Abstract: In order to solve the problems of inefficiency,instability,inaccurate and low degree of automation,the roll position automatic adjustment system is designed for the one time forming of cold-formed steel unit.The automatic control technology,sensor technology,communication technology and Human Machine Interface(HMI) configuration technology are applied to this system and with the high performance PLC controller as control core.Triple-phase asynchronous motor controlled by PLC(S7-1500) driving gear connected with reducer and coupling,so as to drive rolls connected with the upper and lower horizontal axis to move;the osiswitch is used to calibration zero position and the closed-loop control system is constructed by analyzing and feedback the signal of the sensor,and in this way can improve the roll position adjustment accuracy.The practical applications show that the whole system is simple,stable and efficient,the maximum detection error of roller displacement is only±2 mm.The system can automatically call the corresponding roll position data according to the specification of the steel pipe.The system not only improve the change speed and accuracy,but also avoids the waste of manpower,so that make the enterprise production efficiency has been greatly improved.Meanwhile,in order to predict the roller parameters and carry out efficient management of the unit,the unit health management system was used to analyze and monitor the status of the unit in real time.

Key words: one time forming, cold-formed steel unit, PLC, roll position, adjustment accuracy