JP2019170061A - Combustion apparatus - Google Patents

Abstract

To achieve exact detection of a fan current value with a microcomputer even when only one of two circuit boards each mounted with the microcomputer is replaced in a combustion apparatus for controlling a combustion fun with the circuit boards.SOLUTION: A current conversion section 214 converts an A/D conversion value Df1 of a current detection value of a fan motor 130 into a digital current value IfD1. A pulse generation section 216 outputs a pulse signal Spls with a duty ratio Dp obtained by converting the digital current value IfD1 in accordance with a conversion characteristic LN2. A microcomputer 310 converts an A/D conversion value Df2 of an average voltage Van of the pulse signal Spls into a digital current value IfD2. The microcomputer 210 corrects the conversion characteristic LN2 for duty ratio conversion so that the digital current value IfD2 meets the digital current value IfD1 under a state in which the digital current value IfD2 is transmitted by a communication unit 400.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a combustion apparatus, and more particularly to a combustion apparatus having a combustion fan for supplying combustion air.

  The rotation speed control of the fan motor that rotationally drives the combustion fan for supplying the combustion air in the combustion apparatus is not an analog control using only an electronic circuit, but a microcomputer (hereinafter also simply referred to as “microcomputer”). A configuration performed by digital control is described in, for example, Japanese Patent Application Laid-Open No. 2015-159630 (Patent Document 1).

  In particular, FIG. 5 (Embodiment 2) of Patent Document 1 describes a configuration in which a microcomputer or a digital control IC (Integrated Circuit) is mounted on both the primary side circuit and the secondary side circuit that are electrically isolated. ing. In this configuration, the detected value of the fan current is input to the digital control IC (primary side circuit), and then the fan current monitoring signal is transmitted from the digital control IC to the microcomputer (secondary side circuit).

JP2015-159630A

  In the above configuration of Patent Document 1, after the analog detection value is captured as a digital value in the digital control IC of the primary circuit, the analog signal output from the digital control IC is captured as a digital value into the microcomputer. Therefore, in order to make the actual fan current value coincide with the digital current value detected by the microcomputer of the secondary side circuit, it occurs due to component variations in each of the primary side circuit and the secondary side circuit. Adjustment to absorb both individual differences is required.

  On the other hand, in the above configuration, the primary side circuit and the secondary side circuit are generally mounted on separate substrates. However, considering the adjustment for detecting the fan current described above, even if only one board fails, the pair of the primary side circuit and the secondary side circuit that have been adjusted offline needs to be replaced integrally. Is concerned.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a combustion apparatus having a configuration in which a combustion fan is controlled by first and second substrates on which microcomputers are respectively mounted. In this case, even when only one of the boards is replaced, the fan current value is accurately detected by both the first and second microcomputers.

  In one aspect of the present invention, a combustion apparatus includes a combustion mechanism, a combustion fan that supplies combustion air to the combustion mechanism, a fan motor that rotationally drives the combustion fan, and first and second substrates. And a signal transmission path and a communication means. On the first substrate, the current detection unit of the fan motor and the first microcomputer are mounted. A second microcomputer is mounted on the second substrate. The signal transmission path transmits an analog signal with electrical insulation between the first and second substrates. The current detection unit generates a first analog voltage corresponding to the current detection value of the fan motor. The first microcomputer includes a first analog-digital conversion unit, a first current conversion unit, and a pulse generation unit. The first analog-to-digital conversion unit converts the first analog voltage into a first digital value. The first current conversion unit converts the first digital value into a first digital current value in accordance with a predetermined first conversion characteristic. The pulse generation unit generates a pulse signal whose duty ratio changes according to the first digital current value. The pulse generation unit calculates a duty ratio from the first digital current value according to a predetermined second conversion characteristic. The pulse signal is transmitted to the second substrate through the signal transmission path. The second microcomputer includes a second analog / digital conversion unit and a second current conversion unit. The second analog-to-digital conversion unit converts a second analog voltage corresponding to the average voltage of the pulse signal into a second digital value. The second current conversion unit converts the second digital value into a second digital current value according to a predetermined third conversion characteristic. The communication means transmits the second digital current value from the second microcomputer to the first microcomputer. In the first microcomputer, the second digital current value is converted into the first current conversion unit when the second digital current value is transmitted by the communication means in a state where the fan motor is driven at a constant rotational speed. Means for correcting the second conversion characteristic so as to coincide with the first digital current value calculated in (1).

  According to the combustion apparatus described above, when the first substrate fails, after replacement with a new first substrate for which adjustment of the first conversion characteristic has been completed, the second substrate that is not replaced with the first substrate after replacement. The second conversion characteristic for duty ratio conversion can be corrected so that the second digital current value matches the first current value in a state in which the circuit board is connected to the substrate. As a result, errors due to individual differences between the first and second substrates that occur between the pulse generation unit (first microcomputer) and the second current conversion unit (second microcomputer) are integrally absorbed. can do. Furthermore, even when the second board fails, after replacement with a new second board, the second board after replacement and the non-exchanged first board are connected by communication means, Similarly, the second conversion characteristic can be corrected. As a result, the error due to the individual difference of the second substrate can be integrally absorbed by being included in the error occurring between the pulse generation unit and the second current conversion unit.

  According to the present invention, in the combustion apparatus configured to control the combustion fan by the first and second substrates on which the microcomputers are mounted, respectively, even when only one of the substrates is replaced, the first and second microcomputers Both can detect the fan current value accurately.

