In modern building design, the design, fitting and
control systems of these tasks are built-in into a single "HVAC"
system. Modern automatic HVAC control systems are used for temperature,
humidity, and pressure control, and often integrate fire, security, and
lighting controls into single system. These systems typically use one or more
central controllers to command and monitor the remote terminal unit
controllers, and they converse with one or more personal computers that are used
as the operator interface, control systems are typically used on large
commercial and industrial buildings to allow central control of many HVAC units
around the building(s)....