Blocked Example. The CAS BACnet Stack cannot yet perform the B-AS Profile Function - issuing access tokens to authorization clients (ASHRAE 135-2024 Annex L.14.1, Clause 17) - through its customer interface, so this example stays published but is blocked on that stack gap (cas-bacnet-stack#2043). At stack
6.x@64b2cfac5the AuthRequest service handler and the authorization-policy exports compile only into the stack's test-tool build, so a customer build refuses AuthRequest and has no way to configure a policy; on 2026-10-15 the stack owner ruled that they are not promoted to the customer interface for now. What it does today:
- It is a discoverable BACnet/IP device that serves its Device, Network Port and three sensor objects to any client - ReadProperty, Who-Is/I-Am, Who-Has/I-Have and DeviceCommunicationControl (the profile's DS/DM base).
- It does not answer AuthRequest and issues no tokens. AA-AS-B is not claimed.
A minimal, copy-paste-friendly example showing how to implement the BACnet B-AS (BACnet Authorization Server) device profile's DS/DM base in C++ using the CAS BACnet Stack. It listens on BACnet/IP (UDP 47808), answers ReadProperty requests, is discoverable via Who-Is / I-Am and Who-Has / I-Have, and responds to DeviceCommunicationControl.
Download a prebuilt binary (Windows and Linux x64) - or build it yourself, see Build below.
- TUTORIAL.md - how to extend this example and how to review it for conformance. Read it when you start turning this into your own device.
- docs/PICS.md - the Protocol Implementation Conformance Statement: every object, every property, and who answers it.
This example claims only the B-AS profile's DS/DM base - see What this example supports for the one BIBB (AA-AS-B) it does not implement, and why.
Versions: this document describes example v1.1.0, built and verified against CAS BACnet Stack 6.0.23 (
6.x@64b2cfac5), at Protocol_Revision 30, with the vendoredcommon/helper at v3.4.0. Running the example prints all three - if what it prints disagrees with this line, trust the program and checkCHANGELOG.md.
B-AS (BACnet Authorization Server), defined in Annex L.14.1 of ANSI/ASHRAE 135-2024, is "an authorization server that issues access tokens to authorization clients or their helpers" (Clause 17): the server side of the AuthRequest exchange. L.14.1 also requires a persistent database of access policies and a user interface for configuring them.
DeviceCommunicationControl lets a management station tell a device to stop
(or resume) communicating - useful to quiet a device during commissioning. The
CAS BACnet Stack runs the actual enable/disable state machine (and the
optional re-enable timer); this example's DeviceCommunicationControl
callback in main.cpp validates the optional password and logs what was
asked. At Protocol_Revision 30 the plain "disable" value is deprecated - the
stack itself rejects it and only enable and disable-initiation take
effect - see the callback's comments in main.cpp for the full detail. This
example's password is empty (DCC_PASSWORD = ""), so it accepts any request;
set it to require one.
Device 389023 "Chipkin Example B-AS" (Vendor 389 - Chipkin Automation Systems)
│
├── Analog Input 1 "Bronze" Present_Value 21.5 (REAL, degrees Celsius)
├── Binary Input 1 "Emerald" Present_Value inactive (0 = inactive / 1 = active)
├── Multi-State Input 1 "Hot Pink" Present_Value 1 (state, 1..3)
└── Network Port 1 "Vermilion" the BACnet/IP port (required on every device)
These are the same base-series sensor objects every example in the series carries; a real Authorization Server would also carry the Access User / Access Rights / Access Credential objects Clause 17 defines, but those only matter once AA-AS-B itself can be executed (see below) - adding them without a working service exchange behind them would not demonstrate anything.
The example implements the capabilities below - and, deliberately, not AA-AS-B. This is not the full B-AS profile; it is the DS/DM base plus an honestly-documented gap.
| BIBB | Description | Supported |
|---|---|---|
| DS-RP-B | Data Sharing - ReadProperty - B | ✅ |
| DM-DDB-B | Device Management - Dynamic Device Binding - B | ✅ |
| DM-DOB-B | Device Management - Dynamic Object Binding - B | ✅ |
| DM-DCC-B | Device Management - DeviceCommunicationControl - B | ✅ |
| AA-AS-B | Authorization - Authorization Server - B | ❌ blocked on stack #2043 - see TODO.md |
AA-AS-B: blocked on the stack. At the Stack Pin (6.x @ 64b2cfac5,
6.0.23) the policy exports (BACnetStack_AddAuthorizationPolicy,
SetAuthorizationPolicyEntry, SetAuthorizationPolicyEnabled) exist only in
CASBACnetStackTestToolDLL.h, and the AuthRequest service handler itself
(BACnetAuthRequestProcessor) compiles only with BACNET_STACK_TESTTOOL. A
customer build - the only kind this series uses - therefore refuses AuthRequest
and cannot configure a policy for it to be evaluated against. The stack owner
ruled on 2026-10-15 that these are not promoted to the customer interface for
now. Full evidence is in TODO.md. Stack issue:
chipkin/cas-bacnet-stack#2043.
