JPH02219115A - Temperature setting display device - Google Patents

Abstract

PURPOSE:To eliminate the need for a display element dedicated to an abnormality display and to reduce the cost by performing temperature control according to a temperature setting part, displaying a temperature setting when the output of a temperature detection part is normal, and making a corresponding blink display when a high-temperature side or low-temperature side is abnormal. CONSTITUTION:When the signal of a switch 14 is inputted, the temperature setting is updated in low, intermediate, high, low... temperature order and at the same time, the voltage Vth of the temperature detecting circuit composed of a resistance 11 and a thermistor 12 is detected; when the temperature found from the voltage Vth is within a normal range, one of LEDs corresponding to the low, intermediate, and high temperatures for the temperature setting display illuminates. Further, the temperature set value and temperature detected value are compared with each other to control an electric power control element 18 to turn on and off a heater 19. When it is judged that the temperature is abnormal, an LED 17 blinks if the value is in the high temperature range and an LED 15 blinks if the value is in the low temperature range; and the heater 19 is turned off without reference to whether the temperature is high or low. Consequently, temperature abnormality can be displayed by using the display element for temperature set level and the cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a temperature setting display device for equipment that detects temperature and performs temperature control in response to a plurality of temperature settings.

(Prior Art) Conventionally, this type of temperature setting display device includes a temperature setting section 21, a temperature control section 22, and a setting display section 2, as shown in FIG.
3, a temperature detection section 24, and an abnormality display section 25 for displaying an abnormality when the temperature is abnormal.

A general circuit of the temperature detection section will be explained using FIG. 2.

In this circuit, the temperature detection voltage vth is the reference voltage ■
is the value obtained by dividing the resistance by the resistor 11 and the negative characteristic thermistor (hereinafter simply referred to as thermistor) 12. - As an example, Figure 4 shows the temperature detection voltage vth in hot water temperature control and the range in which the temperature is judged to be abnormal. 1'C or less, the thermistor 12 has a disconnection failure, or the resistor 11 has a short circuit failure. Furthermore, an abnormality on the high temperature side is determined when the temperature is 46° C. or higher, a short-circuit failure of the thermistor 12, or a failure of the resistor 11.

(Problems to be Solved by the Invention) However, the above configuration requires a dedicated display element for displaying an abnormality, which increases the cost accordingly.

In addition, because only one display element is required to display an abnormality, it is difficult to distinguish whether the abnormality is due to the temperature being too high or too low, making it impossible to pinpoint the location of the failure, which poses the problem of requiring time for repairs. be. Distinguishing and displaying a plurality of abnormalities requires dedicated display elements for each, which further increases costs.

The present invention solves the above problems and provides a temperature setting display device that displays a temperature abnormality using a display element of a temperature setting level.

(Means for Solving the Problems) In order to solve the above problems, the temperature setting display device of the present invention includes a temperature setting section that sets the temperature, and a temperature control section that controls the temperature based on the temperature setting section. , displays the temperature setting and determines whether the temperature is normal or abnormal, and if the temperature is abnormal on the high temperature side, the display corresponding to the highest setting is displayed blinking, and the abnormality on the low temperature side is displayed. , a display section that flashes a display corresponding to the lowest setting.

(Function) With the above configuration, temperature setting and temperature abnormality are performed by using the same display element, and distinguishing whether the abnormality is on the low temperature side or the high temperature side.

(Example) Hereinafter, one example of the present invention will be described based on the accompanying drawings. FIG. 1 is a block diagram of a temperature setting display device according to the present invention, where l is a temperature setting section, 2 is a temperature control section, 3 is a temperature detection section, and 4 is a display section. FIG. 2 shows a circuit for controlling the water temperature inside the concrete body, and the display section shows, as an example, an LED display for three levels: high, medium, and low. 13 is a microprocessor (hereinafter referred to as microcomputer), which updates the temperature setting in the order of low → medium → high → low, etc. by inputting a signal from switch 14, and at the same time, it is composed of a resistor 11 and a thermistor 12. If the voltage vth of the temperature detection circuit is detected and the temperature determined from this voltage vth is within the normal range, the temperature setting will be displayed as low or medium.

The power control element 18 is controlled by lighting up one of the LEDs, comparing the temperature setting value and the temperature detection value, and turning the heater 19 on and off. If the temperature is judged to be abnormal, the LED 17 will be high if the value is in the high temperature range, and the LED 15 will be low if the value is in the low temperature range.
This will result in an output that flashes. Note that if the temperature is determined to be abnormal, regardless of whether the temperature is high or low, temperature control is stopped for safety and the heater 19 is turned off.

Further, 20 is a thermostat for preventing the temperature of the hot water from rising excessively, and is a safety device that stops energizing the heater when the temperature of the hot water reaches 50°C.

In this circuit, when the low LED 15 flashes, the possible causes of failure are either the temperature below -l'C, a disconnection failure in the thermistor 12, or a short-circuit failure in the resistor 11. If the temperature is -1'C or higher, there is a failure in the thermistor 12 or resistor 11, that is, a failure in the temperature detection circuit, and if the temperature is below 1°C, there is a failure in the heater 19 or the power control element 18. In other words, it can be determined that there is a failure in the heater circuit part.

On the other hand, when the high LED 17 blinks, the likely cause of the failure is that the temperature is 46°C or higher, a short-circuit failure in the thermistor 12, or a disconnection failure in the resistor 11. When the temperature exceeds ℃, the power control element 18
If the failure is below 46゛c, thermistor 12
, it can be determined that there is a failure in the resistor 11, that is, a failure in the temperature detection circuit.

Therefore, the location of the failure can be estimated based on the content of the abnormality display.

Effects of the Invention As described above, the temperature setting display device of the present invention provides the following effects.

(1) Temperature abnormalities can be displayed using a display element at a temperature setting level, so costs can be reduced.

(2) Since the display can be displayed according to the abnormality, it is easy to estimate the cause of the failure and the location of the failure, and accurate maintenance can be performed in a short time.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a temperature setting display device showing an embodiment of the present invention, Fig. 2 is a circuit diagram of the same device, Fig. 3 is a block diagram of a conventional temperature setting display device, and Fig. 4 is a temperature detection device. FIG. 3 is a diagram illustrating an example of a detection voltage of a circuit and an abnormality determination. ■...Temperature setting section, 2...Temperature control section, 3...Temperature detection section, 4...Display section.

Claims (3)

[Claims] (1) a temperature setting unit that sets the temperature; a temperature control unit that performs temperature control based on the temperature setting; detects the temperature, displays the temperature setting, and determines whether the temperature is normal or abnormal; A temperature setting display device comprising a display unit that flashes a display corresponding to the highest setting when the temperature is abnormal on the high temperature side, and flashes a display corresponding to the lowest setting when the temperature is abnormal on the low temperature side. (2) The temperature setting display device according to claim 1, wherein the display section includes the same number of display elements corresponding one-to-one for the plurality of levels. (3) The temperature setting display device according to claim (1), wherein the display section digitally displays any number from 0 to 9.