BACnet Basics: What are Device Profiles?

BACnet Basics: What are Device Profiles?

by | Aug 10, 2022 | BACnet, Continuing Ed, Technology

In this article in our BACnet Basics Series, we look at Device Profiles, why they’re important and how they’re created. We’ve also included a real world example that illustrates how to use device profiles to accurately specify your own projects.

What are Device Profiles?

As we saw in BACnet Basics: What are BIBBs?, device functions come in five basic categories, each containing specific capabilities. For example, the category Data Sharing (DS) includes capabilities like Read Properties (RP), Write Properties (WP) or Change of Value (COV). If we combined all these services into a minimum collection of capabilities, we would be creating a device profile.

As an analogy, think of the profile “Automobile”. Every machine that claims to be an “automobile” needs the functions of Acceleration (A), Deceleration (D) and Maneuverability (M). Of course, there can be automobiles that do much more, but every “automobile” must, at minimum, perform these three functions (A,D,M).

Definition: BACnet device profiles define the minimum set of BACnet Interoperability Building Blocks (BIBBs) supported by a device claiming that profile. When a device claims a specific profile, you know that it contains a preset of specified functions and services. Profiles are handy because they provide a short-hand method for describing a device and its interoperability capabilities. Device profiles are organized into Groups and Families

Device Groups

Device Groups are general categories of device functions. There are four Group types:

  1. Operator Interface—Covers the minimum capabilities for workstations and other user interface devices. Devices normally support A-side (Client) functionality.
  2. Controller Device—Covers anything from programmable building controllers to smart sensors. Devices normally support B-side (Server) functionality, but more advanced supervisory controllers also include A-side (Client) functionality.
  3. Control Station—Covers lighting control stations that are smaller client devices that support specific user controls such as manual light switches.
  4. Basic Device—Covers all “miscellaneous” family functionality. Usually included alongside other device profiles.
Table showing bacnet profile groups

Device Families

Each Profile Group contains various Families within it. Families cover profiles for various, supported building systems like Lighting, Life Safety, and General Purpose. For example, the Controller Device Group contains profiles for the following Family types:

(Example) Controller Family

  • General Purpose—General purpose controllers usually for HVAC and lighting.
  • Access Control—Access control controllers such as an access control panel
  • Lighting—Lighting controllers such as supervisory lighting controller
  • Life Safety—Life safety controllers such as a fire detection panel.
  • Elevator—Elevator controllers

Let’s zoom into the General Purpose profile family within the Controller Device Group and see what BIBBs it contains.

  • Building Controller (B-BC) —Field programmable and configurable supervisory controllers in HVAC and general purpose application.
  • Advanced Application Controller (B-AAC)—Controllers that run advanced HVAC or general purpose control applications.
  • Application Specific Controller (B-ASC)—Controllers that run specific HVAC or general purpose control applications.
  • Smart Actuator (B-SA)—Small, commendable actuator devices.
  • Smart Sensor (B-SS)—Small sensors that provide sensor values to other devices.

BACnet device profile Families are organized in a container hierarchy. As you move up in complexity, you increase the minimum amount of BIBBS required. Like nesting dolls, each profile contains all the minimum profiles from the previous ones. 

For example, the above General Purpose BACnet profiles increase in complexity as you move up from Smart Sensor to Building Controller. All BIBBS included in a Smart Sensor profile are always included in a Smart Actuator profile, and all the BIBBs included in those two profiles are always included in an Application Specific Controller, and so on.

List of general purpose controller bacnet profiles

Although higher level BACnet profiles contain more BIBBs, it’s not the number of profiles that matters. Each profile requires a minimum number and type of profiles. So, even if a device contains or exceeds the minimum number of BIBBs, it doesn’t guarantee it will meet the standard. It must contain the minimum number of the correct BIBBs to meet the profile standard.

