JPH0894074A - Combustion control device - Google Patents

Abstract

PURPOSE: To reduce the number of analogue input terminals to a microcomputer by a method wherein power sources for the electromagnetic pump of the combustion control device of a combustion device having a flame of petroleum and a flame rod are held in common. CONSTITUTION: By effecting the feed and cutoff of a common DC voltage V3 through opening and closing of an operation switch 5 at the same when an applying voltage on a frame rod sensor 23 and an electromagnetic pump 109 is fed from the common DC voltage V3, a microcomputer 12 inputs only the output of a source monitor part 7 to monitor the DC voltage V3. By using the input information for a multipurpose such as on/off information of operation, correction of a flame rod ammeter, and detection of abnormality of the applying voltage of the electromagnetic pump 109, the number of input terminals is reduced.

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 combustion equipment such as petroleum.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 2, a combustion device of this type includes a burner 103, a fan 104 for warm air, and a motor 10 thereof inside a space surrounded by an exterior 101 and a stand 102.
5. The controller 106 is provided to control the overall operation of the louver 1 by mixing the indoor air A with the combustion gas B by the motor 105 to generate warm air C having an appropriate temperature.
It is configured to be discharged from 07 and used for heating the room.

The burner 103 is, as shown in FIG. 3, a vaporization cylinder 108 for vaporizing kerosene for combustion, an electromagnetic pump 109 for supplying a fixed amount of kerosene, and a burner motor 11 for delivering combustion air.
0, an ignition electrode 111 for igniting vaporized kerosene, a combustion detection sensor for monitoring the state of the combustion flame D represented by the frame rod 112, and the like. The electromagnetic pump 1
At 09, the kerosene is sent to the vaporizing cylinder 108, and the vaporized kerosene is ignited by the ignition electrode 111 and burned. The state of combustion is monitored by the frame rod 112, and abnormal combustion such as ignition, misfire and oxygen deficiency is also monitored.

However, in such a combustion device, when the power supply voltage applied to the electromagnetic pump 109 becomes abnormally high, the amount of kerosene supplied to the vaporization cylinder 108 becomes excessive, causing abnormal combustion, and a flame monitoring frame. Since the rod also has a problem that the detection accuracy cannot be relied upon when the power supply voltage fluctuates, the power supply voltage of the electromagnetic pump 109 is monitored, and the fluctuation of the power supply voltage of the combustion detection sensor is detected to detect the detection result of the combustion detection sensor. Is being corrected to improve the accuracy of safety.

Further, it has become commonplace for the control itself of the combustion equipment as described above to be composed mainly of a control device mainly composed of a microcomputer, and in order to improve the safety accuracy as described above. Due to demands, a microcomputer having a large number of input / output terminals has been required.

FIG. 4 illustrates a conventional embodiment of a control device provided in the above combustion equipment. Reference numeral 113 is a commercial power source, and 11 is a commercial power source.
4 is at least an analog / digital converter (hereinafter A /
115 and 116 are built in, and this A / D
Analog input terminal 11 connected to each of the converters
7, 118 and a microcomputer having digital input terminals (hereinafter referred to as input terminals) 119 and 120 and digital output terminals (hereinafter referred to as output terminals) 121 and 122, and 123 includes an on / off switch 124 and a resistor 125. With the operation switch, the microcomputer 1
It is connected to 14 input terminals 119.

Reference numeral 126 is a frame rod sensor which constitutes an electrode by the frame rod 112 and the burner 103 and detects the flame current If flowing between the electrodes. 12
Reference numeral 7 is a power supply circuit for supplying power to the frame rod sensor 126, and a DC voltage V1 is obtained by the secondary side 128-1 of the transformer 128, the rectifying diode bridge 129, and the smoothing capacitor 130 and applied to the frame rod sensor 126. .

