JP2760642B2 - Cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention detects the weight of a food placed on a cooking object placing table in a cooking chamber, and outputs a signal corresponding to the weight. The present invention relates to a heating cooker provided with a weight sensor that outputs a heat signal, and controlling a heating operation based on a detection signal from the weight sensor.

(Prior Art) Conventionally, in a cooking device such as a microwave oven, as shown in FIG. 7, food is placed on a turntable 2 which is a mounting table of an object to be cooked in a cooking chamber 1. Is detected by the weight sensor 3. In this case, since the weight sensor 3 detects the weight of the turntable 2 together with the food, the weight of the turntable 2 on which no food is actually placed is detected in advance,
The weight of only the food is detected by subtracting the detected weight of only the turntable 2 from the detected weight of the turntable 2 on which the food is placed. However, if the weight of the turntable 2 with no food placed thereon is detected in advance,
Because the weight detection is troublesome and the turntables vary in weight individually, the manufacturer adjusts the zero point individually before shipping the product. This zero adjustment is as follows. As shown in FIG. 7, the variable resistor 5 provided at the bottom of the microwave oven main body 4 was adjusted by a screwdriver through a hole 6 at the bottom in a state where only the turntable 2 was arranged, and the variable resistor 5 was provided. The output of the reference value generation circuit
The same level as the output of the weight sensor is set. That is, the variable resistor 5 functions as a storage unit for storing the reference value.

In some cases, the variable resistor 5 for adjusting the zero point is adjusted from the side of the operation panel 7 as shown in FIG.

(Problems to be Solved by the Invention) However, in the above conventional device, the variable resistor 5 must be adjusted so that the output of the reference value generating circuit is at the same level as the output of the weight sensor. It requires delicate adjustment, and it takes time to adjust the zero point. For this reason, when the zero point is adjusted on the production line, the line must be stopped, which causes a problem that the productivity is reduced and eventually the assemblability is reduced.

In addition, the above-described zero point adjustment work can be performed only by the manufacturer side, and cannot be performed by the user side,
There are the following problems. For example, if the output characteristic of the weight sensor 3 changes due to vibration during transportation of the product, an error occurs in the detected weight at the time of use on the user side. Even if the user notices this, the zero point is readjusted. There was a problem that it was not possible.

The present invention has been made in view of the above circumstances, and an object thereof is to perform so-called zero point adjustment easily in a short time, and furthermore, it is possible to perform this on a maker side and a user side, and it is easy to assemble. It is an object of the present invention to provide a heating cooker which can improve the weight, can always obtain an accurate weight detection result, and can suppress an increase in the number of parts.

[Configuration of the Invention] (Means for Solving the Problems) The present invention detects a weight of a food placed on a cooking object placing table in a cooking chamber and outputs a signal corresponding to the weight. And a switch for performing various settings or cancellation of settings, wherein the heating operation is controlled based on an input from the switch and a detection signal from the weight sensor. A non-volatile memory for storing a detection signal from the weight sensor in a state where no food is placed thereon as reference data, and a non-volatile memory for reading the detection signal from the weight sensor and writing the read signal to the non-volatile memory. Writing means;
It is characterized in that a writing control means for executing writing by the writing means when a specific operation different from a normal operation is performed on the switch is provided.

(Operation) When the switch is operated in a state where no food is placed on the work table, the writing unit writes the detection signal from the weight sensor as reference data into the non-volatile memory and stores it. You. The control for such storage can be performed by an electronic control circuit such as a microcomputer. Therefore, unlike the variable resistor of the conventional reference value generating circuit, it is not necessary to make fine adjustment in an analog manner. The adjustment can be easily performed in a short time.

In this case, since the cooking device is individually provided with a writing means and a non-volatile memory, the zero point adjustment can be easily performed not only on the maker side but also on the user side by performing a specific operation of the switch. it can.

Further, in this case, since the above-mentioned switch is a switch originally provided for the heating cooker to perform various settings or cancellation of the settings, it is not necessary to provide a dedicated switch, and it is possible to suppress an increase in the number of parts. .

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

First, FIG. 2 shows a microwave oven as a heating cooker, and a cooking chamber 12 is formed inside a microwave oven main body 11. The cooking chamber 12 is opened and closed by a door 13. An operation panel 14 is provided on the front of the range main body 11, and the operation panel 14 has a "high range" setting switch 15 as shown in FIG.
a, a menu selection switch such as a "low range" setting switch 15b, a "decompression" setting switch 15c, a group of switches 15 such as a cancel switch 15d, a display 16a, and a buzzer 16b
And so on. A motor 17 (see FIG. 1) for driving a turntable is provided below the bottom plate of the cooking chamber 12, and a rotating shaft 17a of the motor 17 projects from the bottom plate of the cooking chamber 12 to the inside. A turntable 18 as a work table is removably attached to the protruding end of the rotating shaft 17a.

