JPH0331972B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a heating device equipped with a weight sensor,
In particular, the present invention relates to an apparatus for detecting the weight of an object on a placing plate in a heating chamber, and is configured such that the weight of the placing plate can be subtracted without a tare operation.

Configuration of conventional example and its problems A heating device equipped with a weight sensor has already been put into practical use. For example, in a microwave oven, the defrosting time is calculated using a weight sensor, and the weight sensor is mounted below a placing tray in a heating chamber. With this configuration, the weight of the object to be heated can be detected simply by placing it in the heating chamber, so users can use this weight sensor without the operational complexity associated with using a scale. can.

On the other hand, in a device that detects the weight of an object to be heated in a heating chamber, the problem is how to subtract the weight of the mounting plate, which is a tare processing operation. In microwave ovens, such placement plates are often made of ceramic or heat-resistant glass, and are inevitably quite heavy, weighing around 1,000 grams. Moreover, there is a large variation in the weight of ceramic plates, which can vary by ±50 grams, or about 100 grams.
However, the weight of the object to be heated is about 50 to 1000 grams, and the total weight of the mounting plate and its variation cannot be ignored. In other words, the method of mechanically subtracting the standard weight of the mounting plate from the measured weight,
The error becomes too large.

In order to subtract the weight of such a placing plate, conventional heating devices equipped with a weight sensor empty the top of the placing plate each time cooking is completed, and measure only the weight of the placing plate. A method of storing and processing it as a tare has been put into practical use. However, with this system, if the user performs an incorrect operation, for example, closes the door without taking the heated items out of the refrigerator after cooking is finished, or takes out the heated items together with the tray, it will naturally occur. The weight of the tray cannot be measured correctly, and taring fails.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to provide a heating device that can accurately subtract the weight of a mounting plate from the total measured weight without taring.

Structure of the Invention In order to achieve the above object, the heating device of the present invention includes a weight sensor that detects the weight of the object to be heated, a mounting plate on which the object to be heated is placed, and a storage device that stores the weight of the mounting plate. Equipped with writable non-volatile or battery-backed memory, the weight sensor detects the weight of only the tray using a special operation method unknown to general users at the time of shipment from the factory, and this value is recorded as above. When storing the weight of the heated object in the memory and detecting the weight of the heated object using the weight sensor, read the stored weight of the mounting plate from the memory and subtract the weight of this mounting plate from the measured total weight. With this configuration, the weight of the mounting plate can be easily subtracted without the troublesome operation of taring.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a heating device according to the present invention. A door body 2 is pivotally supported on the front surface of the main body 1 so as to be freely openable and closable, and an operation panel is provided, and a heating mode key 4 is arranged on the operation panel 3. The heating mode keys 4 include a defrost key using a weight sensor and the like.

FIG. 2 shows the construction of such a heating device. Commands input from the heating mode key 4 on the operation panel 3 are decoded by the control section 5. Now, if a heating mode key using a weight sensor such as a defrost key is pressed, the control unit 5 calculates the weight of the object to be heated 8 placed on the mounting tray 7 in the heating chamber 6 using the weight sensor 9.
Detect using. The weight detected at this time is
This is the total weight of the object to be heated 8 and the mounting plate 7, and the control unit 5 reads the weight of the mounting plate from the memory 10,
By subtracting this, only the weight of the object to be heated is calculated. With this configuration, only the weight of the object to be heated can be detected without a tare operation. Note that the procedure for storing the weight of the mounting plate 7 in the memory 10 will be described in detail later.

The weight sensor 9 can be one that detects changes in capacitance, one that detects displacement using a strain gauge, or a vibration detection method that measures the natural frequency that changes depending on the object to be heated. Data from the weight sensor 9 is input to the control unit 5 via the detection circuit 11. Further, the mounting plate 7 is rotationally driven by a motor 12, and uneven baking during microwave heating is improved.

Memory 10 was backed up by battery.
A memory such as RAM or nonvolatile memory that can retain stored contents even without power supply is used, and the weight of the mounting tray 7 is input at the time of shipment from the factory. As the memory, MN1218 manufactured by Matsushita Corporation can be used.

Now, when the weight of the object to be heated 8 is detected and the heating time is calculated, the control section 5 starts supplying power to the heating means 14 via the driver 13. In the illustrated example, the heating means is a magnetron, which is cooled by a fan 15.

Next, the procedure for inputting the weight of the mounting plate into the memory will be explained with reference to FIG. Normally, zero is displayed on the display section as shown in FIG. When a command is given to shift to the adjustment mode, the detected weight is displayed on the display section as shown in FIG. Therefore, if only the mounting plate is placed in the heating chamber, its weight will be displayed as, for example, "1035" grams. The transition to adjustment mode is performed by using a switch that does not exist on the operation panel, or by pressing specific keys on the operation panel in a specific order, or by pressing multiple specific keys at the same time. . Therefore, general users are not aware of such adjustment modes. If the displayed content is valid, input it into memory by operating a specific key. Then, the display section returns to the original zero display as shown in c of the same figure.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) Since the weight of the mounting plate, which varies widely, is measured using an actual weight sensor which also varies in performance, it is possible to measure the detected value using a combination of the weight sensor installed in the product at the time of factory shipment and the mounting plate. It can be stored accurately in memory.

(2) Such adjustments can be made using switches and keys provided on the equipment without connecting any special equipment to the equipment, and moreover, general users do not know how to do this.

(3) The above memory contents are retained even when power is not supplied, and the control unit can accurately subtract the weight of the loading tray, which may vary, without the user having to perform the troublesome operation of taring.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the main body of a heating device showing an embodiment of the present invention, FIG. 2 is a block diagram showing the same configuration, and FIG. 3 is a diagram showing a procedure for memorizing the weight of the placing tray. 5...Control unit, 6...Heating chamber, 7...Place plate,
8...Object to be heated, 9...Weight sensor, 10...Memory, 14...Heating means.

Claims (1)

[Claims] 1. A placing plate for placing an object to be heated, a heating chamber for storing the object, a heating means provided in this heating chamber, a control unit for controlling power supply to this heating means, and a It consists of a weight sensor that detects the weight of the heated object placed on it, and a writable non-volatile memory that can retain its stored contents even when there is no power supply, and a certain switch that does not exist on the operation panel is operated. The control unit determines that a transition to adjustment mode has been commanded when a specific number of keys on the operation panel are pressed in a specific order, or when a number of specific keys are pressed at the same time. When a command to decode and detect the weight of the placing plate and store it in the non-volatile memory and detect the weight of the object to be heated is input, the control section uses the weight sensor to detect the weight of the object to be heated and to store it in the non-volatile memory. A heating device configured to detect the total weight of the mounting plate and the mounting plate, read out the weight of the mounting plate stored in the nonvolatile memory, and subtract this from the above detection result.