It is a schematic block diagram of the hot water supply apparatus containing the combustion apparatus which concerns on this Embodiment. It is a block diagram explaining the structure which concerns on the comparative example of the controller shown by FIG. It is a wave form diagram for demonstrating the relationship between a fan electric current value and the duty ratio of a pulse signal. FIG. 2 is a block diagram illustrating a configuration according to Embodiment 1 of the controller shown in FIG. 1. FIG. 3 is a block diagram for explaining fan current value correction in the controller according to the first embodiment. It is a conceptual diagram explaining the conversion characteristic in the electric current conversion part of the microcomputer of a power supply board. It is a conceptual diagram explaining the conversion characteristic in the pulse generation part of a power supply board. It is a conceptual diagram explaining the conversion characteristic in the electric current conversion part of the microcomputer of a control board. 3 is a flowchart for explaining a control process for correcting a fan current in a test operation mode of the combustion apparatus according to Embodiment 1. It is a block diagram explaining the structure which concerns on Embodiment 2 of the controller shown by FIG. 6 is a flowchart for explaining control processing for fan current correction in a combustion apparatus according to Embodiment 2. It is a flowchart explaining the control process of fan current correction at the time of power activation. It is a flowchart explaining the control process of fan current correction | amendment at the time of a pre purge operation.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated in principle.

[Embodiment 1]
FIG. 1 is a schematic configuration diagram of a hot water supply apparatus 100 including a combustion apparatus according to the present embodiment.

  Referring to FIG. 1, a combustion burner 115, a heat exchanger 120, a combustion fan 125, a controller 150, a rainproof plate 135, a number of unillustrated pipes and Sensors are stored. A front plate 140 is provided on one surface (for example, the front surface) of the housing 110, and the front plate 140 is provided with an intake port 145 and an exhaust port 147.

  The combustion burner 115 burns a mixture of gas supplied from a gas pipe (not shown) and air supplied from the combustion fan 125. The amount of heat generated by gas combustion in the combustion burner 115 is given to the heat exchanger 120, and is used by the heat exchanger 120 to increase the temperature of hot water in the hot water supply pipe. The combustion fan 125 includes a fan (not shown) and a fan motor 130 that rotationally drives the fan.

  The combustion fan 125 is driven to rotate by a fan motor (not shown), and supplies combustion air to the combustion burner 115. Combustion fan 125 operates based on a command from controller 150 and supplies air taken from intake port 145 toward combustion burner 115.

  The intake port 145 is provided for taking outside air into the housing 110 when the combustion fan 125 is operated. The air taken in from the intake port 145 with the operation of the combustion fan 125 is supplied to the combustion burner 115 by the combustion fan 125. For example, as shown in FIG. 1, the controller 150 is disposed in the vicinity of the air inlet 145 via the rainproof plate 135. The exhaust port 147 is provided to discharge air (or exhaust gas from the combustion operation) to the outside of the housing 110 when the combustion fan 125 is operated. By providing the exhaust port 147, an air flow as shown by an arrow in FIG. 1 is formed when the combustion fan 125 is operated.

  Power is supplied to the controller 150 from an external power source (not shown), and a power source (for example, 15V power source) used in the hot water supply apparatus 100 is generated inside the controller 150. The generated electric power is voltage-converted as necessary, and is supplied to devices such as the combustion burner 115, the combustion fan 125 (fan motor 130), various electromagnetic valves, various sensors, and a remote controller.

  Controller 150 executes various controls of hot water supply apparatus 100 according to a control program stored in advance. The control program includes various programs related to the operation of the combustion burner 115, the combustion fan 125, etc., and the control of the combustion burner 115, the combustion fan 125, etc. is executed based on these programs.

  As a representative function, in order to control the hot water supply temperature from the hot water supply apparatus 100 to the target temperature, the controller 150 is configured to calculate the difference between the incoming water temperature before heating and the temperature difference between the target temperatures (required temperature increase amount) and the hot water supply flow rate. In accordance with the product, a target heat generation amount in the combustion burner 115 is set, and a combustion gas supply amount to the combustion burner 115 is set from the target heat amount. Furthermore, the controller 150 controls the rotational speed of the combustion fan 125 so as to supply combustion air for maintaining a constant air-fuel ratio with respect to the combustion gas supply amount.

  For example, from the controller 150 to the fan motor 130 so that the target rotational speed set corresponding to the required air amount and the detected value by the rotational speed sensor (not shown) disposed in the combustion fan 125 coincide. The number of revolutions of the combustion fan 125 is controlled by variably controlling the drive voltage of the motor.

  At this time, if the air passage of the combustion fan 125 is blocked due to clogging of the intake filter or the fan motor 130 is aged, the current of the fan motor 130 is reduced under the same rotational speed. (Hereinafter, simply referred to as “fan current”) may be reduced. Therefore, monitoring based on detection of fan current is important in controlling the rotational speed of the combustion fan 125.

  In the present embodiment, the configuration of the controller 150 for detecting the fan current value will be mainly described. In the following description, only the portion related to the detection of the fan current value in the function and internal configuration of the controller 150 will be described.

  First, a configuration according to a comparative example of the controller 150 shown in FIG. 1 will be described with reference to FIG.

