PLC-based temperature control system and control method for optical fiber drawing furnace

Abstract

A kind of PLC-based optical fiber drawing furnace temperature control system and control method, including PLC controller, PLC controller is with power regulating circuit, voltage current sensor, high temperature probe, process gas control cabinet, cooling water control cabinet respectively;PLC controller provides electric energy to drawing furnace furnace body by power regulating circuit;High temperature probe is used to collect the temperature of drawing furnace furnace body;Voltage current sensor is used to collect the heating body current, voltage signal of drawing furnace furnace body;Process gas control cabinet is used to provide protective gas to drawing furnace furnace body, cooling water control cabinet is used to provide cooling water to the outside of drawing furnace furnace body.The present application can well control in actual temperature control process, whether it is temperature rising process, or temperature reduction process, and the precision after temperature stabilization, achieves the purpose of accurate control to the whole furnace temperature.

Description

Technical Field

[0001] This invention belongs to the field of optical fiber production equipment control systems, and specifically relates to a PLC-based temperature control system and method for an optical fiber drawing furnace. Background Technology

[0002] With the continuous development of the communications industry, the production cost of optical fibers for mainstream optical fiber and cable manufacturers has been constantly increasing, leading to a near-limited squeeze on their survival space. At the same time, the performance requirements for equipment are becoming increasingly stringent. As a core piece of equipment in the optical fiber production process, the most important performance aspect of the optical fiber drawing furnace is the control of the furnace temperature. The accuracy and precision of temperature control directly determine the quality of the produced optical fiber.

[0003] Currently, the most common temperature control method used for wire drawing furnaces is PID algorithm control. However, in actual production processes, it has been found that when the PID algorithm is applied to the temperature control of wire drawing furnaces, the current and voltage of the heating element change drastically during the heating and cooling processes. This situation reduces the service life of the heating element in the furnace. Therefore, in order to address the existing problems, it is necessary to design a control system that can accurately control the temperature. Summary of the Invention

[0004] In view of the technical problems existing in the background technology, the PLC-based fiber drawing furnace temperature control system and control method provided by the present invention can effectively control the temperature during the actual temperature control process, whether it is the heating process, the cooling process, or the temperature stabilization process, thus achieving the purpose of precise temperature control of the entire furnace.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A PLC-based temperature control system and method for an optical fiber drawing furnace includes a PLC controller, a power regulation circuit, voltage and current sensors, a high-temperature probe, a process gas control cabinet, and a cooling water control cabinet. The PLC controller provides electrical energy to the furnace body through the power regulation circuit. The high-temperature probe is used to collect the temperature of the furnace body. The voltage and current sensors are used to collect the current and voltage signals of the heating element of the furnace body. The process gas control cabinet is used to provide protective gas to the furnace body, and the cooling water control cabinet is used to provide cooling water to the outside of the furnace body.

[0007] In the preferred embodiment, the PLC controller is electrically connected to the touch screen, the PLC controller operates on 220V AC power, and the main circuit of the power regulation circuit operates on 380V AC power.

[0008] Preferably, the control method of the PLC-based fiber optic drawing furnace temperature control system and control method includes the following steps:

[0009] Step 1: Establish a temperature control model;

[0010] Step 2: Set the temperature value on the PLC controller and the temperature value fed back by the high-temperature probe;

[0011] Step 3: Calculate the change in the output power of the power regulator;

[0012] Step 4: Based on the functional relationship between temperature change and power change, deduce and calculate the current setpoint for the output power of the power regulator;

[0013] Step 5: Dynamically control the temperature of the wire drawing furnace body.

[0014] In the preferred embodiment, the temperature control model in step 1 is:

[0015] ΔT=Tpv-Tsv(1)

[0016] ΔI=G(s)*ΔT(2)

[0017] I = Ia0 + ΔI (3)

[0018] I=Ia0+G(s)(Tpv-Tsv)(4)

[0019] Where Tpv represents: actual temperature; Tsv represents: set temperature; Ia0 represents: the current value of the power regulator required for the wire drawing furnace temperature to reach the minimum temperature of 1000 degrees detected by the temperature sensor; G(s) represents: PID function; ΔT represents: the difference between actual temperature and set temperature; ΔI represents: current difference; I represents: current control value of the wire drawing furnace electrode.

[0020] Preferably, the control process in step 5 is as follows: After the control system is started, the temperature inside the furnace gradually increases as the output power current of the power regulation circuit increases, and the temperature of the heating element inside the furnace gradually rises. When the temperature reaches the minimum sensing temperature of 1000 degrees Celsius of the high-temperature probe, it is simultaneously determined whether the actual temperature value and the set value are equal. If they are equal, the process ends; if they are not equal, the set value of the power current of the power regulator is adjusted until the difference between the temperature feedback value and the set value is equal to 0. After the calculation is completed, the loop judgment is restarted. The entire system is always in a dynamic balance of loop judgment and calculation.

