Operation
5.2.3Intelligent Control (Chilled Water Only)
The intelligent control operates from a set of general rules that define how the control output should be adjusted for different system conditions. The rules are designed to duplicate the actions that an experienced human operator would take if manually controlling the system.
Just as an operator might take several things into consideration before making a temperature control decision, the intelligent control can be programmed to do likewise. For example, not only is the cur- rent temperature used in making temperature control decisions, but also conditions such as:
•How fast is the temperature changing?
•What direction is the temperature changing?
•What is the cooling output now?
•What was the cooling output in the past?
•How long ago was the cooling output changed?
•and other factors.
Any number of rules can be used in an intelligent control to define the controls operation under vari- ous operating conditions. Hence, several advantages are gained from this type of control over a more standard control approach that uses a fixed mathematical equation to define the operation of the con- trol for all conditions (such as a proportional or PI control). You can expect intelligent control to be more efficient and precise for most applications, but system performance based on room conditions is not as predictable as standard approaches that use a fixed equation.
31
