on each of the hot water supply side and the bath retreating side. Therefore, the power shutoff circuit 3 includes all these electromagnetic valve driving circuits 2a and 2b. The power supply can be cut off at once. That is, the circuit is configured so that the transistor Q2 functions as a switch common to the solenoid valve drive circuits 2 (see FIG. 2). For example, if a combustion unit on the hot water supply side is provided with a plurality of capacity switching valves (gas electromagnetic valves), a plurality of electromagnetic valve drive circuits 2 are provided on the hot water supply side according to the number of capacity switching valves. Even in such a case, the power cutoff circuit 3 is configured to be a switch common to all the solenoid valve drive circuits 2.

  The collector terminal of the transistor Q3 constituting the OR circuit 6 in FIG. 1 is connected to the base terminal of the transistor Q2 constituting the power shutoff circuit 3, and when the transistor Q3 is turned off, the transistor Q2 is also turned off. Configured to do. That is, when the transistor Q3 is turned off, a power supply cutoff signal is given to the transistor Q2.

  The fuel leakage detection means 4 is a detection circuit for detecting abnormal fuel leakage from the burner. In the present embodiment, since a gas water heater is used as a combustion device, the modes of abnormal fuel leakage include leakage of unburned gas (unburned fuel) and burning of a burner. Therefore, the fuel leakage detection means 4 is constituted by a circuit capable of detecting both leakage and emptying of these unburned gases.

  Specifically, as described above, the fuel leakage detection means 4 is also provided in accordance with the number of combustion sections, and as shown in the figure, there are provided a hot water supply 4a and a bath replenishment 4b. .

  Even though the fuel is supplied to the burner unit (in other words, even though at least one gas solenoid valve A is open), the burner unit is not combusting (in other words, For example, when the flame is in an undetected state), it can be said that there is leakage of unburned gas, so as to detect leakage of unburned gas, solenoid valve monitoring circuits (load monitoring means) 41a and 41b, and a flame detection circuit (Flame detection means) 42a and 42b are used. On the other hand, fuel is supplied to the burner unit in a state where no leakage of the unburned gas is detected (in other words, at least one gas electromagnetic valve A is opened), and the burner unit is burned. The heat exchanger has no water flow (in other words, there is no water flow, or there is water flow) When the water heater is in a state where there is only water flow equal to or less than the minimum operating water amount (MOQ) of the water heater, it can be said that it is empty, so that the solenoid valve monitoring circuits 41a and 41b, the flame detection circuit 42a, 42b and water amount detection circuits (water flow detection means) 43a and 43b are used.

  More specifically, as shown in FIG. 2, the solenoid valve monitoring circuit 41 monitors the drive voltage supplied to the gas solenoid valve A, so that the gas solenoid valve A is opened or closed. If the gas solenoid valve A is open, a valve monitoring signal is output. In the present embodiment, the electromagnetic valve monitoring circuit 41 is configured by a circuit that monitors the voltage applied to both ends of the coil of the gas electromagnetic valve A, but the gas electromagnetic valve A is in either the open or closed state. Therefore, it is possible to adopt another configuration such as monitoring the energization current of the coil of the gas solenoid valve A itself. As described above, when a plurality of capacity switching valves (gas solenoid valves) are provided in one combustion unit, the solenoid valve monitoring circuit 41 opens at least one capacity switching valve among these capacity switching valves. It is configured to output a valve monitoring signal when valved. In other words, the solenoid valve monitoring circuit 41 is configured to monitor whether or not the fuel gas is being supplied in units of combustion units.

  On the other hand, the flame detection circuit 42 detects the presence or absence of combustion with the frame rod B disposed in the vicinity of the burner, and outputs a flame detection signal when burning. Further, the water amount detection circuit 43 detects a water flow rate based on a detection signal obtained from a water amount sensor (or water flow switch) C provided upstream of the heat exchanger, and water flow exceeding the minimum working water amount is detected. If there is, a water detection signal is output. The configurations of the solenoid valve monitoring circuit 41, the flame detection circuit 42, and the water amount detection circuit 43 are all well known and will not be described.

