CN204423747U - Temperature control model experimental device used in university laboratories - Google Patents

Abstract

A temperature control model experimental device for laboratories of colleges and universities. The main purpose is to provide a system experimental device for process control, which achieves the purpose of training the application skills of students. The method is characterized in that: a circuit board is placed in the rectangular base; the upper surface of the upper cover is fixedly connected with a container base with external threads, a cement resistor and a digital temperature sensor are fixed in the container base, and wiring terminals of the cement resistor and the digital temperature sensor penetrate through the upper cover vertically and are inserted into the inner space of the upper cover after being sealed by an insulating sealing rubber gasket; a digital display and a key are fixed beside the container base and on the upper surface of the upper cover; a serial communication terminal and four signal input and output terminals are fixed on the side surface of the upper cover; the experimental device also comprises a container which can be matched with the container base, wherein the container is cylindrical and is provided with an upper opening and a lower opening, and the lower opening is in threaded connection with the container base.

Description

Temperature control model experimental device used in university laboratories

technical field

The utility model relates to an experimental device in higher education teaching experiments, which can provide a miniature control physical model of the actual system.

Background technique

In the course of advanced teaching of automation, it is necessary to cultivate students' ability to apply automation equipment and system debugging ability to put the automatic control system into operation. In the previous training mode, schools need to purchase automated advanced process control system experimental devices to achieve the purpose of training students' application skills. This advanced experimental device has complete functions, rich types of automatic instruments and control devices, many training items, and comprehensive functions. The disadvantages are that each device takes up a lot of space and is expensive, and the number of configurations in each college is limited, resulting in a long time for students to train in rotation, and even can only be used for demonstration experiments or graduation design equipment, and there is no experiment that every student can train at the same time condition. Especially in higher vocational education, this deficiency is very unfavorable to the cultivation of students' applied skills. For this reason, it is necessary to design a miniature experimental device with large-scale cultivation effect.

Contents of the invention

In order to solve the technical problems mentioned in the background technology, the utility model provides a temperature control model experiment device used in college laboratories. This kind of experiment device has low manufacturing cost, small floor space, and is suitable for large-scale training.

The technical scheme of the utility model is: the temperature control model experiment device used in the laboratory of colleges and universities has a rectangular base and an upper cover made of insulating materials, and the rectangular base and the upper cover are fixed by several fastening screws connection, which is unique in that:

A circuit board is placed in the rectangular base; a container base with external threads is fixedly connected to the upper surface of the upper cover, and a cement resistance and a digital temperature sensor are fixed in the container base. Wherein, the terminals of the cement resistance and the digital temperature sensor are all sealed by an insulating sealant gasket and inserted into the inner space of the upper cover after vertically penetrating the upper cover; There are digital displays and keys; on the side of the upper cover, there is a serial communication terminal and four signal input and output terminals fixed.

The experimental device also includes a container that can be matched with the container base. The container is cylindrical and has two openings, the upper and the lower. Wherein, the inner wall of the lower opening is provided with internal threads, and the gap between the lower opening and the container base is The connection between them is threaded; the container and the container base are made of polyethylene material, and there is a liquid level gauge on the container.

The circuit board has a DC 12V power supply, a microprocessor, a digital driver, a 5V DC voltage stabilizer, a power controller and a D/A conversion circuit; wherein the DC 12V power supply is the cement resistor and the voltage stabilizer Power supply, the temperature signal input end of described digital temperature sensor is connected to the sampling signal input end of described microprocessor, and described microprocessor controls digital driver, and described digital driver drives described digital display; The digital signal output end is connected to the digital signal input end of the D/A conversion circuit to convert the temperature signal into a standard analog signal, and the analog signal output end of the D/A conversion circuit is connected to the signal input and output terminals , for the external controller to read; the two-way data flow transmission is realized between the signal input and output terminals and the microprocessor; the power controller receives the control signal from the microprocessor for controlling the The current magnification of the cement resistor.

