JPH0350931B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a combustion control device that is equipped with a seismic sensor and a microcomputer and can be applied to, for example, an oil-burning appliance.

<Prior Art> This type of conventional combustion control device generally has a configuration as shown in FIG. That is, when the operation switch 1 is turned on, the resistor R is connected to the DC power supply 2 of 12V DC, which is obtained by stepping down and rectifying a commercial AC power supply, for example.
1 and the operation switch 1, a high level signal is applied to the set terminal S of the operation switch circuit 3 consisting of a flip-flop, and the operation switch circuit 3
The output high level signal is inverted by the inverter 4 and applied to the base of the PNP transistor Q through the resistor R2, so that the transistor Q is turned on. As a result, the DC voltage of the DC power supply 2 is supplied to the control power supply detection circuit 5 through the transistor Q in the on state, and upon detection of this control power supply, the detection circuit 5 supplies a power supply voltage of, for example, 5V DC to the microcomputer 6. A computer 6 operates to control combustion by a burner (not shown). Next, turn the operation switch 1 to 2.
When it is turned on for the second time, a high level signal is input to the S terminal, which in turn outputs a low level signal from the circuit 3, which is inverted by the inverter 4, which turns off the PNP transistor Q and sends the signal to the microcomputer 6. Power supply is stopped. In other words, the operation is stopped. On the other hand, as for the power supply voltage detection circuit 7, the power supply voltage of the DC power supply 2 is stabilized by a Zener diode ZD, and power is supplied through a capacitor C. When this power supply voltage is normal, a low level signal is applied from the power supply voltage detection circuit 7 to the R terminal of the operation switch circuit 3, and does not affect the operation switch circuit 3. On the other hand, when the power supply voltage falls below a certain voltage, the circuit 7 issues a high level signal to the R terminal, and as a result, the signal is passed through the operation switch circuit 3 and the inverter 4 to the transistor Q.
Turn off. In other words, the operation is stopped.

When the microcomputer 6 detects the operation of the seismic sensor 8 or the combustion abnormality of the burner, it issues a safe operation command such as stopping the supply of fuel.

<Problems to be Solved by the Invention> By the way, when a momentary power outage occurs during safe operation by the microcomputer 6, the control power supply circuit 5 provides an instantaneous It plays the role of continuing to supply power to the microcomputer even during a power outage, and
Its role is to supply power to the microcomputer 6 with a normal voltage within a certain range. On the other hand, the operation switch circuit 3 also has a control power source using a Zener diode ZD, and the voltage can be maintained by a capacitor C to prevent the circuit 3 from turning off at every instantaneous power outage. In these cases, the control voltage of the microcomputer 6 is detected by the control power supply detection circuit 5, and the control voltage of the microcomputer 6 is detected by the control power supply detection circuit 5.
The power supply voltage of the microcomputer 6 is detected by the power supply voltage detection circuit 7, and the power supply voltage detection circuit 7 issues a low level signal to the operation switch circuit 3 before the voltage applied to the microcomputer 6 falls below a certain level and malfunctions. I'm trying to turn it off.

However, in this way, two power supply detection circuits 5 and 7
In practice, a configuration in which the timing of shutting down is adjusted by setting a detection level characteristic and adjusting the operation stop timing has the disadvantage that the configuration is complicated, adjustment is not easy, the cost is high, and the reliability is not very good. It was hot.

<Object of the invention> The present invention eliminates the drawbacks of the above-mentioned prior art and makes it possible for the microcomputer to directly receive the on state of the operating switch by making the respective power supply circuits for the operating switch circuit and the microcomputer into the same system. The technical object is to provide a combustion control device that can cancel the operation switch circuit at the same timing by resetting the microcomputer.

