SCADA of VAV/CAV Air-Conditioning System Base on Lonworks Technology

Constant Air Volume (CAV)and Variable Air Volume (VAV) air-conditioning system become more and more widely used because of it's air volume controlling property and it's energy saving property. In the whole VAV and CAV air-conditioning system, CAV and VAV damper is important component. CAV and VAV damper can control the supply air volume or return/exhaust air volume. And there is lots of parameter can be tested in CAV and VAV damper such as air volume,damper statues, damper position and temperature of room(VAV only). These parameters are craticals for the whole system. Since there are too many parameters to feedback, it cost too much to transform the parameters through analog signal, which will take too many cables and too many channel of DDC controller. The problem can be solved by using lonworks technology. Lonwork technology is a kind of open control network technology. Using lonworks technology DDC controller can acquire the parameters with a couple of cable. This paper introduces how to apply lonworks technology technology to CAV and VAV air-conditioning system, and presents framwork of CAV and VAV control system based on lonworks technology, including the component of whole system such as Variable Frequency Drivers (VFD), CAV VAV damper and network topology. Whitin the proposed framwork CAV and VAV control system can be built easliy and its performance good.