JPH035620A - Combustion controller - Google Patents

Abstract

PURPOSE:To improve productivity and reliability by connecting resistor circuits to the control signal output terminals of various instruments and checking the conditions of sequence control in accordance with voltages generated by a microcomputer in the resistor circuits in the sequence controller of a combustion equipment for a heating system. CONSTITUTION:In a manufacturing process, when the instruction for a checking operation is given, a control signal in accordance with a sequence control is outputted from the control signal output terminal of a microcomputer 20. Then the voltage of a level corresponding to the type and the number of the control signals is generated in a resistor R0. The microcomputer 20 converts the voltage to digital signals and, based on converted data, automatically checks the condition of the sequence control. When the sequence control is abnormal, this is pilot by an operation lamp 28 or a combustion lamp 30. This construction can improve productivity and reliability.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a combustion control device for a combustor.

(Prior art) Combustion machines used for heating etc. are equipped with a solenoid valve for fuel control, an igniter, a flame detector, a combustion fan for supplying combustion air, etc., and combustion control is performed in which these devices are sequentially controlled by a microcomputer. Equipped with equipment.

The manufacturing process for this combustor includes a process to check whether the microcomputer's sequence control is working properly.

That is, in the inspection process, various devices are connected to the control signal output terminal of the microcomputer, and an inspector checks whether the devices operate correctly according to the sequence.

(Problems to be Solved by the Invention) However, there is a drawback that checking by an inspector takes a long time and leads to a decrease in productivity.

Additionally, inspectors are prone to errors in their checks and may miss abnormalities.

This invention was made in view of the above circumstances,
The purpose is to provide a combustion control device that can quickly and accurately check whether microcomputer sequence control is working correctly without manual intervention, and that can improve productivity and reliability. It is in.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a combustion control device equipped with a microcomputer that sequentially controls various devices of a combustion machine, including a resistor connected to a control signal output terminal for the various devices. A circuit and checking means for checking the condition of the sequence control according to the voltage generated in the resistor circuit are provided.

(Function) When a control signal is output from the control signal output terminal of the microcomputer, a voltage of a level corresponding to the type and number of control signals is generated in the resistance circuit.

Based on this voltage, the condition of the sequence control is checked by the checking means.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

First, FIG. 1 shows a part of a combustion machine related to this invention.

In FIG. 1, reference numeral 1 denotes a gas burner, and the gas burner 1 is connected to a gas supply source (not shown) via a gas pipe 2. In FIG. The gas pipe 2 includes an electromagnetic on-off valve 3, a proportional valve 4, and an electromagnetic on-off valve 5 from the gas supply source to the gas burner 1.
are set up in sequence.

A combustion fan 6 for supplying combustion air, an igniter 7, and a flame detector such as a flame rod 8 are provided near the gas burner 1.

Further, a heat exchanger 9 is provided above the gas burner 1, and a convection fan 10 for circulating indoor air is provided near the heat exchanger 9.

FIG. 2 shows a combustion control device of the present invention, which is a component of the above-mentioned combustor.

20 is a microcomputer, and drive circuits 21 and 22 are connected to a large number of control signal output terminals of the microcomputer 20.
．． 23, 24, and 25 are connected.

The drive circuit 21 drives the motor IOM of the convection fan 10 in response to control signals from the microcomputer 20.

The drive circuit 22 drives the motor 6M of the combustion fan 6 in response to control signals from the microcomputer 20.

The drive circuit 23 drives the igniter 7 according to control signals from the microcomputer 20.

The drive circuit 24 drives the electromagnetic on-off valves 3 and 5 in response to control signals from the microcomputer 20.

The drive circuit 25 drives the proportional valve 4 in response to a control signal from the microcomputer 20.

A flame detection circuit 26 is connected to a signal input terminal of the microcomputer 20. This flame detection circuit 26 detects the combustion flame of the gas burner 1 using the flame rod 8 as an actuator, and supplies the detection result to the microcomputer 20.

A drive circuit 27 is connected to a control signal output terminal of the microcomputer 20. This drive circuit 27 drives an operating lamp 28 for informing the operating state in accordance with a control signal from the microcomputer 20.

A drive circuit 29 is connected to a control signal output terminal of the microcomputer 20. This drive circuit 29 drives the combustion lamp 3o for combustion state notification in response to a control signal from the microcomputer 20.

