JPH03191209A - Combustion control device - Google Patents

Abstract

PURPOSE:To enable a power failure safety function part to be formed in a miniature size and at a low cost by a method wherein an off-position sensing means is provided, when an on-position of a switch member is detected, a burner is ignited only when it is detected that the switch member is in an off-position just before it. CONSTITUTION:An off-position sensing circuit 50 is a circuit arranged only for starting an operation when an operation switch 33 is changed from its off-position to its on- position in order to assure a safety while the power failure occurs. In the case that the operation switch 33 is placed at its off-position, an electrical charging circuit is formed by a resistor 52 and a capacitor 53 at an output part of a bridge diode 51 connected to an off-contact point 33c connected to a movable contact point 33a. A light emitting diode 54a of a photo-coupler 54 is connected to a capacitor 53 through a resistor 55. A control circuit 31 may detect that the operation switch 33 is placed at its off-position only when the operation switch 33 is changed from its off-position to its on-position and in turn in the case that a supplying of electrical power is stopped due to a power failure during the operation and subsequently the power supplying is recovered, the fact that the operation switch 33 is kept at its off-position is not detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustion control device having a safety function against power outages that occur during combustion.

[Prior Art] For example, in a combustion type heater that performs ignition operation in response to a switch operation, if a power outage occurs during combustion, combustion may be stopped for a while, and even if the power is restored, the switch must be manually operated. Do not perform cut combustion unless the operation is performed again.
This ensures safety in the event that the switch is inadvertently forgotten to turn off during a prolonged power outage.

To this end, conventionally, a self-holding circuit has been provided with a relay that only engages the circuit when power is being supplied and the switch is in the off position, and the switch is turned on. Sometimes, only when the relay closes the circuit, power is supplied to a solenoid valve for supplying fuel gas, and operation can be started.

Therefore, if you connect the plug to the power line while the switch remains on, or if power is resumed from the power line after a power outage, the relay in the self-holding circuit will not close. I am unable to start driving,
No fuel gas is supplied, ensuring safety against power outages.

In this case, the relay of the self-holding circuit is connected to the 10
It is directly driven by a supply voltage of 0.

[Problems to be Solved by the Invention] As described above, in conventional equipment that has a safety function against power outages, a cement resistor is provided in the self-holding circuit, which increases the mounting area and increases the amount of heat generated. Therefore, there is a problem that the unit constituting the self-holding circuit becomes large and the cost of each component constituting the unit is high.

In addition, it is desirable to continue operation without stopping in case of a short momentary power outage (1' every 0.2 seconds) that occurs due to switching of the power supply system, etc. When installing a self-holding circuit with a simple circuit configuration, there are variations in the relays in the self-holding circuit, and it may take a very long time for the self-holding circuit to be released. In order to continue operation when a problem occurs, it is necessary to make the operating time of the microcomputer longer than the time until release, and for this reason, it is necessary to increase the power supply capacity of the microcomputer.

Alternatively, it may be possible to shorten the time required to release the relay in the self-holding circuit in response to the time required to reset the microcomputer, but in this case, it may be necessary to operate it with slight time accuracy or to shorten the time required to reset the self-holding circuit. Since the circuit is forcibly released, time adjustment is required for this purpose, and there is a problem that the circuit configuration becomes complicated.

Furthermore, in addition to using heaters individually, if you are trying to centrally control multiple heaters from a master unit at one location, in the event of a power outage, there will be variations in each heater, so generally speaking When power is supplied, unless there is a power outage stop signal from the main unit, the engine will be controlled to perform a re-ignition operation so that combustion will continue even when power is restored, etc. , the above-mentioned self-holding circuit becomes unnecessary.

Therefore, when designing a device so that it can be used for both individual use and concentrated use, there is a problem in that the cost burden of the self-holding circuit increases as described above.

An object of the present invention is to provide a small-sized and low-cost power outage safety function section in a fuel control system in which equipment stops when a power outage occurs and does not operate even after the power is restored.

