AUTOMATIC CONTROL OF AIR-HANDLING (HVAC) SYSTEMS Methods for Automation Control

There are unfortunately no established rules or methods for how an industrial process can be controlled. The methods are usually the necessary and desir­able functions and requirements for accuracy, which is necessary for an eco­nomical and quality product.

In providing a correctly optimized and accurate control system, all sec­tions of the professional team involved in the project have to work together as a fully cooperating group. This includes persons who have a working knowl­edge of the process and those who are responsible for the automation and the electrotechnical aspects of the project.

• Initially roughly design the systems.

• Survey the functions of the control system.

• Check the system requirements for the required accuracy.

• Select the control system and the user interface.

• Select the process subproduct.

• State the degree of responsibility for delivery and commissioning.

The user interface and the simplicity of usage are important issues. Like­wise, stabilized and qualified control for some of the control loops must be as simple as possible.

Also important is the interplay between different sensors, controllers, auto­mation equipment, and objects regulated by the control equipment. The require­ments of pumps, fans, batteries, heat exchanger, valves, motors, etc. in standard sizes may greatly differ from the theoretical calculations. Because of this fact, the control equipment, in addition to satisfactory control, must be capable of correct­ing the differences between the calculated and delivered subproducts.

An automated technical installation is normally no better than the weak­est subproduct in the process, system, or installation,

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