A room thermostat 31 is connected to a signal input terminal of the microcomputer 20. This room thermometer 31 is activated by sensing the room temperature, and supplies an operational output to the microcomputer 20.

The operation unit 32 is connected to the signal input terminal of the microcomputer 20.
is connected. This operation unit 32 is used to start and stop operation,
Furthermore, it is used to instruct the microcomputer 20 to start a check operation.

A resistance circuit formed by connecting a resistor R1Ro in series is connected to a control signal output terminal of the microcomputer 20 to which the drive circuit 21 is connected.

A resistance circuit formed by connecting resistors R2*RQ in series is connected to a control signal output terminal of the microcomputer 20 to which the drive circuit 22 is connected.

A resistance circuit formed by connecting resistors R3+RO in series is connected to a control signal output terminal of the microcontroller 20 to which the drive circuit 23 is connected.

A resistance circuit formed by connecting resistors R4 and Ro in series is connected to a control signal output terminal of the microcomputer 20 to which the drive circuit 24 is connected.

A resistance circuit formed by connecting resistors R5 and Ro in series is connected to a control signal output terminal of the microcomputer 20 to which the drive circuit 25 is connected.

Microcomputer 2 to which flame detection circuit 26 is connected
A resistance circuit formed by connecting resistors R6 and Ro in series is connected to the signal input terminal 0.

The voltage generated across the resistor Ro, which is a common element of each resistance circuit, is input to the A/D input terminal of the microcomputer 20.

The microcomputer 20 processes preset programs, the output signal of the flame detection circuit 26, and the room thermometer 3.
Based on the output signal of 1 and instructions from the operation unit 32, the drive circuits 21°22°23.24, 25.27.2
9, a control means for sequentially controlling various devices of the combustion machine by supplying a control signal to 9, an A/D (analog/digital) conversion means for converting the input voltage from the resistor Ro into a digital signal, and this A/D conversion. and checking means for checking the condition of the sequence control by itself according to the output of the means.

Next, the operation of the above configuration will be explained with reference to FIG.

When the operation switch of the operation unit 32 is turned on, the operation lamp 2
8 lights up, and the proportional valve 4 opens to a predetermined opening degree for slow ignition. At the same time, the combustion fan motor 6M operates to send air to the gas burner 1, and unnecessary gas remaining in the vicinity of the gas burner 1 is discharged outside. In other words, a temporary purge is performed.

When a predetermined period of time, for example 25 seconds, has elapsed since the start of the ignition, the igniter 7 is activated. Then, when the ignition time of 2 seconds has elapsed, both the on-off valves 3 and 5 are opened, and gas is ejected from the gas burner 1.

In this way, the gas ejected from the gas burner 1 is ignited by the spark from the igniter 7. In this case, air necessary for combustion is sent to the gas burner 1.

When the ignition of the gas burner 1 is completed, the combustion flame is detected by the flame rod 8, and the output signal of the flame detection circuit 26 becomes high level. At this time, microcomputer 2
0 detects the completion of ignition, and the combustion lamp 30 lights up.

In this case, if ignition is not completed within a safe time of 2.5 seconds, the microcomputer 20 determines that some abnormality has occurred, closes the on-off valves 3 and 5, and stops the operation of the igniter 7. , stop driving.

On the other hand, when ignition is completed and the safety time has elapsed, the operation of the igniter 7 is stopped.

Also, during the 15 seconds after the safety time, the proportional valve 4 “
Slow ignition continues due to the small opening, but after that the proportional valve 4 is set to the required opening.

When the temperature of the heat exchanger 9 rises due to the combustion flame and becomes ready for heating, the convection fan motor 10M operates.

As a result, indoor air circulates through the heat exchanger 9, warming the room.

When the indoor temperature rises and the room thermostat 31 is turned off, the on-off valves 3 and 5 and the non-proportional valve 4 are closed, causing the gas burner 1 to misfire. At the same time, the combustion lamp 30 is turned off and the operation of the combustion fan motor 6M is stopped.

Thereafter, when the room temperature drops and the room thermostat 31 is turned on, the above operation is repeated and the gas burner 1 is ignited again.

When the operation switch of the operation unit 32 is turned off, all operations stop and combustion ends.

