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

PC-based Control, Software and Bus Trendstions. The technology also uses hand-held wireless terminals.Web integration is becoming more important because of the manyadvantages offered by this approach. By using a Web browser, additionalsoftware does not need be installed, since users are already familiarwith these interfaces. Full integration with existing Internet/Intranetresources is also easy to accomplish using this approach.Security for Internet-enabled I/O devices includes firewalls androuters. When the I/O device needs to be stand-alone, it is possible touse hardware/IP address filtering to limit access to known users or touse encryption schemes like the Web-standard Secure Sockets Layer. Thetype and extent of security depends on the device resources and theapplication and/or sensitivity of the data.MaintenanceOne issue to consider is the cost of maintaining a PC. This cost hascontinuously increased while the cost of the PC has decreased. The costof maintenance has increased as the complexity of the software has increased.When software is installed on a PC, there is a moderate chance thateither it will not work, or an existing application will stop working dueto hardware conflicts, software conflicts, software bugs in the installprogram, or operator errors during the installation.Microsoft provides scaled approaches to this problem that rangefrom hand-held devices to low-power PCs to high-end Windows 2000workstations and servers. Other operating systems such as Linus providea scaled, build-to-need approach, that generally requires less hardwarethan Windows-based systems.Web-based applications built on Java and/or ActiveX will requirefewer resources, making systems less expensive and more reliable.Future ComputersComputers will become more human, this means that they willbecome more mobile and intelligent. They will take on more humanattributes such as the ability to react to spoken words or written instructionsand to reply in a way that seems more natural. The results will be©2001 by The Fairmont Press, Inc. All rights reserved.