  Referring to FIG. 2, the controller 150 includes a power supply board 200 and a control board 300. A circuit group including a rectifier circuit 220, a smoothing capacitor 230, a power supply control circuit 240, a current detection unit 250, a pulse generation circuit 255, and a signal transmission circuit 260 is mounted on the power supply substrate 200. A circuit group including a microcomputer 310, a nonvolatile memory 315, and a signal transmission circuit 330 is mounted on the control board 300. In the configuration according to the comparative example, the microcomputer 310 is mounted only on the control board 300, and the microcomputer is not mounted on the power supply board 200.

  Information is exchanged between the power supply board 200 and the control board 300 by transmission of an analog signal (pulse signal) accompanied by electrical insulation by a photocoupler or the like by the signal transmission circuits 260 and 330. Data stored in the nonvolatile memory 315 can be rewritten by the microcomputer 310 and is also retained when the power supply of the hot water supply device 100 is shut off. The microcomputer 310 includes a ROM (Read Only Memory) 311 and a RAM (Random Access Memory) 312. In the ROM 311, a control program executed by the microcomputer 310, control data, and the like are written in advance at the time of manufacture. The contents stored in the ROM 311 cannot be rewritten by the microcomputer 310 and are retained even when the microcomputer 310 is powered off. On the other hand, the data stored in the RAM 312 is lost when the microcomputer 310 is turned off.

  The rectifier circuit 220 is typically constituted by a diode bridge. The rectifier circuit 220 rectifies an AC voltage supplied from an AC power supply 190 (for example, a system AC power supply) electrically connected to the outlet 101 of the hot water supply apparatus 100. Smoothing capacitor 230 smoothes the rectified voltage. The power supply control circuit 240 steps down the DC voltage generated by the smoothing capacitor 230 to generate the power supply voltage Vdc and the fan drive voltage Vfan. Each of power supply voltage Vdc and fan drive voltage Vfan is controlled according to a control signal (pulse signal) transmitted from microcomputer 310 via signal transmission circuit 330. For example, the power supply voltage Vdc and the fan drive voltage Vfan can be controlled by controlling the ON period of a transistor (not shown) in the power supply control circuit 240 according to the duty ratio of the pulse signal. The microcomputer 310 further outputs control signals for circuits other than the power supply control circuit 240.

  As the fan current changes according to the fan drive voltage Vfan supplied to the fan motor 130, the torque generated by the fan motor 130 changes. In FIG. 2, the configuration relating to the fan rotation speed control is not shown, but by inputting the fan rotation speed detection value to the microcomputer 310, according to the difference between the fan rotation speed detection value and the target rotation speed. By adjusting the fan drive voltage Vfan so as to increase or decrease the torque generated by the fan motor 130, the rotational speed of the combustion fan 125 can be controlled.

  Under such rotation speed control of the combustion fan 125, the current detection unit 250 including a current sensor outputs a detection value If of the fan current Ifan. The detection value If is an analog voltage value.

  The pulse generation circuit 255 generates a pulse signal Spls having a duty ratio Dp corresponding to the detection value If detected by the current detection unit 250. FIG. 3 is a waveform diagram for explaining the relationship between the fan current value and the duty ratio of the pulse signal.

  Referring to FIG. 3, pulse signal Spls output from pulse generation circuit 255 has a constant pulse period Tc. The duty ratio Dp of the pulse signal Spls is defined by the ratio of the logic high level period Th to the pulse period Tc (Dp = Th / Tc).

  Corresponding to the detection value If when the fan current Ifan = 0, the duty ratio Dp becomes the minimum value Dmin. When the fan current Ifan> 0, Dp> Dmin.

  The pulse generation circuit 255 performs a duty ratio conversion operation for associating the range of 0 to Imax (maximum detection value) of the fan current Ifan with the range of the minimum value Dmin to the maximum value Dmax of the duty ratio Dp. For example, the duty ratio conversion calculation is executed by a linear function according to circuit constants (resistance value, capacitance value, inductance value) in the analog circuit constituting the pulse generation circuit 255.

  Referring to FIG. 2 again, the pulse signal Spls output from the pulse generation circuit 255 is transmitted to the control board 300 via the signal transmission circuit 260 and input to the microcomputer 310. The microcomputer 310 can detect the duty ratio Dp of the pulse signal Spls by obtaining an average voltage (analog voltage) of the pulse signal Spls using a low-pass filter or the like. Therefore, the microcomputer 310 detects the fan current value IDfan as digital data of a plurality of bits from the A / D conversion value (voltage Van) of the average voltage. In other words, the microcomputer 310 performs a conversion operation for associating the voltage Van with the fan current value IDfan. The conversion operation can also be executed according to a linear function. Data defining a linear function for the conversion operation is stored in the nonvolatile memory 315. For example, the microcomputer 310 can execute the deterioration diagnosis of the combustion fan 125 online based on the fan current value IDfan.

  The detection of the fan current Ifan by the microcomputer 310 is performed through current-voltage conversion by the current detection unit 250, duty ratio conversion by the pulse generation circuit 255, pulse signal transmission by the signal transmission circuit 260, and conversion calculation by the microcomputer 310. Executed. For this reason, if there is a difference (individual difference) in conversion in each of these elements due to characteristic variations of circuit elements between the individual hot water supply apparatuses 100, there is a concern that the detection accuracy of the fan current value may decrease. The

  Accordingly, as part of the pre-shipment inspection of the hot water supply apparatus 100, the fan current value IDfan in the microcomputer 310 and the known input are inputted in a state where a known current value is inputted from the current source (not shown) to the current detecting unit 250. By adjusting the conversion calculation formula in the microcomputer 310 so that the current value matches the current value, it is possible to detect the current while suppressing the individual difference. For example, the adjustment can be performed by correcting the slope and intercept values that define the linear function used as the conversion formula from the default values. At this time, the corrected value can be held by the nonvolatile memory 315 together with the default value stored in the ROM 311. Hereinafter, the adjustment for detecting the fan current is also referred to as “fan current correction”.