FIG. 1 shows an electrical schematic configuration of a microwave oven together with a mechanical schematic configuration. Waveguide 19 at the top of cooking chamber 12
Is formed, and a magnetron 20 is provided at the end of the waveguide 19, and the microwave output from the magnetron 20 is supplied to the cooking chamber 12 to cook the food. . Power is supplied to the magnetron 20 through a first door switch 21, a main relay 22, a rectifier circuit 23, an inverter circuit 24, and a high-frequency transformer 25. The main relay 22 is controlled by a microcomputer 26, and the inverter circuit 24 is controlled by an inverter control circuit 27 which is controlled by the microcomputer 26 to change the output of the magnetron 20. It has become.
Further, the microcomputer 26 has the operation panel 14 described above.
, A display group 16a and a buzzer 16b are connected.

On the other hand, the weight sensor 28 includes a displacement detector 30 and an oscillation circuit 31 provided on a sensor mounting plate 29 as shown in FIG. The displacement detector 30 includes a fixed electrode 32 and a movable electrode 33, and the distance between the movable electrode 33 and the fixed electrode 32 changes according to the vertical displacement of the motor 17, so that the distance between the two electrodes 32, 33 is increased. The capacitance changes. The oscillating circuit 31 processes an electric signal corresponding to the capacitance between the two electrodes 32 and 33 into an oscillating signal and outputs the oscillating signal. In this case, a detection signal (frequency signal) Fout which is directly proportional to the weight applied to the motor 17 Is output (see FIG. 4).

A non-volatile memory 34 is connected to the microcomputer 26. The non-volatile memory 34 has a frequency of a detection signal from the weight sensor 28 in a state where no food is placed on the turntable 18. This is for storing the level as reference data.

Now, the microcomputer 26 includes the switch group 15
In addition to controlling the heating operation based on the detection signal from the weight sensor 28, the nonvolatile memory 34 also has a function as a writing unit for storing reference data in the nonvolatile memory 34, and a writing control for controlling the execution of the writing unit. It also functions as a means.

The operation of the above configuration will be described together with the control contents of the microcomputer 26.

FIG. 5 shows the program contents as the writing means and the writing control means of the microcomputer 26. This program starts when the power plug is plugged into the power supply.

Now, for example, when the worker on the manufacturer side attaches the turntable 18 to the rotating shaft 17a and then plugs the power plug into the power supply, the microcomputer 26 first starts time counting (step S1). And this 2
If the cancel switch 15d is turned on before the minute has elapsed (steps S2 and S3), the detection signal (frequency signal) Fout from the weight sensor 28 is read (step S2).
4) The period from the rise of the first pulse of the signal of the frequency of the detection signal Fout to the rise of the next pulse is counted to determine a cycle, and the frequency (the level of the detection signal) is determined from the cycle. This frequency is converted into reference data F0 (step S5), and the reference data F0 is written to the nonvolatile memory 34 (step S6). Thereafter, the buzzer 16b is notified (step S7) to notify the end of writing.

The reference data F0 is stored in the microcomputer 26.
Is handled as follows when controlling the heating operation. FIG. 6 shows the contents of a control program for the heating operation of the microcomputer 26. First, the reference data F0 is read from the nonvolatile memory 34 (Step P1). In this case, the reference data F0 has a detection signal Fout of 16 kHz (therefore, only the turntable 18 weighs 1120 g, see FIG. 4).
The value corresponds to the case of. Thereafter, the detection signal (frequency signal) Fout from the weight sensor 28 is read (step P
2), Count the time from the rise of the first pulse of the frequency signal of this detection signal Fout to the rise of the next pulse to find the cycle, find the frequency (level of the detection signal) from this cycle, and detect this frequency The data is converted into data Fk (step P3) and stored in the RAM of the microcomputer 26 (step P4). In this case, the detection data Fk is, for example, the detection signal Fout is 28.8 kHz (therefore, the turntable 18)
And the total weight of the food and the food is 5120 g (see Fig. 4).

Next, this detection data Fk is ± 66 Hz with respect to the reference data F0.
(Step P5). The purpose of this determination is to determine whether or not food is placed on the turntable 18. If the detection data Fk is within a range of ± 66 Hz with respect to the reference data F0 ("YES" in step P5) )), It is determined that no food is placed. In this case, the flag FGL1 is turned off (step P6). If it is not within the range ("NO" in step P5), it is determined whether the detection data Fk is lower than the reference data F0 (step P5).
P7) If the detection data Fk exceeds the reference data F0 (“NO” in step P7), that is, if food is placed on the turntable 18, the process proceeds to step P6 and the detection data Fk is changed to the reference data F0. If it is less than (step
If “YES” in P7), that is, if the turntable 18 is not attached, the flag FLG1 is turned on (step P8).

