BACnet Protocol

BACnet

BACnet abbreviates Building Automation And Control Networks. Automation includes the process of storage of process-internal work steps, so that these can be executed continuously without the need for prior processing. Especially in fields of industry with a high level of production, it is important to keep technology up to date. However, this also includes automation of processes in order to be able to manufacture in a larger series and to create unity between system equipment. Protocols are used to reach this target. Here in particular, the BACnet is a product of this. This term stands for “Building Automation and Control networks” and refers to a type of protocol which aims to establish building automation within the functional building, which is characterised by interoperability as well as openness. For specifying the term BACnet, is also suitable to call it a method. This is because these systems enable the HLK technology, i.e. the technology related to heating, ventilation, and air-conditioning, to exchange data with each other. However, other system components such as lighting control, safety engineering, actuators, sensors, and building control technology, also find a connection point here. Additionally, there are more extensive transactions, including not only alarm routing, but also the creation of a process history and the monitoring of the equipment status. Although not occurring generally, but still to be considered here, there is reinitialization, the functions related to date and time, the loading of applications within the automation stations, and backup.

The history of this protocol already stretches back some years. The BACnet was developed for the first time in the year 1987, and eight years later it was consolidated to form a standard. Since 2003, the original ANSI/ASHRAE standard has changed to become a ISO standard. With this protocol, the standard assumes a decisive role. This is because observation of the standard can guarantee interoperability between the different devices of different manufacturers. The BacNet Interoperability Building Block (abbreviated: BIBB) was defined for this. This specifies which components of a system have to be supported in order to really satisfy its requirements and maintain a process that runs smoothly and efficiently. The specified BIBBs are listed in the internal device protocols together with other items such as object types, the communication options, and the character sets. In addition to the services, the BACnet also defines object types:

  • Services – first of all these include the “common use of data”, “alarm and event processing” and the “processing of value changes”. The last communication-relevant application is the “device and network management”.
  • Object types – first of all, this includes the device itself, which is known as a “device object”. The next object types of the BACnet include the analog input, the digital input, and the multi-state input. In addition, there is also the analog output, the digital output and the multi-state output. The third listed object type refers to the value, which may be analog, digital or multi-state. In addition, this section also includes the standards also includes the notification class, the trendlog, the calendar, the schedule, the program, and the accumulator.

Gains through the use of the BACnet protocol

This protocol serves to specify the standard within complex transactions which serve the task of data transmission. However, as this is not a monopoly position, the question is raised as to the benefits of the BACnet protocol within information technology and industrial communication.
The benefits of this method are illustrated when a comparison is made with other types of the protocol, for example the LonTalk protocol. Compared with other protocols, use of the BACnet protocol does not require specific hardware. This makes direct use possible and it is also favorable in terms of the cost aspect, as additional parts such a neuron chip (in the case of LonTalk) can be omitted without influencing the efficiency of the protocol. As such, this development has the proactive advantage that it works both with any operating system, and on the basis of all hardware platforms. Furthermore, the BACnet protocol can be expanded thanks to the so-called BACstacks that can be purchased on the market for developers. This support relates to a collection of high-level language programs. As such, the developer is offered a kind of library from which he can gather the required components. The programmer is guided by the BACstacks through special tasks. As a rule, these concern the automation station and the building control system. This process is facilitated by the fact that with use of BACstacks, the BACnet protocol is controlled by these high-level language programs and the developer can focus his work on the application itself and its optimization. Finally, use of the BACnet protocol and its marketed components results in conformities which are introduced as an additional advantage. Namely, the BACstacks ensure that the respective protocol can be implemented, so that standards can be defined.