  The control means 5 has at least two or more microcomputers each having communication means and monitoring operations by communication, one of which includes at least the electromagnetic valve drive circuits 2a and 2b. The main microcomputer controls the operation of each part of the device, and the other is at least a sub-microcomputer that controls the power shut-off circuit 3. In the present embodiment, a total of two microcomputers including a main microcomputer 51 and a sub microcomputer 52 are used as the control means 5.

  The main microcomputer 51 is a microcomputer for controlling the operation of each part of the gas water heater. In addition to the electromagnetic valve drive circuits 2a and 2b described above, for example, a fan motor for adjusting the amount of combustion air blown, and the amount of water It is electrically connected to a servo motor for control, a spark plug of a burner, etc. to control these operations, and when a remote controller is connected to the gas water heater, it communicates with the remote controller and performs various operations from the remote controller. The basic functions of the microcomputer provided in the conventional gas water heater for controlling the water heater, such as receiving a command and performing processing such as transmitting the operation status of the water heater to the remote controller. It has everything.

  Accordingly, the characteristic configuration of the main microcomputer 51 relating to the present invention will be described. In the present invention, the main microcomputer 51 includes communication terminals TXD (transmission) and RXD (reception) for bidirectional data communication with the sub-microcomputer 52. ) Is provided. These terminals TXD and RXD are connected via a bus to a microprocessor (MPU) and a memory of the main microcomputer 51 via an interface (communication means) not shown, and these terminals TXD and RXD are sub-microcomputers to be described later. By connecting to the communication terminals RXD (reception) and TXD (transmission) on the 52 side, data can be transmitted and received between the microprocessor of the main microcomputer 51 and the microprocessor of the sub-microcomputer 52.

  The main microcomputer 51 is provided with an output terminal for outputting a control signal to the various actuators described above. In the present invention, as the output terminal, a relay drive terminal RL / DRV1 for supplying a relay drive signal (load control signal) to the solenoid valve drive circuit 2a for hot water supply and a solenoid valve drive circuit 2b for bathing in particular are relayed. Relay drive terminals RL / DRV2 for supplying a drive signal and relay standby terminals RL / STB for supplying a relay standby signal to the OR circuit 6 are provided.

  Specifically, the relay driving terminal RL / DRV1 is connected to the base terminal of the transistor Q1 of the relay driving circuit 2a for hot water supply, and the relay driving signal is output from the terminal RL / DRV1 to supply the above-mentioned relay driving terminal RL / DRV1. The transistor Q1 is turned on, and the hot water supply relay RL1 is energized. Similarly, the relay driving terminal RL / DRV2 is connected to the base terminal of the transistor Q1 of the bath driving relay driving circuit 2b, and a relay driving signal is output from the terminal RL / DRV2 for bath driving. The transistor Q1 is turned on, and the relay RL1 for bathing is energized.

  On the other hand, the relay standby terminals RL and STB are connected to the base terminal of the transistor Q3. The transistor Q3 is turned on by the output of the relay standby signal, whereby the transistor Q2 is turned on, and a driving voltage is applied from the driving power source V1 to the relay RL1 for hot water supply and bathing. That is, when the output of the relay standby signal is stopped, the transistor Q3 is turned off and the transistor Q2 is also turned off, and the voltage supply to both the hot water supply and bath reheating relays RL1 is stopped. Therefore, in this embodiment, the output stop of the relay standby signal functions as a power cutoff signal by the main microcomputer 51.

  As the input terminal of the main microcomputer 51, the solenoid valve monitoring input terminal SV · IN1 to which the valve monitoring signal from the solenoid valve monitoring circuit 41a for hot water supply is input corresponding to the configuration of the fuel leakage detection means 4 is provided. A flame detection input terminal FR · IN1 to which a flame detection signal from the flame detection circuit 42a for hot water supply is input, and a water amount input terminal WA · IN1 to which a water flow detection signal from the water amount detection circuit 43a for hot water supply is input. Are connected to the output terminals of the solenoid valve monitoring circuit 41a, the flame detection circuit 42a, and the water amount detection circuit 43a. Similarly, the main microcomputer 51 includes an electromagnetic valve monitoring input terminal SV / IN2 to which a valve monitoring signal is input from an electromagnetic valve monitoring circuit 41b for bathing, and a flame detection circuit 42b for bathing. A flame detection input terminal FR / IN2 to which a flame detection signal is input and a water volume input terminal WA / IN2 to which a water flow detection signal from the water volume detection circuit 43b for bathing is input are provided. Are connected to the output terminals of the solenoid valve monitoring circuit 41b, the flame detection circuit 42b, and the water amount detection circuit 43b.

