基于PLC的聚酯薄膜分切机放卷机张力自适应控制系统

本文介绍了聚酯薄膜分切机放卷机张力自适应控制系统，系统采用西门子S5－115U PLC，交流传动采用6SE70矢量控制变频器，多种检测信号通过ET－2000分布式I／O组件由Profibus-DP传送至PLC。文中介绍了放卷机张力控制的调节原理，由于带薄膜的放卷辊直径变化范围很大，放卷辊的转动惯量变化范围很大，为此系统中采用了自适应控制原理，由PLC、变频器及光电编码器构成转速环，并在放卷机转速环的前向通道中，设置1个与放卷辊直径的平方成比例的系数，以抵消其转动惯量的变化，使转速环在放卷辊直径变化时始终具有良好的动态性能。从而保证良好的张力控制效果。

PLC Based Self-adaptive Tension ControlSystem Used for Unwinder of Polyester Film Slitter

This Paper introduces a self adaptive tension control system used for the unwinder in a polyester film slitter. Siemens S5 115U PLC is used in the system and 6SE70 vector control converter is used as its AC driver.Several measured signals are transmitted to PLC via ET 200 distributed I/O module and Profibus DP. In this paper the tension control principle of the unwinder is introduced. Because the roller diameter varies widely, its moment of inertia also varies wildly. For this reason the principle of self adaptive control is used in the system. The SR loop of the system is made up of PLC, Converter and photoelectricity encoder. In the control channel of the SR loop a parameter is chosen, which is proportional to the square of the roller diameter, to compensate the variation of the moment of inertia. By this way the SR loop can possess good dynamic properties in the whole time during the variation of the roller diameter. Finally the good tension control effect is guaranteed.