Glass cold end drawing section anti-galloping speed synchronous control system and method

Abstract

The invention provides an anti-galloping speed synchronous control system and method for a glass cold end drawing section, and the system is characterized in that a speed measurement encoder is installed at a main transmission motor side of an annealing kiln, and collects an encoder signal in real time; the high-speed counting module records an encoder signal and transmits the encoder signal to the slave station IO controller; the cold-end controller diagnoses the communication state with the hot-end controller in real time, executes a hot-end acquisition mode when the communication state is normal, and acquires a hot-end set speed set by the hot-end controller for the main transmission motor of the annealing kiln as a speed source; in case of abnormality, switching to an encoder switching mode, acquiring an encoder signal from a slave station IO controller in real time, calculating a measurement speed, and taking the measurement speed as a speed source; and forming the control speed of the cold end section drawing section roller way according to the speed source. The speed synchronization of the cooling and heating system is guaranteed, the galloping accident is effectively avoided, the stability and reliability are improved, and the loss is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of glass production, and in particular to a speed synchronization control system and method for preventing runaway of a cold end drawing section of glass. Background Art

[0002] The "flying car" phenomenon of the glass production line, especially in the production of float glass, is a problem worthy of attention. It usually refers to the abnormal high-speed operation of the conveyor rollers on the production line (such as the main drive conveyor rollers of the annealing furnace or the cold end conveyor rollers). Because the cold end system cannot accurately obtain the main drive speed data of the hot end annealing furnace, sometimes the wrong speed feedback signal is input into the system, which not only cannot be corrected, but the error is continuously amplified, resulting in frequent "flying car" accidents of the cold end conveyor rollers. At the entrance of the cold end, the conveyor end cannot stably fit the main drive speed of the annealing furnace. When the speed does not match, it may cause the "flying car" phenomenon of the cold end entrance drive. In order to avoid the flying car phenomenon, once the "flying car" failure occurs, the system cannot identify and alarm. If the production personnel do not find it in time, it may cause the glass ribbon to be broken. "Broken board" is a major accident in the glass production line. In severe cases, the tin bath needs to be opened for cleaning, and a large number of process parameters need to be readjusted. It takes a long time to resume production and the loss is heavy. Therefore, it is necessary to solve the problem of accurate recognition of the main drive speed of the annealing furnace of the hot end system by the cold end system. Summary of the invention

[0003] Based on the above content, the present invention provides a glass cold end drawing section anti-runaway speed synchronization control system and method, which only solves the problem of frequent runaway accidents in glass production in the prior art.

[0004] A glass cold end drawing section anti-runaway speed synchronization control system, comprising:

[0005] The cold-end controller is respectively connected to the hot-end controller and the slave IO controller, the speed encoder is connected to the high-speed counting module, and the high-speed counting module is connected to the slave IO controller;

[0006] The speed encoder is installed on the main drive motor side of the annealing kiln to collect encoder signals of the operation of the main drive motor of the annealing kiln in real time;

[0007] The high-speed counting module records the encoder signal and transmits it to the slave IO controller in real time;

[0008] Cold junction controllers are used for:

[0009] Real-time diagnosis of the communication status with the hot-end controller. When a normal communication status is diagnosed, the hot-end acquisition mode is executed, and when an abnormal communication status is diagnosed, the encoder switching mode is switched;

[0010] In the hot end acquisition mode, the hot end set speed set by the hot end controller for the main drive motor of the annealing kiln is obtained as the speed source;

[0011] In encoder switching mode, the encoder signal is obtained from the slave IO controller in real time to calculate the measured speed as the speed source;

[0012] The control speed of the roller in the cold end section and the drawing section is formed according to the speed source.

[0013] Furthermore, the main drive motor of the annealing furnace has two main and standby running motors for switching use; a speed encoder is installed on each motor side;

[0014] The cold end controller is used to: in the encoder switching mode, obtain the encoder signals of the two speed encoders in real time from the slave IO controller, calculate the measurement speeds corresponding to the two speed encoders, and select the speed encoder corresponding to one of the measurement speeds as the speed source.

[0015] Furthermore, the cold end controller is used to: in the encoder switching mode, when the measurement speeds corresponding to the two speed measuring encoders are normal, select the speed measuring encoder corresponding to the largest measurement speed of the two speed measuring encoders as the speed source.