  On the other hand, in the fan current correction according to the configuration of the comparative example (FIG. 2), the individual difference in the power supply board 200 and the individual difference in the control board 300 are integrated, and the conversion calculation formula in the microcomputer 310 is corrected. Absorbed. For this reason, even when only one of the power supply board 200 and the control board 300 fails and the board needs to be replaced, from the viewpoint of fan current correction, the integrated power supply board 200 and the control board 300 are adjusted. It is necessary to replace each set. Therefore, in the first embodiment, a configuration for accurately detecting the fan current by the microcomputer 310 even when only one of the power supply board 200 and the control board 300 is replaced will be described.

  4 is a block diagram illustrating a configuration according to Embodiment 1 of the controller shown in FIG.

  Referring to FIG. 4, controller 150 according to the first embodiment is different from the comparative example in FIG. 2 in that it further includes a microcomputer 210 and a non-volatile memory 215 mounted on power supply board 200. Further, the arrangement of the pulse generation circuit 255 in FIG. 2 is omitted, and the pulse signal Spls is generated by the pulse generation function of the microcomputer 210.

  The microcomputer 210 also includes a ROM 211 and a RAM 212 that are the same as the ROM 311 and the RAM 312. Similarly to the nonvolatile memory 315, the data stored in the nonvolatile memory 215 can be rewritten by the microcomputer 210 and is also retained when the power supply of the hot water supply device 100 is shut off.

  In the configuration example of FIG. 4, information can be exchanged by transmission of a pulse signal between the microcomputer 210 of the power supply board 200 and the microcomputer 310 of the control board 300 by the signal transmission circuits 260 and 330. For example, the target rotational speed of the combustion fan 125 set by the microcomputer 310 is transmitted to the microcomputer 210, and the microcomputer 210 adjusts the fan drive voltage Vfan according to the error of the rotational speed detection value with respect to the target rotational speed. A control signal for the power supply control circuit 240 can be generated.

  On the other hand, the fan current Ifan is detected by the microcomputer 310 via the microcomputer 210, so that the microcomputer 310 performs a comprehensive diagnosis of the deterioration of the combustion fan 125 described in FIG. Can be executed.

  FIG. 5 is a block diagram for explaining fan current value correction in the controller 150 according to the first embodiment.

  Referring to FIG. 5, the microcomputer 210 includes an A / D conversion unit 213, a current conversion unit 214, and a pulse generation unit 216.

  In the microcomputer 210, the detection value If from the current detection unit 250 is input to the A / D conversion unit 213. The A / D converter 213 outputs a digital value Df1 obtained by A / D converting the detection value If. The current conversion unit 214 converts the digital value Df1 into a digital current value IfD1 that is digital data of a plurality of bits according to the first conversion characteristic LN1. The detection value If corresponds to the “first analog voltage”, the digital value Df1 corresponds to the “first digital value”, and the digital current value IfD1 corresponds to the “first digital current value”.

  The pulse generator 216 generates the same pulse signal Spls as in FIG. 3 according to the digital current value IfD1. That is, the pulse generation unit 216 converts the digital current value IfD1 into the duty ratio Dp according to the second conversion characteristic LN2. The pulse signal Spls is input to the microcomputer 310 of the control board 300 via the signal transmission circuit 260. As the first conversion characteristic LN1 and the second conversion characteristic LN2, linear linear functions can be used as shown in FIGS.

  Referring to FIG. 6, first conversion characteristic LN1 is represented by a linear function that converts digital value Df1 into digital current value IfD1. For example, the default values of the slope and intercept of the linear function are stored in the ROM 211 at the time of manufacturing. A first conversion characteristic LN1 # in FIG. 6 represents a linear function according to the default value.

  For the first conversion characteristic LN1, a correction process is performed on an inspection line or the like before factory shipment to eliminate the variation among individual power supply boards 200. Specifically, (i) a digital current value IfD1 when the input current to the current detection unit 250 is zero (Ifan = 0), and (ii) a state where a known current value is input from a current source (not shown) (Ifan By using the digital current value IfD1 at = Ic) and obtaining the slope and intercept of the linear function, the first conversion characteristic LN1 adjusted for individual differences can be obtained.

  As described above, the information indicating the first conversion characteristic LN1 after the adjustment processing is held in the nonvolatile memory 215 at the time of factory shipment for the power supply board 200 alone or the hot water supply apparatus 100 on which the power supply board 200 is mounted. It becomes. Thereby, about the digital current value IfD1 of the microcomputer 210, the individual difference of the power supply board 200 can be eliminated and the fan current Ifan can be accurately detected offline.

  Referring to FIG. 7, similarly to first conversion characteristic LN1 (FIG. 6), second conversion characteristic LN2 also changes digital current value IfD1 to a duty ratio Dp within the range of minimum value Dmin to maximum value Dmax. It is indicated by a linear function to be converted. For example, the default values of the slope and intercept of the linear function are stored in the ROM 211. A second conversion characteristic LN2 # in FIG. 7 indicates a linear function according to the default value. The correction process for the second conversion characteristic LN2 is executed during a test operation described later.

