JPS6111551A - Water heater using midnight electric power - Google Patents

Abstract

PURPOSE:To permit to find a trouble in an early stage, exclude faulty data and effect stabilized operation by a method wherein a control unit is reset periodically to test and initialize internal memories. CONSTITUTION:The water heater is provided with first electric source 5, which is supplied during only a preset time band having its center at midnight, and second electric source 6, in which the electric power is supplied at all times, while a control circuit 9, operated by the electric source 6, effects a control operation at all times by the signal of a sensor 3 so that a hot-water temperature becomes a predetermined temperature and is equipped with a transformer 11 for forming a conduction signal synchronized with the supply of the electric source 5. The conduction signal, generated from the transformer 11 simultaneously with the supply of the electric source 5, is transmitted to a reset circuit 12 to form a reset signal and is transmitted to the control circuit 9. When the supply of the electric source 5 is stopped, the reset signal is also stopped. In case the voltage of the electric source 6 is dropped due to some cause, the voltage of output of a comparator 31 is dropped, the voltage of RST terminals of a micro- computer 38 is increased, which is reset and the realization of a program is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a late-night power water heater, and more particularly to a control device thereof.

2 Page - Conventional configuration and its problems In general, late-night power water heaters supply power to the heater, which is the heating means, so the first power supply is supplied only during the hours set in advance by the power company, mainly around midnight. power supply and
It is operated by two power sources: a second power source that is constantly supplied to perform cathodic protection of the hot water storage tank and at the same time to supply power to the control device. Conventionally, when a microcomputer is used as a control device for such an electric water heater, power is constantly supplied to the microcomputer, so the control device including the microcomputer generally does not operate from the time the electric water heater is installed until the end of its life. I will continue.

Microcontrollers often test and initialize internal memory using a program at the start of operation, but if for some reason the internal memory fails or the data in the internal memory changes, the control may be performed differently than intended. There was a problem that the vehicle continued to run or became inoperable.

Purpose of the Invention In view of the above points, the present invention has been made to solve these problems.The purpose of the present invention is to periodically reset the control device and test and initialize the internal memory. It is an object of the present invention to provide a late-night power water heater that can detect failures early, eliminate erroneous data, and perform stable operation by performing the following steps.

Structure of the Invention In order to achieve the above object, the present invention forms a reset signal based on a signal for ending the supply of the first power supply, which is supplied only during a time period around midnight set in advance by the electric power company, and performs control. The configuration is such that the device is reset and the internal memory is tested and initialized.

Further, this reset signal is formed by a voltage drop of the second power supply that operates the control device.

Description of examples An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the structure of a late-night electric water heater. 1
2 is a hot water storage tank, 2 is a heater serving as a heating means for supplying heat to the water in the hot water storage tank 1, 3 is a sensor for detecting hot water temperature, and 4 is a control device.

FIG. 2 is a circuit block diagram of a conventional late-night power water heater. 5 is a first power supply that is supplied only during a preset time around midnight, and 6 is a second power supply that is always supplied.
7 is a power supply circuit that can obtain a predetermined voltage from an AC power supply, 8 is an anticorrosive power supply for preventing corrosion of the hot water storage tank 1, 9 is a control circuit, and 10 is operated by the signal U from the control circuit 9. 10 is the contact point of the relay coil.

As shown in FIG. 2, the control circuit 9, which is operated by the second power supply 6 that is constantly supplied, constantly controls the hot water temperature to a predetermined temperature based on the signal from the sensor 3. 3, the control circuit 9 issues a heat request, and when the first power source 5 is supplied while the contact 10' of the relay 10 is closed, the heater 2 is energized and heated, and the water in the hot water storage tank 1 is heated. is heated. After that, when this hot water reaches a predetermined temperature, the signal from the sensor 3 controls the temperature.
The page control circuit 9 sends a boiling signal to the contact 10 of the relay 10.
' is opened, the current supply to the heater 2 is stopped, and heating is stopped. Even if the heat request signal from the control circuit 9 is output and the contact 10' of the relay 10 is closed, if the supply of the first power source 5 is stopped after the late night power supply period, the heater 2 will not be energized. Entrainment heating is also stopped. The life of the microcomputer included in this control circuit 9 will end when the second power supply 6 is started when the late-night electric water heater is installed, except for situations such as power outages. Until now, the internal memory has not been tested or initialized, so even if an internal memory failure or data change occurs, it cannot be expected to be restored automatically.

FIG. 3 shows a circuit block diagram of a late-night power water heater according to an embodiment of the present invention. Note that parts indicated by the same numbers as those given in FIGS. 1 and 2 represent the same parts. The control circuit 9, which is operated by the second power supply 6 that is constantly supplied, always operates to keep the hot water temperature at a predetermined temperature based on the signal from the sensor 3. First supplied
It is equipped with a transformer 11 for forming a communication line synchronized with the supply of power 5. The energization signal generated simultaneously with the supply of the first power source 5 from the transformer 11 is reset I/circuit 1.
2, which forms a reset signal and is transmitted to the control circuit 9. Further, when the supply of the first power source 5 is stopped, the reset signal is also stopped.