[0016] Furthermore, the cold end controller is used to: in the encoder switching mode, when one of the measured speeds corresponding to the two speed measuring encoders is normal and the other is abnormal, select the speed measuring encoder corresponding to the normal measured speed as the speed source.

[0017] Further, the cold end controller is used to: in the encoder switching mode, when the measured speeds corresponding to the two speed measuring encoders are abnormal, switch to the manual mode;

[0018] In manual mode, the cold end controller uses its own set cold end set speed as the speed source.

[0019] Furthermore, the cold end controller is used to: in the encoder switching mode, the selected measurement speed is adjusted according to a predetermined proportional coefficient to form the control speed of the cold end section drawing section roller.

[0020] Furthermore, the cold end controller is used to: in the encoder switching mode, obtain the encoder signals of the two speed encoders in real time and calculate the measured speed; when the measured speed of the speed encoder that is not used as the speed source exceeds the measured speed of the speed encoder that is used as the speed source and meets a predetermined exceeding condition, switch the speed source to the speed encoder that is not used as the speed source.

[0021] A method for synchronously controlling the speed of a cold-end drawing section of glass to prevent runaway, using the aforementioned synchronous control system for the speed of a cold-end drawing section of glass to prevent runaway, comprising:

[0022] Step A1: In the hot-end acquisition mode, the cold-end controller conducts real-time diagnosis to check whether the communication status with the hot-end controller is abnormal:

[0023] If normal, proceed to step A2;

[0024] If abnormal, go to step A3;

[0025] Step A2, continue to maintain the hot end acquisition mode, obtain the hot end set speed set by the hot end controller for the main drive motor of the annealing furnace as the speed source, form the control speed of the cold end section drawing section roller according to the speed source, and continue to perform step A1;

[0026] Step A3, switching to the encoder switching mode, obtaining the encoder signal from the slave station IO controller in real time to calculate the measured speed as the speed source, and forming the control speed of the cold end section drawing section roller according to the speed source.

[0027] Furthermore, the main drive motor of the annealing furnace has two main and standby running motors for switching use; a speed encoder is installed on each motor side;

[0028] In step A3, in the encoder switching mode, encoder signals of two speed encoders are obtained in real time from the slave IO controller, the measurement speeds corresponding to the two speed encoders are calculated, and a speed encoder corresponding to one of the measurement speeds is selected as the speed source.

[0029] Further, in step A3, in the encoder switching mode, when it is detected that the measurement speeds corresponding to the two speed measuring encoders are normal, the speed measuring encoder corresponding to the largest measurement speed of the two speed measuring encoders is selected as the speed source.

[0030] The beneficial technical effect of the present invention is that: the present invention installs a speed encoder on the side of the main drive motor of the annealing furnace to measure the actual speed of the main drive motor of the annealing furnace. When the cold end cannot obtain the set speed of the hot end, it switches to selecting the speed encoder as the speed source, and obtains the measured speed from the speed encoder, thereby improving the accuracy and reliability of identifying the main drive speed of the annealing furnace, ensuring the speed synchronization of the cold and hot systems, and can effectively avoid "running car" accidents, improve system stability and reliability, and reduce glass losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a connection schematic diagram of a glass cold end drawing section anti-runaway speed synchronization control system of the present invention;

[0032] Figure 2 The present invention is a flowchart of the steps of a method for synchronously controlling the speed of the cold-end drawing section of glass to prevent overrunning. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0035] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0036] See also Figure 1 The present invention provides a glass cold end drawing section anti-runaway speed synchronization control system, comprising:

[0037] The cold end controller (1) is respectively connected to the hot end controller (2) and the slave IO controller (3) for communication, the speed encoder (4) is connected to the high-speed counting module (5), and the high-speed counting module (5) is connected to the slave IO controller (3);

[0038] The speed encoder (4) is installed on the main drive motor side of the annealing kiln to collect encoder signals of the operation status of the main drive motor of the annealing kiln in real time;

[0039] The high-speed counting module (5) records the encoder signal and transmits it to the slave IO controller (3) in real time;

[0040] The cold end controller (1) is used to:

[0041] Real-time diagnosis of the communication status with the hot end controller (2), executing the hot end acquisition mode when a normal communication status is diagnosed, and switching to the encoder switching mode when an abnormal communication status is diagnosed;

[0042] In the hot end acquisition mode, the hot end set speed set by the hot end controller (2) for the main drive motor of the annealing furnace is acquired as a speed source;

[0043] In the encoder switching mode, the encoder signal is obtained from the slave IO controller (3) in real time to calculate the measured speed as the speed source;

[0044] The control speed of the roller in the cold end section and the drawing section is formed according to the speed source.

