tion experts and the UML files will facilitate the development of protocol specific implementations of the model. Who Will Use the FSGIM? An information model is an abstraction, not an implementation. There already exists well-established communication protocols used for automation and control in facilities, although these protocols vary with the type of facility. It is unrealistic to think that this installed base will just disappear. There are also practical reasons why protocols used in a manufacturing environment differ from those used in a commercial building or a home. The vision is that this common information model will be adopted by making extensions to the various communication protocols already used within facility markets. Each protocol will use its own existing mechanisms to encode and communicate the information within the facility. The relationship between the information model and the protocols used to implement it is shown in Figure 3. It is inevitable that the situation will arise where a product designed primarily for use in one of these environments will need to be used in another. This would require a protocol translation gateway but because the meaning of the information is based on the same information model standard, this task becomes much easier and more reliable than it otherwise would be. The ASHRAE BACnet standard14 is an example of a target protocol standard that will make use of the FSGIM. Although many of the communication details in BACnet have no counterpart in an information model, the object oriented structure in BACnet does define an extensible information model that already has similarities to the information model components that will make up the FSGIM. In fact, the BACnet Load Control object type was used to develop features of the FSGIM Load model component. Although this example is a close one-to-one mapping of a BACnet object type with an FSGIM model component, generally, that will not be the case. Other parts of the FSGIM will eventually map to combinations of existing BACnet object types and perhaps new ones that must be created by the BACnet committee. It is expected that in most cases several BACnet object types will combine to form the functionality of a single FSGIM model component. The BACnet committee is exploring an extension to the standard that would enable the creation of what are presently called “application interfaces.” The idea is that an application interface would define a collection of parameters important to a particular application in a way that abstracts away the details of the underlying objects and properties that contain this information. This would enable developers to create software ap- BACnet and FSGIM www.info.hotims.com/37992-58 November 2011 BACnet® To d a y & t h e S m a r t G r i d | A S u p p l e m e n t t o A S H R A E J o u r n a l B21