Specifying Device Profiles: Boardroom Example

Let’s use the Device Profile Quick Reference Guide to see an example of how to choose the device profiles for a real-world project. Read the following scenario:

  • You want to outfit a medium-sized boardroom equipped with a control panel with a built-in controller. The panel will control the room’s temperature and lighting. You also need manual lighting controls near the door. 

To determine the device profiles needed for the project, we can start by listing the functionality we need. We will need HVAC controls for temperature. For lighting, we will need controls for both the panel and a manual user control switch on the wall. Therefore, we will need functionality from the Controller Group and Control Station Group.

Next, we can determine what Families we need within each group.

For the Controller Group, we need:

  • General Purpose Family for HVAC
  • Lighting Family for panel control lighting
  • Access Control Family for access

For the Control Station Group, we need:

  • Lighting Family for manual switch lighting control

Finally, we can choose specific profiles to fulfill our HVAC and lighting functionality.

bacnet touch screen device for a boardroom.

HVAC Profiles

In the Reference Guide, we see the following profiles for the General Purpose Controller Family:

  • B-BC: The building controller is intended for field programmable and configurable supervisory controllers in HVAC and general purpose applications.
  • B-AAC: The advanced application controller is intended for controllers that run advanced HVAC or general purpose control applications. It does not require being configurable through BACnet.
  • B-ASC: The application specific controller is intended for controllers that run specific HVAC or general purpose control applications. It does not require being configurable through BACnet.
  • B-SA: The smart actuator is intended for small actuator devices that allow being commanded.
  • B-SS: The smart sensor is intended for small sensor devices that provide sensor values to other devices.

We can ignore the last two profiles, because we need neither actuators (B-SA) or sensors (B-SS) for the project. We can also eliminate the Building Controller (B-BC) profile because it does not require supervisory control. Depending on our HVAC needs, we could choose either the Advanced Application (B-AAC) or the Application Specific (B-ASC) profile.

Lighting Profiles

In the Reference Guide, we see the following profiles for the Lighting Controller Family:

  • B-LS: The lighting supervisory controller is intended for controllers in lighting applications that can command and operate subordinate lighting controllers, in particular through group write commanding.
  • B-LD: The lighting device is intended for lighting controllers that control individual lights or groups of lights. Normally used as leaf nodes in lighting group setups.

We would choose the B-LD profile if the panel only controls one group of lights. However, if the lighting is more complex, we might opt for the B-LS with supervisory controls.

Control Station Profiles

Because the room also requires manual user lighting controls, we need a profile from the Control Station Family. In the Reference Guide, we see the following profiles:

  • B-ALCS: The advanced lighting control station is intended for sophisticated control stations that support user view, control and limited configuration of lighting functionality. Provides full commanding support of lighting objects and group operations for them.
  • B-LCS: The lighting control station is intended for control stations that support simple control of lighting functionality and limited status indication. Provides limited support of commanding lighting objects.

The simpler B-LCS would work for this project. But, again, depending on the complexity of the room’s lighting, we might choose the more complex profile.

Conclusion

Through the Boardroom Example above, we can see how BACnet profiles make project specifications easier and more accurate. Standards and profiles support an accurate procurement process, requiring less change orders and adjustments. Defining capabilities also creates an outcomes-based workflow so that buildings function the way owners and tenants need them to.

BACnet Basics: What are BIBBs? 

BACnet Basics: What are BIBBs? 

by | Jul 5, 2022 | BACnet, Continuing Ed, Technology

Every complex topic or field needs a helpful naming system. Scientists name flora and fauna by genus and species. Even astronomers have their own planetary nomenclature. Standard naming conventions do just that—they standardize how we talk about things. They’re also a convenient way to condense large amounts of information into a short form. Hence, they function like acronyms. We needn’t sound out “self-contained underwater breathing apparatus” when we can simply utter S.C.U.B.A. right?  

In building automation, the same need for standards and compression applies, and BACnet gives us a convenient way to describe the functionality of devices using something called BIBBs.  

