Network feedback control method of cold rolling mill thickness control system

Abstract

The invention provides a network feedback control method for a thickness control system of a cold rolling mill; a thickness tester sends the outlet thickness value of the belt material measured through the Ethernet communication interface to the Ethernet network; the controller receives the thickness value through the Ethernet communication interface from network, calculating the control algorithm, sending the controlled variable to the servo valve, driving the hydraulic pressure screw down the cylinder, completing a calculation of the control circuit; the thickness tester sends the outlet thickness value of the belt material in sequence, the controller receives the thickness value data in sequence, processing calculation, completing thickness controlling process of the cold rolling mill. The invention has the advantages of converting the analog transmission to the digital transmission of the thickness feedback channel through the Ethernet, greatly increasing the control precision and anti-interference capability, reducing the connection cables, extending the connection distance, significantly enhancing fault diagnosis and restoration capability.

Description

technical field [0001] The invention relates to a network feedback control method for a thickness control system of a cold rolling mill, belonging to the technical field of cold rolling mill control. Background technique [0002] In the metallurgical industry, the metal pressure processing equipment cold rolling mill production line is very complex, the computer control level is high, and the automatic control system plays an important role. The automation control system of cold rolling mill is divided into basic automation system and process automation system. For the basic automation system, the thickness control system is a key component and a key means to ensure the thickness accuracy of the rolled strip outlet. The thickness control system of the cold rolling mill measures the exit thickness of the rolled strip through a thickness gauge, and compares the actual measured value with the given value to obtain a deviation signal, and calculates the final value by means of t...

AI Technical Summary

Problems solved by technology

[0003] ①The control accuracy is low. In the analog signal measurement method of the thickness gauge, multiple A / D (analog / digital) and D / A (digital / analog) conversions are required, and each conversion will increase the conversion error , which reduces the control precision;

[0004] ② There are many connecting cables, and each analog feedback connection requires at least two wires. When there are multiple analog feedbacks, the connecting cables are multiplied, which increases the production cost

[0005] ③The connection distance is short. When using analog feedback connection, due to the resistance of the transmission cable, energy loss and voltage drop are caused, so the connection distance is generally short

[0006] ④The anti-interference ability is weak. When the analog feedback connection is used, the analog voltage or current is greatly affected by the surrounding environment. The change of the electromagnetic field in the surrounding environment is likely to cause the analog voltage or current to change, reducing the accuracy of the measurement data

[0007] ⑤ Fault diagnosis and recovery are difficult. In the analog feedback connection, due to the increase of cables and contact points, the number of possible faults also increases, making fault diagnosis more difficult and recovery more troublesome

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