  Referring again to FIG. 5, the microcomputer 310 includes a low-pass filter 313, an A / D conversion unit 314, and a current conversion unit 316.

  The low-pass filter 313 generates an analog voltage Van corresponding to the average voltage of the pulse signal Spls transmitted from the power supply substrate 200 (the microcomputer 210). The A / D converter 314 outputs a digital value Df2 obtained by A / D converting the analog voltage Van. The current conversion unit 316 converts the digital value Df2 into a digital current value IfD2 according to the third conversion characteristic LN3. In this way, the analog voltage Van corresponds to the “second analog voltage”, and the digital value Df2 corresponds to the “second digital value”. The digital current value IfD2 is multi-bit digital data similar to the digital current value IfD1, and corresponds to a “second digital current value”. The digital current value IfD2 corresponds to the fan current value IDfan detected by the microcomputer 310.

  As the third conversion characteristic LN3, a linear function can be used as in the first conversion characteristic LN1 and the second conversion characteristic LN2, as shown in FIG. The third conversion characteristic LN3 is adjusted in advance before shipment from the factory by a test of the control board 300 alone and a test on the hot water supply apparatus 100 on which the power supply board 200 and the control board 300 are mounted.

  In the configuration of the controller 150 according to the first embodiment, the fan current correction accompanied by the correction of the second conversion characteristic LN2 is executed by a trial operation that operates the combustion fan 125 (fan motor 130) at a constant rotational speed. The trial operation can also be executed after the installation of the hot water supply apparatus 100. The communication unit 400 is configured to communicate digital data between the microcomputer 210 and the microcomputer 310.

  In the controller 150 according to the first embodiment, the communication unit 400 only needs to have a function of transmitting the digital current value IfD2 from the microcomputer 310 to the microcomputer 210 at least during the fan current correction. Therefore, the communication unit 400 may be temporarily externally connected between the external terminals (pins, connectors, etc.) of the microcomputers 210 and 310 only by a test run. Alternatively, the communication unit 400 may be always formed by mounting a digital data communication circuit on the power supply board 200 and the control board 300 in the controller 150.

  Thus, in the configuration of the first embodiment, the digital current value IfD2 in the microcomputer 310 can be fed back to the microcomputer 210 by the communication unit 400 during the trial operation.

  FIG. 9 is a flowchart illustrating a control process for correcting the fan current value in the test operation mode of the combustion apparatus according to the first embodiment. The control process shown in FIG. 9 can be executed by the microcomputer 210.

  Referring to FIG. 9, when instructed to start a trial run (when YES is determined in S100), microcomputer 210 activates a trial run mode process in step S110 and subsequent steps. For example, a test run start instruction is manually input by an operator. When the start of trial operation is not instructed (NO in S100), the processes after step S110 are not started.

  In step S110, the microcomputer 210 determines whether the fan motor 130 is stopped. For example, based on the detection value of the rotation speed sensor provided in the fan motor 130, step S110 is determined as YES when the fan rotation speed is zero. If the fan motor 130 is not in a stopped state (NO in S110), the microcomputer 210 generates a control command for stopping the fan motor 130 (S120), and repeatedly executes the determination in step S110.

  If it is confirmed that the fan motor 130 is stopped (YES in S110), the microcomputer 210 obtains the digital value Df1 based on the detection value of the current detection unit 250 when the fan current Ifan = 0 in step S130. Convert to IfD1. The process in step S130 is executed by the current conversion unit 214 using the first conversion characteristic LN1 in which the individual difference of the power supply substrate 200 has been adjusted.

  In step S140, the microcomputer 210 can obtain an intercept of the second conversion characteristic LN2 (after correction) so that the digital current value IfD1 obtained in step S130 is associated with the minimum value Dmin of the duty ratio Dp. .

  In step S150, the microcomputer 210 controls the power supply control circuit 240 (FIG. 4) so as to drive the fan motor 130 at a predetermined test rotation speed Ntst. When the rotation speed detection value of the fan motor 130 becomes stable at the test rotation speed Ntst, the digital value Df1 based on the detection value of the current detection unit 250 at this time is converted into a digital current value IfD1 in step S160. The processing in step S160 is also executed by the current conversion unit 214 in FIG. 5 using the first conversion characteristic LN1.

  In step S170, the microcomputer 210 converts the digital current value IfD1 obtained in step S160 into the duty ratio Dp of the pulse signal Spls according to the current (before correction) second conversion characteristic LN2. Further, in step S180, a pulse signal Spls having the duty ratio Dp obtained in step S170 is generated. The processing in steps S160 and S170 is executed by the pulse generator 216 in FIG.

  The pulse signal Spls is input to the microcomputer 310 via the signal transmission circuit 260. As described with reference to FIG. 5, the microcomputer 310 generates the digital current value IfD2 based on the duty ratio Dp of the pulse signal Spls.

  In step S190, the microcomputer 210 receives the digital current value IfD2 from the microcomputer 310 via the communication unit 400. Thereby, in the microcomputer 210, the digital current values IfD1 and IfD2 calculated based on the same fan current at the test rotation speed Ntst are obtained.

  In step S200, the microcomputer 210 determines whether the digital current value IfD1 calculated in step S160 is equal to the digital current value IfD2 in the microcomputer 310.

  When IfD1 ≠ IfD2 (when NO is determined in S200), the microcomputer 210 executes time-out determination in step S230. In step S230, a YES determination is made when a predetermined time limit elapses from the start of driving of the fan motor 130 in step S150 (timeout detection). On the other hand, step S230 is NO determination until the time limit elapses.

