The control scenario
This chapter focuses on a control scenario for a basic sand filter. The scenario is simplified enough that the control aspects are simple but enough of the languages is explored to understand how to use them and demonstrate strengths and weaknesses.
The languages explored in this chapter will be used for the following control scenario:
The flow control diagram in Figure 5.1 demonstrates a simple method to relay how the controls are expected to operate for each of the languages used in this chapter.
A graphical representation of the process is available via a Comfort Panel Human Machine Interface (HMI).
The liquid to be filtered enters the tank from the left, through the Inlet Valve and exits the tank after passing through the filtration media via the Outlet Valve. The instrumentation consists of a Tank...