Reference numeral 132 denotes a flame rod current measuring section for converting the flame current If into a voltage by means of a resistor 133 inserted in series with the flame rod sensor 126, which is connected to an analog input terminal 117 of the microcomputer 114. 1
Reference numeral 34 is a frame rod power supply voltage monitor unit for monitoring the output of the power supply circuit 127, which is composed of resistors 135 and 136 for dividing the DC voltage V1 and is connected to the analog terminal 118 of the microcomputer 114. Thirteen
Reference numerals 7 and 138 denote operational amplifiers that perform impedance conversion of respective input signals.

Reference numeral 139 denotes a power supply circuit for supplying power to the electromagnetic pump 109, which is a secondary side 128- of the transformer 128.
2. The rectifier diode 140 and the smoothing capacitor 141 are used to output an unstable DC voltage V2, and the constant voltage power supply circuit 142 obtains a stable DC voltage V2, which is applied to the electromagnetic pump 109.

Reference numeral 143 is an electromagnetic pump applied voltage monitor unit for monitoring the DC voltage V2, which is a resistor 144, a Zener diode 145, and an LED 146D of a photo coupler 146.
Are connected in series, and the phototransistor 146T of the photocoupler 146 is a microcomputer 1
It is connected to 14 input terminals 120. Here, the output voltage V2 is the Zener voltage Vz of the Zener diode 145.
When it becomes higher, the LED 146D emits light due to the current flowing through the Zener diode 145, and the phototransistor 14
6T turns on.

A resistor 147 and an LED 148D of a photocoupler 148 are connected in series to the output terminal 121, and a phototransistor 148T of the photocoupler 148 is connected to a base terminal of a transistor 149 which drives the electromagnetic pump 109. 150 and 151 are base resistances of the transistor 149. The output terminal 122 is connected to the base terminal of the transistor 152. 153
Is a safety relay having a normally open contact 153A, which is driven by the transistor 152. The contact 153
A is arranged in series between the power supply circuit 139 and the constant voltage circuit 142, and when the operation is stopped, the contact 153A is opened to cut off the power supply to the constant voltage circuit 142, so that the electromagnetic pump 109 can be securely operated. It is about to stop.

On the other hand, when the operation of the program of the microcomputer 114 is represented by a functional block, the frame rod current measuring section 1 input to the analog input terminal 117 is shown.
An A / D conversion unit 115 that converts the output voltage of 32 into a digital amount If ′, an A / D conversion unit 116 that converts the voltage of the analog input terminal 118 into a digital amount V1 ′, and this I
A frame rod signal calculation unit 154 that calculates If ′ / V1 ′ using f ′ and V1 ′, and an operation control unit 155 that receives a signal from the input terminal 119 to determine whether the operation is on / off.
And a pump signal output unit 156 that outputs a pulse signal to the output terminal 121, and a pump voltage abnormality that outputs a result to the pump signal output unit 156 by receiving a signal from the input terminal 120 and determining an abnormality in the electromagnetic pump applied voltage. Judgment unit 157
And a combustion control unit 158 that receives information from the operation control unit 155 and the flame rod signal calculation unit 154 to perform combustion timing and sequential control, and outputs a signal to the pump signal output unit 156 and the output terminal 122. ing.

With the above configuration, the operation switch 123 incorporated in the microcomputer 114 from the input terminal 119.
Information of the combustion control unit 1 is determined by the operation control unit 155.
58. The combustion control unit 158 receives this,
When the operation is on, the safety relay 153 is turned on, and when the operation is off, a signal for turning off the safety relay 153 is output terminal 12
At the same time that the electromagnetic pump 109 outputs a pulse signal from the output terminal 121 after performing predetermined processing such as preheating of the vaporization cylinder 108 and pre-purge operation when the operation is on.
To drive.

Here, the signal at the input terminal 120 is "L",
That is, when the applied voltage V2 to the electromagnetic pump 109 is higher than the Zener voltage Vz, the pump voltage abnormality determination unit 157 determines that the output is abnormal and the output of the pulse signal is stopped.
On the contrary, when the signal at the input terminal 120 is "H", the pulse signal is continuously output.