[0021] Preferably, in step 5, if the difference between the actual temperature feedback value and the temperature set value is greater than 0, the power setting current of the power regulator is increased by PID control; if the difference between the actual temperature feedback value and the temperature set value is less than 0, the power setting current of the power regulator is decreased by PID control.

[0022] Preferably, in step 1, a control model with a temperature setpoint Tsv is added to the temperature control model:

[0023] Tsv=Tsv0*K(5)

[0024] Where Tsv is the temperature setting value input on the touch screen, Tsv0 is the initial value of the temperature setting value. In the PLC-based fiber optic drawing furnace temperature control system and control method, the minimum detection temperature of the temperature sensor is 1000 degrees, so the value of Tsv0 is selected as 1050 degrees; K is the coefficient for temperature increase and decrease.

[0025] The present invention can achieve the following beneficial effects:

[0026] This invention innovatively employs a temperature control model in the optical fiber drawing furnace industry, enabling precise control of the temperature during the heating, cooling, and stabilization processes, achieving accurate temperature control of the entire furnace. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0028] Figure 1 This is a system structure diagram of the present invention. Detailed Implementation

[0029] Example 1:

[0030] Preferred solutions include Figure 1 As shown, a PLC-based temperature control system and method for an optical fiber drawing furnace includes a PLC controller, a power regulation circuit, voltage and current sensors, a high-temperature probe, a process gas control cabinet, and a cooling water control cabinet. The PLC controller provides electrical energy to the furnace body through the power regulation circuit. The high-temperature probe is used to collect the temperature of the furnace body. The voltage and current sensors are used to collect the current and voltage signals of the heating element in the furnace body. The process gas control cabinet provides protective gas to the furnace body, and the cooling water control cabinet provides cooling water to the outside of the furnace body. The PLC controller is electrically connected to a touch screen. The PLC controller operates on 220V AC power, and the main circuit of the power regulation circuit operates on 380V AC power. The functions and selection of each module in this system are as follows:

[0031] PLC controllers and supporting modules: controllers of brands such as Huichuan or Siemens that can realize analog input and output as well as PID calculation.

[0032] Wire drawing furnace body: The main controlled object of this system. The furnace body is insulated and heated by graphite as the main material.

[0033] Process gas control cabinet and cooling water control cabinet: The controlled object of this system, the wire drawing furnace body, needs to be provided with inert gases such as argon, helium or a mixture of argon and helium during the heating process to protect the graphite heating elements inside the furnace body. The main function of the cooling water control section is to provide cooling to the outside of the furnace body during the heating process.

[0034] Power regulation circuit: Its main function is to perform power conversion, converting the 380V power supply into the input power of the transformer, and adjusting the input voltage of the transformer by a given current value to control the output voltage of the transformer, thereby controlling the power of the heating element in the wire drawing furnace.

[0035] High-temperature probe: A temperature sensor that monitors the temperature inside the drawing furnace in real time and transmits the temperature data to the PLC and its modules for processing.

[0036] Voltage and current sensors: Real-time detection of the voltage across the heating element of the wire drawing furnace and the current flowing through the heating element, and transmission to the PLC and modules for display and processing.

[0037] Touchscreen: This is the operation display terminal of the system. Various operations of the system can be completed on the touchscreen, and real-time data of the system operation can also be viewed through the touchscreen.

[0038] Preferably, the control method of the PLC-based fiber optic drawing furnace temperature control system and control method includes the following steps:

[0039] Step 1: Establish a temperature control model;

[0040] Step 2: Set the temperature value on the PLC controller and the temperature value fed back by the high-temperature probe;

[0041] Step 3: Calculate the change in the output power of the power regulator;

[0042] Step 4: Based on the functional relationship between temperature change and power change, deduce and calculate the current setpoint for the output power of the power regulator;

[0043] Step 5: Dynamically control the temperature of the wire drawing furnace body.

[0044] Furthermore, the temperature control model in step 1 is as follows:

[0045] ΔT=Tpv-Tsv(1)

[0046] ΔI=G(s)*ΔT(2)

[0047] I = Ia0 + ΔI (3)

[0048] I=Ia0+G(s)(Tpv-Tsv)(4)

[0049] Where Tpv represents: actual temperature; Tsv represents: set temperature; Ia0 represents: the current value of the power regulator required for the wire drawing furnace temperature to reach the minimum temperature of 1000 degrees detected by the temperature sensor; G(s) represents: PID function; ΔT represents: the difference between actual temperature and set temperature; ΔI represents: current difference; I represents: current control value of the wire drawing furnace electrode.

[0050] The control process in step 5 is as follows: When all parts of the system are ready, the start-up conditions are met, and all operating parameters are set correctly with no alarms or faults, the system can be started. After the control system starts, the temperature inside the furnace gradually increases as the output power current of the power regulation circuit increases, and the temperature of the heating element inside the furnace gradually rises. When the temperature reaches the minimum sensing temperature of 1000 degrees Celsius of the high-temperature probe, it simultaneously checks whether the actual temperature value and the set value are equal. If they are equal, the process ends; if they are not equal, the set value of the power regulator's power current is adjusted until the difference between the temperature feedback value and the set value is equal to 0. After the calculation is completed, the loop judgment is restarted. The entire system is always in a dynamic balance of loop judgment and calculation.

