KR20130039155A - The proportional-integral-derivative (pid) temperature controller intercepting an electric current with interrupting of temperature sensor - Google Patents

Abstract

The present invention relates to a proportional integral derivative (PID) controller for controlling a heater having a function of blocking a current supply by detecting a temperature sensor when it is not mounted on the heater, and a proportional integral differential (PID) controller, a power controller, and a timer are provided. It consists of basic elements. A timer (3) is installed between the PID control module (2) and the power regulator (4), and one wire (6) of the power supply is connected in parallel to connect one of the alarm terminals (7) of the PID control module (2). Connect with The line coming out is connected to the contact point 8 of the timer, and the other line is connected to the time point contact 9 of the timer. By connecting the two wires coming out from this wire was connected to the power supply terminal 10 of the power regulator, it was configured by connecting to the power supply terminal of the heater (5). This temperature controller has a function to detect and automatically cut off the supply of current to the heater in order to prevent overheating of the heater caused by excessive current being supplied to the heater when the temperature sensor is not correctly mounted on the heater. It is characterized by.

Description

Proportional-integral-derivative (PID) temperature controller intercepting an electric current with interrupting of temperature sensor}

Variable control such as temperature by proportional-integral-derivative (PID) control is a representative precision control technology belonging to the field of automatic control technology and is widely applied to industrial equipment and analyzers. PID controller using proportional-integral-differential method is a precision controller widely used for precise temperature control of heating elements such as coolers and heaters. PID controller not only has the function of reaching the set target temperature while minimizing the temperature deviation, but also has the function of increasing the temperature of the heater while maintaining a constant heating rate. Therefore, PID controller is widely used in temperature control of general industrial heating equipment as well as temperature control of various heating equipments that require precision such as laboratory analysis equipment.

In order to bring the temperature of a cooler or a heater to a desired temperature, a temperature controller employing various temperature control methods is used. Temperature control method

The temperature controller adopting the on-off method and the proportional-integral-derivative method is mainly used. Among them, the PID method which is precise in controlling the temperature rise rate and has a small temperature deviation is adopted.

PID controller, which is a representative type of control method that is used most in practical applications, basically has a form of feedback controller, and it measures the output value of the target to be controlled and then uses it as a reference value or An error is calculated by comparison with a setpoint, and the control value required for control is calculated using this error value.

The PID controller is used in a standard form, but in some cases, it is used in a slightly modified form. For example, it may be used simply in the form of a controller having only proportional terms, or only proportional-integral and proportional-differential terms, which are called P, PI, and PD controllers, respectively.

The temperature control method using the PID controller calculates a control value based on the set temperature (setpoint) and the current temperature value (PV) read through the temperature sensor to adjust the amount of current supplied to the heater. To control the temperature. Therefore, the temperature sensor that transmits the temperature value to the PID controller must be installed on the part of the heater to be temperature-controlled, and if there is a mistake, it will malfunction and cause the current to continue flowing to the heater. This is the same result even when the conductor of the temperature sensor is disconnected from the inside. In this case, when left for a long time, the heater may overheat, causing a fire, an explosion, etc., which often causes a large accident.

In order to prevent a safety accident caused by overheating of a heating element such as a heater, a PID temperature controller having a function of detecting a malfunction of the temperature sensor of the PID controller and blocking a current supply to the heater to prevent a safety accident is required. A controller having such a function can simplify the device and reduce the economic cost by implementing the function in a simple mechanical operation rather than a programmatic automatic control method.

The present invention is to provide a method for removing the risk of fire, explosion, etc. that may occur due to malfunction of the temperature sensor when controlling the temperature of the heating element with a PID controller. In the present invention, since the safety device is formed using a PID control module, a power regulator, and a simple timer, the configuration is simple and economical is high. It provides a safety function that eliminates the risk of fire due to overheating even if the temperature controller is operated when the temperature sensor is not mounted on the heater due to disconnection of the temperature sensor or carelessness of the user.

PID temperature controller is a device that controls heater of various capacity from small size to large size, and if it malfunctions, it may cause fire or explosion. Fire in the laboratory or on the job site is often overheated because the heating element controlled by the controller is not properly controlled.

There are two cases in which the heater controlled by the PID temperature controller malfunctions and overheats. The first case is due to carelessness of the user. The temperature sensor is connected to the PID temperature controller. The temperature sensing part of this temperature sensor must be attached to the heater, and the PID controller controls the temperature of the heater by adjusting the current value sent to the heater based on the temperature value detected through this temperature sensor. Therefore, even though the temperature sensing portion of the temperature sensor must be mounted on the heat source of the heater, sometimes the user operates the temperature controller without leaving the temperature sensor mounted in the heater by mistake of the user. In this case, the current temperature (PV) of the heater detected by the temperature controller is continuously input to the external temperature (or room temperature) in which the temperature sensor is left. However, the temperature controller continuously supplies current to the heater to adjust the temperature of the heater to the target temperature (SV) set by the user. In this case, since the temperature sensor is not mounted on the heater and is left outside the heater, the temperature of the heater provided in the PID controller is continuously transmitted to the room temperature value, not the actual heater temperature. Accordingly, since the PID controller continuously supplies the maximum current to the heater, the heater is overheated and the heat is transferred to the surroundings, causing a fire or an explosion.

The second case is the internal wire of the temperature sensor is broken. Two wires are connected to the temperature sensing part of the temperature sensor, which is covered with metal and protected. Therefore, even if these two lines are broken, they cannot be visually confirmed. In this case, if the user accurately checks the current temperature detected by the PID temperature controller, the problem can be spotted. However, in this case, the temperature controller shows the wrong temperature value which is different from the actual sensing temperature, so it is difficult to identify the problem of the temperature sensor because it seems to operate normally without checking the difference with the actual temperature. Since the temperature sensor always delivers a value lower than the target temperature set in the PID controller's temperature program, the PID controller continues to supply current to the heater. As the difference between the temperature set in the temperature program and the current temperature increases, the maximum current is continuously supplied to the heater, causing the heater to overheat. Therefore, even if the internal line of the temperature sensor is broken, it may cause fire or explosion.

