Module 1 discusses process control concepts including mathematical models of processes, control actions, and controller modes. It describes first and higher order processes, interacting and non-interacting systems, and continuous and batch processes. The basic control actions of on-off, proportional, integral, and derivative control modes are covered as well as combined P+I, P+D, and P+I+D control modes. Both pneumatic and electronic controllers used to realize various control actions are introduced.