| Service | Notes |
|---|---|
| ReadProperty | Responds to property reads (DS-RP-B). |
| Who-Is / I-Am | Answers Who-Is with I-Am, and broadcasts an I-Am on start-up (DM-DDB-B). |
| Who-Has / I-Have | Answers Who-Has with I-Have (DM-DOB-B). |
| DeviceCommunicationControl | Stops/resumes communication, optionally timed/passworded (DM-DCC-B). |
| Object type | Instance | Name |
|---|---|---|
| Device | 389023 | Chipkin Example B-AS |
| Analog Input | 1 | Bronze |
| Binary Input | 1 | Emerald |
| Multi-State Input | 1 | Hot Pink |
| Network Port | 1 | Vermilion |
Every required property of every object, and who answers it, is in docs/PICS.md.
This example builds against the CAS BACnet Stack, which is a commercial Chipkin
product - it is not free or open source, and there is no public/trial build.
The stack is referenced here as the private git submodule
submodules/cas-bacnet-stack; you can only fetch and build it once you have a CAS
BACnet Stack license and access to that repository.
To get the CAS BACnet Stack (and access to build this example), contact Chipkin: https://store.chipkin.com/services/stacks/bacnet-stack or sales@chipkin.com.
You do not need a stack licence to read this example, or to run a prebuilt release binary. The licence is what lets you build it - that is the part the stack submodule gates.
This is a self-contained project. It ships:
main.cpp- the example device.common/- the shared helper (UDP, callbacks, CLI, keyboard) vendored in.CMakeLists.txt- the build, the same on Windows, Linux, and macOS.docs/PICS.md- the conformance statement.TODO.md- the AA-AS-B gap, with evidence and the filed stack issue.tests/- the Wire Tests (see Wire Tests), andwiretest/, the series' shared Python harness they are written against (vendored, likecommon/).submodules/cas-bacnet-stack/- the CAS BACnet Stack as a git submodule (private; requires a license - see above). Its sources are compiled into the executable, so there is no library or DLL to build, ship, or install.
- A C++17 compiler (MSVC, GCC, or Clang).
- CMake >= 3.15.
- Git (to fetch the stack submodule).
- C++ compiler - install Visual Studio Community (free) and select the "Desktop development with C++" workload.
- CMake - from https://cmake.org/download/, or
winget install Kitware.CMake.
- Debian/Ubuntu:
sudo apt install build-essential cmake git - macOS:
xcode-select --installandbrew install cmake
CMake only, and the same two commands on every platform:
git clone --recursive https://github.com/chipkin/BACnetProfileExample-B-AS-CPP.git
cd BACnetProfileExample-B-AS-CPP
cmake -B build -S .
cmake --build build --config ReleaseAlready cloned without --recursive? Run git submodule update --init --recursive
first - the build needs the stack submodule.
The first build takes a few minutes - it compiles the entire CAS BACnet Stack (~600 source files) into the executable. Rebuilds after that are incremental and take seconds.
If your CAS BACnet Stack lives somewhere other than the bundled submodule, point
CMake at it: cmake -B build -S . -D CAS_STACK_DIR=/path/to/cas-bacnet-stack.
# Linux / macOS
./build/BACnetExampleBAS
# Windows
.\build\Release\BACnetExampleBAS.exeExpected output:
BACnet Authorization Server (B-AS) Example - C++ v1.1.0
CAS BACnet Stack version: 6.0.23.0
Common helper (common/) version: 3.4.0
FYI: Listening for BACnet/IP on UDP port 47808 (Network Port 1).
TX 21 bytes to 192.168.3.255:47808 (broadcast) (Network Port 1) - Unconfirmed: I-Am
FYI: Device 389023 ("Chipkin Example B-AS") ready. Vendor ID 389. Press 'h' for help.
The TX line is the start-up I-Am the device broadcasts to announce itself. It
goes to the local subnet broadcast address (here 192.168.3.255, computed
from the Network Port's interface), not the global 255.255.255.255. As clients
talk to the device you'll see RX ... bytes from ... and TX ... bytes to ...
lines showing the traffic.
The device listens on UDP 47808 (BACnet/IP). Allow that port through your
firewall. To use a different port, pass --port (see below).
