GB2276020A

GB2276020A - Operation control device for washing machines

Info

Publication number: GB2276020A
Application number: GB9408255A
Authority: GB
Inventors: Masahiro Imai; Yosiyuki Makino; Hiroshi Ikeda
Original assignee: Toshiba Corp; Toshiba Audio Video Engineering Co Ltd
Current assignee: Toshiba Corp; Toshiba AVE Co Ltd
Priority date: 1990-08-27
Filing date: 1991-08-27
Publication date: 1994-09-14
Anticipated expiration: 2011-08-27
Also published as: GB2276021A; GB9408256D0; GB2276020B; GB2276021B; GB9408255D0

Abstract

An operation control device for a washing machine incorporating equipments such as a motor (4) and electromagnetic valves (2, 3) includes a sub microcomputer (25) for controlling the equipments and a host microcomputer (24) supplying control commands to the sub microcomputer (25) to control the same. The sub microcomputer (25) is provided with a first function of returning a command supplied from the host microcomputer (24) to the host microcomputer (24). The host microcomputer (24) is provided with a second function of collating the command returned from the sub microcomputer (25) with a corresponding command stored therein to thereby determine whether or not the command returned from the sub microcomputer (25) agrees with the corresponding command and a third function of supplying an operation command to the sub microcomputer (25) so that the command is executed by the sub microcomputer (25) when a result obtained by the second function is an affirmative. <IMAGE>

Description

OPERATION CONTROL DEVICE FOR WASHING MACHINES This invention relates generally to a washing machine controlled by a microcomputer, and more particularly to an operation control device for the washing machine including a host microcomputer and a sub microcomputer operated in response to a control command from the host microcomputer so that equipments such as a motor are controlled by these microcomputers in association.

Conventional washing machines are provided with a microcomputer-based operation control circuit. Control and operation equipments such as electromagnetic valves and a motor incorporated in the washing machine are controlled based on operation of the microcomputer. These equipments incorporated in the washing machine will be referred to as "incorporated equipments" hereafter. A single microcomputer is usually provided in the conventional washing machine.

The cost of a one-chip microcomputer employed in the conventional washing machines has recently been increased progressively as the increases in the number of terminals and the memory capacity of the microcomputer. A plurality of, for example two, microcomputers have recently been employed in the washing machine for the purpose of cost reduction. In such a case a sub microcomputer controls the incorporated equipments based on control commands from a host microcomputer.

However, the following defects can be found in the conventional washing machine employing a plurality of microcomputers. First, influences of noise or the like cause data error in the control commands transferred from the host microcomputer to the sub microcomputer as the increase in the number of microcomputers. Furthermore, the probability of occurrence of runaway of the microcomputers is increased. Consequently, the incorporated equipments are abnormally operated and in the extreme, the washing machine runs into danger.

Second, if the runaway of the sub microcomputer should occur, a washing machine motor would keep running even when the operation command for running it is not supplied from the host microcomputer. In this case the washing machine motor could not be interrupted by the host microcomputer.

Third, where noise invades a transmission line during transmission of serial data between the computers or an error occurs in the output of the host microcomputer, the serial data lacks a plurality of bits thereof or error data invades the data on the transmission line. As the result of occurrence of such a situation, the subsequent serial data transfer timing is deviated by the lacked bits of data or increased data, resulting in change in the contents of the transferred data.

Therefore, an object of the present invention is to provide an operation control device for a washing machine wherein a plurality of microcomputers are incorporated and the equipments incorporated in the washing machine can be prevented from being abnormally operated because of runaway of the microcomputers, the abnormal condition of the data transmission line, and data missing due to noise.

According to the present invention, there is provided an operation control device for a washing machine incorporating equipments such as a motor and electromagnetic valves, the operation control device comprising a sub microcomputer for controlling the equipments incorporated in the washing machine and a host microcomputer supplying control commands to the sub microcomputer to control the same, the sub microcomputer being provided with a first function of returning a command supplied from the host microcomputer to the host microcomputer, the host microcomputer being provided with a second function of collating the command returned from the sub microcomputer with a corresponding command stored therein to thereby determine whether or not the command returned from the sub microcomputer agrees with the corresponding command and a third function of supplying an operation command to the sub microcomputer so that the command is executed by the sub microcomputer when a result obtained by the second function is an affirmative.

The contents of the control command transferred to the sub microcomputer are compared with the contents of the control command returned to the host microcomputer.

When the contents of the former agree with those of the latter, the operation of the sub microcomputer is initiated. Consequently, the incorporated equipments can be controlled based on the control command free of error.

The invention will be described, merely by way of example, with reference to the accompanying drawings in which: FIG. 1 is a circuit diagram showing an electrical arrangement of the washing machine in accordance with an embodiment of the invention; and FIG. 2 is a time chart showing an example of the washing operation performed by the washing machine in FIG. 1.

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

FIG. 1 shows an electrical arrangement of a fully automatic washing machine, electromagnetically driven water supply and drain valves 2 and 3 each serving as an incorporated equipment and a washing machine motor 4 also serving as the incorporated equipment are connected through respective triacs 5 to 8 and a power supply switch 9 between terminals la and ib of a power supply plug 1 to be connected to a commercial ac power source.

