JPS62297625A - Control device for burning appliance - Google Patents

Abstract

PURPOSE:To allow an automatic restarting and continued stable operation as long as the noise does not persist in case of a 'running away' of a microcomputer by shutting off the fuel supply and restarting the operation from the beginning. CONSTITUTION:When a microcomputer 12 shows erratic operations while a heating appliance is burning due to external noises etc., the output signal of a first output port P1 stops its cyclic reversals to cause a switching circuit to go off. Therefore, a fuel pump 4 connected to its contact 11 stops its action to shut off the fuel. However, when the switching circuit 4 goes off, pulses having a certain length is fed to a reversal input terminal (-) of a comparator IC35. As the pulses have a potential at the L level, they assume a potential at the H level for a duration which corresponds to the width of the pulses, and the microcomputer 12 is reset thereupon. When the pulses are over, the output terminal of IC35 again assumes the potential at the L level, and the microcomputer 12 runs the predetermined program to restore a normal burning.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a control device for a combustion appliance that controls the operation of the combustion appliance.

2. Description of the Related Art A conventional control device for a combustion appliance was constructed as shown in FIG. That is, in this FIG. 3, the fan motor 2, the ignition device 3, and the fuel pump 4 are connected to the circuit of the AC power source 8. 12 is supplied with power from a constant voltage power supply consisting of a resistor 47, a Zener diode 48, and a capacitor 41, and is the first to fourth output port (P1 to P4).
and a reset terminal (R8T).

According to the signal output to the output capacitors P2 to P4 according to the sequence created by the program stored in the microcomputer 12, the signal is amplified by the transistor 13 connected to the output capacitor P4, and the power relay 16 is excited. When the contact 9 closes, the fan motor 2 operates.

Next, the signal is amplified by the transistor 14 connected to the output capacitor P3, the power relay 17 is energized, and the contact 10 thereof is closed, thereby operating the ignition device 3. Next, the signal is amplified by the transistor 15 connected to the output port (P2), and the inverted signal repeatedly output from the first output port (P1) causes the first output port P
1 connected to resistor 25, 30.31, capacitor 26
．． 29, diodes 27, 28,) A switching circuit composed of a combination of a differential circuit and an integrating circuit using a transistor 32 is turned on, and the relay is driven, which is connected to the switching circuit and composed of a resistor 23, 24 and a transistor 22. When the safety circuit is turned ON, the power relay 18 is excited, and when its contacts 11 are closed, the fuel pump 4 is operated and combustion in the combustion appliance is started. 19.20° 21 is a diode, and 33 is a DC power supply.

Next, when the microcomputer 12 is affected by external noise etc. while the combustion appliance is burning, and starts to operate randomly without executing a certain processing routine according to the program, the first
Since the output signal of the output port Pl of the microcomputer 12 stops regular inversion, the switching circuit turns OFF, and as a result, the relay drive safety circuit connected to the switching circuit turns OFF. ) The signal output to P2 causes the signal to be amplified by the transistor 15 connected to the second output port P2.
Since the power relay 18 is not energized and therefore the operation of the fuel pump 4 connected to its contacts 11 is stopped, the combustion of the combustion appliance is stopped, and even if said external noise disappears, the DC power source 33 It is impossible to start combustion again without stopping and re-injecting the fuel. When the DC power supply 33 is turned on again, the voltage of the constant voltage power supply consisting of the resistor 47, the Zener diode 48, and the capacitor 41 is first supplied to the power supply terminal VDD -vss of the microcomputer 12. At this time, the voltage at the non-inverting input terminal (■) of the comparator IC35 is also applied at the same time, but the voltage at the inverting input terminal (○) is determined by the time constant provided by the resistor 37 and the capacitor 40.
After a slight delay, the voltage is stabilized at a voltage provided by the resistors 37 and 38 and higher than the voltage at the non-inverting input terminal Φ. At this time, since the output terminal of the comparator IC35 is initially OFF, it is at the H level voltage given by the resistor 34. Therefore, the microcomputer 12 is in a reset state, but when the voltage at the inverting input terminal e rises and exceeds the voltage at the non-inverting input terminal ■, the output terminal turns ON and the reset terminal (R8T) of the microcomputer 12 goes low. Since the voltage reaches this level, execution of a predetermined program is started. In this case, the reset circuit consists of resistors 34, 37, and 38, and a comparator IC 35 designed to start program execution after the power supply voltage of the microcomputer 12 is sufficiently stabilized.
, capacitors 36 and 40, and a diode 39.