[0045] Specifically, the cold end controller is a cold end PLC controller (Programmable Logic Controller).

[0046] Specifically, the hot end controller is a hot end PLC controller.

[0047] Specifically, the cold end controller is connected to the optical fiber switch (6), the optical fiber switch (6) is connected to the slave station IO controller (3), the optical fiber switch (6) is also connected to the gateway (7), and the gateway (7) is connected to the hot end controller (2). A hardware communication module is added between the cold end controller and the hot end controller to realize real-time data interaction between the two controllers and obtain the hot end set speed of the main drive motor of the annealing furnace.

[0048] Specifically, the optical fiber switch (6) is also connected to a human-machine operation computer (8), and the human-machine operation computer (8) can perform parameter configuration on the cold end controller (1).

[0049] Specifically, the installation position of the speed encoder on the end roller of the annealing furnace in the prior art can be changed to be installed on the side of the main drive motor of the annealing furnace to obtain the actual speed of the main drive motor of the annealing furnace.

[0050] Specifically, the speed encoder is installed on the main drive motor side of the annealing kiln, and the collected encoder signal is connected to the high-speed counting module of the slave IO controller through a shielded twisted pair cable. The cold end controller realizes real-time data reading and writing with the slave IO controller through optical fiber and collects the encoder signal.

[0051] The present invention installs a speed encoder on the side of the main transmission motor of the annealing furnace to measure the actual speed of the main transmission motor of the annealing furnace. When the cold end cannot obtain the set speed of the hot end, the speed encoder is switched to be selected as the speed source, and the measured speed is obtained from the speed encoder, so as to improve the accuracy and reliability of the recognition of the main transmission speed of the annealing furnace, ensure the speed synchronization of the cold and hot systems, effectively avoid "runaway" accidents, improve the stability and reliability of the system, and reduce glass losses.

[0052] Furthermore, the main drive motor of the annealing furnace has two main and standby running motors for switching use; a speed encoder (4) is installed on each motor side;

[0053] The cold end controller (1) is used to: in an encoder switching mode, obtain encoder signals of two speed measuring encoders (4) in real time from a slave station IO controller (3), calculate the measurement speeds corresponding to the two speed measuring encoders (4), and select the speed measuring encoder (4) corresponding to one of the measurement speeds as a speed source.

[0054] If the communication status between the hot end controller and the hot end controller is abnormal, it means that it is difficult to obtain the correct hot end set speed from the hot end controller, so it switches to the encoder switching mode and achieves speed matching and synchronization through the measured actual speed. That is, in the case of abnormal communication status, the hot end set speed data no longer participates in logical judgment, and the cold end controller uses the coded signal fed back by the speed encoder to control the cold end conveyor roller.

[0055] Because there are two main and spare motors on the main drive motor side of the annealing kiln, one of them needs to be selected as the speed source according to the selection rules.

[0056] When the diagnostic communication is normal, the cold end controller also determines whether the measured speed calculated from the encoder signal deviates from the hot end set speed. If the deviation is large, the encoder signal is considered abnormal and an alarm may be issued. For example, if the diagnostic communication is normal, the measured speed calculated from the encoder signal is greater than the result value of the hot end set speed multiplied by the first coefficient, or less than the result value of the hot end set speed multiplied by the second coefficient, the encoder signal is considered to be an abnormal signal. Specifically, the first coefficient is, for example, 1.1, and the second coefficient is, for example, 0.9. That is, the measured speed deviates greatly from the obtained hot end set speed, and the speed encoder may be loose, etc., and an alarm is issued to remind the staff to check.

[0057] Furthermore, the cold end controller (1) is used to: in the encoder switching mode, when the measurement speeds corresponding to the two speed measuring encoders (4) are both normal, select the speed measuring encoder (4) corresponding to the largest measurement speed among the measurement speeds corresponding to the two speed measuring encoders (4) as the speed source.