The triacs 7, 8 are provided for forward and reverse rotations of the washing machine motor 4, respectively.

The power supply switch 9 is provided for a power circuit to which the incorporated equipments such as the valves 2, 3 and the motor 4 are connected. The power supply switch 9 is locked in an on-state and is unlocked into an off-state alternately when operated repeatedly.

The power supply switch 9 has a coil 9a and is forced to be unlocked into the off-state when the coil 9a is energized.

A rectifying and smoothing circuit 10 is also connected between the terminals la, 1b of the power supply plug 1. A voltage regulating circuit 11 is connected to an output side of the rectifying and smoothing circuit 10. A host microcomputer 24 and a sub microcomputer 25 are connected to an output side of the voltage regulating circuit 11. Reset circuits 14 and 15 are also connected to the output side of the rectifying and smoothing circuit 10. Outputs of the reset circuits 14, 15 are supplied to a reset input terminal RI of the host microcomputer 24 and a reset input terminal RI of the sub microcomputer 25 respectively. When an electrical power is supplied to the washing machine, the reset circuits 14, 15 maintain the respective outputs at the low level for an instant and subsequently, maintain the respective outputs at the high level. The microcomputers 24, 25 are reset when the low-level voltage is applied to the respective reset input terminals RI. Each microcomputer is changed from the reset state to the reset release state when the voltage is switched from the low-level to the high-level. The reset state refers to an initial condition of each microcomputer and the reset release state to the condition that a control command from an outer circuit can be supplied to each microcomputer and each microcomputer is operable in accordance with the control command. The host microcomputer 24 delivers control signals to a display circuit 17.

The water supply valve 2 and the drain valve 3 are controlled by the host microcomputer 24 and the washing machine motor 4 is controlled by the sub microcomputer 25. The control of the washing machine motor 4 is performed by the sub microcomputer 25 after it is confirmed that the control command has been exactly delivered from the host microcomputer 24 to the sub microcomputer 25. More specifically, as shown in FIG.

1, five signal lines are provided between the host microcomputer 24 and the sub microcomputer 25, that is, a signal line 26 through which a timing signal is transferred from the host microcomputer 24 to the sub microcomputer 25, a signal line 27 through which data or the control command is transferred in the unit of 1 bit in synchronism with the timing signal, a signal line 28 through which data with the same contents as those of the data transferred from the host microcomputer 24 to the sub microcomputer 25 is returned to host microcomputer 24 in the unit of 1 bit, a signal line 29 through which a data return timing signal is delivered so that the timing for returning the data to the host microcomputer 24 is given to the sub microcomputer 25, and a signal line 30 through which the host microcomputer 24 delivers the operation command so that the sub microcomputer 25 initiates its operation in accordance with the control command.

Now referring to FIG. 2, the host microcomputer 24 delivers the control command data to the sub microcomputer 25 (step S2) in the condition that the operation commands for driving the incorporated equipments are not generated (step S1). Then, the sub microcomputer 25 returns the data with the same contents as those of the delivered control command data to the host microcomputer 24 and the host microcomputer 24 receives the data returned from the sub microcomputer 25 (step S3). The sub microcomputer 25 thus serves as data returning means. Then, the host microcomputer 24 determines whether or not the control command data delivered to the sub microcomputer 25 agrees with the data returned thereto from the sub microcomputer 25 (step S4). When determining that the delivered control command data agrees with the returned data, the host microcomputer 24 delivers the operation command, which command is received by-the sub microcomputer 25. The sub microcomputer 25 then drives and controls the washing machine motor 4 in accordance with the operation and control commands.

On the other hand, when determining that the delivered data does not agree with the returned data (step S4), the host microcomputer 24 redelivers the data to the sub microcomputer 25 and delivers the operation command to the same when all the transferred data agrees with the returned data.

In accordance with this embodiment, the sub microcomputer 25 is arranged to start controlling the washing machine motor 4 after it is confirmed that the contents of the control command delivered to the sub microcomputer 25 from the host microcomputer 24 are correct. Consequently, the sub microcomputer 25 can be prevented from starting its operation in accordance with an error control command and the safety can be secured.

The foregoing disclosure and drawings are merely illustrative of the principles of the present invention and are not to be interpreted in a limiting sense. The only limitation is to be determined from the scope of the appended claims.

Claims

1. An operation control device for a washing machine incorporating equipments such as a motor and electromagnetic valves, the operation control device comprising a sub microcomputer for controlling the equipments incorporated in the washing machine and a host microcomputer supplying control commands to the sub microcomputer to control the same, the sub microcomputer being provided with a first function of returning a command supplied from the host microcomputer to the host microcomputer, the host microcomputer being provided with a second function of collating the command returned from the sub microcomputer with a corresponding command stored therein to thereby determine whether or not the command returned from the sub microcomputer agrees with the corresponding command and a third function of supplying an operation command to the sub microcomputer so that the command is executed by the sub microcomputer when a result obtained by the second function is an affirmative.

2. An operation control device for a washing machine substantially as herein described with reference to the accompanying drawings.