Because of these risks, it is very important for PID controllers to ensure safety functions as well as convenience and accuracy, and a safety device that completely solves this problem is necessary.

In order to solve this problem, the present invention provides a PID temperature controller capable of preventing a safety accident due to overheating of a heater by detecting a malfunction of a temperature sensor using an existing PID controller, a power controller, and a timer.

This method installs by connecting a timer to the alarm terminal installed in the existing PID controller and controls the current supply amount of the power regulator through the means that can safely control the amount of current supplied to the heater. Specific methods will be described in detail in the detailed description for carrying out the invention including the embodiments.

The present invention provides a method for preventing a safety accident that may occur due to factors such as carelessness of a user or disconnection of a temperature sensor in controlling a heater that always carries a fire risk with a PID controller. The present invention uses a conventional PID control method and uses an inexpensive and simple timer to provide a device and method that can prevent disasters such as heater damage, fire or explosion, and thus have a very high utility value.

1 is a block diagram of a configuration of a proportional integral differential (PID) temperature control device and a heater control
* Explanation of symbols on the main parts of the drawing
1. Safety Function PID Temperature Controller 2. Proportional-Integral-Derivative (PID) Control Module
3. Timer 4. Power Regulator (TPR)
5. Heater 6. Power
7. Alarm terminal 8. Timer control switch
9. Power delay switch 10. Power terminal of power regulator
11. Power terminal of heater

 The PID temperature controller for controlling the temperature of the heater is largely composed of a PID controller, a power controller, and a temperature sensor. The PID controller usually has a function of sensing and controlling the temperature by connecting a temperature sensor, but also has an alarm function, which allows external operation according to the temperature condition. For example, if the temperature rises above the allowable temperature by using the alarm function, it may be used to alert the user.

The present invention provides a method for configuring a safety device using the alarm function that the PID controller basically has. As shown in FIG. 1, the safety function PID temperature controller 1 installs and connects a timer 3 between the PID controller 2 and the power regulator 4. As shown in the circuit diagram of FIG. 1, the timer is connected to the alarm terminal 7 of the PID control module 2, and the line from the timer is connected to one terminal 10 for power supply of the power regulator. The timer uses a general timer with a time contact (9).

Set the alarm function of the PID controller to operate at a temperature slightly higher than the indoor or outdoor temperature (up to 40 ℃ based on the outside temperature in summer). According to the circuit diagram shown in FIG. 1, when the alarm function is activated, the timer also starts to operate, so the timer setting time is also set to about 10 to 30 minutes according to the user's judgment. This time can be set slightly higher than the time taken to reach 40 ° C when the temperature is increased by the temperature increase rate setting value of the PID controller. If the PID controller is operated after setting in this way, the current sent from the PID controller to the power controller is cut off if the current temperature detected by the temperature sensor does not rise above the alarm set temperature within the timer set time. Therefore, the heater is no longer supplied with current, so that it is not heated.

The heater and the PID temperature control system for heating purposes use the temperature higher than the room temperature as the target temperature. Thus, if the temperature sensor is mounted on the heater again, the current temperature detected by the PID will rise as set in the temperature program. Therefore, since the current temperature of the heater detected by the temperature sensor is higher than the room temperature in a short time, the time that is higher than the temperature of the indoor and outdoor space is within a few minutes. In this case, since the heater and PID controller are operating normally, the power is not cut off by the timer's temporary contact function even when the timer is set, and the current is supplied to the heater through the power controller normally. Here, the timer's power on delay function means that if it is determined that the function proceeds normally before the time set in the timer, even if the timer reaches the set time, it continues to supply current to continue operation without stopping the device. It is a function of timer.

<Examples>

In the place where the room temperature is 20 ℃, the PID controller was to keep the heater temperature at 200 ℃ constant. Set the time to reach 200 ℃ to 40 minutes,

After setting the alarm temperature of the proportional integral derivative (PID) controller to 40 ° C, the timer time was set to 25 minutes. If the temperature sensor is connected normally and the internal line is not disconnected, operate the PID controller and the current temperature will match the set temperature well.

After setting to the same condition as above, the PID controller was constructed without leaving the sensing unit of the temperature sensor in the heater. The present temperature continues to show the room temperature of 20 ° C, but the set temperature continued to increase as set in the temperature program. At this time, the heater is supplied with current, and the actual temperature of the heater becomes high.

However, since the temperature sensor of the PID controller is left indoors, the present temperature was continuously shown at 20 ° C. In this way, the current temperature is kept constant and the set temperature of the PID controller keeps increasing. When the time set for the timer (25 minutes), the current supplied to the power controller is cut off. Then the heater stopped heating because no more current was supplied to the heater. Here, the timer set time and alarm set temperature can be arbitrarily set by the user.

none.

Claims (2)

Proportional-Integral-Derivative (PID) temperature controller with basic components consisting of a PID controller, a power regulator and a timer

The PID control module according to claim 1, wherein a timer (3) is installed between the proportional-integral-differential (PID) control module (2) and the power regulator (4), and one line of power is connected in parallel. Connect the alarm terminal (2) of (2), connect the line coming out to the timer, and connect the other line to the time contact (9) of the timer, and then connect the two lines coming out together. Proportional-integral-differential temperature control device connected to the power supply terminal 10 of the power regulator and connected to the power supply terminal of the heater

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