[0058] Specifically, when the cold end controller receives the encoder signal, it performs high-frequency filtering on the encoder signal to reduce the impact of signal interference on the accuracy of the signal source, and then calculates the measurement speed. Specifically, if the calculated measurement speed is greater than the maximum threshold value or less than the minimum threshold value, it indicates that the encoder signal of the speed measurement encoder is abnormal and unavailable. If the measurement speed is within the range between the minimum threshold value and the maximum threshold value, it indicates that the encoder signal is normal.

[0059] If both are normal, the speed encoder with the larger measured speed is selected as the speed source to form the control speed. The two main and standby motors on the main drive motor side of the annealing kiln are switched through the clutch. Generally, the motor in use has a higher speed, and the other standby speed may be lower. Therefore, the motor corresponding to the speed encoder is determined according to the measured speed. The selection of this speed encoder as the speed source is selected in real time according to the real-time measured speed.

[0060] Furthermore, the cold end controller (1) is used to: in the encoder switching mode, when one of the measured speeds corresponding to the two speed measuring encoders (4) is normal and the other is abnormal, select the speed measuring encoder (4) corresponding to the normal measured speed as the speed source.

[0061] If a measured speed is obviously abnormal, that is, greater than the maximum threshold value or less than the minimum threshold value, the corresponding speed encoder may be loose or have other abnormalities, resulting in abnormal signals. If the measured speed obtained based on the encoder signal of this speed encoder is used as the speed source, it is easy to cause the speed to run away. Therefore, it is more appropriate to switch to the speed encoder corresponding to the normal measured speed as the speed source.

[0062] Furthermore, the cold end controller (1) is used to: in the encoder switching mode, when the measurement speeds corresponding to the two speed measuring encoders (4) are both abnormal, switch to the manual mode;

[0063] In manual mode, the cold end controller (1) uses its own set cold end set speed as the speed source.

[0064] If the two measured speeds are obviously abnormal, that is, greater than the maximum threshold value or less than the minimum threshold value, the two speed encoders may be loose or other abnormalities, resulting in abnormal signals. It is no longer appropriate to continue using them as speed sources. At this time, the cold end controller switches to manual mode and forms the control speed based on the cold end set speed as the speed source. Specifically, before switching to manual mode, the cold end set speed is synchronized with the control speed memory used by the cold end controller according to the preset time interval. After switching to manual mode, the cold end controller forms the control speed according to the latest cold end set speed.

[0065] That is, at each preset time interval, the cold end set speed is updated to the control speed currently used by the cold end controller. This can avoid accidents caused by a large difference between the cold end set speed set by the cold end controller a long time ago and the current speed when the cold end controller suddenly switches to manual mode. Therefore, when switching to manual mode, the cold end set speed updated at the preset time interval can avoid accidents.

[0066] After switching to manual mode, the cold end set speed is no longer updated. However, the HMI computer can manually change the cold end set speed after switching to manual mode.

[0067] The preset time interval is preferably 5 seconds, for example.

[0068] Furthermore, the cold end controller (1) is used to: in the encoder switching mode, the selected measurement speed is adjusted according to a predetermined proportional coefficient to form the control speed of the cold end section drawing section roller.

[0069] Because the thermal expansion of the cold end and the hot end is different, the proportional coefficient is adjusted to control the speed to achieve speed matching and synchronization of the hot and cold end systems.

[0070] Furthermore, the cold end controller (1) is used to: in an encoder switching mode, acquire encoder signals of two speed measuring encoders (4) in real time and calculate the measured speed; when the measured speed of the speed measuring encoder (4) not used as the speed source exceeds the measured speed of the speed measuring encoder (4) used as the speed source and satisfies a predetermined exceeding condition, switch the speed source to the speed measuring encoder (4) not used as the speed source.

[0071] If the first speed encoder is used as the current speed source, and in the real-time speed measurement comparison, it is found that the measured speed of the other speed encoder is higher, if the difference is not large, it will switch immediately, which seems to be too frequent. Therefore, a predetermined exceeding condition is set, and only when the two measured speeds meet the predetermined exceeding condition will the second speed encoder be switched as the speed source.