  When time-out is not detected (NO in S230), the microcomputer 210 corrects the slope of the second conversion characteristic LN2 so that the digital current value IfD2 approaches IfD1 in step S240 and performs the processing step. Return to S150. In steps S150 to S190, when the duty ratio Dp of the pulse signal Spls output from the microcomputer 210 changes according to the second conversion characteristic LN2 corrected in step S240, the digital current value IfD2 in the microcomputer 310 is also corrected. It is corrected to reflect the second conversion characteristic LN2.

  The microcomputer 210 determines whether IfD1 = IfD2 is satisfied in step S200 under the corrected second conversion characteristic LN2 (S240). If the determination in step S200 is YES, the microcomputer 210 stores information indicating the second conversion characteristic LN2 (IfD1 → Dp) at that time in the nonvolatile memory 215. Thus, the fan current correction is completed, and the trial operation mode is terminated by further stopping the fan motor 130 in step S220.

  As described above, the second conversion characteristic LN2 corrected so that IfD1 = IfD2 is established by absorbing individual differences between the power supply board 200 and the control board 300 in the hot water supply device 100 by correcting the fan current in the trial operation mode. Can be held by the non-volatile memory 215. That is, the corrected second conversion characteristic LN2 is maintained even when the power source of the microcomputer 210 is shut off.

  Until the timeout is detected (NO in S230), the process for correcting the second conversion characteristic LN2 (S150 to S200, S240) is repeatedly executed until IfD1 = IfD2 is satisfied.

  If a timeout is detected without the digital current value IfD1 = IfD2 being established (YES in S230), the microcomputer 210 notifies an error in step S250, stops the fan motor 130 in step S220, and performs a test run. Exit mode.

  According to the combustion apparatus according to the first embodiment, when the power supply board 200 fails, after the replacement with the new power supply board 200 whose first conversion characteristic LN1 has been adjusted, the replacement of the power supply board 200 after the replacement is not performed. With the communication unit 400 connected to the substrate 300, the test operation mode described with reference to FIG. In the test operation mode, as described above, the second conversion characteristic LN2 (IfD1 → Dp) for converting the duty ratio is corrected so that the digital current value IfD2 coincides with the digital current value IfD1, as shown in FIG. Errors due to individual differences between the power supply substrate 200 and the control substrate 300 that occur between the pulse generation unit 216 and the current conversion unit 316 can be absorbed integrally.

  That is, even when the control board 300 fails, after the replacement with the new control board 300, the communication board 400 connects the control board 300 after replacement and the non-replaceable power supply board 200 in FIG. The described test run mode is executed. As a result, by correcting the second conversion characteristic LN2, errors due to individual differences of the control board 300 are also included in the errors generated between the pulse generation unit 216 and the current conversion unit 316 in FIG. can do.

  As described above, according to the combustion apparatus of the first embodiment, in the configuration in which the microcomputers 210 and 310 are mounted on the power supply substrate 200 and the control substrate 300, respectively, even if only one substrate is replaced, the communication unit 400 By executing a trial operation that involves feedback of the digital current value IfD2 by, the fan current value IDfan (digital current value IfD2) detected by the microcomputer 310 of the control board 300 is prevented from causing errors due to individual differences of the replaced boards. it can. That is, even when only one of the power supply board 200 and the control board 300 is replaced, the fan current can be accurately detected by both the microcomputers 210 and 310.

[Embodiment 2]
In the first embodiment, the offline fan current correction by starting the test operation mode has been described. In the second embodiment, the fan current correction automatically executed online will be described.

  FIG. 10 is a block diagram illustrating a configuration according to Embodiment 2 of the controller shown in FIG.

  Referring to FIG. 10, controller 150 according to the second embodiment is different from the first embodiment (FIG. 4) in that communication circuits 270 and 370 are mounted on power supply board 200 and control board 300. . Furthermore, in the power supply substrate 200, the arrangement of the nonvolatile memory 215 for storing the information of the second conversion characteristic LN2 after the fan current correction can be omitted.

  In the microcomputer 210, information indicating the first conversion characteristic LN1 in which individual differences of the power supply substrate 200 have been adjusted is written in the ROM 211 before shipment from the factory. The default value of the second conversion characteristic LN2 is also written in the ROM 211 before shipping from the factory.

  In the controller 150 according to the second embodiment, the communication circuit 270 and 370 always secures a path for transmitting digital data between the microcomputers 210 and 310, so that fan current correction with transmission of the digital current value IfD2 is automatically performed. Can be activated automatically. Since the configuration of other parts of controller 150 is the same as that of the first embodiment (FIG. 4), detailed description will not be repeated.

  FIG. 11 is a flowchart for explaining control processing for fan current correction in the combustion apparatus according to the second embodiment.

  Referring to FIG. 11, in step S300, microcomputer 210 determines whether the start condition for the fan current correction mode is satisfied. The start condition of the fan current correction mode is satisfied at least when the microcomputer 210 is turned on. That is, the fan current correction mode is executed as part of the initialization process of the microcomputer 210 when the power is turned on.

  Furthermore, the start condition of the fan current correction mode can be established even in a so-called pre-purge operation after the power is turned on and before the combustion operation by the combustion burner 115 is started. The start condition of the fan current correction mode may be established for each pre-purge operation, or may be established only during the pre-purge operation when a predetermined period has elapsed since the previous execution of the fan current correction mode. .