[iI! Means for Solving the Problem] The present invention provides a combustion control device that controls a bar t according to the state of a switch member that sets a maintainable on position and an off position, respectively, in which the switch member is in an off position. The technology includes an off position detection means for detecting that the switch member is in the on position, and ignites the burner only when it is detected that the switch member was in the off position immediately before the on position of the switch member is detected. As a practical means.

[Operation] In the present invention, operation is started and the burner is ignited only when the switch member is detected to be in the off position and then changed to the on position.

Therefore, if a power outage occurs during operation with the switch member in the on position, and then the power is restored with the operation switch still in the on position, it will be detected that the switch member is in the on position, but the switch member will remain in the on position. Since the burner remains in the on position during a power outage and after the power is restored, it is not detected that the switch member was in the off position immediately before the switch member was detected to be in the on position, so the burner may not be ignited. do not have.

[Effects of the Invention] In the present invention, when the ON position of the switch member is detected, operation will not start unless it is detected that the switch member was in the OFF position immediately before. If you forget to turn the switch member to the OFF position when the system stops, the equipment will not start operating automatically when the power is restored afterwards, so safety during a power outage can be ensured.

In addition, in order to detect the off position of the switch member, a simple and compact circuit using a photocoupler element such as a light emitting diode and a phototransistor can be used, which reduces the cost and reduces the mounting area. and the cost burden is low.

Therefore, even if the equipment is used for centralized control, there is little loss due to the provision of the power failure safety function section.Example: Next, the present invention will be described based on an example.

FIG. 2 shows a schematic configuration of a gas hot air heater 1 as an embodiment of the present invention, which includes an air circulation path 10, a fuel supply path 20, a control device 30, It consists of

The air circulation path 10 includes a casing 1. Air is sucked in through the suction port 12 formed by O▽a and equipped with a filter 11 by the operation of a convection fan 13. A part of the air sucked into the casing 10a is guided as combustion air through the air guide pipe 14.
Together with the fuel gas ejected from the nozzle 21 provided therein, it is supplied to the fuel mixing chamber ]-5. Fuel mixing chamber 15
The fuel gas mixed with air passes through one flame of the burner 16 and burns in the combustion chamber 16a, and the combustion gas flows into the air mixing chamber 17.
is mixed with other air sucked in from the suction port 12,
The convection fan 13 blows hot air into the room from the hot air blower [ ] 18 .

The fuel supply path 20 guides fuel gas supplied from a fuel supply source (not shown) to the nozzle 21 through a gas pipe 22, and the gas pipe 22 has two electromagnetic valves 23 and 24 provided from the upstream side, and a supply valve. Governor to keep gas pressure constant 25. A proportional valve 26 for controlling the gas supply amount is provided, and the upstream side and the flow side of the proportional valve 26 are communicated through a bypass pipe 2▽7a provided with an orifice 27.

Note that a spark electrode 2 for ignition is provided in the combustion chamber 16a.
8 and two thermocouples that detect combustion temperature for controlling the convection fan 13 and detecting misfires.

The gas hot air heater 1 having the above configuration has a control device 30
controlled by

Next, a first embodiment of the control device 30 will be described based on FIG.

The control device 30 of the first embodiment controls the operation of the gas hot air heater 1 by a control circuit 31.
is mainly composed of a microcomputer 32, and operates according to the operation state of the operation switch 33.

The operation switch 33 is provided to use the gas hot air heater 1 individually, and the operation switch 33 includes a movable contact 33a and a movable contact 33a for supplying power from a plug 34 connected to a power line. Gas hot air heater 1
On contact 3 that turns on when in the on position for operation.
3t) and an off contact 33c that closes when in the off position to stop operation.
Lock 1 mechanically fixes the on and off positions.
1! 1 ellipse, and each contact point 33a, 33b, 33
(= is connected to the connection part 35 provided in the control device 30.

The connection part 35 includes a power connection part 35a connected to the movable contact 33a of the operation switch 33, an on position connection part 35b connected to the on contact 33b of the operation switch 33, and an off position connection part connected to the off contact 33c. There is 35c,
The power connection part 35a is connected to the plug 34.