  In the present embodiment, the output terminals of the solenoid valve monitoring circuits 41a and 41b, the flame detection circuits 42a and 42b, and the water amount detection circuits 43a and 43b are input terminals similar to the above (electromagnetic) provided in the sub-microcomputer 52 described later. Valve monitoring input terminals SV · IN1, SV · IN2, flame detection input terminals FR · IN1, FR · IN2, and water amount input terminals WA · IN1, WA · IN2). The supply of these signals to the sub-microcomputer 52 can be configured to be given to the sub-microcomputer 52 by communication via the main microcomputer 51, for example.

  Further, the main microcomputer 51 has a reset output terminal RST / OUT for outputting a reset signal to the sub-microcomputer 52 and a reset input terminal RST / IN for inputting a reset signal output from the sub-microcomputer 52. And are provided. Details of reset signal input / output will be described later.

  On the other hand, the sub-microcomputer 52 is a microcomputer that mainly performs a monitoring function (watchdog function) and a fail-safe function of the main microcomputer 51. In the present invention, in addition to these functions, a function for sharing a combustion stop process, which will be described later, etc. It is programmed to fulfill.

  The sub-microcomputer 52 is also provided with an interface (communication means) as in the main microcomputer 51, and as shown in FIG. 2, the sub-microcomputer 52 includes communication terminals TXD and RXD as input terminals, as shown in FIG. For hot water supply and for bathing, baths have solenoid valve monitoring input terminals SV / IN1, SV / IN2, flame detection input terminals FR / IN1, FR / IN2, and water volume input terminals WA / IN1, WA / IN2, respectively. . The main microcomputer 51 is also provided with a reset output terminal RST · OUT and a reset input terminal RST · IN for resetting the main microcomputer 51 and resetting the sub-microcomputer 52.

  The sub-microcomputer 52 is provided with fail-safe output terminals FS / OUT as output terminals. The fail-safe output terminal FS / OUT is a terminal configured to be open (open) when the water heater is operating normally, and to be short-circuited (Lo) during fail-safe output described later, The OR circuit 6 is connected to the base terminal of the transistor Q3. That is, at the time of fail-safe output, the fail-safe output terminal FS · OUT becomes Lo, so that the transistor Q3 is turned off, thereby turning off the transistor Q2, and the power supply to the solenoid valve drive circuits 2a and 2b is cut off (voltage supply) Is stopped). In other words, the fail-safe output also functions as a power cutoff signal. In FIG. 2, reference numeral 8 denotes a thermal fuse.

  Next, operation | movement of the control apparatus 1 comprised in this way is demonstrated in detail.

A. Watchdog function :
First, the mutual monitoring function (watchdog function) of the main microcomputer 51 and the sub microcomputer 52 will be described. Note that this watchdog function consists of a communication monitoring process that monitors whether the other party's microcomputer is in an abnormal state such as a runaway, and a subsequent process when it is determined that the other party microcomputer has an abnormality. Separately described.

  First, communication monitoring processing will be described. In the control device 1 according to the present invention, whether the counterpart microcomputer has fallen into an abnormal state while transmitting and receiving data to each other at a constant cycle by the interfaces (communication means) provided to the main microcomputer 51 and the sub-microcomputer 52 described above. To monitor.

  Specifically, for example, the main microcomputer 51 transmits data to the sub-microcomputer 52 at a predetermined constant cycle (for example, a cycle of 100 ms). As the data to be transmitted here, data representing a command to the sub-microcomputer 52 or data indicating the state of the gas water heater in a predetermined format is used. On the other hand, when the sub microcomputer 52 receives the data transmitted from the main microcomputer 51, the sub microcomputer 52 returns data of a predetermined format to the main microcomputer 51 within a predetermined time.

