Automatic control system for plating thickness of hot galvanizing line

Abstract

The invention provides an automatic control system for plating thickness of cold rolling hot galvanizing line, which comprises an air knife, a thickness gauge, an industrial PC (Personal Computer), a PLC (Programmable logic Controller) and a plating thickness control program, wherein the control program is run in the industrial PC; the industrial PC and the PLC controller are connected by using a PROFIBUS (Process Field Bus) DP field bus; the PLC controller acquires the actual value of plating thickness and data in production process and sends into the industrial PC; the control program adopts cascade control method; a minor loop is designed into a servo system by utilizing the advantages of conventional PID (Proportion Integration Differentiation) dense sampling; the sampling period of a major loop is 50-100 times of that of the minor loop; the control program calculates the setting values of air knife pressure, distance and frame position in real time according to the actual value of plating thickness and the data in production process and sends into the PLC controller so as to realize the adjustments of the air knife pressure, distance and frame position; and simultaneously, the controls for undisturbed switching and plating variable specification switching in manual / automatic mode are further designed. According to the automatic control system, the deviation of plating thickness can be quickly eliminated, and the system has good control effect on variable specification in the processes of accelerating and decelerating.

Description

technical field [0001] The invention belongs to the technical field of iron and steel production equipment, and is suitable for coating thickness control of a hot-dip galvanizing production line. Background technique [0002] Hot-dip galvanized sheets are widely used in construction, home appliances, automobiles and other industries due to their good corrosion resistance. In recent years, with the increasingly fierce competition in the hot-dip galvanized sheet market, users have higher and higher requirements for the quality of hot-dip galvanized sheets. The thickness and uniformity of the coating are an important indicator for evaluating the quality of galvanized sheets. Too thin a coating affects the corrosion resistance of the product, and too thick a coating affects the spot weldability and adhesion of the product and causes waste of zinc raw materials. At present, most domestic hot-dip galvanizing production lines still adopt the traditional control method for the cont...

AI Technical Summary

Problems solved by technology

The system can realize automatic control of coating thickness, but the predictive control loop and feedback control loop are based on the model, the control performance is too dependent on the model accuracy, and the control effect is not good when the model is mismatched

[0007] At present, the coating thickness control of most domestic hot-dip galvanizing production lines is still manually adjusted by the operator, which will inevitably cause excessive coating thickness deviation

The existing automatic coating thickness control system also has the defects of long adjustment time and poor control effect

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