CN201045173Y - Washing machine laundry automatic weighing detection control device - Google Patents

Abstract

The utility model relates to an automatic weighing detection control device for clothes of a washing machine which uses a displacement sensor for weighing, and belongs to the technical field of household appliances. It consists of an amplifying rectifier circuit, an amplifying filter circuit, an amplifying circuit, an operational amplifier comparison value setting circuit, an MCU interface circuit, and an oscillating circuit. , form a voltage control loop with the control terminal of the operational amplifier circuit in the amplifier circuit, and the output terminal of the amplifier circuit is connected with the output port of the single-chip microcomputer in the operational amplifier comparison value setting circuit through an isolation resistor to form a closed-loop control loop. The utility model has the characteristics of simple structure, low cost and high measurement accuracy. The circuit can be widely used in various weighing occasions, especially in drum washing machines.

Description

Washing machine laundry automatic weighing detection control device

technical field

The utility model relates to an automatic weighing detection control device for clothes of a washing machine which uses a displacement sensor for weighing, and belongs to the technical field of household appliances.

Background technique

The weighing method currently being used in drum washing machines can be found in Chinese patent CN1690291A, which discloses a washing machine weighing method and a washing machine that realizes the method. It combines a displacement sensor and an air damping oscillator to detect the weight of the clothes and the weight of the clothes. Water intake, which includes the casing, outer barrel, two elastic support shock absorbers, inner drum, motor transmission device, etc.; one of the elastic support shock absorbers is an air damping type with a displacement sensor, and the displacement sensor passes through the weighing module connected to the microprocessor. There is also a washing machine that can be found in Chinese patent ZL200420072922, which discloses a washing machine that can automatically weigh and has a reinforced piston rod. Laundry weight and water intake. They have the following defects in common: 1. High requirements for displacement sensors; 2. Poor detection synchronization is prone to measurement errors.

Contents of the invention

Aiming at the deficiencies of the prior art, the utility model provides a laundry automatic weighing detection control device for a washing machine that can simplify the requirements for displacement sensors and has a high degree of automation.

The technical feature of the utility model is that a synchronous control switch circuit is designed, and at the beginning of weighing, the initial state of the weighing module is synchronized with the computer detection, avoiding the error caused by the asynchronous initial state of the weighing module and the computer detection .

The laundry automatic weighing detection control device for the washing machine is composed of an amplifying and rectifying circuit connected with the output end of the displacement sensor, an amplifying and filtering circuit connected with the amplifying and rectifying circuit, an amplifying circuit connected with the amplifying and filtering circuit, and an operating circuit connected with the amplifying circuit. It is composed of an amplifier comparison value setting circuit, an MCU interface circuit connected to the operational amplifier comparison value setting circuit, and an oscillation circuit.

The amplifying and rectifying circuit is composed of an amplifying circuit and a rectifying circuit connected in sequence, and the amplifying circuit is composed of an operational amplifier integrated circuit; the rectifying circuit is composed of a crystal diode rectifier, a filter capacitor and a load resistor.

The amplification and filtering circuit is composed of an operational amplifier integrated circuit.

The amplifying circuit is composed of an operational amplifier integrated circuit.

The operational amplifier comparison value setting circuit can be composed of the output port of the single-chip microcomputer connected with a multiplier resistor; it can also be composed of the output port of the single-chip microcomputer connected with a D/A conversion circuit or a PWM voltage adjustment circuit to obtain higher output accuracy.

The MCU interface circuit includes the output port of the single-chip microcomputer connected with the comparison value setting circuit of the operational amplifier, and the output port of the amplifier circuit.

The oscillation circuit consists of a square wave generator circuit. It can be composed of an amplifying output circuit with a single-chip microcomputer as a signal source, or it can be composed of an independent oscillator circuit.

The characteristics of the overall circuit composition are: the output port of the single-chip microcomputer in the operational amplifier comparison value setting circuit is connected in parallel with a multiplier resistor, and forms a voltage control loop with the control terminal of the operational amplifier circuit in the amplifier circuit, and the output terminal of the amplifier circuit is connected to the operational amplifier through an isolation resistor. The output port of the single-chip microcomputer in the comparison value setting circuit is connected to form a closed-loop control loop.