  As described above, the data is transmitted from the main microcomputer 51 to the sub-microcomputer 52 at a constant period, and the data is returned from the sub-microcomputer 52 within a certain time. Therefore, the main microcomputer 51 passes a certain time after the transmission of the data. However, if there is no reply from the sub-microcomputer 52, it can be determined that the sub-microcomputer 52 has an abnormality. On the other hand, the sub-microcomputer 52 can determine that there is an abnormality in the main microcomputer 51 when the data from the main microcomputer 51 cannot be received even after the predetermined period of time has elapsed.

  This abnormality determination can be immediately determined as an abnormality of the other party even if the data non-reception state is even once. For example, when the data non-reception state is repeated a predetermined number of times, It is possible to determine that the counterpart microcomputer is abnormal when it continues for a predetermined time. In the present embodiment, when the data non-reception state is repeated N times, the other party's abnormality is determined.

  Next, the processing when it is determined that the counterpart microcomputer is abnormal as a result of the communication monitoring will be described. In this process, the main microcomputer 51 and the sub-microcomputer 52 perform different processes as follows.

  First, the case where the sub microcomputer 52 determines that the main microcomputer 51 has an abnormality will be described. In this case, the sub-microcomputer 52 outputs a reset signal from its reset output terminal RST · OUT (specifically, for example, the reset input terminal RST · IN of the main microcomputer 51 is set to Lo for 10 ms), and the main microcomputer 52 The microcomputer 51 is reset (initialized).

  At that time, the sub-microcomputer 52 changes the fail-safe output terminal FS / OUT from the open state to the Lo state (fail-safe output) in parallel with the output of the reset signal as a safe operation accompanying the reset of the main microcomputer 51. . As a result, the transistors Q3 and Q2 are turned off, the power supply to the solenoid valve drive circuits 2a and 2b is shut off, and both the gas solenoid valves A for hot water supply and bath replenishment are closed. The fail-safe output is programmed so as to be released when communication from the main microcomputer 51 is normally received by the communication monitoring process.

  When the main microcomputer 51 is reset in this manner, the main microcomputer 51 returns to a normal state and resumes communication with the sub-microcomputer 52 unless the main microcomputer 51 has a particular failure.

  Next, a case where it is determined that the sub-microcomputer 52 has an abnormality by the communication monitoring process on the main microcomputer 51 side will be described. In this case, the main microcomputer 51 stops the operation of the gas water heater by the process of the main microcomputer 51 itself without resetting the sub-microcomputer 52. That is, in this case, since the main microcomputer 51 determines that the sub-microcomputer 52 has an abnormality, the burner combustion is stopped by the control of the main microcomputer 51 itself without using the above-described fail-safe output of the sub-microcomputer 52. Let

  Specifically, the main microcomputer 51 stops the output of the relay standby signal from the relay standby terminals RL and STB described above and turns off the transistors Q3 and Q2, or relay drive from the relay drive terminals RL and DRV. The output of the signal is stopped, the transistor Q1 is turned off, the operation of the solenoid valve drive circuit 2 is stopped, and the gas solenoid valve A is closed (safe operation by the main microcomputer 51).

  In parallel with such combustion stop processing, the main microcomputer 51 notifies the abnormality of the sub-microcomputer 52 through a predetermined notification means (not shown) provided in the remote controller or the water heater body. For example, the abnormality of the sub-microcomputer 52 is notified by an error display by the display device, a warning sound output by the notification sound output device, or the like.

  The safe operation canceling method by the main microcomputer 51 can be appropriately set by a program of the main microcomputer 51. For example, when a remote controller is provided, the remote controller can be canceled by a predetermined operation of the remote controller (for example, a reactivation operation of the operation switch). Alternatively, the safety operation can be canceled by a closing operation of a tip such as a curan (an operation for reducing the water flow rate to the heat exchanger to be equal to or lower than the minimum working water flow rate).

  On the other hand, with respect to resetting (initialization) of the sub-microcomputer 52, the main microcomputer 51 executes reset processing of the sub-microcomputer 52, triggered by the fact that predetermined conditions are satisfied.