The utility model has the following beneficial effects: the experimental device uses a microprocessor and a digital sensor to construct a temperature control model experimental device. Use polyethylene container to physically simulate the heated object in the actual production process, with good heat preservation effect and small model distortion; use digital temperature sensor to physically simulate the transmitter of the automatic control instrument, and use cement resistance to physically simulate the heater in the actual production process, cement The resistance is more accurate and stable than the resistance wire, and it is easy to protect. This device displays the temperature locally on the digital display on the model device through the microprocessor, and at the same time converts the temperature into an analog standard signal of 0 to 5V and sends it to the terminal for use by an external controller. In addition, the microprocessor can read the control quantity of the external controller from the input terminal, control the power device to convert it into heat, and heat the air medium in the container. Utilizing the serial communication interface of the utility model, the external computer can monitor the whole heating process. Due to the miniaturization and low cost of this experimental device, every student can have one. When learning to use automation control equipment, such as PID regulator, programmable controller, computer input/output control module, configuration software application, etc., you can personally experience and practice the operation and use skills of the equipment. It can also play an effective practice role in the debugging process of the automatic control system. The utility model has the advantages of low cost, small volume, easy manufacture and maintenance, and is suitable for the application of automatic experiment teaching.

Description of drawings:

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a block diagram of the utility model.

Fig. 3 is a schematic circuit diagram of the utility model.

Detailed ways:

Below in conjunction with accompanying drawing, the utility model is further described:

As shown in Figure 1, this kind of temperature control model experimental device used in university laboratories has a rectangular base 1 and an upper cover 5 made of insulating materials, and several fastening screws are passed between the rectangular base 1 and the upper cover 5 2 Make a fixed connection. Its unique features are:

The upper surface of the upper cover 5 is fixedly connected with a container base 6 with external threads, and a cement resistor 12 and a digital temperature sensor 7 are fixed in the container base 6 . Wherein, the terminals of the cement resistance 12 and the digital temperature sensor 7 are sealed by an insulating sealant gasket and vertically penetrate the upper cover 5 and then inserted into the inner space of the upper cover. Next to the container base 6, on the upper surface of the upper cover 5, a digital display 13 and buttons 14 are fixed; on the side of the upper cover 5, a serial communication terminal 4 and four signal input and output terminals 3 are fixed .

Described experimental device also comprises a container 9 that can cooperate with container base 6, and described container is cylindrical, has upper opening 10 and lower opening 8, wherein, the inner wall of lower opening 8 is provided with internal thread, and lower opening 8 is threadedly connected to the container base 6; both the container 9 and the container base 6 are made of polyethylene material, and the container 9 is provided with a liquid level gauge 11.

A circuit board is placed in the rectangular base 1, and its block diagram is shown in Figure 2. The circuit board has a DC 12V power supply, a microprocessor, a digital driver, a 5V DC voltage stabilizer, a power controller and a D/A conversion circuit ; Wherein, the DC 12V power supply supplies power for the cement resistance and voltage stabilizer, the temperature signal input end of the digital temperature sensor is connected to the sampling signal input end of the microprocessor, and the microprocessor controls the digital driver , the digital driver drives the digital display; the digital signal output of the microprocessor is connected to the digital signal input of the D/A conversion circuit to convert the temperature signal into a standard analog signal, and the D/A The analog signal output terminal of the A conversion circuit is connected to the signal input and output terminal for reading by an external controller; two-way data flow transmission is realized between the signal input and output terminal and the microprocessor; the power control The controller receives the control signal from the microprocessor to control the current amplification factor of the cement resistor. The specific working process is: DC12V supplies power to the cement resistor and the voltage stabilizer with 5VDC, and the heated medium in the container is used as the controlled object. The digital temperature sensor detects the temperature in the container and sends it to the microprocessor, which controls the digital driver. The digital driver drives the digital display to display it. At the same time, the temperature is converted into a standard analog signal, which is output at the signal output end for the external controller to read. The control quantity of the external controller is input from the signal input end, and the microprocessor reads it and converts it into a control signal of the power controller, and then Control the calorific value of the cement resistance, so as to achieve the purpose of controlling the temperature in the container. The serial communication terminal can be connected with an external computer, and the external computer can monitor the temperature in the container. The buttons are used for function switching and manual control. The voltage regulator 5VDC provides a stable voltage for the microprocessor and digital drives.

