JPH02106627A - Water level take in device for apparatus for automatic hot water supply to bath tub - Google Patents

Abstract

PURPOSE:To enlarge the output signal range of a pressure sensor only to a practically required range and hence obtain required accuracy by adding an output signal of a pressure sensor to a D/A signal output from a microcomputer, taking deviation from an arbitrary reference value, and amplifying the deviation signal so that it may conform to accuracy required. CONSTITUTION:When a pressure sensor 1 detects a hydraulic pressure in a bath tub, a signal correlated with the detected hydraulic pressure is output. In order to incorpo rate an arbitrary range of an output signal of the pressure sensor, a digital signal of a certain bit number is adapted to come out from a D/A signal output section 2; it is converted into an analog signal at a D/A converter 3, and added into the signal of the pressure sensor at an adder 4. The signal added at the adder 4 is deviated from an arbitrary reference value at a deviation amplifier 5 and the deviation is amplified therein. The analog signal transmitted from the deviation amplifier 5 is converted into a digital value at an A/D converter 6. A digital value comparison control section 8 compares this digital value with the digital value or the range of the digital value stored in a reference digital value memory section 7 and detects the water level.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a water level intake device for an automatic hot water supply system for a bathtub.

BACKGROUND OF THE INVENTION In recent years, automatic hot water supply systems for bathtubs have indirectly determined the water level using a pressure sensor that uses the water level, and controlled the supply of hot water to the bathtub with an on-off valve that opens and closes the hot water supply line. In addition, to detect the water level and input the signal of the pressure sensor to the microcomputer to judge the water level, take the absolute value of the entire range of the output signal of the pressure sensor, convert it to A/D, and input it to the microcomputer that performs control. A water level capture device was used to determine the digital value as the water level in the bathtub.

Problems to be Solved by the Invention However, in the water level capture device as described above, in order to capture a certain range of output signals from the entire range of output signals of the pressure sensor to the microcomputer with a certain accuracy or higher, it is necessary to The entire range of the output signal needs to be within the microcomputer power supply voltage range, and the accuracy is also limited by the microcomputer A/D acquisition capability (resolution).

The present invention solves such conventional problems, and when capturing the output signal of the pressure sensor, even if the range of the output signal of the pressure sensor exceeds the power supply voltage of the microcomputer, A/D capture can be performed, and the pressure sensor output The signal acquisition accuracy is not limited by the A/D resolution of the microcomputer and can be set to any desired accuracy.In other words, the aim is to expand only the actually necessary range of the pressure sensor output signal range and achieve the required accuracy. It is something to do.

Means for Solving the Problems In order to solve the above-mentioned problems, the water level intake device of the automatic hot water supply device for bathtubs of the present invention includes a pressure sensor that detects bathtub water pressure and outputs a signal correlated to the bathtub water pressure. a D/A signal output section that outputs a digital signal with a certain number of bits; a D/A conversion section that converts the digital signal from the D/A signal output section into an analog signal; and an output signal of the pressure sensor. an addition section that adds analog signals from the D/A conversion section; a deviation amplification section that calculates a deviation between the analog signal output from the addition section and an arbitrary reference value and increases the deviation by 11; an A/D conversion section that converts the analog signal from the deviation amplification section into a digital value, a reference digital value storage section that stores a certain digital value or a certain digital value range, and a digital value output from the A/D conversion section. The value is compared with the reference digital value or digital value range of the digital storage section, and if the value is different or outside the range, the D/
and a digital value comparison control section that outputs a signal that changes the digital signal output from the A signal output section.

