JPH01185710A - Water level controller - Google Patents

Abstract

PURPOSE:To control a water level with high accuracy corresponding to a various kinds of initial conditions by performing the control of the water level with a prescribed value when the water level in a tank at the time of starting feedwater is set less than a prescribed value and also when the output signal of a water level detecting means at the time of starting the feedwater is set outside the dispersion range of the output signal at the water level of zero. CONSTITUTION:The water level detecting means to convert the water level by detecting to frequency data, and a control means 4 which stores a prescribed frequency and calculates a decision frequency corresponding to a desired water level by inputting the frequency data outputted from the water level detecting means 3 and performs the control of the whole of an equipment are provided. And when the water level is tank at the time of starting the feedwater is less than the prescribed value and also the frequency at that time is set outside the dispersion range of the frequency at the water level of zero of the water level detecting means 3, the control of the water level is performed by the prescribed value. In such a way, the dispersion of the water level detecting means 3 at a low water level can be corrected, and the control of the water level can be performed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a water level converting device used to control the water level in appliances such as electric washing machines and electric dishwashers.

BACKGROUND OF THE INVENTION In recent years, water level detection means have been increasingly used to control the water level of equipment. Therefore, the principle of general water level detection will be explained using FIGS. 2, 3, and 4. Second
The figure is a plan view of a displacement detection unit that converts changes in pressure proportional to the water level into changes in coil inductance, and Figure 3 is an electrical circuit diagram of an oscillation circuit that converts changes in coil inductance into changes in frequency. It is. In Figure 2, P
15 is a thin film diaphragm made of rubber or the like, 1e is a coil, and 17 is a magnetic body fixed to the diaphragm 15 and movable in the vertical direction in FIG. , 18 is a spring that suppresses the displacement of the magnetic body 17, 19 is an adjustment screw, 2o is an outer frame for fixing the circumferential portion of the diaphragm 16, the coil 1v1e, and the adjustment screw 19), and the coil 16 is wJs. It is part of the oscillation circuit shown in the figure. In Figure 3,
21 is an inverter, 22 is a feedback resistor, and 23 and 24 are capacitors.

With the above configuration, when the pressure P proportional to the water level applied to the diaphragm 15 changes, the magnetic body 17 is displaced in the vertical direction while being acted on by the spring 18. At this time, carp 7t, 16
As the magnetic body 17 moves inside the coil A/1/16, the inductance changes.The frequency of the oscillation circuit is determined by the inductance of the coil 1e and the capacitances of the capacitors 23 and 24, so the inductance of the coil A/16 changes. When the water level changes, the frequency changes.The relationship between the water level and the frequency is expressed in a graph as shown in Figure 4.In the figure, the relationship between the water level and the frequency is one-to-one, so when trying to detect a certain water level, Then all you had to do was detect the frequency at that time.

Problems to be Solved by the Invention However, when the ambient temperature used changes, and even during mass production, the diaphragm 16° coil/l/16
．． Magnetic material 17. Spring 18. If the characteristics of the capacitors 23, 24, etc. vary, the relationship between the water level and frequency will be as shown in FIG. In the figure, q represents the upper limit of variation, h represents the lower limit of variation, and i is indicated by a broken line.
is its center line. The reason why the variation is minimized when h=hb when the water level is 0≦h≦hb is because the adjustment screw 19 is used to adjust the frequency so that when the water level h=hb at room temperature, the frequency f=fb. be. If the relationship between water level and island frequency varies in this way, for example, if you try to set the water level to ha and detect that the frequency has become 8, the actual water level will vary from hal to ha2, and especially at low water levels, the water level will vary. There was a problem that control could not be performed with high precision.

Therefore, the output frequency of the water level detection means before the start of water supply is regarded as the value of the water level 0, and the value at the time of the water level 0 (fh in Fig. 7,
f,, fg) to correct the detected water level data (7th
Although it is conceivable that the straight line he'-q in the figure may occur, it could not be corrected if data outside the variation range of the detection means (X in FIG. 7) was output from the detection means. Moreover, if there is residual water in the tank before water supply starts, an error occurs in water level data correction, and water level control cannot be performed accurately.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to accurately control water level by correcting water level data in accordance with various initial conditions.