FIG. 4 is a detailed circuit diagram of the reset circuit 12.

FIG. 5 is a schematic flowchart showing the program of the microcomputer 38.

In Fig. 5, the program is executed sequentially from ``Start'', and after ``Heater Control'', ``Temperature Capacitor 16
The voltage rectified and smoothed by the resistors 17, 18 and divided into 7 pages is applied to the base of the transistor 190. As a result, the collector voltage of the transistor 19 decreases, and the voltage of the transistor 24, which was divided and supplied by the resistors 20, 21, and 22, is applied to the base of the transistor 190. The base voltage decreases and the collector voltage of transistor 24 increases by the voltage applied through resistor 23. At this time, the comparator 31
The voltage at the non-inverting input terminal (hereinafter referred to as the ``■'' terminal) of the terminal also increases, but the voltage applied by the resistor 27.29 has already reached the inverting input terminal (hereinafter referred to as the ``O'' terminal) applied by the resistor 28.30. Since the voltage exceeds the voltage, the output voltage of the comparator 31 becomes the voltage supplied by the resistor 32.33. Since the base voltage of the transistor 34 is high, the collector voltage of the transistor 34 is lowered by the resistor 35.37. The R8T input terminal voltage is also low and does not serve as a reset signal.

Next, when the power supply of the first power supply 5 is stopped and the voltage of the transformer 11 disappears, the voltage explained above is completely reversed, and the voltage at the terminal 7' of the comparator 31 decreases through the capacitor 25, and the Microcontroller 3 because the voltage is lower than the terminal voltage
The voltage at the R8T terminal of the microcomputer 3/8 rises and the microcomputer 3/ is reset, stopping the execution of the program. Capacitor 25 is then charged again through resistor 27 and comparator 3
Since the voltage of the ■ terminal of 1 exceeds the voltage of the e terminal again, the voltage of the R8T terminal of the microcomputer 38 decreases, and the voltage of the microcomputer 381[5
The program will be executed from the "Start-1" program in the flowchart shown in the figure.

Next, if the voltage of the second power supply 6 drops for some reason,
Eventually, the voltage at the V+ terminal of the microcomputer 38 also decreases, and if it becomes below the operating voltage of the microcomputer 38, its operation is not guaranteed. Therefore, it is necessary to stop the microcomputer 38 with a reset signal at a voltage within a range where the operation of the microcomputer 38 is guaranteed.

The input voltage of the voltage stabilizing element 13 is divided by the resistor 27.29 and applied to the terminal of the comparator 31. On the other hand, when the output voltage of the voltage stabilizing element 13, that is, the voltage of the power supply 6 which is divided and applied by the resistor 28 and 30, decreases to the O terminal, the input voltage of the voltage stabilizing element 130 decreases almost proportionally. However, the negative output voltage maintains the conventional voltage until a certain voltage value. As a result, the e terminal voltage of the comparator 31 is stable, but the ■ terminal voltage decreases and finally falls below the O terminal voltage, so the voltage at the I (ST terminal) of the comparator 31 becomes 1
The microcomputer 31 is set and the execution of the program is stopped.

Next, when the voltage of the power supply 6 is restored again, the microcomputer 3# starts executing the program from "1 START" in the flowchart of FIG.

Effects of the Invention As described above, in the control circuit of the present invention, when the supply of the first voltage that is supplied for a certain period of time in the middle of the night is completed, the control device temporarily stops and then tests and initializes the internal memory again. The controller is configured to perform the control operation after the control operation is performed.

In other words, by performing the above operations once a day,
Even in the unlikely event that an internal memory failure occurs, it is not only possible to detect it early, but even if the data in the internal memory 10 pages changes, the desired control operation can be performed without the data being accumulated. be. In addition, since a reset signal is generated in the event of a voltage drop in the control power supply, the late-night power water heater can perform safe and stable control operations.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of a late-night power water heater, FIG. 2 is a circuit block diagram of a conventional late-night power water heater, and FIG. 3 is a circuit block diagram of a late-night power water heater according to an embodiment of the present invention. 4
The figure is a circuit diagram of the reset circuit of the present invention, and FIG. 5 is a schematic flowchart of the program of the microcomputer. 9... Control circuit (control device), 13... Voltage stabilizing element, 14 Capacitor, 26 Limiting die, t-de, 36 - Capacitor, 38 Microcomputer. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 7L/ Figure 3

Claims (2)

[Claims] (1) A hot water storage tank, a heating means for supplying heat to the water in the hot water storage tank, a sensor that is circumscribed or inserted into the hot water storage tank to detect the temperature of hot water in the hot water storage tank, and a power source for the heating means; has a control device operated by a separate power source, and is provided with a circuit that generates a reset signal to the control device when the control voltage to the control device decreases and when the power supply to the heating means stops. Late night electric water heater. (2) Late-night power hot water according to claim 1, wherein when power supply to the heating means and power supply to the control device are started at the same time, the initial state is set by a reset signal of the control device. vessel.