It was a valued export in Silk Road trading, but the manufacturing process was kept secret. During the Tang Dynasty (618-907) and the Song Dynasty (960-1279), varieties of paper were developed for different purposes.
April 7, 2015 Written by controlguru. Like the P-Only controller, the Proportional-Integral (PI) algorithm computes and transmits a controller output (CO) signal every sample time, T, to the final control element (e.g., valve, variable speed pump).
As a PID controller relies only on the measured process variable, not on knowledge of the underlying process, it is a broadly useful controller.By tuning the three parameters of the model, one can design a PID controller for specific process requirements.f the PID controller parameters (the gains of the proportional, integral and derivative terms) are chosen incorrectly, the controlled process input can be unstable, i.e., its output diverges, with or without oscillation, and is limited only by saturation or mechanical breakage.