  For example, in the present embodiment, the main microcomputer is released when the above-described safe operation is canceled and every time a predetermined time Y has elapsed since the power was turned on (however, after the combustion is stopped when the burner is in combustion when the predetermined time Y elapses). 51 is set to perform reset processing of the sub-microcomputer 52. The predetermined time Y is measured by a time measuring means (not shown) set by a program using an internal clock of the main microcomputer 51. The internal clock is configured to operate based on a clock signal input from a clock oscillator connected to a clock terminal (not shown) (the same applies hereinafter).

  Thus, in the control apparatus 1 shown in this embodiment, when the main microcomputer 51 detects an abnormality of the sub-microcomputer 52, it is configured to execute a predetermined safe operation including the combustion stop process. Safety can be ensured.

  Further, since the sub-microcomputer 52 is reset periodically (when the safe operation is released or every predetermined time), the sub-microcomputer 52 can be always kept in a normal state, and the reliability of the mutual monitoring function can be improved. .

B. Fail-safe function :
Next, the fail safe function in the control device 1 of the present invention will be described. This fail-safe function is a function for preventing leakage and emptying of unburned gas, and is realized by the sub-microcomputer 52 described above.

  Specifically, this fail-safe function is performed when the sub-microcomputer 52 makes a predetermined logic determination based on the information acquired from the fuel leakage detection means 4 even when the control by the main microcomputer 51 does not function normally. It is a function for detecting the occurrence of combustion gas leakage and air scoring and executing burner combustion stop processing.

  Specifically, the sub-microcomputer 52 makes the following determination for both the hot water supply side and the bath reheating side. That is, the valve monitoring signal from the electromagnetic valve monitoring circuit 41 indicates the valve open state (valve monitoring signal on), and the flame detection signal from the flame detection circuit 42 is not detected (flame detection signal off). If it continues for a certain time (at least longer than the time when the ignition operation (ignition sequence) by the igniter is completed, for example, 15 seconds), it is determined that the unburned gas has leaked. The valve monitoring signal indicates the valve open state (valve monitoring signal ON) and the flame is detected (flame detection signal ON) in a state where leakage of unburned gas is not detected. In addition, a state in which the water flow detection signal from the water flow detection circuit 43 detects only the water flow below the minimum operating water flow rate (water flow detection signal off) is for a certain period of time (for example, 15 seconds as in the case of the unburned gas leakage determination). If it continues, it is determined that it is empty.

  Here, when the state indicating the fuel leakage or the air-burning sign continues for a certain period of time, it is determined that the fuel leaks or air-fired. Because there is a fear. In addition, the reason why the predetermined time is set to 15 seconds in the present embodiment is that if this time is set too long, it is not preferable that fuel leakage or air blowing will last for a long time, and this time can be changed as appropriate. is there. In addition, the measurement of this fixed time is performed by the fail safe timer which is not shown in figure. The fail-safe timer is realized by providing a timer unit (fail-safe timer) that performs timing processing based on the internal clock by programming the sub-microcomputer 52.

  Then, when any one of the leakage of unburned gas and the emptying is detected by these determinations, the sub-microcomputer 52 changes the fail-safe output terminal FS / OUT from the open state to the Lo state (fail-safe output). Then, the power supply to the solenoid valve drive circuits 2a and 2b is shut off, and the gas solenoid valve A for both hot water supply and bath reheating is closed.

C. Combustion control function :
Next, burner combustion control by the control device 1 will be described. In the present invention, two microcomputers of a main microcomputer 51 and a sub-microcomputer 52 are used as the hot water controller control means 5, and the main microcomputer 51 controls the operation of each part of the water heater, and the sub-microcomputer 52 has the watch dog function described above. As described above, the main microcomputer 51 performs control of each part of the water heater to control the combustion stop associated with the normal hot water supply operation. 52 is also configured to share the processing.

  In this type of water heater, during normal hot water operation, the tip of the heat exchanger is closed during combustion of the burner, etc., so that the water flow rate of the heat exchanger falls below the minimum operating water flow rate, or the operation switch of the remote control is turned off. If a certain condition is satisfied, the burner combustion stop process is executed. However, since the condition for the normal combustion stop is well known, detailed description thereof will be omitted.

