JPH036834B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a washing machine control device that detects the turbidity of washing liquid and rinsing liquid to control the washing and rinsing processes. Conventional Structure and Problems Conventionally, as a method for detecting washing of a washing machine, there is a method of measuring the dirtiness (turbidity) in the washing liquid using a light emitting element and a light receiving element to measure the change in turbidity. However, there is a problem in that turbidity changes are difficult to detect depending on the type of detergent, the amount of detergent, the degree of dirtiness of the laundry, etc., and it is necessary to change the sensitivity of the detector. Additionally, since the output voltage of the photodetector of the detector changes slightly due to turbidity changes due to dirt, foam, etc. in the washing liquid, a smoothing capacitor is generally used to smooth the output voltage waveform of the detector for detection. take a method. However, in order to switch the sensitivity of the detector to multiple stages of two or more and set the amount of light emitted from the light emitting element to an appropriate detectable sensitivity, the time constant caused by the smoothing capacitor requires stability due to transient phenomena. It takes time to reach a certain voltage, and the disadvantage is that it is not possible to switch the sensitivity and set the amount of light emitted by the light emitting element in a short time. Purpose of the Invention The present invention eliminates the above-mentioned drawbacks and uses means for switching the sensitivity of the detector in multiple stages.
To provide a washing machine control device that can switch sensitivity in a short time and set a desired amount of light emission. Structure of the Invention The present invention includes a detector that detects the turbidity of washing liquid, a light emission output switching section that switches the light emission output of the detector in multiple stages, a smoothing section that smoothes the output of the detector, and a preset standard. It has a comparison section that compares the voltage with the output voltage of the detector, and when setting the light emission output, the light emission output switching section is sequentially switched to increase the light emission output, and the output voltage of the previous stage of the smoothing section at that time and the light emission output are increased. When the output voltage of the detector becomes higher than the reference voltage when the reference voltage is compared with the reference voltage, that is, when the output of the comparison section is inverted (from H level to L level or from L level to H level), light is emitted. output,
This is to set the light emission output for detection. DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. Fig. 1 shows the schematic configuration of a fully automatic washing machine. 1 is the main body, 2 is an outer tank, and 3 is an inner tank for washing, rinsing, and spin-drying clothes. During spin-drying, the inner tank 3 rotates for spin-drying. , perform centrifugal dehydration. 4
is a motor installed under the outer tank 2, which is used for washing,
The pulsator 5 is rotated during rinsing, and the inner tank 3 is rotated during dehydration. 6 is a detector attached to the drainage part of the outer tank 2, inside of which a light-emitting element and a light-receiving element, which will be described later, are provided facing each other, and between the light-emitting element and the light-receiving element, washing saliva and rinsing liquid are removed. The structure is such that people can come and go freely. Figure 2 shows detector 6
7 shows a control circuit mainly consisting of a light emitting element and an infrared light emitting diode. Reference numeral 8 denotes a light receiving element, which is composed of a phototransistor. The light emitting output of the light emitting element 7 passes through the washing liquid medium, is attenuated and reaches the light receiving element 8, and a light receiving output voltage is generated. 9 is a light emitting element 7
When the transmittance of the medium is low, the light receiving output becomes low and the rate of change in transmittance becomes difficult to detect, so increasing the light emitting output increases the light receiving output voltage. , allowing changes in transparency to be detected. This is generally expressed as the received light output voltage V _O =A·P _O e ^−B 〓. Furthermore, V _O :
Light reception output voltage, P _O : Light emission output of the light emitting element μ: Light attenuation coefficient (corresponds to the turbidity of laundry saliva) A, B: Coefficients. The slight change in the luminescence output voltage with respect to the turbidity μ is dVo/dμ = −A・B・Po・e ^−B 〓,
As the turbidity μ increases, the luminescence output voltage change dVo/
dμ becomes extremely small, making it difficult to detect changes in the received light output voltage. By increasing the light emission output Po, the light reception output voltage change dVo/dμ also increases, and the change in the light emission output voltage with respect to the turbidity μ can be increased. Note that the light emission output switching section 9 is composed of a ladder resistance circuit and a constant current circuit.
Reference numeral 10 denotes a smoothing section, which smoothes the output voltage of the detector 6 by using a time constant formed by a resistor _R3 and a capacitor C, since the output voltage of the detector 6 varies slightly depending on the state of the washing liquid, foam, etc. Reference numeral 11 is a comparison section, which is a predetermined reference voltage.
This circuit compares Vr (Vr=Vcc×R ₅ (R ₄ +R ₅ )) and the light emission output Vb of the detector 6. Reference numeral 12 denotes an operation control section, which controls the light emission output switching section 9 and the comparison section 11, and also controls the light emission output switching section 9 and the comparison section 11.
A control unit that controls the operation of the motor 4, display, switches, etc. via an interface circuit,
It consists of a microcomputer consisting of ROM, RAM, input/output ports, etc. The operation in the above configuration will be explained. Note that the figure shows the case where the light emission output switching section 9 is switched in eight stages. When setting the light emission output, A, B,
When the C output terminal is sequentially outputted in binary code, the ladder resistance output voltage Va is sequentially increased in a stepwise manner by the ladder resistance of the light emission output switching section 9.
The status is shown in the table below.