What are BIBBs? 

Definition: BIBBs stands for “BACnet Interoperability Building Blocks” and is a standard naming convention for representing specific device capabilities using simple acronyms. That is, it creates simple categories to describe how one device works with another.    

Without short-form descriptions, listing all the capabilities and services that a device offers would turn functional descriptions into a messy scrawl of technical jargon. By condensing these functions into acronyms, BIBBs makes it easier for FMs, system integrators, and building engineers to talk about the same things. BIBBs help buyers get the minimum number of services for the job without over-engineering and spending for extraneous functionality. 

man holding smartphone with words automation

BIBB Categories  

The BIBB naming system starts with five broad categories that list interoperability functions. These are high level functions that host specific capabilities within them. Categories include: 

Data Sharing (DS) 

The data sharing function describes how devices exchange data. Data sharing is essential for reading and writing data from one device to another. For example. If you wanted to regularly check the water temp of your boiler to monitor its performance, you would need the DS functionality.   

Alarm & Event Management (AE) 

The alarm and event management functionality is for detecting and notifying alarms and events. For example, if your boiler temps exceeded a specified setpoint, the AE function would allow you to receive an alert.  

Scheduling (SCHED) 

The scheduling functionality is for scheduling values based on date, time, and calendar. For example, if you wanted to schedule your boiler to provide after-hours heating for tenants.  

Trending (T) 

The trending functionality is for trend logging and historical data support. For example, if you wanted to store your boiler’s temp data to create a history for your engineer.  

Device Management/Network Management (DM/NM) 

The DM/NM is for setting up device and network management. It allows devices to discover each other, to synchronize clocks, and to reset a device to factory settings (reinitialize). For example, if you wanted to discover a newly installed boiler temp sensor.  

Specific Capabilities 

Specific capabilities, or sometimes called services, are distinct functions that exist within a BIBBs category. Capabilities also have acronyms. For example, the Read Property (RP) service is under the data sharing (DS) category. The service must exist for data sharing to occur. That is, a device (e.g., controller) must be able to read data, while another device (e.g., thermostat) must be able to send it. Many devices have both capabilities. Here are some examples of services for different BIBBs categories: 

Data Sharing (DS) 

  • Read Property Multiple (RPM) 
  • Write Property (WP) 
  • Change of Value (COV) 

Alarm & Event Management (AE) 

  • Notification (N) 
  • Alarm Summary (ASUM) 
  • View Notifications (VN) 

Device and Network Management 

  • Dynamic Device Binding (DDB) 
  • Text Message (TM) 
  • Reinitialize Device (RD) 

Find a more extensive list of device capabilities here. 

Clients and Servers 

BIBBs also distinguishes between clients and servers, assigning and A and B category to each respectively. Client devices (A) can initiate or call for data or service from a device that can respond to that request (B). An example of this would be a controller (A) requesting temp data from a thermostat (B), which responds with the requested data. You can remember this order by recalling that the letter “A” comes before “B” in the alphabet, just as a request must precede a response.  

Putting It All Together 

Now that we have all three parts of BIBBs, let’s look at a full interoperability description. The BIBBs naming syntax places the category first, specific capability second, and server/client designation third. Each acronym is separated by a dash. Consider a BACnet controller that has data sharing (DS), a read property service (RP), and client capability (A). It would be designated as DS-RP-A. Can you guess what functionality a thermostat would require to send temp data back to the controller? If you answered DS-RP-B, you’re correct!   

Conclusion 

As we’ve seen, BIBBs are the “building blocks” of the standardized system of naming devices and their interoperability functions. Devices can have many different functions, so there’s also a need to group them. For example, controllers, sensors, and actuators must all have a minimum number of specific functions to work. These groups of functions are called BACnet device profiles. Like BIBBs acronyms, profiles give us a shorthand way of quickly designating and describing a device. Read BACnet Basics: What are Device Profiles? to learn more or visit The BACnet Institute for free training.