  Therefore, the sharing of combustion stop processing by the main microcomputer 51 and the sub-microcomputer 52, which is a feature of the present invention, will be described.

  In sharing the combustion stop process, the sub-microcomputer 52 is programmed to stop the combustion by the above-described fail-safe output when receiving the execution command of the combustion stop process given from the main microcomputer 51 by the data communication described above. That is, when the sub-microcomputer 52 receives the execution command from the main microcomputer 51, the sub-microcomputer 52 is configured to execute the combustion stop process by setting the fail-safe output terminal FS • OUT to Lo and operating the power shut-off circuit 3. The

  On the other hand, the main microcomputer 51 determines which of the main microcomputer 51 and the sub-microcomputer 52 performs the combustion stop process when it is necessary to stop the combustion in the burner, for example, when the tip plug is closed. A program that defines predetermined rules is installed. Based on the above rules, the main microcomputer 51 transmits an execution command for the combustion stop process to the sub microcomputer 52 when the sub microcomputer 52 performs the combustion stop process.

  In this embodiment, the program installed in the main microcomputer 51 is the next combustion stop process performed by the sub microcomputer 52 after the main microcomputer 51 executes the combustion stop process, and the next program after the sub microcomputer 52 executes the combustion stop process. As the main microcomputer 51 performs the combustion stop process, the main microcomputer 51 and the sub-microcomputer 52 are set to alternately perform the combustion stop process once.

  This is because the combustion stop process by fail-safe output is periodically performed during normal hot water supply operation, and the fail-safe function including the fuel control system circuit such as the power shut-off circuit 3 and the solenoid valve drive circuit 2 is performed. This is because it is effective for the main microcomputer 51 and the sub-microcomputer 52 to alternately execute the combustion stop process once every time. Therefore, if it is within such a purpose range, for example, the main microcomputer 51 performs the combustion stop process twice, and then the sub-microcomputer 52 performs the combustion stop process once. There may be. In short, as long as it is within a range where it can be confirmed whether or not the fail-safe function of the sub-microcomputer 52 functions normally, the specific method for sharing the combustion stop process can be changed as appropriate.

  With regard to the sharing of such combustion stop processing, the main microcomputer 51 side records in the memory a history regarding the combustion stop processing by the main microcomputer 51 itself and the transmission of execution instructions for the combustion stop processing to the sub-microcomputer 52 described later. The alternate combustion stop process described above is executed based on the recording.

  When the main microcomputer 51 performs combustion stop processing by determining the program, the combustion stop processing is performed by stopping the output of the relay drive signal and closing the gas solenoid valve A under its own control. The combustion stop process on the main remote controller 51 side can extinguish the hot water supply side and the bath retreat side individually by the relay drive signal output terminals RL / DRV1, RL / DRV2.

  In this way, when the combustion stop process is executed by either the main microcomputer 51 or the sub-microcomputer 52, the main microcomputer 51 normally performs the fire extinguishing operation based on the valve monitoring signal from the electromagnetic valve monitoring circuit 41. Whether or not (fire extinguishing judgment process) is not performed normally, the combustion is stopped by the following process.

  That is, when the combustion stop process performed on the main microcomputer 51 side does not function normally, an execution command for the combustion stop process is output to the sub-microcomputer 52 by communication, and the combustion stop process is performed on the sub-microcomputer 52 side. Let it run. On the other hand, when the combustion stop process performed on the sub-microcomputer 52 side does not function normally, the output of the relay drive signal is stopped and the combustion stop process is executed on the main microcomputer 51 side.

  By the way, in the configuration in which the combustion stop process is shared between the main microcomputer 51 and the sub-microcomputer 52 in this way, for example, both the hot water supply side and the bath reheating side combustion parts are in a combustion state (both electromagnetic valve drive circuits 2a and 2b are in the same state). (When the relay drive signal is being output) When the end plug is closed or the bath is stopped, for example, combustion in one of the combustion sections becomes unnecessary (that is, If the combustion stop process at this time is performed on the sub-microcomputer 52 side in the case of shifting from simultaneous combustion to single combustion), the power supply to both the solenoid valve drive circuits 2a and 2b is cut off, and the combustion The fuel supply to the other combustion section that needs to be continued is also stopped.