Operation The present invention uses the above-described configuration to expand only the actually necessary range of the pressure sensor output signal and achieve a certain required accuracy. That is, the pressure sensor detects the water pressure in the bathtub and outputs a signal correlated to the water pressure. Then, a digital signal with a certain number of bits is output from the microcomputer and converted into an analog signal by a D/A converter. D/
The analog signal from the A converter is added to the pressure sensor signal in the adder, the added signal takes the deviation from an arbitrary reference value, and the deviation signal is converted to the required accuracy in the deviation amplifier. Amplify at an arbitrary amplification rate so that Then, in order to convert the amplified analog signal into a digital value, an A/
It is converted into a digital value by the D conversion unit and compared with a reference digital value (or reference digital range) that serves as a reference for determining the actually necessary range of the pressure sensor output signal range,
If they are different, only the actually necessary range of the pressure sensor output signal range can be determined by changing the digital signal from the microcontroller until it matches the reference digital value (or reference digital range). be.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. FIG. 1 shows a configuration diagram of a water level intake device of a hot water supply device for a bathtub in an embodiment of the present invention.

In FIG. 1, a pressure sensor 1 detects water pressure in a bathtub and outputs a signal correlated to the water pressure. Then, in order to input an arbitrary range of the output signal of the pressure sensor into the microcomputer, a certain number of bits and twos of digital signals are outputted from the D/A signal output section 2. The digital signal output from the D/A signal output section 2 is converted into an analog signal by the D/A converter 3, and added to the pressure sensor signal by the adder 4.

The signal added by the adder 4 is subjected to a deviation from an arbitrary reference value by a deviation amplification part 5, and the deviation is amplified. The analog signal from the deviation amplification section 5 is sent to the A/D conversion section 6.
converted to digital value. Then, the digital value comparison control unit 8 compares the converted digital value with the digital value or digital value range stored in the reference digital value storage unit 7, and if it is different or outside the range, D The digital signal output from the /A signal output section 2 is changed, and the above-described acquisition is repeated until they match. If they match, the digital signal output from the D/A signal output section 2 is not changed. As described above, only the actually necessary range is expanded in the pressure sensor output signal range.75. Determine the digital signal value of the I)/A output part to achieve the required accuracy, and from then on, the water level will be detected by changing the value of the captured digital signal as only the pressure sensor output changes. It can be carried out.

Effects of the Invention As described above, the water level intake device for a hot water supply device for a bathtub according to the present invention provides the following effects.

Add the pressure sensor output signal and the D/A signal output from the microcomputer, take the deviation between the added signal and an arbitrary reference value, amplify the deviation, and convert the amplified signal to the A/A signal.
D-convert, compare whether it is within a certain reference digital value or a certain reference digital value range, and if it does not match, change the D/A signal from the microcomputer until it matches the output signal range of the pressure sensor. It is possible to enlarge and capture only the range that is actually required by C, and by amplifying it to an arbitrary magnification, it is possible to capture the pressure sensor output signal to the microcomputer with the necessary accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention. 1...Pressure sensor, 2...D/A signal output section, 3...D/A conversion section, 4...
Addition section, 5...Deviation increase l] section, 6...
A/D conversion unit, 7...Reference digital value storage unit,
8...--Digital value comparison control section.

Claims (1)

[Claims] A pressure sensor that detects bathtub water pressure and outputs a signal correlated to the bathtub water pressure, a D/A signal output section that outputs a digital signal of a certain number of bits, and an analog converter for converting the digital signal from the D/A signal output section. a D/A converter that converts into a signal; an adder that adds the output signal of the pressure sensor and the analog signal from the D/A converter; and an analog signal output from the adder and an arbitrary reference value. Take the deviation of
a deviation amplification section that amplifies the deviation; an A/D conversion section that converts the analog signal from the deviation amplification section into a digital value; and a reference digital value that stores a certain digital value or a certain digital value range. The digital value from the storage unit and the A/D conversion unit is compared with the reference digital value or digital value range of the digital value storage unit, and if the value is different or outside the range, the digital value is output from the D/A signal output unit. A water level intake device for an automatic water heater for a bathtub, which includes a digital value comparison control section that outputs a signal for converting an output digital signal.