After this, the menu selection switch is operated (step
(Determined in P9), the start switch is operated (step
If the door switch 37 (see FIG. 1) is ON (determined in step P11), the flag FLG1 is determined.
Is on or off (Step P1
2). If the flag FLG1 is on, the message "Turntable 18
"No" is displayed on the display 16 (step P13).
If the flag FLG1 is off, it is determined whether the flag FLG2 is either on or off (step P14). This flag FLG2 is previously set to off by initial setting. Therefore, the flag FLG2 is initially off, and the weight Fs of the food is determined based on the reference data F0 and the detection data Fk (step P15). That is, the weight Fs of the food is determined by subtracting the reference data F0 from the detection data Fk. In this case, the detection data Fk is 28.8 kHz as described
(Equivalent to 5120 g) and the reference value data F0 is 16 kHz (equivalent to 1120 g), so that the weight Fs of the food is determined to be 4000 g. Thereafter, the determined weight is displayed and the heating time is set accordingly (step P16), and the magnetron 20 is driven to start the heating operation (step P17).
The flag FLG2 is turned on (step P18). Thereafter, if the heating time does not exceed the set time (determined in Step P19), the process returns to Step P11. If the heating time has elapsed, the flags FLG1 and FLG2 are turned off, and the driving of the magnetron 20 is stopped to end the heating operation. (Step P20).

As is clear from the above description, the turntable
If there is a specific operation such as turning on the cancel switch 15d, which is not normally operated, within two minutes after the power plug is inserted and no food is placed on the device 18, the writing means is executed and the weight is reduced. The detection signal Fout from the sensor 28 is written and stored in the nonvolatile memory 34 as the reference data F0. The control for such storage can be performed by an electronic control circuit such as the microcomputer 26. Therefore, unlike the variable resistor of the conventional reference value generating circuit, there is no need to make fine adjustments in an analog manner. Zero point adjustment can be easily performed in a short time.

In this case, since the microwave oven includes the writing means, the writing control means, and the nonvolatile memory 34, the zero point adjustment can be easily performed not only on the maker side but also on the user side by performing a specific operation of the switch group 15. It can be performed. Therefore, if the output characteristics of the weight sensor 28 change due to vibrations or the like during transportation of the product, an error occurs in the detected weight at the time of use on the user side, but this is determined by the user based on the weight display in step P16. You can readjust the zero.

Furthermore, in this case, the cancel switch 15d for executing writing is a switch originally provided for canceling the setting of the microwave oven, so that a dedicated switch is not required, and an increase in the number of parts is suppressed. be able to.

In the above-described embodiment, the cancel switch 15d is exemplified as a switch that is specifically operated to execute writing. However, this may be a switch for various settings.

In addition, the present invention is not limited to the above embodiment, and can be implemented with various modifications without departing from the scope of the invention.

[Effects of the Invention] As is clear from the above description, the present invention detects the weight of a food placed on a cooking object placing table in a cooking chamber and outputs a signal corresponding to the weight. A sensor for controlling the heating operation based on an input from the switch and a detection signal from the weight sensor, wherein the heating operation is controlled based on an input from the switch and a detection signal from the weight sensor. A non-volatile memory for storing a detection signal from the weight sensor in a state where no food is placed on the table as reference data, and a detection signal from the weight sensor for reading and writing to the non-volatile memory Writing means, and writing control means for executing writing by the writing means when a specific operation different from a normal operation is performed on the switch. With this, the so-called zero point adjustment can be easily performed in a short time, and
This can be performed by the manufacturer and the user,
It is possible to improve the assemblability, always obtain an accurate weight detection result, and suppress an increase in the number of parts.

[Brief description of the drawings]

1 to 6 show an embodiment of the present invention, FIG. 1 is a block diagram showing a structure of a main part together with FIG. 2, FIG. 2 is a perspective view of a microwave oven, and FIG. , Fourth
FIG. 5 is a diagram showing the relationship between the detection signal and the weight, FIG. 5 is a flowchart showing the contents of the writing control, and FIG. 6 is a flowchart showing the contents of the heating cooking control. FIG. 7 is a schematic vertical sectional front view showing a conventional example, and FIG. 8 is a perspective view from the rear of an operation panel showing a different conventional example. In the figure, 12 is a cooking chamber, 15 is a switch group, 18 is a turntable (table to be cooked), 20 is a magnetron, 26 is a microcomputer (writing means, writing control means), 28 is a weight sensor, 30 is A displacement detector, 31 is an oscillation circuit, and 34 is a nonvolatile memory.

Claims (1)

(57) [Claims] 1. A weight sensor for detecting the weight of a food placed on a cooking object placing table in a cooking chamber and outputting a signal corresponding to the weight, and for performing various settings or canceling the settings. A switch, wherein the heating operation is controlled based on the input from the switch and the detection signal from the weight sensor, wherein the food is not placed on the work table. A non-volatile memory for storing a detection signal from the weight sensor as reference data, and a writing unit for reading the detection signal from the weight sensor and writing the read signal to the non-volatile memory;
A heating control unit for performing writing by the writing unit when a specific operation different from a normal operation is performed on the switch;