This BACnet protocol stack library provides a BACnet application layer, network layer and media access (MAC) layer communications services. It is an open source, royalty-free library for an embedded system, Windows, Linux, or other operating system. Example BACnet client and server applications are included.
BACnet - A Data Communication Protocol for Building Automation and Control Networks - see bacnet.org. BACnet is a standard data communication protocol for Building Automation and Control Networks. BACnet is an open protocol, which means anyone can contribute to the standard, and anyone may use it. The only caveat is that the BACnet standard document itself is copyrighted by ASHRAE, and they sell the document to help defray costs of developing and maintaining the standard (similar to IEEE or ANSI or ISO).
For software developers, the BACnet protocol is a standard way to send and receive messages on the wire containing data that is understood by other BACnet compliant devices. The BACnet standard defines a standard way to communicate over a number of wires, known as Data Link/Physical Layers: Ethernet, EIA-485, EIA-232, ARCNET, and LonTalk. The BACnet standard also defines a standard way to communicate using UDP (IPv4 and IPv6) and TCP (HTTP for RESTful Web Services and HTTPS for Secure Connect).
There are other open source projects for BACnet:There are also commercial BACnet protocol source code libraries for BACnet that are designed for embedded use:
Our BACnet protocol stack implementation is specifically designed for the embedded BACnet appliance, using a GPL with exception license (like eCos), which means that any changes to the core code that are distributed are made available, but the BACnet library can be linked to proprietary code without it becoming licensed under the GPL. See the eCos license overview for easy to read details about this exception to the GPL. The license does not require users to release the source code of any applications that are developed with this BACnet stack - only portions of the BACnet stack that have been modified. Note that those files in this BACnet stack that are expected to be modified are licensed using the MIT License.
The text of the GPL exception included in each source file is as follows:
"As a special exception, if other files instantiate templates or use macros or inline functions from this file, or you compile this file and link it with other works to produce a work based on this file, this file does not by itself cause the resulting work to be covered by the GNU General Public License. However the source code for this file must still be made available in accordance with section (3) of the GNU General Public License."
The source code is written in C for portability, and includes unit tests (PC based unit tests) and example application code. Since the code is designed to be portable, it compiles with GCC as well as other compilers, such as Visual C++, MinGW, IAR, or MicroChip XC. The source code is also designed to be high quality, readable, understandable, and easy to use.
The BACnet protocol is an ASHRAE/ANSI/ISO standard, so this library adheres to that standard. BACnet has no royalties or licensing restrictions, and registration for a BACnet vendor ID is free.
The BACnet stack comes with example applications that can be run under Linux, Win32, MacOS, or BSD. There are also example projects for embedded systems and microcontrollers.
The unit tests use CMake and may be run with the command sequence:
$ make test
The unit test framework uses a slightly modified ztest, and
the tests are located in the test/ folder. The test
coverage tool is LCOV. The HTML results of the unit testing
coverage are available starting in the
test/build/lcoverage/index.html file. The unit tests
can be run on computer and run with every commit within the
Continuous Integration environment.
The BACnet stack was functionally tested using a variety of tools as well as various controllers and workstations. It has been included in many products that successfully completed BTL testing.
Using the Makefile in the project root directory, a dozen sample applications are created that run under Windows or Linux. They use the BACnet/IPv4 datalink layer for communication by default, but could be compiled to use BACnet IPv6, Ethernet, ARCNET, or MS/TP.
To build all the demo applications under Linux/Unix/Cygwin using the BACnet/IP datalink layer, use the familiar make command:
$ make clean all
You can also modify the Makefile variabiles from the command line to build with the BACnet MS/TP datalink layer, for example:
$ make BACDL_DEFINE=-DBACDL_MSTP=1 clean
all
To build all the demo applications under Windows with the BACnet/IP datalink layer and utilizing the MinGW tools from BASH:
$
make win32
From Windows Command Line
c:\> build.bat
The library is also instrumented to use CMake which can generate a project or Makefiles for a variety of IDE or compiler. For example, to generate a Code::Blocks project:
$ mkdir build $ cd build/ $ cmake ..