[Table] On the other hand, the current I _F flowing through the light emitting element 7 is
A current of I _F =Va/R ₁ flows through the constant current circuit composed of the OP and the transistor Q. In other words, when the ladder resistance output voltage Va increases, the current I _F flowing through the light emitting element 7 also increases, and the light emitting output Po increases with the current
Since it is proportional to _IF , the light emission output can be increased. The light emitting output of this light emitting element 7 is transmitted to the light receiving element 8.
, the collector current I _C flows through the resistor R ₂ and the light receiving output Vb is generated. Light receiving output voltage Vb and smoothing section 10
As shown in Figure 3a and b, Vb shows a step characteristic and Vc shows a _transient characteristic. ) is required, so the light emitting output is increased sequentially and the light receiving output is equal to the reference voltage of the comparison section 11.
When comparing whether the value has exceeded Vr, smooth part 11
When compared with the output voltage Vc, it takes time to set the light emitting output because the comparison needs to be made after the saturation voltage of Vc is reached. By comparing the light reception output Vb of the previous stage of the smoothing section 10 and the reference voltage Vr, it becomes possible to set the light emission output by sequentially switching the light emission output until it becomes equal to or higher than the reference voltage Vr in a short time. Figures 4a and 4b are characteristic diagrams for explaining the operation, in which the light emission output is increased by one level at time _t1 (C, B, A output terminals L, L, H level of the operation control section 12) and the light reception output Compare Vb and reference voltage Vr, Vb<
When Vr, the output voltage Vd of the comparison section 11 becomes Vcc, that is, the D input terminal of the operation control section 12 becomes H level,
The operation control unit 12 determines that Vb<Vr, and then increases the light emission output by one level at time _t2 and performs the same determination process. At time _t4 , since Vb<Vr, the output voltage of the comparator 11 is o, that is, the D input terminal is at level, and the operation control section 12 determines that Vb>Vr, and detects the light emission output at this time. The light emission output setting process is completed. In other words, in the method of switching the sensitivity of the detector 6 in multiple stages, the sensitivity setting value of the detector is set so that the received light output voltage is higher than a predetermined reference voltage, and the received light is compared with the reference voltage. By using the output voltage as the voltage before the smoothing section and reducing the influence of the time constant of the smoothing section, sensitivity can be set in a short time. In addition, in the sensitivity setting of the above example, the sensitivity of the detector was gradually increased (the light emission output was increased) and the received light output was set to be higher than the reference voltage. It is also possible to sequentially lower the sensitivity (reduce the light emitting output) and set the light receiving output lower than the reference voltage as the set value. Effects of the Invention As is clear from the above embodiments, according to the present invention, the light emission output of the detector is switched in multiple stages, and the output voltage of the detector is smoothed to detect changes in the turbidity of the liquid in a short time. It is possible to switch the sensitivity of the detector and set the sensitivity to achieve the desired sensitivity.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view showing a schematic configuration of a fully automatic washing machine equipped with a washing machine control device according to the present invention, FIG. 2 is a circuit diagram of a washing machine control device according to an embodiment of the present invention, and FIG. Figures a and b are signal waveform diagrams at each point of the detector and smoothing section of the same device, and Figures 4a and b are signal waveform diagrams at each point of the detector and comparison section of the same device. 6...Detector, 7...Light emitting element, 8...Light receiving element, 9...Light emission output switching section, 10...Smoothing section, 1
1... Comparison section, Vr... Reference voltage, 12... Operation control section.

Claims (1)

[Claims] 1. A detector that includes a light-emitting element and a light-receiving element facing each other and detects the turbidity of the washing liquid and the rinsing liquid based on the transmittance of light; and a light-emission output switching section that switches the light-emission output of the detector in multiple stages. , comprising a smoothing section consisting of a capacitor and a resistor that smooths the output voltage of the detector, and a comparison section that compares the output voltage of the detector with a preset reference voltage,
The turbidity change is detected by the output voltage of the smoothing part, and when setting the light emission output, the light emission output is sequentially switched by the light emission output switching part, and the voltage of the previous stage of the smoothing part and the reference voltage are compared, A washing machine control device that sets the light emission output when the output of the comparison section is reversed.