Fig. 3 is a schematic circuit diagram of the device during specific implementation. The container volume of this device can be set as 100mL, and the container, cement resistance _R3 and digital temperature sensor _U5 constitute the physical model of this experimental device. The temperature in the container _T1 is detected by the digital temperature sensor _U5 , and the pin 1 of the microprocessor _U4 reads the pin 2 of the digital temperature sensor _U5 to obtain the temperature value, which is displayed on the digital display _U3 of the device. From pin 4 of the microprocessor U ₄ through the D/A conversion circuit composed of resistors R ₅ , R ₆ , capacitors C ₄ , C ₅ and operational amplifier U ₆ A, it is converted into a standard analog signal DC (0-5) V, It is output by pins 3 and 4 of port J ₂ via line number PLCAD for reading by an external controller. The heating control amount DC (4-20) mA standard signal of the external controller enters through pins 1 and 2 of the wiring port J ₂ , and is converted into a DC (1-5) V voltage signal by the resistor R ₂ , and is transmitted by the microprocessor U ₄ The analog input channel 5-pin reads, the microprocessor _U4 converts the control quantity into a PWM signal, through the 3-pin of the microprocessor _U4 , the resistor _R4 and the power control element _Q1 , thereby controlling the flow through the cement resistor R ₃ current value to achieve the purpose of heating. The computer can directly monitor the temperature in the container _T1 through a USB-to-TTL level cable through the RXD and TXD lines of the port _J1 . The buttons S ₁ and S ₂ are used for switching the functions of the experimental device and for manual control. The microprocessor U ₄ serially controls the digital tube driver U ₂ , and the digital tube driver U ₂ drives the digital display U ₃ . The voltage regulator U ₁ and the capacitors C ₁ and C ₂ convert the power supply of the experimental device from DC12V to DC5V to supply power to the microprocessor U ₄ and the digital tube driver U ₂ .

Claims (1)

1. one kind for the Temperature Control Model experimental provision in Scientific Research in University Laboratory, there is the rectangular base (1) and upper cover (5) that adopt insulating material to make, be fixed connection by some trip bolts (2) between rectangular base (1) and upper cover (5), it is characterized in that:

Circuit board is placed in rectangular base (1);

The upper surface of upper cover (5) is fixedly connected with one with externally threaded container base (6), container base (6) internal fixtion has cement resistor (12) and digital temperature sensor (7), wherein, cement resistor (12) all inserts in the inner space of described upper cover by the vertical upper cover (5) that penetrates of insulated enclosure rubber cushion sealing with the terminals of digital temperature sensor (7) afterwards; Other at container base (6), be positioned on the upper surface of described upper cover (5), be fixed with nixie display (13) and button (14); On the side of upper cover (5), be fixed with a serial communication terminal (4) and four signal input output end (3);

Described experimental provision also comprises a container (9) that can match with container base (6), described container is cylindric, there are upper and lower two openings (10,8), wherein, the inwall of under shed (8) has internal thread, is threaded connection between under shed (8) and container base (6); Container (9) and container base (6) all adopt polythene material to make, with Liquid level scale (11) on container (9);

Described circuit board have direct current 12V power supply, microprocessor, digital driver, the direct current stabilizer of 5V, power controller and D/A change-over circuit; Wherein, described direct current 12V power supply is that described cement resistor and voltage stabilizer are powered, the temperature signal input of described digital temperature sensor is connected to the sampled signal input end of described microprocessor, the digital driver of described Microprocessor S3C44B0X, nixie display described in described digital driver drives; The digital signal output end of described microprocessor is connected to the digital signal input end of described D/A change-over circuit to realize converting temperature signal to standard analog signal, the analog signal output of described D/A change-over circuit is connected on described signal input output end, reads for peripheral control unit; Bidirectional traffic transmission is realized between described signal input output end and described microprocessor; Described power controller receives and comes from described microprocessor-based control signal for controlling the current amplification factor of described cement resistor.