In general, combustion control devices that use a microcomputer are equipped with various double safety devices to prevent the microcomputer's program from running out of control. The fuel pump or The configuration is such that the fuel valve is driven, and once the microcontroller goes out of control and the output of a predetermined port is no longer regularly reversed, the switching circuit turns OFF and cuts off the fuel supply. A common method is to ensure the safety of combustion appliances.

Problems to be Solved by the Invention However, this method does not include the microcomputer in order to stop the combustion appliance and restart it even if the microcomputer is affected by accidental extremely short-period noise that is likely to occur in practical applications. It is necessary to turn on the power again, and as a result,
This significantly impairs the convenience of users.

An object of the present invention is to provide a control device for a combustion appliance that solves these problems.

Means for Solving the Problems In order to solve the above problems, a control device for a combustion appliance according to the present invention includes a microcomputer, a first output port for determining runaway of a program of the microcomputer, and a fuel supply means. and a second output port for controlling the operation of the microcomputer, and only when a logical product relationship is established between the signal from the first output port of the microcomputer and the signal from the second output port, the fuel supply means operates. A circuit is provided to apply a reset signal for a certain period of time to the reset terminal of the microcomputer when the signal from the first output port stops, and when the microcomputer goes out of control, the fuel supply is stopped and the fuel supply is automatically stopped. A reset signal is given to the microcontroller to restart operation from the initial state, and even in the event of an accidental noise, if the noise does not continue, it will automatically restore again, ensuring stable operation. It has been made possible.

Effect With the above configuration, if the microcomputer that is executing a predetermined processing routine goes out of control due to the influence of external noise, the inverted signal output from the first output port of the microcomputer is inverted. In order to stop the operation, the switching circuit is turned off, and immediately after that, a pulse of a predetermined length is applied from the pulse generation circuit to the reset circuit, and a reset signal is input to the reset terminal of the microcomputer. This signal resets the microcomputer and restarts operation from the initial state.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. Note that in FIGS. 1 and 2, the same parts as those in FIG. 3 shown in the conventional example are given the same numbers.

First, Fig. 2 shows an example of a combustion appliance equipped with a combustion appliance control device according to an embodiment of the present invention, where 1 is a can body, 2 is a fan motor, 3 is an ignition device, and 4 is a fuel pump. , 5 is a combustion control device, and 6 is a nozzle. According to the sequence set by the combustion control device 5, the fan motor 2 inputs outside air and blows it to the burner, and the fuel pump 4 pumps fuel into the nozzle 6 while discharging the high voltage generated by the ignition device 3 at the electrode 7. It ejects and burns. The structure is such that the water inside the can body 1 is heated by the combustion heat.

FIG. 1 shows a circuit diagram of the control device for the combustion appliance shown in FIG. 2, in which a fan motor 2, an ignition device 3, and a fuel pump 4 are connected to an AC power source 8 circuit. 12 is supplied with power from a constant voltage power supply consisting of a resistor 47, a Zener diode 4B, and a capacitor 41, and is connected to the first to fourth output ports (PI to P4) and a reset terminal ()tsT.
).

According to the signal outputted to the output ports P2 to P4 according to the sequence created by the program stored in the microcomputer 12, the signal is amplified by the transistor 13 connected to the output port P4, and the power relay 16 is excited. When the contact 9 closes, the fan motor 2 operates. Next, the signal is amplified by the transistor 14 connected to the output port P3, the power relay 7 is energized, and the contact 10 thereof is closed, thereby operating the ignition device 3. Next, the signal is amplified by the transistor 15 connected to the output coupler P2, and the signal is amplified by the transistor 15 connected to the output coupler P2.
By the inverted signal repeatedly output from l, a differentiating circuit and an integrator consisting of resistors 25, 30, 31, capacitors 26, 29, diodes 27, 28, and transistor 32 connected to the first output port P1 are connected to the first output port P1. A switching circuit made up of a combination of circuits is turned on, and a relay drive safety circuit connected to the switching circuit and made up of resistors 23 and 24 and transistor 22 is turned on, and power relay 18 is turned on.
is energized and its contacts 11 are closed, thereby operating the fuel pump 4 and starting combustion in the combustion appliance. 33 is a first DC power supply for driving the relay.