  When the start condition of the fan current correction mode is satisfied (YES in S300), the microcomputer 210 determines whether or not the power is turned on in step S310. When the fan current correction mode is executed as part of the initialization process described above, step S310 is determined as YES. On the other hand, when the fan current correction mode is executed along with the pre-purge operation after turning on the power, step S310 is executed. Is NO.

  When power is turned on (YES in S310), the microcomputer 210 performs fan current correction according to the flowchart shown in FIG. 12 in step S400A. In this case, since the stored contents of the RAM 212 of the microcomputer 210 are lost by power-off, even if the second conversion characteristic LN2 has been corrected by the fan current correction so far, the second conversion characteristic after the correction is corrected. Data indicating LN2 is lost.

  Referring to FIG. 12, microcomputer 210 performs steps S410 to S440 equivalent to steps S110 to S140 of FIG. 9 to determine the output and duty ratio of current detection unit 250 when fan motor 130 is stopped (Ifan = 0). The intercept of the linear function indicating the second conversion characteristic LN2 for duty ratio conversion is determined so as to be associated with the minimum value Dmin.

  Further, the microcomputer 210 performs the digital current value IfD1 (the microcomputer 210) and the digital current value IfD2 when the fan motor 130 is driven at the test rotation speed Ntst by steps S450 to S490 similar to steps S150 to S190 in FIG. (Microcomputer 310) is acquired. At this time, since the data (slope) of the second conversion characteristic LN2 corrected in the previous fan current correction mode is lost due to the power shutdown, the second conversion characteristic according to the default value stored in the ROM 311 is lost. LN2 (before correction) is defined.

  In step S495, the microcomputer 210 determines whether the difference (| IfD1-IfD2 |) between the digital current values IfD1 and IfD2 is larger than the limit value Tlim. When | IfD1-IfD2 |> Tlim (when the determination is YES in S495), that is, according to the second conversion characteristic LN2 using the default value, the difference in the recognized value of the fan current between the microcomputers 210 and 310 is excessive. In step S550, the microcomputer 210 detects an abnormality in the combustion fan 125 and notifies the error. Further, the microcomputer 210 prohibits the operation (combustion operation) of the combustion burner 115 in step S555, and generates a stop command for the fan motor 130 and ends the fan current correction mode in step S520.

  On the other hand, when | IfD1-IfD2 | ≦ Tlim (NO determination in S495), the microcomputer 210 does not detect the abnormality of the combustion fan 125 and does not detect the abnormality in the combustion fan 125 in steps S200, S210, S230, and S240 of FIG. In steps S500, S510, S530, and S540 equivalent to the above, the slope of the second conversion characteristic LN2 is corrected so that the digital current value IfD2 (microcomputer 310) approaches the digital current value IfD1 (microcomputer 210). By continuously executing steps S450 to S490 until IfD1 = IfD2, the second conversion characteristic LN2 can be corrected as in the first embodiment.

  As described above, in the fan current correction when the power is turned on, the linear current function is equivalently expressed on the basis of the digital current value IfD1 when the fan motor 130 is stopped and when the fan motor 130 is driven at the test rotation speed Ntst. The second conversion characteristic LN2 can be obtained in a manner that determines the two points. The data (intercept and slope of the linear function) indicating the corrected second conversion characteristic LN2 is stored in the RAM 212 of the microcomputer 210.

  Referring to FIG. 11 again, in the fan current correction associated with the pre-purge operation (when NO is determined in S310), microcomputer 210 performs the fan current correction according to the flowchart shown in FIG. 13 in step S400B. At the timing when step S400B is executed, the data of the second conversion characteristic LN2 determined by the fan current correction at the time of power-on (FIG. 12) is held in the RAM 212.

  Referring to FIG. 13, in step S405, the microcomputer 210 temporarily disables error detection related to the fan motor 130 during online processing, and then performs fan current correction by the processing in step S450 and subsequent steps. Specifically, the microcomputer 210 performs the second conversion characteristic LN2 by using the digital current value IfD1 when the fan motor 130 is driven at the test rotation speed Ntst as a reference in steps S450 to S540 similar to FIG. Correct the slope of the (linear function). This is because the value obtained in step S440 in FIG. 11 can be used for the information indicating the intercept of the second conversion characteristic LN2 (linear function) in the fan current correction at power-on.

  If the difference between the digital current values IfD1 and IfD2 is larger than the limit value Tlim when the second conversion characteristic LN2 before correction is used in step S495 similar to FIG. ), Together with error notification (S550), combustion by the combustion burner 115 is prohibited (S555).

  On the other hand, if the error is not notified, the microcomputer 210 returns the fan error detection invalidated in step S405 to valid in step S600, stops the fan motor 130 (S520), and corrects the fan current. finish. In this case, the combustion operation by the combustion burner 115 is permitted.

  As described above, according to the configuration of the controller according to the second embodiment, fan current correction is automatically executed when power is turned on using communication circuits 270 and 370 mounted on power supply board 200 and control board 300. Can do. As a result, even if the nonvolatile memory 215 is not disposed corresponding to the microcomputer 210, the same effect as in the first embodiment can be obtained.

  Further, by executing the fan current correction together with the pre-purge operation, the correction frequency of the second conversion characteristic LN2 can be increased to improve the detection accuracy of the fan current Ifan, and the fan motor 130 (the combustion fan) 125) abnormality diagnosis frequency can be increased.

