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).
Once you have the information on how well the system is performing, you have to do something with that information. The problem the control system designer faces is to determine how to use the information available to develop and apply a control signal that will make the system do what he or she wants it to do.