JP3143257B2 - Combustion control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control device for a hot oil heater or the like.

[0002]

2. Description of the Related Art A conventional combustion control apparatus of this type is described as follows.
For example, as in Japanese Patent Application Laid-Open No. 61-72930, a backup power supply is connected to a microcomputer, and the function of the microcomputer itself is maintained even when a commercial power supply fails. The computer observes the voltage of the commercial power supply itself through the power failure detection circuit, and determines that the commercial power supply is in a power failure state when predetermined conditions relating to the power failure such as a voltage drop are met.

[0003] In a control device that generates a clock signal by shaping the waveform of a DC voltage obtained by rectifying a commercial power supply and operates by taking in the clock signal, if a failure occurs in the clock signal generation circuit, that is, the waveform shaping circuit, Since the power failure detection operation of the microcomputer itself becomes difficult, in the above-described conventional example, attention is paid to the fact that the waveform shaping circuit itself does not perform a predetermined normal operation when a power failure occurs or when a failure occurs in the waveform shaping circuit. However, when an abnormal operation of the waveform shaping circuit is observed, fail-safe control is started at a time to drive and control the combustion heater to the safe side. And the control operation in that case was called power failure processing.

[0004]

However, when the above-described conventional power failure processing is performed, it is not possible to specify whether a real power failure has occurred or a failure of the waveform shaping circuit has occurred, and the repair work has been performed. There is a problem that is not easy.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is intended that a DC voltage obtained by rectifying a commercial power supply and a commercial power supply voltage obtained by waveform shaping by a waveform shaping circuit are respectively provided. Input to the microcomputer, the microcomputer observes whether or not the predetermined output of the waveform shaping circuit is not input for a predetermined time or more, and if it is not input for a predetermined time or more, Value is "LOW" or "HIGH"
Observe The microcomputer says that "LO
If "W", it is determined that the commercial power supply voltage is not supplied, that is, a power failure has occurred. Conversely, if "HIGH", it is determined that a failure of the waveform shaping circuit has occurred instead of a power failure.

At this time, when the DC voltage is “LOW”,
The microcomputer turns off the fuel supply unit to put it into a fire extinguishing state, keeps that state, that is, the power failure processing state, and stores the fact that the power failure processing was performed in the storage unit. Then, control is performed so that restarting does not start after recovery from the power failure. On the other hand, when the DC voltage is "HIGH", the microcomputer turns off the fuel supply unit to put out the fire extinguishing state and drives the notification means to display that the waveform forming circuit has failed as in the above-described power failure processing. .

[0007]

The present invention is configured as described above. During the heating operation, the DC voltage obtained by rectifying the commercial power and the commercial power voltage obtained by waveform shaping by the waveform shaping circuit are respectively provided. It is input to the microcomputer, and the microcomputer observes whether or not a predetermined output of the waveform shaping circuit is not input for a predetermined time or more. Value is "LOW" or "HIGH"
Observe The microcomputer says that "LO
If "W", it is determined that the commercial power supply voltage is not supplied, that is, a power failure has occurred. Conversely, if "HIGH", it is determined that a failure has occurred in the waveform shaping circuit instead of a power failure.

At this time, when the DC voltage is “LOW”,
The microcomputer turns off the fuel supply unit to put the combustion device in a fire extinguishing state, continues the state, that is, the power failure processing state, and stores the fact that the power failure processing has been performed in the storage unit. Then, control is performed so that restarting does not start after recovery from the power failure. On the other hand, when the DC voltage is "HIGH", the microcomputer turns off the fuel supply unit to put it into a fire extinguishing state as in the case of the above-described power failure processing, and drives the alarm unit to display that the wave forming circuit has failed. .