On the other hand, the flame current If indicating the state of combustion is converted into a voltage by the flame rod current measuring unit 132,
In order to cancel the fluctuations and variations of the power supply voltage V1, the voltage input to the analog input terminal 118 is used to perform calculation processing in the flame rod signal calculation unit 154, and then the combustion state of ignition, misfire, oxygen deficiency, etc. Used for detection.

[0016]

For the microcomputer, the input / output terminals are eyes and limbs for receiving information from an external sensor, driving a display and driving a motor. The number cannot be increased indefinitely due to the difficulty, and the increase in the number of input / output terminals also becomes an important factor in cost increase.

However, in the conventional configuration as described above, each of the input terminal for receiving information from the electromagnetic pump applied voltage monitor section, the input terminal for the frame rod applied voltage monitor, and the input terminal of the operation switch is the input of the microcomputer. It is difficult to say that the terminals are individually occupied and efficient.

Further, the above-mentioned combustor control device is required to have a safety that it must never burn when the operation switch is off. Therefore, the electromagnetic pump is interlocked with the operation switch. A safety relay is provided as a means for shutting off the power supply of, and the output terminal of the microcomputer is exclusively assigned to drive the safety relay.

The present invention is intended to solve the above-mentioned problems.
The purpose of is to save the number of input terminals that need to be assigned to the terminals of the microcomputer.

The second purpose is to eliminate safety relays while ensuring safety.

[0021]

In order to achieve the above first object, the present invention provides a flame rod sensor which is inserted into a combustion flame and detects the combustion state of the flame by a flame ion current, and a flame rod sensor of the flame rod sensor. A flame rod signal calculation unit that measures the flame current flowing between the electrodes and proportionally calculates the flame current according to the DC voltage applied to the flame rod sensor, and an electromagnetic pump that supplies fuel to the combustion unit.
A pump drive circuit that drives this electromagnetic pump, a pump signal control unit that controls a pump drive signal according to a DC voltage applied to the electromagnetic pump, and a DC voltage that is common to at least the frame rod sensor and the electromagnetic pump. It is provided with a power supply circuit for applying a voltage and a voltage monitor section for outputting an output proportional to the DC voltage.

In order to achieve the second object, a switch having an operation function and turning on / off of the operation according to the input voltage are used.
An operation control unit for turning off, an electromagnetic pump for supplying fuel to the combustion unit, a pump drive circuit for driving the electromagnetic pump, and a pump signal control unit for controlling a pump drive signal according to a DC voltage applied to the electromagnetic pump. And a power supply circuit for applying a DC voltage to the electromagnetic pump, and a voltage monitor unit for outputting an output proportional to the DC voltage, and a switch having the above-mentioned operation function is arranged in series in front of the power supply circuit. It is a thing.

[0023]

According to the first means for solving the above problems, the present invention provides:
Since the voltages applied to the frame rod sensor and the electromagnetic pump are simultaneously input to the microcomputer from the voltage monitor section, the number of input terminals can be reduced.

Further, in the case where the operation switch is arranged in the front stage of the power supply circuit monitored by the voltage monitor,
Based on the information from the voltage monitor, it is possible to determine whether the operation is on or off.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the figure, the same parts as those in the conventional example described above are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 1 is a power supply circuit for outputting a DC voltage by a transformer 2, a rectifying diode bridge 3, and a smoothing capacitor 4. The output of the power supply circuit 1 is connected to a constant voltage power supply 6 via an operation switch 5. The output of the constant voltage power supply 6 applies a predetermined voltage V3 to the electromagnetic pump 109 and the frame rod sensor 126, and at the same time, the power supply monitor 7 monitors the output voltage V3 of the constant voltage power supply 6. 1
Reference numeral 2 denotes a microcomputer, which has at least analog input terminals 13 and 14 and an output terminal 15. In this embodiment, the predetermined voltage V3 is set to about DC20v.