  Therefore, in the control device 1 shown in the present embodiment, the combustion stop process at the time of shifting from the simultaneous combustion to the single combustion is set to be performed on the main microcomputer 51 side. That is, the main microcomputer 51 is configured to perform the combustion stop process on the main microcomputer 51 side without applying the predetermined rule by the program when shifting from simultaneous combustion to single combustion.

  Specifically, at the time of transition from simultaneous combustion to single combustion, the main microcomputer 51 side first determines whether combustion stop processing is necessary in the combustion section on either the hot water supply or bath reheating side. In this determination, for example, on the hot water supply side, it is determined that the combustion stop is necessary when the water flow detection signal from the water amount detection circuit 43a is turned off. On the other hand, for example, when the detected value of the bath temperature sensor provided in the bath circulation pipe reaches a predetermined target temperature, the bath retreating side determines that it is necessary to stop combustion on the bath retreating side.

  When the main microcomputer 51 determines that the combustion stop process for the hot water supply side combustion section is necessary, the main microcomputer 51 uses the relay drive signal output terminal RL / DRV1 to shut off the fuel supply by the gas solenoid valve A on the hot water supply side. The relay drive signal is stopped, the energization of the solenoid valve drive circuit 2a to the relay RL1 is cut off, and the hot water supply side gas solenoid valve A is closed. Further, when it is determined that a combustion stop process is required for the combustion part on the bath reheating side, in order to cut off the fuel supply by the gas solenoid valve A on the bath retreating side, the relay drive signal output terminal RL / DRV2 The output of the relay drive signal is stopped, the energization to the relay RL1 of the solenoid valve drive circuit 2b is cut off, and the gas solenoid valve A on the bath retreating side is closed.

  If the combustion stop process is required for the combustion section that has continued to burn by the closing operation of the tip plug (or the operation of stopping the bath retreat) during the subsequent single combustion, Combustion stop processing is executed by the sub-microcomputer 52 in accordance with the original order defined in the rules.

  As described above, in the control device 1 shown in the present embodiment, two or more combustion portions are burning, and when the combustion of one of the combustion portions is stopped, regardless of the order according to the predetermined rule described above. Since the main microcomputer 51 is configured to execute the combustion stop process, in a so-called multi-function model, the combustion does not occur such that the combustion in all the combustion portions stops when shifting from the simultaneous combustion to the single combustion. Stop processing can be performed smoothly.

  Note that the above-described embodiments merely show preferred embodiments of the present invention, and the present invention is not limited to these, and various design changes can be made within the scope thereof.

  For example, in the above-described embodiment, the case where the present invention is used in a gas water heater has been shown. However, the present invention is not limited to this and can be applied to a water heater using oil as fuel. Furthermore, any combustion apparatus provided with a combustion section can be applied to other than a water heater (for example, a heating single-function combustion apparatus).

  In the above-described embodiment, the electromagnetic valve drive circuit 2 is shown as the load drive means. However, the specific circuit configuration of the load drive means can be appropriately changed in design according to the mode of the load for supplying fuel to the combustion unit. It is. Further, the design of the specific circuit of the power shut-off circuit 3 can be changed as appropriate.

  Further, in the above-described embodiment, when the main microcomputer 51 detects an abnormality of the sub-microcomputer 52 by the watchdog function, the case where the reset process of the sub-microcomputer 52 is not immediately performed is shown. It is also possible to configure so that the reset process of the microcomputer 52 is executed immediately.

  Further, in the above-described embodiment, the case where the fire extinguishing determination process during the normal hot water supply operation is performed only on the main microcomputer side is shown, but the main microcomputer 51 and the sub microcomputer 52 are also configured to share this fire extinguishing determination process. You can also. That is, when the combustion stop process is executed on the main microcomputer side, the fire extinguishing judgment process is performed based on the detection signal from the fuel leakage detection means 4 (specifically, the valve monitoring signal from the valve monitoring circuit 41). The main microcomputer 51 can be configured to perform the fire extinguishing determination process when the combustion stop process is executed on the sub-microcomputer side. As a result of such a fire extinguishing determination, if it is determined that the combustion stop process by the other party is not normally performed, the microcomputer on the side that performed the fire extinguishing determination is set to perform the combustion stop process. Even in this case, the combustion stop process in the normal hot water supply operation can be surely executed.

