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).
The SCR's (1CD and 2CD) are phase controlled to control power. delivered to the machine field. The voltage regulator controls the machine field voltage by controlling the. firing of 1CD and 2CD on respective positive half cycles. See Figure 2.