The power supply monitor section 7 is configured to output the output voltage V
It is composed of resistors 8 and 9 for dividing the voltage of the power source 3. The resistors 8 and 9 are used for the power source monitor unit 7 when the output voltage V3 is DC 20v.
Output is set to DC 2.5 V and is connected to the analog input terminal 13 of the microcomputer 12.

Reference numeral 23 is a combustion detection sensor of the type in which the output also changes when the applied power supply voltage changes. In this embodiment, the flame rod 112 will be used for explanation. 1
0 is a resistor 1 inserted in series with the combustion detection sensor 23.
A flame rod current measuring unit for converting the flame current If into a voltage by 1 is connected to the analog input terminal 14 of the microcomputer 12.

Reference numeral 24 denotes a pump drive circuit composed of a pump drive transistor and a resistor, which receives the signal output from the output terminal 15 of the microcomputer 12 and drives the electromagnetic pump 109.

Next, when the operation of the program of the microcomputer 12 is represented by functional blocks, 16 and 17 are A / D converters connected to the analog input terminals 13 and 14, respectively.
The output of the A / D converter 17 is connected to the frame rod signal calculator 19. The output of one A / D conversion unit 16 is connected to each of the operation control unit 18, the input abnormality determination unit 26, the frame rod signal calculation unit 19, and the pump voltage abnormality determination unit 20.

The operation control section 18 determines that the operation is on when the input voltage of the analog input terminal 13 is in a predetermined range, for example, Va or more and Vb or less, and otherwise, the operation is off. Is connected to the combustion control unit 21.

The input abnormality judging section 26 detects a short circuit defect or an open circuit defect of the analog input terminal 13, and when the input potential exceeds Vc and is extremely high or is lower than the operation off level Vb. When a voltage is applied halfway, it is judged as abnormal.

The frame rod signal calculation unit 19 uses the input voltage of the analog input terminal 13 to perform proportional calculation to the input voltage of the analog input terminal 14, as in the conventional example.

Reference numeral 25 denotes a pump signal control unit, which is composed of the pump voltage abnormality determination unit 20 and the pump signal output unit 22.

The pump voltage abnormality determining section 20 determines that the input voltage of the analog input terminal 13 is abnormal when the input voltage is equal to or higher than a predetermined level, such as Vc, and suppresses the pump signal output. , Its output is connected to the pump signal output unit 22.

The pump signal output section 22 receives an instruction from the combustion control section 21 and outputs an electromagnetic pump drive signal to the output terminal 15.

The operation of the embodiment having the above configuration will be described. Here, it is assumed that the values of Va, Vb, and Vc are set to DC4v, DC1v, and DC3v, respectively.

First, when the operation switch 5 is turned on, DC 20v is output from the constant voltage power supply 6, divided by the power supply monitor unit 7 to DC 2.5v, and input to the analog input terminal 13. The operation control unit 18 determines that the operation is on because the voltage of the analog input terminal 13 is in the range of DC1v to 4v, and issues an operation start instruction to the combustion control unit 21.

In response to this, the combustion control section 21 receives the vaporization cylinder 1
After performing predetermined processing such as preheating of 08 and pre-purge operation, a pulse signal is output from the output terminal 15 via the pump signal output unit 22 to drive the electromagnetic pump 109. Here, the pump voltage abnormality determination unit 20 uses the analog input terminal 13
If the voltage is lower than DC3v, it is judged to be normal, but D
When C3v or more, it is determined that the voltage applied to the electromagnetic pump 109 is abnormally high, and the pump signal output unit 22 is instructed to stop outputting the pulse signal.

When the electromagnetic pump 109 is normally driven and combustion is started, the frame rod current converted into a voltage by the frame rod current measuring unit 10 is taken in from the analog input terminal 14, and the frame rod signal calculating unit 19 is operated. Correction processing is performed using the voltage of the analog input terminal 13.

Although the A / D converters 16 and 17 have been described as being built in the microcomputer 12, a microcomputer for performing A / D conversion outside the microcomputer 12 is used. 12
It is not necessary to provide the A / D conversion unit in.