-G"CodeBlocks - Unix Makefiles" c:\> mkdir build c:\> cd
build/ c:\> cmake .. -G"CodeBlocks - MinGW
Makefiles"
The demo application accept command line arguments. To specify
an array index of ALL, use "-1". To make a priority optional, use
"0". The applications also use environment variables to set
datalink layer preferences. Use --help on the
command line to see more options.
$ apps/server/bacsrv
123
BACnet Server Demo - Device #123
$ apps/readprop/bacrp
bacrp device-instance object-type object-instance property
[index]
$ apps/writeprop/bacwp
bacwp device-instance object-type object-instance property
priority index tag value [tag value...]
$ apps/readfile/bacarf
bacarf device-instance file-instance local-name
$ apps/writefile/bacawf
bacawf device-instance file-instance local-name
$ apps/reinit/bacrd
Usage: bacrd device-instance state [password]
Send BACnet ReinitializeDevice service to device.
$ apps/whohas/bacwh
Usage: bacwh object-type object-instance | object-name
Send BACnet WhoHas request to devices, and wait for
responses.
$ apps/dcc/bacdcc
Usage: bacdcc device-instance state timeout [password]
Send BACnet DeviceCommunicationControl service to device.
$ apps/timesync/bacts
Received TimeSyncronization Request
2006/8/30 07:10:45.00
$ apps/ucov/bacucov
Usage: bacucov pid device-id object-type object-instance time
property tag value [priority] [index]
$ apps/whois/bacwi
Usage: bacwi device-instance | device-instance-min
device-instance-max
Send BACnet WhoIs request to devices, and wait for responses.
The device-instance can be 0 to 4194303, or -1 for ALL.
The device-instance can also be specified as a range.
The demos can be compiled for Win32 platform using MinGW - Minimalist GNU for Windows or any compiler build environment supported by CMake.
BACnet-Tools - the example applications are compiled for Windows and can be downloaded from SourceForge.
To build the demo applications under Linux, such as Ubuntu, you may need to install some build tools. There are two ways to install all the build tools needed to compile the BACnet stack and the demo applications using the APT package manager. The first way uses the configure script:
$ sudo ./configure
The second way to install the build tools is using bash-aptfile:
$ sudo tools/bash-aptfile/bin/aptfile
aptfile
The BACnet stack currently implements the following services listed in the the table. Services are added as needed for a variety of implemetations. With the services that are implemented, you could build a BACnet device that meets the standardized profile for a BACnet Smart Sensor, BACnet Smart Actuator, or a BACnet Application Specific Controller.
The BACnet stack currently implements an example Device Object, and handles all of the ReadProperty and ReadPropertyMultiple inquiries for the required Device Object properties. The stack handles Who-Is inquiries with an I-Am, WhoHas with I-Have, and handles reject messages for services not currently supported or implemented by your device. There is built-in handling for DeviceCommunicationControl.
The example handlers interact with example objects by way of the Device object. There are example objects for the developer to use as a template when customizing the objects for their device.
File Objects are conditionally included in the demonstation applications. The files can be accessed using WriteProperty, ReadProperty, Who-Has, AtomicWriteFile, or AtomicReadFile services.
