JPH0720951A - Temperature controller - Google Patents

Abstract

PURPOSE:To enable heating to an extent where no abnormal overheating is caused without completely stopping the heating even if a temperature sensor becomes abnormal. CONSTITUTION:The temperature controller which detects the temperature of a part to be detected with the temperature sensor 1 and automatically control the temperature of a heating part heating the part to be detected on the basis of the temperature detected by the temperature sensor 1 is provided with a normal control path 2 which controls power supply to the heating part when the temperature sensor 1 is normal. Further, the controller is provided with an abnormality control path 3 which decreases the rate of power supply to the heating part when the temperature sensor 1 is abnormal, an abnormality detection part 4 which detects the abnormality of the temperature sensor 1, and a switching part 5 which is automatically switched to the side of the normal control path when the temperature sensor 1 is normal and to the side of the abnormal control path 2 once the abnormality detection part 4 detects the abnormality of the temperature sensor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The temperature control device of the present invention is, for example,
It is used for temperature control of the floor heating system.

[0002]

2. Description of the Related Art When a temperature sensor such as a thermistor that changes negatively with respect to temperature is used as the temperature sensor, it is determined that the temperature of the controlled object (for example, the floor temperature of the floor heating device) is low when the temperature sensor is disconnected, and The control device may continue to energize to continue heating in the heating section, resulting in abnormal overheating. When a positively changing one such as a platinum sensor is used as the temperature sensor, the same is true when the temperature sensor is short-circuited. Therefore, in general, the temperature control device is provided with a protection mechanism which, when the temperature sensor detects an abnormality, cuts off energization to prevent abnormal overheating and ensures safety.

[0003]

However, with the above-mentioned protection mechanism, when there is an abnormality such as a break in the temperature sensor, the protection mechanism operates and heating is stopped. In this case, floor heating, and particularly large-scale floor heating equipment, poses a serious problem because it is difficult to urgently perform alternative heating once heating is stopped.

SUMMARY OF THE INVENTION An object of the present invention is to provide a temperature control device capable of heating the temperature sensor so that the heating does not completely stop even if the temperature sensor has an abnormality such as a disconnection or a short circuit, and the temperature does not become abnormally overheated.

[0005]

As shown in FIG. 1, a temperature control device of the present invention detects a temperature of a detected portion by a temperature sensor 1 and detects the detected portion based on the detected temperature of the temperature sensor 1. In a temperature control device in which the temperature of a heating unit to be heated is automatically controlled, a normal control system path 2 for controlling power supply to the heating unit when the temperature sensor 1 is normal, and an abnormal condition of the temperature sensor 1 It is connected to the abnormal control system path 3 that controls to reduce the power supply rate to the heating unit, the abnormality detection unit 4 that detects an abnormality of the temperature sensor 1, and the normal control system path 2 side when the temperature sensor 1 is normal. , Temperature sensor 1 in the abnormality detection unit 4
The switching unit 5 is provided to automatically switch to the abnormal control system path 2 when the abnormal condition is detected.

[0006]

In the temperature control device of the present invention, the normal control system path 2 for controlling the power supply to the heating portion for heating the detected portion during the normal operation of the temperature sensor 1 and the abnormality detection for detecting the abnormality of the temperature sensor 1 Abnormal control system path 3 for controlling so as to reduce the power supply rate to the heating unit when the temperature sensor 1 is abnormal.
Since the temperature sensor 1 is connected to the normal control system path 2 side when the temperature sensor 1 is normal, and the switching unit 5 that can be automatically switched to the abnormal control system path 2 side when abnormal is provided, when the temperature sensor 1 becomes abnormal, An abnormality is detected by the abnormality detection unit 4, and the switching unit 5 causes the abnormality control system path 3 to operate in response to a signal from the abnormality detection unit 4.
Is switched to, the power supply rate to the heating unit decreases, and heating is continued to the extent that the heating unit does not overheat abnormally.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A temperature control device of the present invention will be described based on the embodiment of FIG. Reference numeral 1 in FIG. 1 is a temperature sensor for detecting the temperature of a region (detected portion) heated by a heating unit, 2 is a normal control system path for controlling power supply to the heating unit when the temperature sensor 1 is normal, 3 is a This is an abnormal control system path that controls so that the power supply rate to the heating unit is lowered when the temperature sensor 1 is abnormal.

Reference numeral 4 in FIG. 1 denotes an abnormality detecting section for detecting an abnormality of the temperature sensor 1. This is for determining an abnormality when the temperature of the detected section largely deviates from the normal temperature range. Is. For example, when the temperature sensor 1 is a thermistor (the resistance decreases as the temperature rises), when the resistance of the thermistor increases (for heating, when the value exceeds -30 ° C, for example). Is judged to be a wire break, and conversely, it is judged to be a short circuit when the temperature becomes lower than the value of 100 ° C.

Reference numeral 6 in FIG. 1 is a temperature detecting portion for converting the temperature detected by the temperature sensor 1 into an electric signal, and reference numeral 7 is a comparison of the detected temperature from the temperature detecting portion 6 with a reference signal. Is a temperature determination unit that determines whether the temperature is higher or lower than
These are provided in the normal control system path 3.

Reference numeral 5 in FIG. 1 is connected to the normal control system path 2 side when the temperature sensor 1 is normal, and automatically switches to the abnormal control system path 2 side when the abnormality detecting section 4 detects an abnormality of the temperature sensor 1. It is a switching unit. The switching unit 4 is an electronic switch, and is composed of, for example, a transistor or an analog switch.