Means for Solving the Problem In order to achieve this object, the first means of the present invention is to ensure that the water level in the tank at the start of water supply is below a predetermined value, and that the output of the water level detection means at the start of water supply is The water level is controlled at a predetermined value when the signal is outside the variation range of the output signal when the water level is 0.

Furthermore, if the second technical means of the present invention detects that the water level in the tank at the start of water supply is equal to or higher than a predetermined value, the water level is controlled based on the water level data from the previous water supply. If time data is not available, water level control is performed based on predetermined water level data.

Operation: With this first means, the water level can be controlled by correcting the water level data even when the output of the water level machine 8 means is outside the variation range. Further, by using the second means, water level control can be performed with high accuracy even when water initially remains in the tank.Embodiments Below, embodiments of the present invention will be described with reference to the drawings.

Figure 1 is a block diagram of the main parts when the present invention is applied to a fully automatic washing machine, Figure 6 is a characteristic diagram for describing the method of calculating the frequency corresponding to a desired water level, and Figure 6 is an actual water supply. It is a main part flowchart showing the operation. In Figure 1, 1
2 is an input means for setting the washing time, number of rinses, dehydration time, etc.; 2 is a display means for informing the user of the contents set by the input means 1 and the progress face; 3a is a display means for detecting the water level; 6 and 6 are bidirectional thyristors for driving the washing and dewatering basket 13, and 7 is a bidirectional water valve driving means for driving the water supply valve 12. A thyristor 8 is a bidirectional thyristor for driving the drainage magnet 11, 9 is a commercial power supply, 1o is a power switch, 14 is a phase advance capacitor, and 4 is a water level detection means 3 which stores a predetermined frequency. This is a control means that inputs the frequency data output by the system, calculates a judgment frequency corresponding to a desired water level, and controls the entire device. The configuration of the water level detection means 3 is shown in FIGS. 2 and 3.
The cylinder shown in the figure is 6D, which is the same as the configuration of the conventional example.

In the above configuration, the actual water supply operation will be explained with reference to the characteristic diagram shown in FIG. 6 and the flowchart shown in FIG. In Fig. 6, the characteristics shown by the broken line C are the characteristics indicating the center of the dispersion of the water level detection means 3, a is the characteristic of the sample at its upper limit, and b is the characteristic of the sample at the lower limit. Output frequency f of the water level detection means 3. a to f. It will vary within the range of b. Further, X indicates a characteristic of a certain sample.

For example, consider that a sample having characteristics X is used as the water level detection means and water is supplied to a water level of .

First, in step 400, the initial frequency is measured and set as f. 8
shall be. Next, in step 401, the initial frequency f is determined. Compare X with a constant value fd, and if fox; zfd, that is, if the water level in the tank is lower than the water level corresponding to fd, the process goes to step 402, and in step 402 f. ! and f, which is the frequency of the water level detecting means when the water level is 0, as shown by the characteristic b in FIG. Compare b, fO well f. If b, then f. When the output frequency is outside the range of variation in the output frequency of the water level detection means when the water level is 0, the process goes to step 403.

On the other hand f. If X≧job, the process goes to step 404, where the initial frequency f08 is compared with f, which is the frequency when the water level of the water level detection means is 0, as shown by the characteristic C in FIG.
If 'Ox≧f0°, then in step 408c, fOx<fo. If so, in step 406, each determination frequency is corrected based on the initial frequency.

To explain the principle of the correction here, in Fig. 5,
If (foa-fo.) or (fo.-f.b) is 1, then by proportional calculation F) Cf1a-ftC”) or (flC-ftb) is (hh-h,)7/hh(=A ), so step 405 or step 40
In step 6, the proportional calculation as described above is performed, and when 'Ox≧fOc, in step 405, the determination frequency fj=fLc+(fo
x-foc)×A, and when fQz <'QC, the judgment frequency ft' = flo-Cf at step 77'406
0゜-fo,)XA where ft, ftb, ft
0 is the frequency of the water level detecting means having characteristics a, b, and C in FIG. 6, respectively, when the water level is ht. Also, in step 402, f0 is processed. To explain the case of b, this means that the frequency when there is no water in the tank is f. b to f. The frequency fluctuates within the range of a, but due to changes in the ambient temperature used, aging of the water level detection means, etc., the frequency may change to f even though there is no water in the tank. b
The determination frequency is corrected even when the frequency is less than the threshold. This is done in step 403 if 'Ox≧j
Using the same principle as the correction method for ob, the initial frequency is set to f
. Judgment frequency 't'``'la''Oc
'Ob)XA. Above 1. The flow from step 400 to step 403 is performed when the water level in the tank at the start of water supply is below a predetermined value and the initial frequency is outside the variation range of the water level detection means 3 when the water level is 0. This shows that water level control is performed. Also,
f in step 401. The process goes to step 407 where it is determined whether the judgment frequency has been corrected in the past. If the judgment frequency has been corrected in the past, the process proceeds to step 408 and the past correction is performed. The value is directly used as the determination frequency ft'. If the judgment frequency has not been corrected in the past, the process goes to step 409, and the judgment frequency f, / shall be.