| BACnet Object | Code Example |
| Accumulator | Yes |
| Analog Input | Yes |
| Analog Output | Yes |
| Analog Value | Yes |
| Averaging | - |
| Binary Input | Yes |
| Binary Output | Yes |
| Binary Value | Yes |
| Calendar | Yes |
| Command | Yes |
| Device | Yes |
| Event Enrollment | - |
| File | Yes |
| Group | - |
| Life Safety Point | Yes |
| Life Safety Zone | Yes |
| Loop | - |
| Multi-state Input | Yes |
| Multi-state Output | Yes |
| Multi-state Value | Yes |
| Notification Class | Yes |
| Program | - |
| Pulse Converter | - |
| Schedule | Yes |
| Trend Log | Yes |
| Access Door | Yes |
| Event Log | - |
| Load Control | Yes |
| Structured View | Yes |
| Trend Log Multiple | - |
| Access Point | Yes |
| Access Zone | Yes |
| Access User | Yes |
| Access Rights | Yes |
| Access Credential | Yes |
| Credential Data Input | Yes |
| CharacterString Value | Yes |
| DateTime Value | - |
| Large Analog Value | - |
| BitString Value | - |
| OctetString Value | Yes |
| Time Value | Yes |
| Integer Value | Yes |
| Positive Integer Value | Yes |
| Date Value | - |
| DateTime Pattern Value | - |
| Time Pattern Value | - |
| Date Pattern Value | - |
| Network Security | - |
| Global Group | - |
| Notification Forwarder | - |
| Alert Enrollment | - |
| Channel | Yes |
| Lighting Output | Yes |
| Network Port | Yes |
| Binary Lighting Output | Yes |
| Elevator Group | - |
| Escalator | - |
| Lift | - |
| Staging | - |
| Audit Log | - |
| Audit Reporter | - |
| Color | Yes |
| Color Temperature | Yes |
If you want to contribute to this project, join us via GitHub.com or via SourceForge.net and create a fork or branch, and eventually a pull request to have your code or document considered for inclusion.
If you find a bug in this project, please tell us about it at SourceForge.net Bugs or Github.com Issue
If you have a support request, you can post it at SourceForge.net Support
If you have a feature request, you can post it at SourceForge.net Feature Request
If you have a problem getting this library to work for your device, or have a BACnet question, post the question to the Open Discussion, Developers, or Help forums at SourceForge.net Forums
More details about the project can be found on the BACnet Source Forge Project Page
There is documentation that describes the mechanisms in the BACnet Stack. I wrote up some answers to some frequently asked questions. Of course, there are a handful of text files in the doc directory of the project with more useful information.
BACnet Stack released files download
You can get the latest BACnet protocol stack source code using the Git version control system. The main development branch is at: https://sourceforge.net/p/bacnet/src/ci/master/tree/. This has the absolute latest code and features. Anyone doing development on the BACnet protocol stack should be using this branch. The stable release tags are at: https://sourceforge.net/p/bacnet/src/ref/master/tags/. This matches the released version downloadable through SourceForge. Anyone doing project development using the BACnet protocol stack should be using the tags branch and an appropriate version tag. The custom and vendor branches are at: https://sourceforge.net/p/bacnet/src/ref/master/branches/.
Did you develop a product using this BACnet stack?
Beremiz - an integrated development environment for machine automation. It is Free Software, conforming to IEC-61131 among other standards.
BACnet Development Kit - An Atmel ATmega644 based development kit designed to kickstart BACnet MS/TP development.
Digital Lighting Management - offers connectivity without complexity for remote system management and control of lights and plug loads. Just one device in each room network has to be connected to a BACnet MS/TP segment for centralized control.
CSWorks - a development framework for building web-based HMI (Human Machine Interface), SCADA (Supervisory Control And Data Acquisition), EMI (Enterprise Manufacturing Intelligence) and M2M (Machine to Machine) software applications.
SCInterface™ = Sensor Control Interface - middleware platform for managing legacy and modern-day sensors through a centralized interface.
BACnetSim - a portable implementation of the BACnet data communication protocol. BACnetSim is meant for embedded devices and use MS/TP as the media access layer. BACnetSim is a fork of bacnet-stack-0.0.1
Building Controls Virtual Test Bed - a software environment that allows coupling different simulation programs including Dymola, EnergyPlus, MATLAB/Simulink and Radiance for co-simulation, and to couple these programs to control systems.
The coelostat in the Linde + Robinson Laboratory at Caltech.
ASHRAE® and BACnet® are registered trademarks of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 180 Technology Parkway NW, Peachtree Corners, Georgia 30092 US.
Website updated 04-November-2024 by Steve Karg.