[0072] Specifically, the predetermined exceeding condition is: the measured speed of the first speed measuring encoder is less than the result value of multiplying the measured speed of the second speed measuring encoder by the third coefficient, or the measured speed of the second speed measuring encoder is greater than the result value of multiplying the measured speed of the first speed measuring encoder by the fourth coefficient. The first speed measuring encoder refers to a speed measuring encoder used as a speed source, and the second speed measuring encoder is a speed measuring encoder not used as a speed source. The third coefficient is, for example, 0.9, and the fourth coefficient is, for example, 1.1.

[0073] See also Figure 2 The present invention also provides a method for synchronously controlling the speed of the cold end drawing section of glass to prevent the vehicle from running away, using the aforementioned synchronous control system for the speed of the cold end drawing section of glass to prevent the vehicle from running away, comprising:

[0074] Step A1: In the hot-end acquisition mode, the cold-end controller conducts real-time diagnosis to check whether the communication status with the hot-end controller is abnormal:

[0075] If normal, proceed to step A2;

[0076] If abnormal, go to step A3;

[0077] Step A2, continue to maintain the hot end acquisition mode, obtain the hot end set speed set by the hot end controller for the main drive motor of the annealing furnace as the speed source, form the control speed of the cold end section drawing section roller according to the speed source, and continue to perform step A1;

[0078] Step A3, switching to the encoder switching mode, obtaining the encoder signal from the slave station IO controller in real time to calculate the measured speed as the speed source, and forming the control speed of the cold end section drawing section roller according to the speed source.

[0079] The present invention installs a speed encoder on the side of the main transmission motor of the annealing furnace to measure the actual speed of the main transmission motor of the annealing furnace. When the cold end cannot obtain the set speed of the hot end, the speed encoder is switched to be selected as the speed source, and the measured speed is obtained from the speed encoder, so as to improve the accuracy and reliability of the recognition of the main transmission speed of the annealing furnace, ensure the speed synchronization of the cold and hot systems, effectively avoid "runaway" accidents, improve the stability and reliability of the system, and reduce glass losses.

[0080] Furthermore, the main drive motor of the annealing furnace has two main and standby running motors for switching use; a speed encoder is installed on each motor side;

[0081] In step A3, in the encoder switching mode, encoder signals of two speed encoders are obtained in real time from the slave IO controller, the measurement speeds corresponding to the two speed encoders are calculated, and a speed encoder corresponding to one of the measurement speeds is selected as the speed source.

[0082] If the communication status between the hot end controller and the hot end controller is abnormal, it means that it is difficult to obtain the correct hot end set speed from the hot end controller, so it switches to the encoder switching mode and achieves speed matching and synchronization through the measured actual speed. That is, in the case of abnormal communication status, the hot end set speed data no longer participates in logical judgment, and the cold end controller uses the coded signal fed back by the speed encoder to control the cold end conveyor roller.

[0083] Further, in step A3, in the encoder switching mode, when it is detected that the measurement speeds corresponding to the two speed measuring encoders are normal, the speed measuring encoder corresponding to the largest measurement speed of the two speed measuring encoders is selected as the speed source.

[0084] The present invention adopts the above technical solution, which has the advantages of:

[0085] This method realizes two-way communication between the hot and cold end control systems, enables real-time digital signal interaction, and improves system sensitivity.

[0086] This method can obtain the accurate main transmission synchronous speed signal source and effectively prevent runaway accidents.

[0087] This method adds abnormal diagnosis and emergency switching mechanism for speed source, improving system reliability.

[0088] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A glass cold end drawing section anti-runaway speed synchronization control system, characterized in that: include: The cold end controller is respectively connected to the hot end controller and the slave IO controller in communication, the speed encoder is connected to the high-speed counting module, and the high-speed counting module is connected to the slave IO controller; The speed encoder is installed on the main drive motor side of the annealing kiln to collect encoder signals of the operation status of the main drive motor of the annealing kiln in real time; The high-speed counting module records the encoder signal and transmits it to the slave IO controller in real time; The cold end controller is used for: Real-time diagnosis of the communication status with the hot end controller, executing the hot end acquisition mode when a normal communication status is diagnosed, and switching to the encoder switching mode when an abnormal communication status is diagnosed; In the hot end acquisition mode, the hot end set speed set by the hot end controller for the main drive motor of the annealing furnace is obtained as a speed source; In the encoder switching mode, the encoder signal is obtained from the slave IO controller in real time to calculate the measured speed as a speed source; The control speed of the roller in the cold end section and the drawing section is formed according to the speed source.