If the pump voltage abnormality judging section 20 feeds back the information of the voltage of the analog input terminal 13 to the pump signal output section 22, it outputs the information to the electromagnetic pump 109 according to the voltage of the analog input terminal 13, for example. It may be something like a pulse width changing means for changing the pulse width.

[0043]

As is apparent from the above embodiments, in the conventional configuration, the ON / OFF information of the operation switch, the abnormal voltage information applied to the electromagnetic pump 109, and the power supply voltage information of the frame rod are separately dedicated. While it was taken into the microcomputer 114 from the input terminal of
In the present invention, the above three pieces of information can be taken in only by the analog input terminal 13 that takes in the voltage of the power supply monitor section 7.

That is, by supplying the voltage applied to the flame rod sensor and the electromagnetic pump from the common DC voltage V3, and simultaneously supplying / cutting off the DC voltage V3 by opening / closing the operation switch, The computer 12 inputs only the output of the power supply monitor unit 7 for monitoring the DC voltage V3, and uses the input information for various purposes such as on / off information of operation, correction of the flame rod ammeter, and detection of an abnormal voltage applied to the electromagnetic pump. This has the effect of reducing the number of input terminals.

Furthermore, since the operation switch 5 is arranged in series between the power supply circuit 1 and the constant voltage power supply 6, not only is the operation switch on / off instructed, but also when the operation switch is open, that is, operation off. Sometimes the power supply to the constant voltage power supply 6 is cut off,
The electromagnetic pump 109 can be surely stopped. As a result, there is an effect that the conventional safety relay can be abolished without compromising the safety that the combustion switch must never burn when it is off.

Further, the output of the power supply monitor 7 is received at the analog input terminal, and the range of Va to Vb is used for the operation on / off, and Vc or more is used for the abnormality determination of the pump voltage. In contrast to signal processing with Lo, there is an effect that it is less susceptible to malfunction such as noise.

Further, as in the present invention, by reducing the number of input terminals without changing the amount of information to be input, the number of input terminals can be reduced even in the abnormal processing for the input terminals themselves such as short circuit failure and open failure. There is also an effect that the reduction can be simplified.

[Brief description of drawings]

FIG. 1 is a circuit diagram illustrating a combustion control device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a combustion device used in the present invention and a conventional example.

FIG. 3 is a structural explanatory view showing a burner portion of the combustion device.

FIG. 4 is a circuit diagram illustrating a conventional combustion control device.

[Explanation of symbols]

 1 Power Supply Circuit 5 Operation Switch 7 Voltage Monitor Section 18 Operation Control Section 19 Frame Rod Signal Calculation Section 23 Frame Rod Sensor 24 Pump Drive Circuit 25 Pump Signal Control Section 109 Electromagnetic Pump

Claims (2)

[Claims] 1. A flame rod sensor which is inserted into a combustion flame to detect a combustion state of the flame by a flame ion current, and a DC voltage applied to the flame rod sensor which measures a flame current flowing between electrodes of the flame rod sensor. In response to a flame rod signal calculation unit that proportionally processes the flame current, an electromagnetic pump that supplies fuel to the combustion unit, a pump drive circuit that drives this electromagnetic pump, and a DC voltage that is applied to the electromagnetic pump. A pump signal control unit that controls a pump drive signal, a power supply circuit that applies at least a DC voltage common to the frame rod sensor and the electromagnetic pump, and a voltage monitor unit that outputs an output proportional to the DC voltage. Combustion control device. 2. A switch having an operation function, an operation control section for turning on / off operation according to an input voltage, an electromagnetic pump for supplying fuel to a combustion section, and a pump drive circuit for driving this electromagnetic pump. And a pump signal control unit that controls a pump drive signal according to a DC voltage applied to the electromagnetic pump, and a power supply circuit that applies a DC voltage to the electromagnetic pump,
A combustion control device comprising: a voltage monitor unit that outputs an output proportional to the DC voltage; and a switch having the above-mentioned operation function, which is arranged in series in front of the power supply circuit.