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a circuit according to one embodiment of the present invention. In FIG. 1, 1 is a commercial power supply, 2 is a power transformer that insulates the commercial power and steps down, 3 is a rectifying bridge diode, and 4 is a smoothing capacitor. The power supply smoothed by the bridge diode 3 and the smoothing capacitor 4 is connected to a DC stabilized power supply circuit 5. Further, the DC voltage generated by the DC stabilized power supply circuit 5 is supplied to the microcomputer 7 via the diode 6 as a driving power supply, and is connected to the input port of the microcomputer 7 via the diode 8 as a voltage signal of the commercial power supply. are doing. Although not shown in detail, the DC power supply via the diode 8 is also supplied to a detection circuit 9 connected to sensors for detecting the presence of a flame, room air temperature, combustor temperature, and the like. The backup power supply 10 is connected to the drive power supply circuit of the microcomputer 7 which is supplied via the above-described diode 6, and serves as a backup power supply for the microcomputer 11 in the event of a power failure.
The diode 6 is a diode for preventing back-up of the backup power supply at the time of power failure. Reference numeral 11 denotes a waveform shaping circuit for shaping the waveform of the commercial power supply voltage, and its output is input to the microcomputer 7. 12-a is a relay driven by the microcomputer 7, 12-b is a contact that is opened and closed by the relay 12-a, 13
Is a fuel supply unit controlled by opening and closing the relay contact 12-b. Reference numeral 14 denotes a display device that displays a clock and the like in addition to the fact that the waveform shaping circuit 11 has failed.

Next, the operation of this configuration will be described with reference to the flowchart of FIG.

When no power failure has occurred in the commercial power supply and the microcomputer 7 of the combustion control device is normally energized, energization processing is performed. Is driving,
The microcomputer 7 outputs an ON signal to the relay 12-a, turns on the relay 12-b, turns on the fuel supply unit 13, and causes the burner to supply fuel to perform a combustion operation. If the relay 12 is stopped,
b is turned off so that fuel is not supplied to the burner. At this time, the microcomputer 7 is connected to the commercial power supply 1
The output from the waveform shaping circuit 8 for shaping the voltage waveform is always observed (monitored), and if a predetermined normal output signal is input, that is, the predetermined output signal is not input for a predetermined time or more. Unless otherwise, the energization process is continued, and when it is observed that the input of the predetermined output signal is not performed for a predetermined time or more, it is determined whether the power supply failure or the failure of the waveform shaping circuit has occurred. In order to observe the situation of the output voltage of the DC stabilized power supply circuit 5 as a voltage signal of the power supply via the diode 8, ie, the commercial power supply, if the input state is “LOW”, it means that there is no power supply voltage. It is determined that there is a power outage, and the relay 12
-A is driven to open the contact 12-b, and the fact that the power failure process has been executed is stored in the storage unit, and control is performed so that restarting does not start after power failure recovery.

On the other hand, if the input state is "HIGH", which means that the power supply voltage is present, it is determined that the waveform shaping circuit has failed. In this case, too, the microcomputer 7 drives the relay 12-a to drive the relay 12-a. The contact 12-b is controlled to open, that is, the fuel supply unit is extinguished. At the same time, the display 14 is driven to notify that fact.

[0013]

As described above, according to the present invention, it is possible to determine whether the operation has been stopped due to a power failure or a failure in the waveform shaping circuit, so that there is an effect that the repair is facilitated.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control circuit according to one embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Power transformer 3 Bridge diode 4 Smoothing capacitor 5 DC stabilized power supply circuit 6 Diode 7 Microcomputer 8 Diode 10 Backup power supply 11 Waveform shaping circuit 12-a Relay 12-b Relay contact 13 Fuel supply unit

Claims (1)

(57) [Claims] A fuel supply unit for supplying fuel to the burner;
A microcomputer for controlling the fuel supply unit, a DC stabilized power supply circuit for rectifying a commercial power supply to supply power to the microcomputer, a backup power supply for supplying power to the microcomputer when the commercial power supply fails, And a waveform shaping circuit for shaping the waveform of the commercial power supply voltage, wherein the stabilized DC power supply circuit (5) is connected to the microcomputer (7) via a diode (6) as a driving power supply for the microcomputer (7). ) Is divided into a system connected to an input port of the microcomputer (7) via a diode (8) as a voltage signal of the commercial power supply, and a voltage signal from the waveform shaping circuit (11). The output is also connected to the input port of the microcomputer (7), In 7), when a predetermined signal of the waveform shaping circuit (11) is not input for a predetermined time or more, a voltage signal of the DC stabilized power supply circuit (5) input through the diode (8) is observed. When the voltage is "LOW", it is determined that the commercial power supply has failed, so that the fuel supply unit (13) is extinguished and stored as a power failure process. When it is determined that the circuit (11) has failed, the fuel supply unit (13) is controlled to extinguish the fire and the notification unit (1
4) A combustion control device for driving the waveform shaping circuit to notify the failure of the waveform shaping circuit.