[0051] In step 5, if the difference between the actual temperature feedback value and the temperature set value is greater than 0, the power setting current of the power regulator is increased through PID control; if the difference between the actual temperature feedback value and the temperature set value is less than 0, the power setting current of the power regulator is decreased through PID control.

[0052] In step 1, a control model with a temperature setpoint Tsv is added to the temperature control model:

[0053] Tsv=Tsv0*K(5)

[0054] Where Tsv is the temperature setting value input on the touch screen, Tsv0 is the initial value of the temperature setting value. In the PLC-based fiber optic drawing furnace temperature control system and control method, the minimum detection temperature of the temperature sensor is 1000 degrees, so the value of Tsv0 is selected as 1050 degrees; K is the coefficient for temperature increase and decrease.

[0055] This temperature setpoint control model, which mainly operates during the heating and cooling processes in actual production, controls the rate of temperature change by controlling the setpoint, and has good benefits in actual production.

[0056] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A control method for a PLC-based temperature control system of an optical fiber drawing furnace, characterized in that: A PLC-based temperature control system for an optical fiber drawing furnace was adopted. The system includes a PLC controller, a power regulation circuit, voltage and current sensors, a high-temperature probe, a process gas control cabinet, and a cooling water control cabinet. The PLC controller provides electrical energy to the furnace body through the power regulation circuit. The high-temperature probe is used to collect the temperature of the drawing furnace body; the voltage and current sensor is used to collect the current and voltage signals of the heating element of the drawing furnace body; the process gas control cabinet is used to provide protective gas to the drawing furnace body; and the cooling water control cabinet is used to provide cooling water to the outside of the drawing furnace body. The control method for a PLC-based temperature control system for an optical fiber drawing furnace includes the following steps: Step 1: Establish a temperature control model; Step 2: Set the temperature value on the PLC controller and the temperature value fed back by the high-temperature probe; Step 3: Calculate the change in the output power of the power regulator; Step 4: Based on the functional relationship between temperature change and power change, deduce and calculate the current setpoint for the output power of the power regulator; Step 5: Dynamically control the temperature of the wire drawing furnace body; The temperature control model in step 1 is: ΔT = Tpv - Tsv (1); ΔI=G(s) ΔT(2); I = Ia0 + ΔI (3); I=Ia0+G(s)(Tpv-Tsv)(4); Where Tpv represents: actual temperature; Tsv represents: set temperature; Ia0 represents: the current value of the power regulator required for the wire drawing furnace temperature to reach the minimum temperature of 1000 degrees detected by the temperature sensor; G(s) represents: PID function; ΔT represents: the difference between the actual temperature and the set temperature; ΔI represents: the current difference; I represents: the current control value of the wire drawing furnace electrode.

2. The control method for the PLC-based temperature control system of the optical fiber drawing furnace according to claim 1, characterized in that: The PLC controller is electrically connected to the touch screen. The PLC controller operates on 220V AC power, while the main circuit of the power regulation circuit operates on 380V AC power.

3. The control method for the PLC-based temperature control system of the optical fiber drawing furnace according to claim 1, characterized in that: The control process in step 5 is as follows: After the control system is started, the temperature inside the furnace gradually increases as the output power current of the power regulation circuit increases, and the temperature of the heating element inside the furnace gradually rises. When the temperature reaches the minimum sensing temperature of 1000 degrees Celsius of the high-temperature probe, it is simultaneously determined whether the actual temperature value and the set value are equal. If they are equal, the process ends; if they are not equal, the set value of the power current of the power regulator is adjusted until the difference between the temperature feedback value and the set value is equal to 0. After the calculation is completed, the loop judgment is restarted. The entire system is always in a dynamic balance of loop judgment and calculation.

4. The control method for the PLC-based temperature control system of the optical fiber drawing furnace according to claim 3, characterized in that: In step 5, if the difference between the actual temperature feedback value and the temperature set value is greater than 0, the power setting current of the power regulator is increased through PID control; if the difference between the actual temperature feedback value and the temperature set value is less than 0, the power setting current of the power regulator is decreased through PID control.

5. The control method for the PLC-based temperature control system of the optical fiber drawing furnace according to claim 1, characterized in that: In step 1, a control model with a temperature setpoint Tsv is added to the temperature control model: Tsv=Tsv0 K(5); Where Tsv is the temperature setting value input on the touch screen, Tsv0 is the initial value of the temperature setting value. In the PLC-based fiber optic drawing furnace temperature control system and control method, the minimum detection temperature of the temperature sensor is 1000 degrees, so the value of Tsv0 is selected as 1050 degrees; K is the coefficient for temperature increase and decrease.

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