<Means for Solving the Problems> In order to achieve the above object, the combustion control device of the present invention controls the combustion of the burner 12 and detects the operation of the seismic sensor 8 or detects the operation of the burner 12, as shown in FIG. The combustion control device is equipped with a microcomputer 6 that instructs safe operation of the burner 12 by detecting combustion abnormality in the burner, and has a reset signal line that outputs a reset signal to the microcomputer 6 when the voltage falls below a certain level. A detection circuit 9, an operation switch circuit formed by connecting an operation switch 1 and a switching element Q turned on by the operation switch 1 to a DC power supply 2, and a control voltage detection circuit 9 disposed between the operation switch circuit and the control voltage detection circuit 9. A time constant circuit consisting of a resistor R4 and a capacitor C1 and the operation signal of the operation switch 1 are input to the microcomputer 6, and the operation ON/OFF signal from the microcomputer 6 is output to the switching element Q of the operation switch circuit. It is characterized by having an input/output circuit 10.

<Function> With the above configuration, when the operation switch is turned on and the switching element is turned on, power is supplied to the voltage detection circuit via the operation switch circuit in the ON state and the time constant circuit, and when this voltage exceeds a predetermined value. When the voltage drops, power is supplied from the voltage detection circuit to the power supply circuit of the microcomputer, and the microcomputer operates to keep the switching element in the on state. That is, the microcomputer directly receives input from the operation switch and keeps the switching element on. In this way, both the operation switch circuit and the microcomputer power supply circuit are connected to the same system, so in the event of a momentary power outage, the input voltage of the voltage detection circuit is maintained above the control voltage by the time constant circuit, and the microcomputer The computer retains the state it was in before the power outage. On the other hand, if the power outage continues for more than the time determined by the time constant of the time constant circuit, the input voltage of the voltage detection circuit becomes lower than the control voltage, the microcomputer is reset, and the switching element is activated by the operation signal of the microcomputer. is turned off. That is, by resetting the microcomputer, the switching elements of the operation switch circuit are turned off at the same timing.

<Example> Hereinafter, a preferred example of the present invention will be described with reference to the drawings.

In FIG. 1 showing one embodiment, the same or equivalent parts as in FIG. 4 are given the same reference numerals. When the operating switch 1 is turned on, the switching element Q has its base connected to the negative terminal of the DC power supply 2 via resistors R3, R2 and a diode D1, and is turned on. and the switching element Q constitute an operation switch circuit. A time constant circuit is configured by the resistor R4 and the capacitor C1, and when the switching element Q is turned on, the capacitor C1 is turned on through the diode D2 and the resistor R4.
is charged. Further, the voltage detection circuit 9 detects an input voltage of, for example, 5V when the switching element Q is turned on.
It is converted into a control voltage and supplied to the input/output circuit 10 and the power supply terminal of the microcomputer 6, and when this control voltage V exceeds the set detection level Vs, a high signal is sent to the reset signal line 11 to the microcomputer 6. Outputs level signal.
The microcomputer 6 is activated by being supplied with a high-level signal through the reset signal line 11, receives the ON signal of the switching element Q via the resistor R5, the diode D2, and the input/output circuit 10, and by receiving this signal, the microcomputer 6 operates. , the switching element Q is held on via the input/output circuit 10, the diode D3, and the resistor R2, and the combustion of the burner 12 is controlled via the input/output circuit 10.

Next, the operation of the embodiment will be explained with reference to the flowcharts of FIGS. 2 and 3.

First, to explain normal operation with reference to FIG. 2, when operation switch 1 is turned on [flow A], the base of switching element Q is connected to resistor R.
2. The switching element Q is turned on by being connected to the negative side terminal of the DC power supply 2 via the diode D1 and the operation switch 1 [Flow B]. The capacitor C1 is charged through the on-state switching element Q, the diode D2, and the resistor R4, and power is supplied to the voltage detection circuit 9. The voltage detection circuit 9 converts it into a control voltage V, which is then applied to the microcomputer 6 and the input/output circuit 10. When the control voltage exceeds the set detection level Vs and the control voltage is detected [Flow C], the voltage detection circuit 9 converts the signal on the reset signal line 11 from low level to high level. As a result, the microcomputer 6 operates [Flow D] and outputs the ON signal of the operation switch 1.
Input/output circuit 10, diode D2 and resistor R5
[Flow E] By receiving the ON signal as described above, the microcomputer 6 controls the input/output circuit 10 and the diode D.
3. Output a driving signal through resistors R2 and R3 to keep switching element Q on [flow F],
Combustion control of the burner 12 is performed by the microcomputer 6 [Flow G].