The control device 30 includes a power transformer 36 and its secondary transformer for supplying power from a plug 34 connected to a power line to the control circuit 31 via the operation switch 33 when the operation switch 33 is in the on position. A control power supply unit 37 that rectifies the 8-voltage voltage into a predetermined DC voltage, and a drive unit 40 that supplies power to drive each part of the gas hot air heater R1 are provided, and the power supply transformer 36 and The drive unit 40 is
It is connected to the on position connection part 351).

The control device 30 is also provided with an off-position detection circuit 50 for detecting when the operation switch 33 is in the off-position, and the off-position detection circuit 50 is connected to the off-position connection part 35c. There is.

The control power supply section 37 supplies a predetermined DC power obtained from the AC voltage ▽47- of the power transformer 36 to the control circuit 31 when the operation switch 33 is in the on position and the movable contact 33a is connected to the on contact 33b. and the microcomputer 32, after the operation switch 33 changes from the OFF position to the ON position, or when the operation switch 33 is continuously in the ON position, power is restored after a power outage, and the plug 34 is connected to the outlet. for a certain period of time (several μ
A predetermined amount of power is supplied to the control circuit 31 and the like within a few milliseconds (seconds to several milliseconds).

The drive unit 40 is provided with a bridge diode 41 that rectifies the power supplied when the operation switch 33 is in the on position, and connects each electromagnetic valve 23, 24 and the spark electric If! The igniter 2 consists of a high voltage generation circuit for generating spark discharge at 28.
8a are connected to the output of the bridge diode 41 via respective relay contacts 42a and 43a of a solenoid valve relay 42 and an igniter relay 43, respectively.

The off position detection circuit 50 is designed to ensure safety during power outages.
A circuit provided in order to start operation only when the operation switch 33 changes from the off position 1 to the on position,
When the operation switch 33 is in the off position, the movable contact 3▽3
Off contact 3 connected to a JP-A-3-191209 (
4) The output of the bridge diode 51 connected to 3C is
A charging circuit is formed by a resistor 52 and a capacitor 53, and a light emitting diode 54a of a photocoupler 54 is connected to the capacitor 53 via a resistor 55.

Also, a phototransistor 5 serves as a light receiving part of the photocoupler 54.
4b is provided, and its output signal obtained by resistor 56 is transmitted to control circuit 31.

As a result, the light emitting diode 54a lights up when the operation switch 33 is in the OFF position and power is being supplied from the plug 34 at that time, and after the operation switch 33 is changed from the OFF position to the ON position.

The lighting time after the operation switch 33 is turned on is set to be longer than the turn-on time of the control power supply unit 37 (several microseconds to several milliseconds), and the control circuit 31 After the microcomputer 32 resets, lighting of the light emitting diode 54a can be detected.

On the other hand, in the phototransistor 54b and the control circuit 31, the light emission from the light emitting diode 54a can be detected only after the operation switch 33 is switched to the on position and power is supplied from the control power supply section 37.
The control circuit 31 determines that the operation switch 33 is in the OFF position only when power is continuously supplied from the power line through the 0-head plug 34 and the operation switch 33 is changed from the OFF position to the ON position. If the power supply is stopped due to a power outage during operation when the operation switch 33 is in the ON position, and then the power is restored, the operation switch 33 is not in the OFF position and the light emitting diode 54a does not emit light. , it is not detected that the operating switch 33 is in the OFF position.The control device 30 is also provided with a fan circuit 38 directly connected to the 1 lug 34 in order to operate the convection fan 13 independently of the operating switch 33. A temperature switch 38a is connected in series with the motor 13a for driving the convection fan 13.

The control circuit 31 controls the gas hot air heater 1 using a microcomputer 32, and starts operation in a predetermined sequence according to the operation of the operation switch 33, and during operation, the temperature is controlled by the user. The combustion amount is adjusted by controlling the proportional valve 26 based on the set temperature of the setting device 61 and the temperature detected by the thermistor 62 that detects the room temperature.

Also, thermo cuggle 29, overheat switch 6
3. Based on signals from the overturning switch 64 and other temperature fuses, if there is an abnormally high temperature or installation abnormality,
Safety is ensured by stopping combustion in a predetermined sequence to prevent fires or gas leaks.