  Furthermore, in the above-described embodiment, regarding the fire extinguishing determination process performed on the main microcomputer 51 side, when it is determined that the combustion stop process on the main microcomputer 51 side is not functioning normally, the combustion stop process is performed on the sub-microcomputer 52. In this case, the output of the relay standby signal from the main microcomputer 51 is stopped and the power supply to the solenoid valve drive circuit 2 is stopped through the power shut-off means 3. It is also possible.

  Furthermore, in the above-described embodiment, the case where data communication between the main microcomputer 51 and the sub-microcomputer 52 is performed using the two terminals of the communication terminals TXD and RXD, but data communication is performed using one communication terminal for both transmission and reception. It can also be configured to do so.

  Moreover, although the case where the capacity switching valve is closed during the fail-safe function operation has been described in the above-described embodiment, the original gas solenoid valve can be configured to be closed. In other words, in a normal water heater, an original gas solenoid valve that controls the supply / cutoff of gas from the gas pipe is provided upstream of the capacity switching valve. Therefore, by closing this solenoid valve, the burner unit is connected to the burner unit. The gas supply can also be cut off.

The circuit block diagram when applying this invention to the control apparatus of a hot-water supply apparatus is shown. The circuit diagram of the control apparatus of the hot-water supply apparatus is shown. It is a circuit block diagram of the conventional combustion apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Solenoid valve drive circuit (load drive means)
3 Power-off circuit (power-off means)
4 Fuel leakage detection circuit (Fuel leakage detection means)
41 Solenoid valve monitoring circuit (load monitoring means)
42 Flame detection circuit 43 Water quantity detection circuit 5 Control means 51 Main microcomputer 52 Sub microcomputer 6 OR circuit A Gas solenoid valve B Frame rod C Water quantity sensor, water flow switch

Claims (6)

A control device for a combustion apparatus having a plurality of combustion sections and having a load for supplying fuel to each combustion section,
A power shut-off means configured to be able to shut off the power supplied to the load drive means, and a control means having at least two or more microcomputers that have communication means and mutually monitor operations by communication. Become
One of the microcomputers is at least a main microcomputer for controlling the operation of each part of the combustion apparatus including the load driving means, and the other is at least a sub-microcomputer for controlling the power shut-off means, and the combustion stopping process of the combustion part is performed. In performing the control, the main microcomputer and the sub-microcomputer are configured to alternately perform the combustion stop process based on a predetermined rule.
Two or more combustion parts are combusting, and when the combustion of one of the combustion parts is stopped, the main microcomputer is configured to execute the combustion stop process regardless of the predetermined rule. A control device for a combustion apparatus. The combustion apparatus control device according to claim 1, wherein the combustion stop process by the main microcomputer is performed through a load driving means. Comprising fuel leakage detection means for detecting abnormal leakage of fuel from the combustion section,
The fire extinguishing judgment process for confirming whether or not the fire extinguishing operation is normally performed based on information from the fuel leakage detection means is executed by the main microcomputer after the combustion stop process based on the predetermined rule. Item 3. The control apparatus for a combustion apparatus according to Item 1 or 2. Comprising fuel leakage detection means for detecting abnormal leakage of fuel from the combustion section,
After the combustion stop process based on the predetermined rule, a microcomputer that has not performed the combustion stop process performs a fire extinguishing determination process for confirming whether or not the fire extinguishing operation has been normally performed based on information from the fuel leakage detection means. The control device for a combustion apparatus according to claim 1, wherein the control device is executed. The combustion stop process is executed by the microcomputer on the side that performed the fire extinguishing determination process when it is determined that the fire extinguishing operation is not normally performed as a result of the fire extinguishing determination process. The control apparatus of the combustion apparatus as described. 4. The control device for a combustion apparatus according to claim 3, wherein when the fire extinguishing determination process determines that the combustion stop process by the main microcomputer is not normally performed, the sub-microcomputer is instructed to execute the combustion stop process. A control apparatus for a combustion apparatus, characterized by comprising a configuration.

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