Next, when the microcomputer 12 is affected by external noise etc. while the combustion appliance is burning, and starts to operate randomly without executing a certain processing routine according to the program, the first
Since the output signal of the output port P1 of the microcomputer 12 stops regular inversion, the switching circuit turns OFF, and as a result, the relay drive safety circuit connected to the switching circuit turns OFF. Even if the signal output to the transistor 15 connected to the second output port P2 amplifies the signal, the power relay 18 is not energized, and therefore the fuel pump 4 connected to the contact 11 Since the operation of the combustion equipment stops, the combustion of the combustion appliance stops. However, when the switching circuit is turned off, the collector potential of the transistor 32 starts to rise, and a differential circuit made up of the resistor 23, the resistor 24, and the capacitor 42 turns on the transistor 46 for a certain period of time. Resistance 44.
45, a transistor 46, and a diode 43, a pulse of a predetermined length is applied to an inverting input terminal e of a comparator IC35 constituting a reset circuit. Since the pulse has an L level potential, the output terminal of the comparator C36 has an H level potential for a time corresponding to the width of the pulse, and the microcomputer 12 is in a reset state during that time. When the pulse time has elapsed, the output terminal of the comparator IC35 returns to the L level potential again, and from that point on, the microcomputer 12 starts executing a predetermined program. In this case, if the external noise has disappeared at that point, normal combustion will return to normal combustion after repeating the sequence 13 operation.

Note that the control device for combustion appliances according to the present invention has the same effect even if the driving object is one that controls fuel supply, which corresponds to the "fuel pump" mentioned in this embodiment. Needless to say, we can expect

As described in detail, according to the present invention, when the microcomputer goes out of control, the fuel supply is stopped and, at the same time, a reset signal is automatically given to the microcomputer to restart operation from the initial state. Therefore, it is possible to provide a control device for a combustion appliance that can automatically recover even in the event of an accidental noise and operate stably if the noise does not continue. On the other hand, if the noise continues or cannot be reset due to damage to the microcomputer itself, the switching circuit and relay drive safety circuit will independently stop the fuel pump operation, so safety is guaranteed. be.

14゛

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a control device for a combustion appliance showing an embodiment of the present invention, Fig. 2 is a sectional view of a combustion appliance equipped with the same control device, and Fig. 3 is a diagram of a conventional control device for a combustion appliance. It is a circuit diagram. 4... Fuel pump, 12... Microcomputer, Pl... First output port, P
2...Second output port, R8T...Reset terminal.

Claims (2)

[Claims] (1) A microcomputer, a first output port for determining runaway of a program of the microcomputer, and a second output port for controlling the operation of a fuel supply means, the first output port of the microcomputer; The fuel supply means operates only when a logical product relationship is established between the signal from the first output port and the signal from the second output port. A combustion appliance control device equipped with a circuit for applying a reset signal. (2) The first output port of the microcomputer outputs a predetermined initial setting value when starting to execute a certain processing routine according to a predetermined stored program, and Claim 1, wherein the initial setting value is inverted and returned to the original initial setting value after a predetermined period of time has elapsed, and the inverted value is output every time the process execution of the certain processing routine is repeated. A control device for a combustion appliance as described in Section 1. (2) A circuit that applies a reset signal for a certain period of time to a reset terminal is connected to the first output port, and
ON only while the output of the output port is repeatedly inverted.
A transistor switching circuit, a relay drive safety circuit driven by the switching circuit,
a reset circuit connected to a reset terminal of the microcomputer, and a reset circuit disposed between the switching circuit and the reset circuit, the switching circuit being OFF.
2. The control device for a combustion appliance according to claim 1, comprising a one-shot pulse circuit that is turned on for a certain period of time when the temperature is reached.