Furthermore, in the event that combustion stops due to a power outage, power is removed from the plug 34 based on the detection signal of the phototransistor 54b of the off-position detection circuit 50 in order to prevent combustion from occurring even when the power is restored. Only when the operation switch 33 changes from the off position ▽48- to the on position when the power is supplied, the operation is started and the igniter h of the burner 16 is activated; otherwise, the operation switch 33 Even if the switch is in the on position, -/off operation is not started.

Note that FIG. 1 shows the case where the operation switch 33 is in the off position t6. Below, the sequence control operation related to the start of operation of the microcomputer 32 at the time of starting power supply to the control circuit 31 is as follows.
This will be explained based on FIG.

When power is supplied from the control power supply unit 37 and the microcomputer 32 is reset and starts control operation, the operation switch 33
The phototransistor 54t indicates that the phototransistor 54t is in the off position.
1, it is determined whether there is an off signal or not, and if there is no off signal (NO in step 1), the operation switch 33 continues to be in the on position, and the power is restored after a power outage or the plug remains in the on position. It is determined that 34 is connected to the power line, and the power is stopped (step 2), and operation is not started.

Conversely, if an off signal is detected (Stella Unexamined Patent Publication No. 3
-191209 (5) If YES in step 1), power is being continuously supplied from the power line through the plug 34, and the operation switch 33 is changed from the OFF position to the ON position by the user, Performs operation start control in a predetermined sequence,
Open each electromagnetic valve 23 and 24 to supply fuel gas to burner 1.
At the same time, the igniter 28a is driven to ignite the burner 16 to perform an ag operation (step 3).

During operation, it is determined whether or not an abnormality has occurred, and if no abnormality is detected, No is selected in step 4.
), the operation continues, and when the operation switch 33 is switched to the OFF position, the operation is stopped.

If an abnormality such as abnormal high temperature, abnormal installation condition, abnormal combustion, etc. is detected (YES in step 4), the supply of fuel gas is stopped as an abnormality has occurred, combustion is stopped, and operation is stopped (
Step 5).

In the event of an abnormal stop, the operation switch 33 is returned to the OFF position, and then the power is turned on again to reset the microcomputer 32 and restart the operation.

In addition, from step 3 onward, if a momentary power outage occurs during operation with the operation switch 33 in the on position, if the power outage time is 0.2 seconds or less, the control power supply section 37 continues to operate the microcomputer 32. It can be activated by
In the case of more than that, the control power supply section 37 uses the microcomputer 3.
2 cannot be maintained, the microcomputer 32 resets once,
The determination in step 1 is performed again. In this case, since the off signal is not detected, the result in step 1 is No, and the power outage is stopped (step 2).

As described above, in the first embodiment, the operation starts only when power is continuously supplied from the power line and the operation switch 33 is changed from the off position to the on position, and the operation switch 33 is simply turned on. Since operation does not start just by being in the position, it is safe because even if a power outage occurs during operation and the power is restored, the operation will not start.

Furthermore, the off-position detection circuit 50 for detecting that the operation switch 33 is in the off-position can be configured with a small element such as a photocoupler 54 that generates less heat, so that the cost burden and the mounting area can be reduced. .

Next, the above gas hot air heater 1 is not used individually,
- A second embodiment will be described in which a plurality of gas hot air heaters 1 are centrally controlled from a location.

FIG. 4 is a control system diagram when the gas hot air heater 1 is centrally controlled.

For example, gas hot air heaters 1 are installed in multiple rooms of buildings, schools, hospitals, etc., and the gas hot air heaters 1 are integrated by a central control device 100 installed in a central control room. Each gas hot air heater attempts to control the overall operating status! I! 1 are each equipped with a management handset 2 that operates in response to a control signal from the central management device 100.

As shown in FIG. 5, each managed slave device 2 is provided with an "r-machine relay 3" that is driven in response to a control signal from the central management device 100, and the slave device relay 3 is operated in accordance with the above-mentioned operation. It is connected to the connection section 35 of each control device 30 instead of the switch 33.