A wall of red
Error:lines at start-up is expected and is not your bug - it is the stack's own debug logging (the device hearing its own broadcast I-Am, and a one-time BACnet/SC UUID notice). TUTORIAL.md explains both.
| Option | Default | Meaning |
|---|---|---|
--port <n> |
47808 |
UDP port to listen on (BACnet/IP). |
--deviceID <n> |
389023 |
The device's BACnet instance number (BACnet requires this to be configurable). |
--help, -h |
- | Show usage and exit. |
--version |
- | Print the example, stack, and common/ helper versions, then exit. |
While the example runs, these keys are available:
| Key | Action |
|---|---|
h |
Show the version information and this command list. |
q |
Quit. |
| up arrow | Increase Analog Input 1 (Bronze) by 1.1. |
| down arrow | Decrease Analog Input 1 (Bronze) by 1.1. |
The up/down keys change the live Present_Value of the analog input, so a client
re-reading it sees the new value.
Use a BACnet client such as the CAS BACnet Explorer:
- Discover - send a Who-Is. The device replies with I-Am from instance 389023 (vendor 389). It also broadcasts an I-Am at start-up.
- Who-Has / I-Have - send a Who-Has for object name
Bronze. The device replies with I-Have. - Browse the object model - the device shows five objects: the Device
(
Chipkin Example B-AS), the three sensors, and the Network Port (Vermilion). Reading the Device'sObject_Listreturns all five. - Read the Device - ReadProperty
389023->Object_Namereturns"Chipkin Example B-AS";Protocol_Revisionreturns30;Descriptionreturns the profile description string;Protocol_Services_Supportedlistsread-property,device-communication-control,i-am,i-have,who-has,who-is- and nothing else. - Read a sensor - ReadProperty Analog Input
1->Present_Valuereturns21.5;Unitsreturnsdegrees-Celsius. Repeat for Binary Input1("Emerald") and Multi-State Input1("Hot Pink"). - Confirm the profile boundary - a WriteProperty or
ReadPropertyMultiple to any object is rejected with
unrecognized-service- neither is part of this profile's required set. - DeviceCommunicationControl (DM-DCC-B) - send
DeviceCommunicationControlwithenableDisable = disable-initiation. The device answers with a SimpleACK and logs the request; sendenableto restore normal operation.
For a property-by-property review against the conformance statement, see TUTORIAL.md.
Part of the checks above, automated: a Python BACnet client drives the running
example over BACnet/IP from outside it, the way a client discovers a device -
Who-Is, the Device's Object_List, then for every object its Property_List and
a ReadProperty of every property it lists. Every read must come back as a value;
an Error, Reject or Abort fails the run. Python 3 standard library only:
python3 tests/run_wire_tests.py --exe build/BACnetExampleBAS # Linux/macOS
python tests\run_wire_tests.py --exe build\Release\BACnetExampleBAS.exe # WindowsIt ends with ALL WIRE TESTS PASSED (exit 0). CI runs it on Linux after the
smoke test. tests/README.md says what each check proves. It
tests the DS/DM base only: there is no AuthRequest to test (see the Blocked
Example note at the top).
There is one example repository per standardized device profile in ASHRAE 135-2024 Annex L. An example marked ⛔ is blocked: the stack cannot yet perform that profile's function through its customer interface, and the example's README says what it does today. Pick the profile your device claims, then the language you build in. "Ask" means the example hasn't been built yet for that language - contact Chipkin if you need one.
| Profile | C++ | Node.js | C# | Rust | Python | Go |
|---|---|---|---|---|---|---|
| B-SS Smart Sensor | B-SS-CPP | B-SS-Node | B-SS-CS | B-SS-Rust | B-SS-Python | B-SS-Go |
| B-SA Smart Actuator | B-SA-CPP | Ask | Ask | Ask | Ask | Ask |
| B-ASC Application Specific Controller | B-ASC-CPP | B-ASC-Node | Ask | Ask | Ask | Ask |
| B-AAC Advanced Application Controller | B-AAC-CPP | Ask | Ask | Ask | Ask | Ask |
| B-BC Building Controller | B-BC-CPP | Ask | Ask | Ask | Ask | Ask |
| Profile | C++ | Node.js | C# | Rust | Python | Go |
|---|---|---|---|---|---|---|
| B-LSC Life Safety Controller | B-LSC-CPP 🚧 | Ask | Ask | Ask | Ask | Ask |