Calculate the judgment frequency f, / by the above method, and then turn on the water supply valve 12 in step 410 to start water supply,
After a certain time delay in step 411, step 412
Then, the water level detection means 3 measures the frequency f8. In step 413, the measured frequency f is compared with the judgment frequency ft', and if fx>ft', the process returns to step 411.
f), if f,≦ft', it is assumed that the desired water level hzK has been reached, and the process goes to step 414, where the water supply valve 12 is turned off.
Press F to end the water supply operation.

Although this embodiment has been described for the time of water supply to a fully automatic washing machine, it can also be applied to a device that controls water supply, such as an electric dishwasher. Furthermore, although a frequency signal was used as the output signal of the water level detection means, this may also be a water level detection means whose voltage changes according to changes in the water level, and furthermore, the value of the water level detection signal decreases as the water level increases. Although I have explained this for objects, the same effect also applies to objects that grow larger as the water level increases.

Effects of the Invention As is clear from the above embodiments, the water level converting device of the present invention is effective when the water level in the tank at the start of water supply is below a predetermined value.
, and if the frequency at that time is outside the frequency variation range of the water level detection means when the water level is 0, the water level is controlled at a predetermined value, thereby correcting the variation in the water level detection means when the water level is low. This makes it possible to perform water level control with high accuracy even under various conditions, making it possible to realize a highly accurate water level control device.

Furthermore, if the measured initial frequency is below a certain frequency, that is, when the water level in the tank is above a predetermined value, the water level converter of the present invention can store water level data from the previous water supply. The water level is controlled based on that water level data, and if the water level data from the previous water supply is not stored, the water level is controlled based on the predetermined water level data. Accurate water level control is possible even when water is present.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a fully automatic washing machine which is an embodiment of the present invention, Fig. 2 is a sectional view of the displacement detection section of the water level detection means, Fig. 3 is an electric circuit diagram of the oscillation circuit, and Fig. 4. is a characteristic diagram showing the relationship between water level and frequency, FIG. 6 is a characteristic diagram showing the relationship between water level and frequency explaining one embodiment of the present invention, and FIG. 6 is a flowchart showing the processing method by the same control means. , FIG. 7 is a characteristic diagram of water level and frequency showing a conventional water level detection method. 3... Water level detection means, 4... Control means, 7... Water supply valve driving means. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 4 Water level Water level Figure 6

Claims (2)

[Claims] (1) A water supply valve driving means for driving a water supply valve, a water level detection means for detecting the water level in the tank due to water supply from the water supply valve and converting it into an electric signal, and inputting the output signal of the water level detection means, The control means is configured to control the water supply valve driving means, and the control means determines that the water level in the tank at the start of water supply is below a predetermined value, and that the value of the output signal of the water level detection means at the start of water supply is A water level control device that performs water level control based on a predetermined value when the output signal of the water level detecting means when the water level is 0 is outside the variation range. (2) A water supply valve driving means for driving a water supply valve, a water level detection means for detecting the water level in the tank due to water supply from the water supply valve and converting it into an electric signal, and inputting an output signal of the water level detection means, The control means controls the water supply valve driving means, and if the control means detects that the water level in the tank at the time of starting water supply is below a predetermined value, the control means controls the water supply valve based on the water level data from the previous water supply. A water level control device configured to perform water level control and to perform water level control based on predetermined water level data when water level data from the previous water supply is not stored.