Here, the slave relay 3 includes a relay contact 3a corresponding to the ON contact 33b of the operation switch 33▽49-, and does not include a contact corresponding to the OFF contact 33c of the operation switch 33.

Instead, the off contact 33c of the operation switch 33 is connected to the management unit 2 in order to always supply the power supplied from the plug 34 to the off position detection circuit 50 regardless of the control state of the slave unit relay 3. A harness is provided with a connecting wire 4 for short-circuiting the off-contact connecting portion 35c of the connecting portion 35 and the power connecting portion 35a.

As a result, in the off-position detection circuit 50, the light emitting diode 54a always emits light when power is being supplied from the plug 34, regardless of whether the relay contact 3a of the child unit relay 3 is open or closed.

Therefore, when central control is performed by the central control device 100, by connecting the above-mentioned connection line 4, the control circuit 31 of each gas hot air heater 1 is supplied with power from the 1 lug 34. When the tI9 relay 3 is touching the contact, an off signal is always obtained after the reset I of the microcomputer 32. Therefore, when the operation signal is being sent from the central control device 100, the plug 34 is connected to the power line. The ignition operation is always performed when the power is restored or when the power is restored after operation has stopped due to a power outage.

Correspondingly, in the centralized control device 100, even if there are variations in the operation timing when power is supplied to the microcomputer 32 in each gas hot air heater 1, when a power outage occurs, the centralized control device 100 always In order to obtain an operating state according to the control signal from the management device 100, management is performed such that power outage stop control is performed only when the power outage duration is, for example, 0.5 seconds or more. In the case of a momentary power outage for a short period of time, the operation signal will continue to be sent.

As a result, when a momentary power outage of less than 0.5 seconds occurs,
In each gas warm air heater 1, even if the microcomputer 32 does not reset properly for each gas hot air III heater 1 due to the relationship between the control power supply unit 37 and the control circuit 31, the central control device 100 If the control signal from the plug 34 instructs operation, the sequence operation shown in FIG. Proceeding to step 3, all the gas hot air rooms 1a1 connected to each management slave device 2 are always in the operating state.

In addition, when using the gas hot air 9g machine 1 under centralized control, the slave unit relay 3 and the connection line 4 are connected to the connection part 35 as described above, so the off position detection circuit 50
cannot be used to detect the off position, but
The off signal detected when the off position is detected is used in the sequence for starting operation by the microcomputer 32, and operation is always performed when there is an off signal, so the operation switch 33 can be turned on without any particularly complicated modifications. Prepare or manage handset 2
Individual use or intensive use can be freely selected depending on whether the product is equipped with the following features, and the number of products manufactured can be reduced.

Next, a third embodiment of the control device 30 will be constructed based on FIG.

In this embodiment, the power transformer 36 is directly connected to the plug 34, and a control circuit 31a is provided which ensures that power is supplied regardless of the state of the operation switch 33 while power is being supplied from the power line. It is being

Further, in order to indicate that the operation switch 33 is turned on, a photocoupler 44 is provided, and its light emitting diode 44a is connected to the drive unit 40.
Phototransistor 44 as a light receiving part of photocoupler 44
The on signal detected by the control circuit 31b is transmitted to the control circuit 31a.

As a result, the control circuit 31a can detect whether the operation switch 33 is in the on position or the off position as long as power is supplied.

Next, the operation of the microcomputer 32a in the control circuit 31a having the above configuration will be explained based on FIG.

Since power is normally supplied to the control circuit 31a regardless of the operating switch 33, the control circuit 31a is reset when the plug 34 is connected to the power line or when the power is restored from a power outage.

A relay contact 3a corresponding to the on contact 33b of the operation switch 33 is provided, and a contact corresponding to the off contact 33c of the operation switch 33 is not provided.

Instead, tube Fl? el12 includes a connection part 35 to which the OFF contact 33c of the operation switch 33 is connected in order to always supply the power supplied from the 1 lug 34 to the OFF position detection circuit 50 regardless of the control state of the slave relay 3. A harness is provided with a connecting wire 4 for short-circuiting the off-contact connecting portion 35c and the power connecting portion 35a.