| B-ALSC Advanced Life Safety Controller | B-ALSC-CPP | Ask | Ask | Ask | Ask | Ask |
| Profile | C++ | Node.js | C# | Rust | Python | Go |
|---|---|---|---|---|---|---|
| B-ACC Access Control Controller | B-ACC-CPP ⛔ blocked on stack #2150, #2044 | Ask | Ask | Ask | Ask | Ask |
| B-AACC Advanced Access Control Controller | B-AACC-CPP ⛔ blocked on stack #2150, #2044 | Ask | Ask | Ask | Ask | Ask |
| Profile | C++ | Node.js | C# | Rust | Python | Go |
|---|---|---|---|---|---|---|
| B-LD Lighting Device | B-LD-CPP | Ask | Ask | Ask | Ask | Ask |
| B-LS Lighting Supervisor | B-LS-CPP | Ask | Ask | Ask | Ask | Ask |
| Profile | C++ | Node.js | C# | Rust | Python | Go |
|---|---|---|---|---|---|---|
| B-EM Elevator Monitor | B-EM-CPP | Ask | Ask | Ask | Ask | Ask |
| B-EC Elevator Controller | B-EC-CPP | Ask | Ask | Ask | Ask | Ask |
| B-AEC Advanced Elevator Controller | B-AEC-CPP | Ask | Ask | Ask | Ask | Ask |
| Profile | C++ | Node.js | C# | Rust | Python | Go |
|---|---|---|---|---|---|---|
| B-AS Authorization Server | B-AS-CPP ⛔ blocked on stack #2043 | Ask | Ask | Ask | Ask | Ask |
| Profile | C++ | Node.js | C# | Rust | Python | Go |
|---|---|---|---|---|---|---|
| B-BBMD Broadcast Management Device | B-BBMD-CPP | Ask | Ask | Ask | Ask | Ask |
| B-ACDC Access Control Door Controller | B-ACDC-CPP | Ask | Ask | Ask | Ask | Ask |
| B-ACCR Access Control Credential Reader | B-ACCR-CPP ⛔ blocked on stack #3934 | Ask | Ask | Ask | Ask | Ask |
| B-RTR Router | B-RTR-CPP | Ask | Ask | Ask | Ask | Ask |
| B-GW Gateway | B-GW-CPP | Ask | Ask | Ask | Ask | Ask |
| B-DAP Device Address Proxy | B-DAP-CPP ⛔ blocked on stack #2032 | Ask | Ask | Ask | Ask | Ask |
| B-SCHUB BACnet/SC Hub | B-SCHUB-CPP | Ask | Ask | Ask | Ask | Ask |
| B-GENERAL General device (Annex L.8) | (satisfied by every example above) | — | — | — | — | — |
Client-side profiles.
| Profile | C++ | Node.js | C# | Rust | Python | Go |
|---|---|---|---|---|---|---|
| B-OD Operator Display | B-OD-CPP | Ask | Ask | Ask | Ask | Ask |
| B-OWS Operator Workstation | planned | — | — | — | — | — |
| B-AWS Advanced Operator Workstation | planned | — | — | — | — | — |
| B-XAWS Extended Advanced Operator Workstation | planned | — | — | — | — | — |
| B-LSAP Life Safety Annunciator Panel | planned | — | — | — | — | — |
| B-LSWS Life Safety Workstation | planned | — | — | — | — | — |
| B-ALSWS Advanced Life Safety Workstation | planned | — | — | — | — | — |
| B-ACSD Access Control Security Display | planned | — | — | — | — | — |
| B-ACWS Access Control Workstation | planned | — | — | — | — | — |
| B-AACWS Advanced Access Control Workstation | planned | — | — | — | — | — |
| B-LOD Lighting Operator Display | planned | — | — | — | — | — |
| B-ALWS Advanced Lighting Workstation | planned | — | — | — | — | — |
| B-LCS Lighting Control Station | planned | — | — | — | — | — |
| B-ALCS Advanced Lighting Control Station | planned | — | — | — | — | — |
| B-ED Elevator Display | planned | — | — | — | — | — |
| B-EWS Elevator Workstation | planned | — | — | — | — | — |
| B-AEWS Advanced Elevator Workstation | planned | — | — | — | — | — |
🚧 = in progress. ⛔ = Blocked Example (blocked on the named stack gap). "Ask" = not yet built for that language; contact Chipkin if you need it. Profile definitions: ANSI/ASHRAE 135-2024 Annex L. BIBB definitions: Annex K. Get the stack: https://store.chipkin.com/services/stacks/bacnet-stack.
- ANSI/ASHRAE Standard 135 (BACnet) - the protocol standard. Object model (Clause 12), services (Clause 15), Access control authorization (Clause 17), BACnet/IP (Annex J), device profiles (Annex L). Purchase / preview via the ASHRAE store.
- What is BACnet? - Chipkin's introduction: https://docs.chipkin.com/protocols/bacnet/.
- CAS BACnet Stack - product page and documentation: https://store.chipkin.com/services/stacks/bacnet-stack.
- CAS BACnet Explorer - client for testing this device: https://store.chipkin.com/products/tools/cas-bacnet-explorer.
- Shared helper used by this example -
common/README.md. - The AA-AS-B gap -
TODO.md.
See also TUTORIAL.md, docs/PICS.md, CHANGELOG.md, AGENTS.md, and TODO.md.