When combustion control by the burner 12 is started, it is determined whether or not the seismic sensor 8 is activated [flow H].
If this operation is detected, the process proceeds to [Flow J] and a safety operation is performed. If the operation of the seismic sensor 8 is not detected, it is determined whether or not a combustion abnormality in the burner 12 has occurred [Flow I], and if it has occurred, a similar safety operation is performed. That is, if no abnormality occurs, flows A to I are repeated. On the other hand, when an abnormality occurs and a safety operation is performed, it is determined whether or not the operating switch 1 is turned on (Flow K), and the safe operation is maintained until the operating switch 1 is operated. When the operation switch 1 is turned on, the microcomputer 6 is reset [flow L] and the switching element Q is turned off [flow M].

Next, a case where a power outage occurs during safe operation will be described with reference to FIG. When an abnormality is detected, the microcomputer 6 maintains safe operation [flow O] as described above.
If a power outage occurs at this time [flow P], the DC power supply 2 will no longer be supplied. And capacitor C
1 is discharged, so if this power outage is momentary, the control voltage V will not fall below the set detection level Vs, and in flow Q
If it is determined as YES, the process returns to flow O and maintains safe operation. Here, if the power outage continues, the control voltage V drops below the set detection level Vs, a low level signal is output from the voltage detection circuit 9 to the reset signal line 11, and the microcomputer 6 is reset [Flow S]. , the operation signal from the microcomputer 6 is turned off [flow T], and the switching element Q is turned off [flow U].
Combustion of the burner 12 stops [flow V]. Therefore, when the power is restored after a relatively long power outage, the burner 12 will not recombust unless the operating switch 1 is turned on. Note that even if a power outage occurs during normal operation, the system operates based on the flowchart in FIG. 3.

<Effects of the Invention> The present invention consists of the above configuration and operation, and claims 1
According to the combustion control device described in , the microcomputer accepts operation switch input, and the microcomputer can also keep the switching element ON, so maintaining safe operation and turning off the operation is done only in relation to the microcomputer. It can be determined by In other words, the circuit configuration becomes simple and the control operation can be adjusted very easily. Reliability is also improved.

In addition, since both the power supply for the operation switch circuit and the microcomputer are connected to the same system, there is no need for two power supply voltage detection circuits as in the past, and the previous state is maintained both during safe operation and normal operation, and when the power outage is short. can be held for a long time, and the operation can be stopped.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.
FIGS. 2 and 3 are a flowchart of FIG. 1, and FIG. 4 is a block diagram of the conventional apparatus. 1: Operation switch, 2: Power supply, 6: Microcomputer, 8: Earthquake sensor, 9: Voltage detection circuit, 1
2: Burner, Q: Switching element, R4, C
1: Resistor and capacitor that make up the time constant circuit.

Claims (1)

[Claims] 1 Controls combustion of burner 12 and seismic sensor 8
The combustion control device is equipped with a microcomputer 6 that instructs safe operation of the burner 12 by detecting the operation of the burner 12 or by detecting abnormal combustion in the burner 12, and a reset signal line that outputs a reset signal to the microcomputer 6 when the voltage falls below a certain level. a microcomputer control voltage detection circuit 9 having a microcomputer control voltage detection circuit 9; A time constant circuit consisting of a resistor R4 and a capacitor C1 placed between the two inputs the operation signal of the operation switch 1 to the microcomputer 6, and inputs the operation ON/OFF signal from the microcomputer 6 to the operation switch circuit. A combustion control device comprising an input/output circuit 10 that outputs to a switching element Q.