As a result, in the off position detection circuit 50, the slave unit relay ~
Regardless of whether relay contact 3a is open or closed, when power is being supplied from plug 34, light emitting diode 54a always emits light.

Therefore, when central control is performed by the central control device 100, by connecting the above connection line 4, the control circuit 31 of each gas hot air heater 1 is supplied with power from the 7 lug 34. If the handset relay is touching the contact, an off signal will always be obtained after the microcomputer 32 resets I, so if the central control device 100 is sending out an operation signal, the plug 34 should be connected to the power line. The ignition operation is always performed when the power is restored or when the power is restored after operation has stopped due to a power outage.

Correspondingly, in the centralized control device 100, even if there are variations in the operation timing when power is supplied to the microcomputer 32 in each gas hot air heater 1, when a power outage occurs, the centralized control device 100 always In order to obtain an operating state according to the control signal from the management device 100, management is performed such that power outage stop control is performed only when the power outage duration is, for example, 0.5 seconds or more. In the case of a momentary power outage for a short period of time, the operation signal will continue to be sent.

As a result, when a momentary power outage of less than 0.5 seconds occurs,
In each gas warm air heater 1, even if the microcomputer 32 of each gas hot air heater 1 does not reset properly due to the relationship between the control power supply unit 37 and the control circuit 31, the control from the central control device 11100 If the control signal instructs operation, in order to always reset after power is supplied from the plug 34, the sequence operation shown in FIG. Then, all the gas hot air heaters 1a1 connected to each management unit 2 are always in operation.

In addition, when using the gas hot air @ room unit 1 under centralized control, the slave unit relay 3 and the connection line 4 are connected to the connection part 35 as described above, so the off position detection circuit 50
cannot be used to detect the off position, but
The off signal detected when the off position is detected is used in the sequence for starting operation by the microcomputer 32, and operation is always performed when there is an off signal, so the operation switch 33 Individual use or intensive use can be freely selected depending on whether the device is equipped with a control unit or a management slave unit 2, and the number of manufactured models can be reduced.

Next, a third embodiment of the control device 30 will be constructed based on FIG.

In this embodiment, the power transformer 36 is directly connected to the plug 34, and while power is being supplied from the power line, power is always supplied regardless of the state of the operation switch 33. ! 31a is provided.

Further, a photocoupler 44 is provided to indicate that the operation switch 33 is turned on, and its light emitting diode 44a is connected to the drive section 40 and serves as a light receiving section of the photocoupler 44. Phototransistor 4
The on signal detected by 4b is transmitted to the control circuit 31a.

As a result, the control circuit 31a can detect whether the operation switch 33 is in the on position or the off position as long as power is supplied.

Next, the operation of the microcomputer 32a in the control circuit 31a having the above configuration will be explained based on FIG.

Since power is normally supplied to the control circuit 31a regardless of the operating switch 33, the control circuit 31a is reset when the plug 34 is connected to the power line or when the power is restored from a power outage.

At the time of reset, it is determined whether there is an off signal or not, and if there is an off signal, YF, S
), indicating that the operation switch 33 is in the OFF position, and therefore does not start operation and enters a standby state (step 12).
, operation will be stopped.

If there is no off signal (No in step 11)
, it is determined whether there is an on signal or not, and if there is an on signal (YES in step 13), the operation switch 33 continues to be in the 'ζ on position, and the power supply is started by power restoration after a power outage or when the plug is plugged in. 34 is connected to the Dengen line and power supply is started, the power supply is stopped without operation (step 14).

In the case of step 111, the operation switch 33 is the one? The power outage stop state continues unless the switch is changed to the OFF position.

In the standby state of step 12, it is determined whether or not there is an on signal, and if there is no on signal, the process is stopped in step 15.
If NO>, the process moves to step 12 to continue the stopped state.

In the standby state, if the ON signal is detected (YES in step 15), combustion is started in a predetermined sequence and heating operation is started (step 16).