  In the combustion apparatus according to the first and second embodiments, combustion burner 115 corresponds to an example of “combustion mechanism” in the present invention. As the combustion burner 115, for example, an oil burner may be used instead of the gas burner. Moreover, the hot water supply apparatus according to the present invention does not necessarily have to be configured for hot water supply, and may be configured as a hot water supply apparatus for heating, for example.

  Furthermore, in the combustion apparatus according to the first and second embodiments, power supply substrate 200 corresponds to an example of “first substrate”, and microcomputer 210 corresponds to an example of “first microcomputer”, and is controlled. The board 300 corresponds to an example of a “second board”, and the microcomputer 310 corresponds to an example of a “second microcomputer”. In the first embodiment, a “signal transmission path” is formed by the communication unit 400, and in the second embodiment, a “signal transmission path” is formed by the communication circuits 270 and 370.

  In the first and second embodiments, the example in which the fan current value is used for monitoring the abnormality has been described. However, when the fan current value is directly used for controlling the rotation speed of the fan motor 130, the microcomputer is configured with the same configuration. It is possible to control the fan motor 130 using the fan current value accurately detected in both 210 and 310.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 100 Hot-water supply apparatus, 101 Outlet, 110 Housing, 115 Combustion burner, 120 Heat exchanger, 125 Combustion fan, 130 Fan motor, 135 Rainproof plate, 140 Front plate, 145 Inlet, 147 Exhaust, 150 Controller, 190 AC Power supply, 200 Power supply board, 210 Microcomputer (power supply board), 211, 311 ROM, 212, 312 RAM, 213, 314 A / D converter, 214, 316 Current converter, 215, 315 Non-volatile memory, 216 Pulse generation Unit, 220 rectifier circuit, 230 smoothing capacitor, 240 power supply control circuit, 250 current detection unit, 255 pulse generation circuit, 260, 330 signal transmission circuit, 270, 370 communication circuit, 300 control board, 310 microcomputer (control board), 313 Low-pass filter, 400 communication unit, Df1, Df2 digital value, Dmax maximum value (duty ratio), Dmin minimum value (duty ratio), Dp duty ratio, IDfan fan current value, IfD1 digital current value (power supply board), IfD2 digital current Value (control board), Ifan fan current, LN1 first conversion characteristic, LN2 second conversion characteristic, LN3 third conversion characteristic, Ntst test rotation speed, Spls pulse signal, Tc pulse period, Vfan fan drive voltage.

Claims (5)

A combustion device,
A combustion mechanism;
A combustion fan for supplying combustion air to the combustion mechanism;
A fan motor that rotationally drives the combustion fan;
A first substrate on which the current detection unit of the fan motor and the first microcomputer are mounted;
A second substrate on which a second microcomputer is mounted;
A signal transmission path for transmitting an analog signal with electrical insulation between the first and second substrates,
The current detection unit generates a first analog voltage corresponding to a current detection value of the fan motor,
The first microcomputer is:
A first analog-to-digital converter that converts the first analog voltage into a first digital value;
A first current conversion unit that converts the first digital value into a first digital current value according to a predetermined first conversion characteristic;
A pulse generator that generates a pulse signal whose duty ratio changes according to the first digital current value;
The pulse generation unit calculates the duty ratio from the first digital current value according to a predetermined second conversion characteristic;
The pulse signal is transmitted to the second substrate through the signal transmission path,
The second microcomputer is:
A second analog-to-digital converter that converts a second analog voltage corresponding to the average voltage of the pulse signal into a second digital value;
A second current conversion unit that converts the second digital value into a second digital current value in accordance with a predetermined third conversion characteristic;
The combustion device comprises:
Communication means for transmitting the second digital current value from the second microcomputer to the first microcomputer;
In the first microcomputer, when the second digital current value is transmitted by the communication unit in a state where the fan motor is driven at a constant rotation speed, the second digital current value is A combustion apparatus comprising means for correcting the second conversion characteristic so as to coincide with the first digital current value calculated by the first current conversion unit. The combustion device comprises:
A non-volatile memory mounted on the first substrate and configured to rewrite stored data by the first microcomputer;
The first microcomputer writes data indicating the second conversion characteristic after correction to the nonvolatile memory,
2. The combustion apparatus according to claim 1, wherein the communication unit is a communication unit that is mounted between external terminals of the first and second microcomputers during a trial operation of the combustion apparatus. The communication means is a digital data communication circuit mounted on the first and second substrates;
The first microcomputer corrects an intercept of a linear function indicating the second conversion characteristic from a default value according to the first digital current value when the fan motor is stopped when power is turned on, and the fan motor The second digital current value transmitted from the second microcomputer by the communication circuit under the state where the motor is driven at the constant rotational speed is the first digital current calculated by the first current conversion unit. The combustion apparatus according to claim 1, wherein the slope of the linear function is corrected from a default value so as to coincide with the value.   In the pre-purge operation of the combustion fan when the combustion mechanism starts operation, the first microcomputer performs the second microcomputer by the communication circuit under a state where the fan motor is driven at the constant rotational speed. The slope of the linear function is corrected so that the second digital current value transmitted from the computer matches the first digital current value calculated by the first current conversion unit. Combustion device.   In the first microcomputer, the second digital current value is transmitted from the second microcomputer by the communication means in a state where the fan motor is driven at the constant rotation speed. The combustion apparatus according to claim 3 or 4, wherein when the error between the first and second digital current values is larger than a predetermined limit value, the operation of the combustion mechanism is prohibited.

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