HVAC Control in the New Millennium.pdf - HVAC.Amickracing

HVAC Control in the New Millenniumlow voltage DC power and data. The unit reads temperatures andchecks whether they are changed since the last reading. It passes anynew data to the PC, with instant notification of alarm conditions. Sinceit only transmits changed data, the network traffic is minimized. You canmove the device around without worrying about where it is on thenetwork. It always identifies itself.The device comprises an intelligent isothermal box. It has 30 screwterminals for connecting the thermocouple wires, a sensor to measurethe temperature of the unit (the cold junction sensor), an A-D converterand a processor. It can handle B, E, J, K, N, R, S and T type thermocouples.A Windows software package called Windmill is included with thesystem. It provides data logging, charting, output control and real-timelinks to other software. A distributed thermocouple system can increasethe accuracy of temperature measurements. Resistance temperature devices(RTDs) are also available as Lon units.Open Building ControlsAs standards of open interoperability continue to evolve, somebuilding control systems promise compliance with several standards.Siebe Environmental Controls has their I/A Series with flexibility andscalability in LonMark and LonWorks controllers. WorkPlace is used asthe Human Machine Interface (HMI). Based on Wonderware, WorkPlaceprovides single seat control of building systems. The system is optimizedand configured using an integrating driver with the Tech Suite or by addingcapabilities through Microsoft Active XCOM object technologies.The Lon Network Controller provides connectivity, alarming, timeof day schedule optimization, maintenance reminders and global informationmanagement. The Tech Suite module uses graphical layout andpresentation technology, combined with the intuitive assistance of VISIO.The MicroNet controller family allows tailoring of the control strategy.As technologies move forward, they should remain focused onbackward compatibility to assure that users have an opportunity to takeadvantage of their installed infrastructure. Connectivity ranging fromdial-up PBX, to full integration at the workstation and control systemlevels are expected by today’s building owner. The I/A Series addressesthese requirements and provides client/server functionality through©2001 by The Fairmont Press, Inc. All rights reserved.