If an off signal is detected during operation (step 17
If the answer is YES), the operation is stopped (step 18), and then the process moves to step 12).

If no off signal is detected during operation (step 1)
7), it is determined whether an abnormality is detected or not.

If no abnormality is detected (N in step 19)
o), proceed to step 16 and continue operation.

If an abnormality is detected (YES in one step)
S), the operation is stopped as an abnormal stop condition (Step 2)
0).

If the operation is stopped due to abnormality detection, it is determined whether an off signal is detected or not, and if an off signal is not detected (No in step 21) = step 20
Repeat the following steps to continue the abnormal stop state.

If the off signal is detected while the operation is stopped due to an abnormality detection, the signal will be turned off in step 21 (YI", S).
, - indicates that the operation switch 33 has been turned off.
Therefore, the stop due to the abnormal stop is interrupted and the process moves to step 18, where the normal operation is stopped, and then step 12
and enters the standby state.

As described above, also in the third embodiment, the operation switch 3
Since operation will not be resumed unless the operation switch 33 is turned to the OFF position after 3 turns, even if a power outage occurs and the ON signal is detected when the power is restored, operation will not start. It is safe because it does not cause any problems.

Further, in this embodiment, when power is supplied to the control port N31a, the ON signal and OFF signal of the operation switch 33 can always be detected, so that the OFF position detection port v@50
In this case, a capacitor for extending the lighting time of the light emitting diode 54 is not required, and step 2 described above
In the abnormal stop state of 0, even if the operation switch 33 is quickly returned from the on position to the off position and then switched to the on position, the microcomputer 32a quickly responds and starts operation after going through the standby state. be able to.

Furthermore, since power is constantly supplied to the microcomputer 32a from the control power supply unit 37, the operating information set by the user can be stored at all times, and there is no need to set it again every time the user runs the microcomputer 32a.

The gas hot air heater 1 equipped with the control circuit 31a according to the third embodiment also has the feature that the manager 112 provided with the "fIl! relay 3 and the connection line 4 is connected to the connection part 35 instead of the operation switch 33. Accordingly, centralized management can be performed by the central management device 100 and the management 7-machine 2 shown in FIGS. 4 and 5.

As described above, according to the present invention, when each gas hot air heater 1 is used individually, if the gas hot air heater 1 stops operating due to a power outage, even if the power is restored,
Since the operation will not be resumed unless the operation switch is changed to the OFF position, there will be no gas leakage, etc., and it is safe.

In addition, since operation is restarted after detecting an off signal, it is easy to centrally manage multiple gas hot air heaters 1 by simply connecting relay contacts and connection wires instead of using an operation switch. In addition, in the case of centralized control, in the event of a momentary power outage, even if some of the gas hot air heaters stop operating due to variations, the central control device can control the operation to stop the operation. As long as no signal is transmitted, the microcomputer can be reset and restarted, allowing for reliable management.

Although the gas hot air heater was shown as an example above, other combustion equipment such as a gas water heater may also be used.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a control device showing a first embodiment of the invention, Fig. 2 is a schematic configuration diagram of a gas hot air heater showing an embodiment of the invention, and Fig. 3 is a block diagram of a control device showing a first embodiment of the invention. FIG. 4 is a flowchart for explaining the operation of the example control device, FIG. 4 is a control system diagram of the central management device showing the second embodiment of the present invention, and FIG.
FIG. 6 is a block diagram showing a schematic configuration of the management slave device of the embodiment, FIG. 6 is a block diagram of a control device showing a third embodiment of the present invention, and FIG. 7 is a block diagram for explaining the operation of the control device of the third embodiment. This is a flowchart. In the figure, 16...burner, 30... control device (combustion control device), 33... operation switch (switch member),
50... Off position detection circuit (off position detection means).

Claims (1)

[Scope of Claims] 1) A combustion control device that controls a burner according to the state of a switch member that has an on position and an off position that can each be maintained, including an off position that detects that the switch member is in an off position. A combustion control device comprising a position detecting means, and igniting the burner only when detecting the on position of the switch member and detecting that the switch member was in the off position immediately before that.