2. A glass cold end drawing section anti-runaway speed synchronization control system as claimed in claim 1, characterized in that: The main drive motor of the annealing furnace has two main and spare running motors for switching use; a speed encoder is installed on each motor side; The cold end controller is used to: in the encoder switching mode, obtain the encoder signals of the two speed measuring encoders in real time from the slave station IO controller, calculate the measurement speeds corresponding to the two speed measuring encoders, and select the speed measuring encoder corresponding to one of the measurement speeds as the speed source.

3. A glass cold end drawing section anti-runaway speed synchronization control system as claimed in claim 2, characterized in that: The cold end controller is used to: in the encoder switching mode, when the measurement speeds corresponding to the two speed measuring encoders are normal, select the speed measuring encoder corresponding to the largest measurement speed of the two speed measuring encoders as the speed source.

4. A glass cold end drawing section anti-runaway speed synchronization control system as claimed in claim 2, characterized in that: The cold end controller is used for: in the encoder switching mode, when one of the measured speeds corresponding to the two speed measuring encoders is normal and the other is abnormal, selecting the speed measuring encoder corresponding to the normal measured speed as the speed source.

5. A glass cold end drawing section anti-runaway speed synchronization control system as claimed in claim 2, characterized in that: The cold end controller is used to: in the encoder switching mode, when the measured speeds corresponding to the two speed measuring encoders are abnormal, switch to the manual mode; In the manual mode, the cold end controller uses the cold end setting speed set by itself as the speed source.

6. A glass cold end drawing section anti-runaway speed synchronization control system as claimed in claim 2, characterized in that: The cold end controller is used to: in the encoder switching mode, the selected measurement speed is adjusted according to a predetermined proportional coefficient to form the control speed of the cold end section drawing section roller.

7. A glass cold end drawing section anti-runaway speed synchronization control system as claimed in claim 3, characterized in that: The cold end controller is used to: in the encoder switching mode, acquire the encoder signals of the two speed measuring encoders in real time and calculate the measured speed, and when the measured speed of the speed measuring encoder not used as the speed source exceeds the measured speed of the speed measuring encoder used as the speed source and satisfies a predetermined exceeding condition, switch the speed source to the speed measuring encoder not used as the speed source.

8. A method for synchronously controlling the speed of the cold end drawing section of glass to prevent overrunning, characterized in that: A glass cold end drawing section anti-runaway speed synchronization control system according to any one of claims 1 to 7 comprises: Step A1, the cold end controller in the hot end acquisition mode, diagnoses in real time whether the communication status with the hot end controller is abnormal: If normal, proceed to step A2; If abnormal, go to step A3; Step A2, continuing to maintain the hot end acquisition mode, obtaining the hot end set speed set by the hot end controller for the main drive motor of the annealing furnace as a speed source, forming the control speed of the cold end section drawing section roller according to the speed source, and continuing the step A1; Step A3, switching to the encoder switching mode, obtaining the encoder signal from the slave station IO controller in real time to calculate the measured speed as the speed source, and forming the control speed of the cold end section drawing section roller according to the speed source.

9. A method for synchronously controlling the speed of the cold end drawing section of glass to prevent overrunning as claimed in claim 8, characterized in that: The main drive motor of the annealing furnace has two main and spare running motors for switching use; a speed encoder is installed on each motor side; In the step A3, in the encoder switching mode, the encoder signals of the two speed measuring encoders are obtained in real time from the slave station IO controller, the measurement speeds corresponding to the two speed measuring encoders are calculated, and the speed measuring encoder corresponding to one of the measurement speeds is selected as the speed source.

10. A method for synchronously controlling the speed of the cold end drawing section of glass to prevent overrunning as claimed in claim 9, characterized in that: In step A3, in the encoder switching mode, when it is detected that the measurement speeds corresponding to the two speed measuring encoders are normal, the speed measuring encoder corresponding to the largest measurement speed of the two speed measuring encoders is selected as the speed source.

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