Lesson 2 - Principles of Process Control
This lesson explores exactly what process control is and explains why it is important. It examines the various levels within process control systems and identifies the associated equipment. It also takes a detailed look at the various automation communication and control elements.
Lines
The figure below shows the most common lines that you will find on a P&ID diagram:
Figure: Lines on a P&ID diagram
Thick lines indicate the process piping, and thin solid lines indicate process connections, showing where instruments are connected within the process. The other lines represent electrical, pneumatic and data/software signals.