JPH087460Y2 - Rice jar control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a control device for a cooker, and more particularly to a control device for controlling an electric part such as a heater for heating a cooker by using a microcomputer.

(Prior Art) Generally, in a cooker with a built-in microcomputer, for example, a rice cooker with a built-in microcomputer, it is necessary to detect a number of temperatures with one temperature detection element, and therefore, it is necessary to set a plurality of reference temperatures The D / A conversion circuit is adopted in. However, since the D / A data that sets the reference temperature is stored in the memory (ROM) together with the program, if one reference temperature needs to be slightly changed during mass production of the rice cooker, for example, rice cooker Since the control device with the same configuration is applied to rice cookers with different capacities, it is impossible to change the D / A data even when it is necessary to change the heat retention temperature according to the capacities. Therefore, it is usually performed by changing the resistance constant of the temperature detection circuit.

(Problems to be solved by the invention) However, in this case, not only the target reference temperature but also other reference temperatures are shifted in parallel, so that there is a problem that the best cooking result cannot be obtained.

Therefore, even if the rice cookers are of the same model, if the rice cookers have different rice cooking capacities, the control devices cannot be shared. Therefore, there is a drawback in that a dedicated control device must be designed and manufactured, which increases the manufacturing cost. It was

(Means for Solving Problems) In order to solve this problem, the present invention provides a temperature detecting element, reference temperature setting means including a D / A conversion circuit for setting various reference temperatures, the temperature detecting element, and Built-in comparator for comparing signals from the reference temperature setting means, and storage means for storing D / A data and operating programs for setting various reference temperatures, and heaters according to the operating programs based on the signals from the comparators. In a rice cooker control device comprising a microcomputer for controlling, the microcomputer is provided with at least one D / A data changing input port for changing the reference voltage corresponding to the reference temperature when the rice cooker is kept warm. It is characterized by being selectively connected to the level line or the low level line.

(Operation) The control device according to the present invention is particularly suitable for D /
By providing a D / A data change input port for changing A data and connecting the input port with a jumper wire to a high level or low level line of a printed circuit board on which a microcomputer is mounted, D / A data is changed depending on the status. Therefore, even if it is necessary to change the reference temperature during mass production, simply switch the connection of the input port of the microcomputer to the printed board from the high level line to the low level line or vice versa. You can change only the reference temperature you want to change.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is a microcomputer, 2 is D /
A conversion circuit, 3 is a temperature detecting element, 4 is a comparator, Rn (n =
1 to 11) are resistors, the temperature detecting element 3 constitutes the temperature detecting means together with the resistor R ₃ , and the resistors R ₁ and R ₂ constitute the reference temperature setting means together with the D / A conversion circuit 2. The non-inverting input terminal of the comparator 4 has a voltage corresponding to the reference temperature, that is, a resistance.
A reference voltage set by R ₁ , R ₂ and the D / A conversion circuit 2 is input, and a voltage corresponding to the detected temperature detected by the temperature detection element 3 is input to its inverting input terminal.

The microcomputer ₁ is provided with a D / A data changing input port A ₁ for changing a particularly important reference temperature, for example, a reference voltage corresponding to a reference temperature during heat retention.
When the data change input port A ₁ is connected to VDD, for example, as shown in FIG.
(A0) in base, and (A0 when connected to Vss
1) is programmed to choose.

When using the prototype, for example, connect the input port A ₁ for changing D / A data to VDD to
If the data is set to (AO) and it is necessary to change the D / A data to (A1) during mass production, the input port for changing the D / A data that should be connected to the VDD line on the board By connecting A ₁ to the Vss line on the board with a jumper wire, the D / A data is changed to (A 1) and the reference voltage input to the comparator 4 is changed from V ₁ to V _{2 accordingly.} . In this case, the reference voltages corresponding to the other reference temperatures are maintained as they are.

The operation of the microcomputer 1 at this time is as follows. First, when the rice cooking is completed and the heat retention mode is entered, it is first determined whether or not the D / A data changing input port A ₁ is at the high level (step 1). Is set to hexadecimal (A0) (step 2), and if it is low level, (A1) is set (step 3).

As a result, the reference voltage corresponding to the reference temperature during heat retention is set, and if the input from the comparator 4 that compares the detected temperature with the reference temperature is at high level (step 4), the heater is energized (step 5). If the level is low, the power to the heater is stopped (step 6) and the temperature of the cooked rice in the rice cooker is maintained at a predetermined temperature.

In the above description, only one input port for changing D / A data is provided and only the reference voltage corresponding to the warm reference temperature is changed, but two or more input ports for changing D / A data are used. May be provided so that a plurality of types of D / A data can be selected. For example, if two D / A data changing input ports are provided, four types of selection can be made as the reference temperature setting D / A data depending on the combination of their connection states to the board.

(Effects of the Invention) As is apparent from the above description, according to the present invention, by programming so that the D / A data of the program is changed according to the state of the input port of the microcomputer, the input port and the board Only by changing the connection of the jumper wire to be connected with, it is possible to change only the reference temperature that is desired to be changed independently, and it is possible to manufacture a cooker having desired characteristics.

[Brief description of drawings]

FIG. 1 is a block diagram of a control device for a cooker according to the present invention,
FIG. 2 is a characteristic diagram of the D / A data conversion, and FIG. 3 is a flow chart diagram thereof. 1 ... Microcomputer, 2 ... D / A conversion circuit, 3
...... Temperature detection element, 4 …… Comparator, Rn (n = 1 to 11)…
…resistance.

Claims (1)

[Scope of utility model registration request] 1. A temperature detecting element and various reference temperatures are set.
Reference temperature setting means including a D / A conversion circuit, a comparator for comparing signals from the temperature detection element and the reference temperature setting means, and storage means for storing D / A data and operating programs for setting various reference temperatures In a rice cooker control device including a microcomputer for controlling a heater according to the operation program based on a signal from the comparator, at least one D for changing a reference voltage corresponding to a reference temperature when the rice cooker is kept warm. A rice cooker control device characterized in that a microcomputer is provided with an input port for changing data, and the input port is selectively connected to a high level line or a low level line.