JPS62176412A - Controller of heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Technical Field> The present invention relates to a control device for a heater such as a glossy rice cooker that uses a microcomputer (hereinafter referred to as a microcomputer) to perform various controls, and in particular, it relates to a control device for a heater such as a glossy rice cooker that uses a microcomputer (hereinafter referred to as a microcomputer). This is a way to avoid it. There are various modes in which a microcomputer may run out of control, but here we will discuss what happens when the microcomputer's program counter becomes abnormal and the process moves to an AV-less computer that does not have a regular program written on it.

Prior Art> Unexplained malfunctions sometimes occur in products equipped with microcomputers. In these cases, it is assumed that the microcomputer has gone out of control for some reason.

The circuits and software are used to assume various types of runaway states and conditions and take appropriate actions, but there is no way to deal with cases where the microcontroller's program counter malfunctions and the program invades an area where no program is written. It wasn't.

Currently, a T-bit one-chip microcomputer is generally used as the microcomputer in the rice cooker. This type of MyFun has a program area divided into several pages. When there is no jump command at the end of each page, there is one that returns to the beginning of that page, and one that moves to page 0 of the next page.

On the other hand, programs are generally filled in from the top of the page,
Leave some room at the end of the page. In the empty spaces on these pages, write (○O)H or (F'F).
)H, which is not considered to be an instruction food, has been the usual practice up until now.

There are a lot of defects in the market that are thought to be caused by runaway microcomputers, and one possible scenario is that the program progresses to a place where no program has been written. If the processing where the program is not written contains (00)H or (FF)H as data as described above, the subsequent operation will vary depending on the microcomputer's instruction system, but as shown in Figure 5 ( If the program rotates in area A where no program is written as shown in a) and does not exit, or if it enters from the middle of the regular program (B) as shown in (b) of the same figure, the next step is as shown in (c) of the same figure. It is conceivable that the computer may infiltrate the page of the user, and eventually it will go out of control.

If the program progresses to an area where no program has been written, it is thought to be caused by external noise, etc. In such cases, it is not necessarily necessary to return to normal operation, but rather to cause a runaway state. FAIL when
5AFE operation is required.

The first FAIL 5AFE in the case of a rice cooker is that the microcomputer does not go out of control while the rice is being cooked. If the microcomputer goes out of control while the rice is being cooked, the rice cooker will heat up rapidly and continue in this state until the temperature fuse goes out (even if smoke or fire occurs). This is a phenomenon that occurs because even if the microcomputer is operating, temperature control is not effective because it does not pass the regular program.

Purpose 〉 In view of the above, the present invention provides a heating system that can prevent continuous heating without the need for measures such as adding circuits that lead to increased costs when the progress of a program moves to an area where the program is not written due to causes such as noise. The purpose is to provide a control device for equipment.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

First, to explain the general structure of a heater such as a jar rice cooker according to the present invention, Fig. 1 is a block diagram of a heater such as a jar rice cooker, in which 1 is an AC power supply and 2 is a control circuit. A DC power supply circuit that supplies a constant current to the microcomputer 2, 4 a heating section whose heating is controlled by a heating signal from the microcomputer 2, 5 a key manual section, 6 a temperature sensor such as a thermistor,
7 is a display section. Figure 4 is an electric circuit diagram of a jar rice cooker, in which a DC power supply circuit 2 (rectifying circuit) is connected to an AC 100V AC power supply 1 via a transformer 8 and a capacitor 9, and a constant voltage circuit 10 (switching circuit) is connected to the circuit 2. ) to which the microcomputer 2 is connected. and,
A rice cooking relay circuit 12 is connected to an output terminal of the microcomputer 2 via a drive circuit 11, and heating of a rice cooking heater 13 is controlled by ON/OFF operation of a relay contact 12a of the relay circuit 12.

In FIG. 4, reference numeral 13 indicates a switching transistor of the constant voltage circuit, and reference numeral 14 indicates a Zener diode. Further, 15 is a transistor of the drive circuit 11. And the heating section 4 is
It consists of the drive circuit 11 and a rice cooking heater 13.

The microcomputer 2 is a 4-bit one-chip microcomputer, and has a program ROM 1G, a data RAM 17, an ALU 18, and a register 19, as shown in FIG. It is driven. How many pages (for example, 64 pages) does the program ROM 1G of the microcomputer 2 have?
)), and one page can store, for example, 64 instructions.

As shown in FIG. 3, of the program writing area 22 of each page, area 2 where the regular program is written
Heating signal stop commands 25 for resetting the signal output of the drive circuit 11 are written in the empty areas 24 other than 3. That is, the blank page area 24 contains the Do of the microcomputer 2.
The command (REDO) to zero the boat 26 is arranged,
That sky? A jump command 25a for returning to the beginning of the empty area 4 is written at the end of the n area 2.t.

Note that the Do boat 26 of the microcomputer 2 is connected to the base of the transistor 15 of the drive circuit 11, and is set so that a Hi signal from the DO boat turns on the transistor 15 and turns on the contact 12a of the relay circuit 12. Therefore, the LO double signal zero signal from Do port 26)
As a result, the transistor 15 becomes 0FFL, and the contact 12a of the relay circuit 12 becomes OFF.

In the above configuration, if an abnormality occurs in the programming power of the microcomputer 2 and the program progresses to an area where no regular program is written, a signal to reset the DO boat 26 to zero will be input no matter where in the empty area 24 the program proceeds. Even if the microcomputer 2 goes out of control and the heater 13 is continuously heated, a signal to turn off the transistor 15 of the drive circuit 11 is output from the D◯ port 26.

Therefore, the fill 121) of the relay circuit 12 is cut off, the contact 12a is turned OFF, and the energization to the heater 13 is stopped.

Since the heating signal stop command is written in the empty program area 24 of all the program writing areas 22 as described above, the error status 7 when the microcomputer 2 goes out of control can be maintained.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

Effect> As is clear from the above description, the present invention includes a 17 control circuit that controls energization of a heater, and a drive circuit that turns on and off the heater according to an output signal of the control circuit, and a program of the control circuit. A heating signal stop command for resetting the output signal to the drive circuit is written in an empty area in the write area where no regular program is written.
The present invention relates to a heater control device characterized by the following features.

Therefore, according to the present invention, if the progress of the program moves to an area where no program is written due to noise or other causes, there is an excellent effect that continuous heating can be prevented without requiring measures such as adding a circuit that would lead to an increase in cost. .

[Brief explanation of drawings]

Fig. 1 is a configuration block diagram of a heater showing an embodiment of the present invention, Fig. 2 is a configuration diagram of the MyFun, Fig. 3 is a diagram showing a part of the program, and Fig. 4 is an electric circuit of the heater. figure,@
FIGS. 5(a), 5(b), and 5(c) are diagrams showing how a conventional program runs out of control. 2: Control circuit, 10: Constant voltage circuit, 11: Drive circuit, 1
2: Relay circuit, 13: Heater, 14: Zener diode, 15: Transistor, 22: Area, 24: Empty area,
25: Heating signal stop command, 26: DO port.

Claims (1)

[Claims] The control circuit includes a control circuit that controls energization of the heater, and a drive circuit that turns the heater on and off according to an output signal of the control circuit, and a blank area in which a regular program is not written in the program write area of the control circuit is provided. A control device for a heater, characterized in that a heating signal stop command for resetting an output signal to the drive circuit is written in parallel.