When the utility model works, the oscillating circuit generates a high-precision oscillating frequency waveform Xout, which is sent to the external displacement sensor, and then the amplifying and rectifying circuit amplifies and rectifies the feedback AC signal Xin to convert it into a DC signal; The filter circuit performs comparison and amplification after further amplification and filtering to obtain the output voltage signal Uout of the amplification circuit. It can be seen that when the output of the displacement sensor (that is, the input Xin of the weighing module) changes correspondingly with the change of the weight of the clothes in the washing machine, the amplitude of the output voltage signal Uout also changes accordingly. Afterwards, the measured analog voltage value Uout is sent to the external MCU for processing.

The device is connected with an external MCU microprocessor through the MCU interface circuit to process data interactively, so as to realize the start of weighing work. The MCU interface circuit receives the Start signal input from the external MCU—after the low level time is greater than 10mS negative pulse, adjust the amplification comparison value of the amplification circuit through the op amp comparison value setting circuit, so that the output signal Uout reaches a suitable amplitude, and then The MCU interface circuit sends a high level to the external MCU—the weighing start is completed. Thereafter, the external MCU can convert the weight of clothes in the washing machine according to the change of the output voltage Uout of the amplifying circuit. The signal determination, response method and time setting here can be changed according to the work needs of the external MCU.

To sum up, an automatic weighing detection control device for washing machine clothes consists of an amplifying and rectifying circuit connected to the output end of the displacement sensor, an amplifying and filtering circuit connected to the amplifying and rectifying circuit, and an amplifying and filtering circuit connected to the amplifying and filtering circuit, The operational amplifier comparison value setting circuit connected with the amplifier circuit, the MCU interface circuit connected with the operational amplifier comparison value setting circuit, and the oscillation circuit are composed, and the characteristic is: the output port of the single-chip microcomputer in the operational amplifier comparison value setting circuit The multiplier resistor is connected in parallel to form a voltage control loop with the control terminal of the operational amplifier circuit in the amplifier circuit, and the output terminal of the amplifier circuit is connected with the output port of the single-chip microcomputer in the operational amplifier comparison value setting circuit through an isolation resistor to form a closed-loop control loop.

The utility model provides a circuit for weighing by cooperating with a displacement sensor to convert the signal of the displacement sensor into a DC voltage signal that is easy to measure and identify, and has the characteristics of simple structure, low cost, and high measurement accuracy. The circuit can be widely used in various weighing occasions, especially in drum washing machines.

The utility model is further disclosed below in conjunction with the accompanying drawings of the description.

Description of drawings

Fig. 1 is a schematic block diagram of the utility model,

Fig. 2 is a schematic diagram of the utility model.

In the figure: 1-amplifying and rectifying circuit, 2-amplifying and filtering circuit, 3-amplifying circuit, 4-oscillating circuit, 5-operation amplifier comparison value setting circuit, 6-MCU interface circuit, 7-displacement sensor.

Figure 3 is a schematic diagram of the interface sequence of the MCU.

Detailed ways

Example:

An automatic weighing detection control device for washing machine clothes, comprising an amplification and rectification circuit 1 connected to the output end of a displacement sensor 7, an amplification and filtering circuit 2 connected to the amplification and rectification circuit 1, and an amplification and filtering circuit 3 connected to the amplification and filtering circuit 2 , the op-amp comparison value setting circuit 5 connected with the amplifying circuit 3 and the MCU interface circuit 6, and an oscillation circuit 4 are formed, and it is characterized in that: the output port of the single-chip microcomputer IC1 in the op-amp comparison value setting circuit 5 is connected in parallel with a multiplier resistor Devices R3-R8 form a voltage control loop with the control terminal of the operational amplifier circuit IC3B in the amplifier circuit 3, and the output terminal of the amplifier circuit 3 is connected with the output port 12 of the single-chip microcomputer IC1 in the operational amplifier comparison value setting circuit 5 through the isolation resistor R27 Form a closed-loop control loop.