Incidentally, the series of operations of the various devices described above is based on the sequence control of the microcomputer 2o, and the status of the sequence control of the microcomputer 2o can be automatically checked during the manufacturing process of the combustion machine. .

That is, in the manufacturing process, when a check operation instruction is given from the operation unit 32, a control signal taken over by sequence control is output from the control signal output terminal of the microcomputer 20.

When a control signal is output, a voltage of a level corresponding to the type and number of control signals is generated in the resistor RO.

This voltage is converted into a digital signal by the microcomputer 20.

The microcomputer 20 automatically checks the condition of the sequence control based on the conversion data. Here, if a check result is obtained that the sequence control is not working normally, the inspector is notified of this using the operation lamp 28 and the combustion lamp 30. Upon making this announcement,
The user can determine that there is an abnormality in the control function or control signal output function of the microcomputer 20 and take appropriate measures.

In this way, it is possible to quickly and accurately check whether the sequence control of the microcomputer 20 is working correctly without manual intervention, and therefore productivity is greatly improved compared to the conventional checking by an inspector. Furthermore, unlike inspectors, there is no need to worry about making mistakes in checking, so reliability can be improved.

In the above embodiment, only the checking of the sequence control has been described, but it is also possible to add a checking function to the proportional valve 4.

That is, as shown in FIG. 4, a rectifier circuit 42 is connected to a commercial AC power source 40 via a transformer 41. A smoothing capacitor 43 is connected to the output end of the rectifier circuit 42, and the voltage generated in the smoothing capacitor 43 is supplied to the proportional valve 4 via the drive circuit 25. In addition, the smoothing capacitor 43
A series circuit of resistors 44 and 45 is connected across the resistors 44 and 45, and the voltage generated across the resistors 45 is input to the microcomputer 20.

The checking operation of the proportional valve 4 with this configuration will be explained with reference to FIG. 5.

Normally, the microcomputer 20 adjusts the current flowing through the proportional valve 4 using the drive circuit 25, and sets the proportional valve 4 to an opening corresponding to the required combustion amount.

At this time, the microcomputer 20 detects the current flowing through the proportional valve 4 in the drive circuit 25, and if the detected current is abnormal, takes corrective action so that the abnormality is canceled.

After this corrective action, the microcomputer 20 detects the current again, and if the abnormality has not been cleared at that point, it checks the voltage generated across the resistor 45. That is, the driving voltage applied to the proportional valve 4 is indirectly detected.

Here, if there is an abnormality in the drive voltage, the microcomputer 20 determines that the peripheral portion of the proportional valve 4 is abnormal, displays this on a display (not shown), and immediately stops the operation.

If there is no abnormality in the drive voltage, the microcomputer 20
determines that the proportional valve 4 itself is abnormal, and displays a message to that effect on the display (
(not shown) and immediately stop operation.

In this manner, by immediately stopping the operation when the proportional valve 4 cannot be properly controlled, gas leakage due to misfire or excessive combustion can be prevented, and sufficient safety can be ensured.

In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without changing the gist.

[Effects of the Invention] As described above, according to the present invention, the resistance circuit connected to the control signal output terminal for various devices of the combustion machine and the sequence control of the microcomputer are adjusted according to the voltage generated in this resistance circuit. This combustion control device is equipped with a check means for checking whether the sequence control of the microcomputer is working correctly, so it can be quickly and accurately checked without manual intervention to see if the sequence control of the microcomputer is working correctly, thereby improving productivity and reliability. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a part of a combustion machine according to an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a control circuit according to an embodiment of the present invention, and FIG. 3 is a diagram showing the configuration of a control circuit according to an embodiment of the invention. FIG. 4 is a time chart for explaining the operation, FIG. 4 is a diagram showing the configuration of a main part of a modification of the same embodiment, and FIG. 5 is a flow chart for explaining the operation of the modification. 1... Gas burner, 4... Proportional valve, 7... Igniter, 8... Flame rod, 0... Micrometer, 0 1 to R6... Resistor.

Claims (1)

[Claims] A combustion control device equipped with a microcomputer that sequentially controls various devices of a combustion machine includes a resistance circuit connected to a control signal output terminal for the various devices, and a condition of the sequence control according to a voltage generated in this resistance circuit. A combustion control device characterized by comprising a checking means for checking.