Reference numeral 8 in FIG. 1 is a temperature setting knob for setting the heating temperature of the heating portion, and is designed so that the temperature sensor 1 can set the heating temperature in a normal state.

Reference numeral 9 in FIG. 1 denotes a temperature setting reference signal generator, which outputs a reference signal for controlling energization of the heating unit (heater) so that the temperature set by the temperature setting knob 8 is output, It is input to the temperature determination unit 7.

Reference numeral 10 in FIG. 1 denotes a duty factor signal generator, which outputs a duty factor signal for controlling so that the duty factor to the heating portion is lowered when the abnormality detector 4 detects an abnormality of the temperature sensor 1. The switching unit 5 is switched to the abnormal control system path 3.

Various types of the duty factor signal generator 10 are conceivable. For example, as shown in FIG.
0, a time signal transmitter 21, a preset counter 22 and a counter 23, and generates a signal for turning on only T × preset value of control cycle = T × 12. For heating, T = 5-60 seconds is usually used. That is, the control cycle is about 1 to 12 minutes.

Reference numeral 11 in FIG. 1 denotes an output section for outputting signals from the normal control system path 2 and the abnormal control system path 3.

Reference numeral 12 in FIG. 1 is a load control unit, which is an output unit 1.
It is turned on and off by a signal from 1 to supply and stop the current from the power source to the heating unit (heater), and is configured by a relay or an SCR device, for example.

[0017]

[Example of Use] Next, an example of use of the temperature control device shown in FIG. 1 will be described. When the temperature sensor 1 of FIG. 1 is normal, the temperature detected by the temperature sensor 1 is converted into an electric signal proportional to the temperature by the temperature detection unit 6 and input to the temperature determination unit 7. At this time, since the reference signal according to the setting of the temperature setting knob 8 is input from the temperature setting reference signal generator 9 to the temperature determining unit 7, the electric signal input to the temperature determining unit 7 is as described above. The temperature determination unit 7 compares it with the reference signal.

When it is determined that the temperature detected by the temperature sensor 1 is lower than the temperature of the reference signal, the temperature determining section 7 outputs a signal of "energize", and the output side movable terminal of the switching section 5 is output. 25 is connected to the normal control system path 2, and the signal from the temperature determination unit 7 is input to the output unit 9. Then, the load control unit 12 is driven by the output signal from the output unit 9, and the heater of the heating unit is energized from the power supply. The energized state under normal conditions is as shown by the thick line in FIG.

When the temperature sensor 1 of FIG. 1 is abnormal, the temperature determination unit 7 determines that the temperature detected by the temperature sensor 1 is lower than the temperature of the reference signal. At that time, the abnormality detection unit 4 detects the abnormality of the temperature sensor 1, and the output side movable terminal 25 of the switching unit 5 is switched to the abnormality control system path 3. As a result, the signal from the duty factor signal generator 10 is input to the output unit 11.

Then, the load control unit 12 is driven by the output signal from the output unit 11, and the power supply from the power source to the heater of the heating unit is repeatedly turned on and off based on the duty ratio signal from the duty ratio signal generating unit 10. , The average power control is performed. The energized state at the time of this abnormality is as shown by the broken line in FIG. As a result, the heater follows an appropriate temperature suitable for heat dissipation. At this time, since the automatic control based on the temperature of the detected portion is not performed, the heating portion can maintain substantially appropriate warmth even if the temperature sensor 1 is abnormal.

Most parts of FIG. 1 can be made into a microcomputer, and an actual product depends on the microcomputer.

The temperature sensor 1 is used to shift to the duty ratio control.
Not only the automatic transfer at the time of abnormality detection, but also the duty ratio control can be selected by a small switch (a dip switch or the like) provided in the temperature control device. As a result, even if the floor temperature sensor is not installed and the duty ratio control is planned in advance, it can be used in a state where the abnormality display of the temperature sensor 1 is not lit.

According to the present invention, when an abnormality of the temperature sensor 1 is detected, at least an abnormality display that can be recognized by a service person who performs inspection and repair, such as generation of an alarm, lighting of a lamp, blinking, etc., is performed. Is desirable.

[0024]

The temperature control device of the present invention has the following effects. ． Even if the temperature sensor 1 is broken or short-circuited, the heating effect (for example, heating) can be maintained by the operation based on the duty ratio signal until inspection and repair. ． For example, when the heating device is installed, even if the temperature sensor 1 is not installed due to a construction error or the like, heating can be performed by the operation based on the duty ratio signal until the installation of the temperature sensor 1 is completed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a temperature control device of the present invention.

FIG. 2 is a block diagram illustrating an example of a duty ratio signal generator in the temperature control device of the present invention.

FIG. 3 is an explanatory view of temperature control when the sensor is normal and abnormal by the temperature control device of the present invention.

[Explanation of symbols]

 1 Temperature sensor 2 Normal control system path 3 Abnormal control system path 4 Abnormality detection section 5 Switching section

Claims (1)

[Claims] 1. A temperature sensor (1) detects the temperature of a detected part, and the temperature of a heating part for heating the detected part is automatically controlled based on the temperature detected by the temperature sensor (1). In the temperature control device described above, a normal control system path (2) that controls the power supply to the heating unit when the temperature sensor (1) normally operates, and a power supply to the heating unit when the temperature sensor (1) is abnormal. An abnormal control system path (3) for controlling the rate to decrease, an abnormality detection section (4) for detecting an abnormality of the temperature sensor (1), and a normal control system path (2) side when the temperature sensor (1) is normal. And a switching unit (5) that is automatically switched to the abnormality control system path (3) when an abnormality of the temperature sensor (1) is detected by the abnormality detection unit (4). Temperature control device.