Amplifying and rectifying circuit 1 is composed of an amplifying circuit and a rectifying circuit connected sequentially: the amplifying circuit is composed of an operational amplifier integrated circuit IC3A, and the operational amplifier integrated circuit IC3A is composed of a low-power dual operational amplifier integrated circuit LM358DT; the rectifying circuit is composed of a crystal diode rectifier and a filter A capacitor and a load resistor are formed, a crystal diode D1 forms a half-wave rectifier, and a filter capacitor C13 and a load resistor R18 are connected in parallel to form a filter.

The amplification filter circuit 2 is composed of an operational amplifier integrated circuit IC2A, and the operational amplifier integrated circuit IC2A is composed of a low power consumption dual operational amplifier integrated circuit LM358DT.

The amplifying circuit 3 is composed of operational amplifier integrated circuits IC2B and IC3B, and is composed of low power consumption dual operational amplifier integrated circuits LM358DT.

The operational amplifier comparison value setting circuit 5 is composed of the output port of the single-chip microcomputer connected with the multiplier resistors R3-R8; it can also be composed of the output port of the single-chip microcomputer connected with the D/A conversion circuit to obtain higher output precision.

The MCU interface circuit includes the output ports 1 and 13 of the single-chip microcomputer connected to the operational amplifier comparison value setting circuit 5, and the output terminal 7 of the output terminal of the amplifier circuit 3 and the operational amplifier integrated circuit IC2B.

The oscillation circuit 4 is constituted by a square wave generator circuit. It can be composed of an amplifying output circuit with a single-chip microcomputer as a signal source, or it can be composed of an independent oscillator circuit.

The utility model generates a high-precision oscillation frequency waveform Xout through the oscillation circuit 4, sends it to the displacement sensor 7 outside, and then amplifies and rectifies the AC signal Xin fed back by the amplification and rectification circuit 1, and converts it into a DC signal; The amplification and filtering circuit 2 performs comparison and amplification after further amplification and filtering to obtain the output voltage signal Uout of the amplification circuit 3 . It can be seen that when the output of the displacement sensor (that is, the input Xin of the weighing module) changes correspondingly with the change of the weight of the clothes in the washing machine, the amplitude of the output voltage signal Uout also changes accordingly. Afterwards, the measured analog voltage value Uout is sent to the external MCU for processing. The magnification of each amplifying circuit can be adjusted to obtain the corresponding weighing accuracy as required, and each functional part can also be streamlined as required.

The weighing module is connected with an external MCU microprocessor through the MCU interface circuit 6 to process data interactively, thereby realizing the starting of the weighing module. After the MCU interface circuit 6 receives the Start signal input from the external MCU—the low level time is greater than 10mS negative pulse, it adjusts the amplification comparison value of the amplification circuit 3 through the operational amplifier comparison value setting circuit 5 to make the output signal Uout reach a suitable value. amplitude, and then the MCU interface circuit 6 sends a high level to the external MCU—the weighing start is completed. Thereafter, the external MCU can convert the weight of clothes in the washing machine according to the change of the output voltage Uout of the amplifying circuit 3 . The signal determination, response method and time setting here can be changed according to the work needs of the external MCU.

The MCU interface circuit 6 is connected with an external MCU microprocessor to process data interactively, thereby realizing the start of the weighing work. The MCU interface circuit 6 receives the Start signal input from the external MCU—after the low level time is greater than 10mS negative pulse, adjusts the amplification comparison value of the amplification circuit 3 through the operational amplifier comparison value setting circuit 5, and initializes the output of the weighing module. Make the output signal Uout reach the appropriate amplitude, and the output is sampled from the 7th pin of the op amp IC2 to the 12th pin of the single-chip microcomputer IC1, and the single-chip microcomputer judges whether the voltage is an appropriate value, if not, adjust the 6th-pin of the single-chip microcomputer 11 pin output, change the value of the voltage output to the fifth pin of IC3, and then change the comparison voltage of the fifth pin of the operational amplifier IC2, thereby adjusting the output voltage of the operational amplifier IC2, and adjust the value to a suitable value value, the microcontroller stops adjusting. Then the MCU interface circuit 6 sends a high level to the external MCU—the weighing start is completed. Thereafter, the external MCU can convert the weight of clothes in the washing machine according to the change of the output voltage Uout of the amplifying circuit 3 . The signal determination, response method and time setting here can be changed according to the work needs of the external MCU.

