GB2276021A

GB2276021A - Operation control device for washing machines

Info

Publication number: GB2276021A
Application number: GB9408256A
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: GB2276021B; GB2276020B; GB9408255D0; GB9408256D0; GB2276020A

Description

2276021 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 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 t for example two p -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 2 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 microcomputert 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 25 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 3 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 host microcomputer being provided with a first function of determining whether or not interruption of signal transmission from the host microcomputer to the sub microcomputer is continuous for a predetermined period of time and a second function of interrupting operation of the incorporated equipments when a result obtained by the first function is an affirmative.

The incorporated equipments being driven under control of the sub microcomputer are interrupted when the condition that data is not transferred from the host microcomputer to the sub microcomputer continues for the predetermined period of time. The runaway of the host microcomputer is included in the condition that data is 4 not transferred from the host microcomputer to the sub microcomputer for the predetermined period of time or more. Consequently, where the program runaway occurs in the host microcomputer, an abnormal condition that the incorporated equipments are kept driving can be prevented.

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 FI G. 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 1b 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 onstate and is unlocked into an off-state alternately when operated repeatedly. The power supply switch 9 has a coil ga 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 22 and a sub microcomputer 23 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 2.2 and a reset input terminal RI of the sub microcomputer 23 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 6 the respective outputs at the high level. The microcomputers 22, 23 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 22 delivers control signals to a display circuit 17. Clock signals S CK' control commands and serial signals S HD as control data are supplied from the host microcomputer 22 to the sub microcomputer 23. A status signal S SD representative of whether or not the sub microcomputer 23 is in the reset state is supplied to the host microcomputer 22 from the sub microcomputer 23.

Referring to FIG. 1, the water supply valve 2 and the drain valve 3 are controlled by the host microcomputer 22 while the washing machine motor 4 is controlled by the sub microcomputer 23. The sub microcomputer 23 detects the disconnection of the signal line between the host and sub microcomputers 22, 23 and 7 the runaway of the host microcomputer 22, thereby interrupting the washing machine motor 4. FIG. 2 shows a detection routine of the sub microcomputer 23. In execution of the detection routine, the sub microcomputer 23 first determines whether or not the control command S HD has been delivered thereto from the host microcomputer 22 (step S1). When determining that the control command S HD has not been delivered from the host microcomputer 22, the sub microcomputer 23 starts timing (step S2). The sub microcomputer 23 determines whether or not the clock signal S CK has been delivered thereto from the host microcomputer 22 (step S3). When determining that the clock signal S CK has been delivered from the host microcomputer 22, the sub 8 microcomputer 23 clears the timed value to zero (step S4). These operations of the sub microcomputer 23 as described above are repeated. The sub microcomputer 23 receives the control signal from the host microcomputer 22 to drive the washing machine motor 4 based on the control signal when there is no disconnection in the signal line nor runaway of the host microcomputer 22.

On the other hand, the clock signal SCK cannot be exactly input to-the sub microcomputer 23 in the case where there is a disconnection in the signal line or occurrence of the runaway of the host microcomputer 22. In this case the sub microcomputer 23 determines at step S3 that the clock skgnal has not been delivered thereto from the host microcomputer 22. When the condition that the clock signal is not input to the sub microcomputer 23 continues for a predetermined period of time# for example 10 microseconds (step S5)i the sub microcomputer 23 interrupts the washing machine motor 4 where it is being driven or maintains the motor 4 in the of f state until the clock signal SCK is normally input to the sub microcomputer 23 where the motor 4 is turned off (step S6).

in accordance with this embodiment.the sub microcomputer 23 determines that there is a disconnection in the signal line or an occurrence of runaway of the host microcomputer 220 where the clock signal SCK is not delivered to the sub microcomputer 23 from the host microcomputer 22 for the predetermined period of time. The 9 sub microcomputer 23 then interrupts the motor 4. Consequently, the washing machine motor 4 can be prevented from being continuously driven under the condition of the occurrence of the signal line disconnection or runaway of the host microcomputer 22. The motor 4 can also be prevented from being started based on the previously supplied drive command from the host microcomputer 22.

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 host microcomputer being provided with a first function of determining whether or not interruption of signal transmission from the host microcomputer to the sub microcomputer is continuous for a predetermined period of time and a second function of interrupting operation of the incorporated equipments when a result obtained by the first function is an affirmative.

2. An operation control device according to claim 1, wherein the host microcomputer determines in the first function whether or not interruption of transfer of clock signals from the host microcomputer to the sub microcomputer is continuous for the predetermined period of time.

3. An operation control device for a washing machine 11 substantially as herein described with reference to the accompanying drawings.