Interresting article:
TCP/IP in building management systems
http://www.automatedbuildings.com/news/ ... /priva.htm
Internet technology has been introduced into modern building management systems (BMS) with browser control, e-mail reporting and XML data exchange being integrated into intelligent controllers. All of these technologies are based on the same system: TCP/IP. This article provides details on the technology behind this network protocol plus the building management system options provided by Internet technology.
"TCP/IP can be used in two different ways for communications between the BMS and workstations. Until now most workstations were equipped with a control application on the PC, which retrieves and processes information from the BMS via the TCP/IP network. The workstation application must therefore be compatible with the BMS. The disadvantage of this set-up is that if modifications are made to the BMS the software needs to be modified in all workstations."
"The browser receives information from the BMS via HTTP, the standard transfer protocol of the World Wide Web. The information is supplied ready for use so that the operator at the workstation does not need any specific BMS knowledge to display it."
"To this end the BMS is equipped with a web server. The web server converts information from the installation into HTML code to be used by the browser. It is transmitted via the HTTP Internet protocol and a TCP/IP connection to the browser, such as Microsoft Internet Explorer. As the web server supplies all actual information, access is no longer required to the operator workstations should the installation change. This is particularly useful for multi-operator buildings or by remote control."
"To provide the same ease of operation with a browser as with an individual PC application on a workstation, a new display language, SVG (Scalable Vector Graphics), has been developed. Photographs, drawings, installation diagrams, etc are displayed in detail and at a surprisingly high speed."
"This makes XML a powerful connection medium: it is suitable for transmissions across modern TCP/IP networks, it is clearly legible and easy to debug. The formal and logical notation method makes it possible to evaluate whether the data is presented correctly.
XML is, therefore, increasingly used to exchange information between two equipment items and will become an important technology in building management systems."
"Standard products can be used for communication purposes, such as firewalls and security protocols as well as software and network analysis. New technologies, yet to be developed or conceived, can also be applied later."