Xout is the square wave signal output to the displacement sensor (0-5V square wave output), Xin is the input signal fed back from the displacement sensor to the weighing module (-5V-+5V square wave signal), Uout is the weighing measurement signal output ( 1.5V-4.5V, output impedance 1000 ohms), VCC is power supply (4.75-5.25V), GND is ground, START is I/O weight measurement start signal (0-5V, internal pull-up resistor), handshake signal. The above signals can be adjusted to appropriate amplitudes as required.

Claims (9)

1. A washing machine clothing automatic weighing detection control device is composed of an amplifying and rectifying circuit (1) connected to the output end of the displacement sensor (7), an amplifying and filtering circuit (2) connected with the amplifying and rectifying circuit (1), and The amplifying circuit (3) connected with the amplifying filter circuit (2), the operational amplifier comparison value setting circuit (5) connected with the amplifying circuit (3), the MCU interface circuit (6), and the oscillation circuit (4) constitute, It is characterized in that: the output port of the single-chip microcomputer IC1 in the operational amplifier comparison value setting circuit (5) is connected in parallel with the multiplier resistors R3-R8, and forms a voltage control loop with the control terminal of the operational amplifier circuit IC3B in the amplifier circuit (3), and the amplifier circuit The output terminal of (3) is connected with the 12 pins of the output port of the single-chip microcomputer IC1 in the operational amplifier comparison value setting circuit (5) through the isolation resistor R27 to form a closed-loop control loop. 2. The automatic weighing detection control device for washing machine clothes according to claim 1, characterized in that the amplifying and rectifying circuit (1) is composed of an amplifying circuit and a rectifying circuit sequentially connected: the amplifying circuit is composed of an operational amplifier integrated circuit IC3A, and the operational amplifier is integrated The circuit IC3A is composed of low power consumption dual operational amplifier integrated circuit LM358DT; the rectification circuit is composed of a crystal diode rectifier, a filter capacitor, and a load resistor. The crystal diode D1 forms a half-wave rectifier, and the filter capacitor C13 and load resistor R18 are connected in parallel to form a filter. . 3. The automatic weighing detection control device for washing machine clothes according to claim 1, characterized in that the amplifying filter circuit (2) is made of an operational amplifier integrated circuit IC2A, and the operational amplifier integrated circuit IC2A is composed of a low power consumption dual operational amplifier integrated circuit LM358DT composition. 4. The automatic weighing detection control device for washing machine clothes according to claim 1, characterized in that the amplifying circuit (3) is composed of operational amplifier integrated circuits IC2B and IC3B, and is composed of low power consumption dual operational amplifier integrated circuits LM358DT. 5. The automatic weighing detection control device for washing machine clothes according to claim 1, characterized in that the operational amplifier comparison value setting circuit (5) is made up of the output port of the single-chip microcomputer connected with multiplier resistors R3-R8; The output port is connected with D/A conversion circuit. 6. The automatic weighing detection control device for washing machine clothes according to claim 1, characterized in that the MCU interface circuit includes the output port 1, 13 pins of the single-chip microcomputer connected to the operational amplifier comparison value setting circuit (5), and the amplifier circuit ( 3) The output terminal of the operational amplifier integrated circuit IC2B is the 7-pin output terminal. 7. The automatic weighing detection control device for washing machine clothes according to claim 1, characterized in that the oscillating circuit (4) is composed of a square wave generator circuit. 8. The automatic weighing detection control device for washing machine clothes according to claim 1, characterized in that the oscillating circuit (4) is composed of a square wave generator circuit, and is composed of an amplifying output circuit with a single-chip microcomputer as a signal source. 9. The laundry automatic weighing detection control device for washing machine according to claim 1, characterized in that the oscillating circuit (4) is composed of a square wave generator circuit and is composed of an independent oscillating circuit.

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