ioBroker BACnet Flex

BACnet adapter for ioBroker with BACnet/IP client and server modes, BACnet MS/TP access through an external BACnet/IP-to-MS/TP router, and BACnet/SC client access through a Secure Connect hub.

German documentation is available here: README.de.md.

Supported transports

| Transport | Support | Notes | | --- | --- | --- | | BACnet/IP | Client and server | Uses UDP, default port 47808. | | BACnet MS/TP | Via external router/gateway | The adapter communicates BACnet/IP to a router that bridges to RS-485 MS/TP. Direct serial token-passing MS/TP is not implemented in this JavaScript adapter. | | BACnet/SC | Client reads/writes | Uses a BACnet/SC hub URL such as wss://192.168.2.50:47809. Server mode is not available for BACnet/SC yet. |

Requirements

• ioBroker with js-controller 6 or newer.
• Node.js 22 or newer.
• BACnet/IP network access for BACnet/IP and MS/TP-router mode.
• For MS/TP: a configured BACnet/IP-to-MS/TP router or gateway connected to the RS-485 bus.
• For BACnet/SC: a reachable BACnet/SC hub and valid WebSocket/TLS trust configuration on the host.

Client mode

For one BACnet/IP device, configure:

• clientTargetIp: IP address of the BACnet/IP device or MS/TP router target
• clientTargetDeviceId: optional BACnet device ID
• clientObjectsJson: objects to read from that target

Example for clientObjectsJson:

[
  { "id": "temp", "name": "Supply temperature", "type": "analogValue", "instance": 1, "write": false },
  { "id": "enable", "name": "Enable", "type": "binaryValue", "instance": 2, "write": true }
]

For multiple BACnet/IP devices, configure clientDevicesJson as an advanced array:

[
  {
    "id": "ahu1",
    "name": "AHU 1",
    "address": "192.168.2.50",
    "deviceId": 12345,
    "objects": [
      { "id": "temp", "name": "Supply temperature", "type": "analogValue", "instance": 1, "write": false },
      { "id": "enable", "name": "Enable", "type": "binaryValue", "instance": 2, "write": true }
    ]
  }
]

Client values are created below:

bacnet-flex.0.client.<device>.<object>

Writable BACnet objects also get a _set state. Writes are sent as WriteProperty presentValue.

BACnet MS/TP

MS/TP is a serial RS-485 field bus with token passing. This adapter does not implement direct serial MS/TP framing. Use an external BACnet/IP-to-MS/TP router or gateway and select transport BACnet MS/TP via BACnet/IP router.

Typical setup:

1. Connect the MS/TP devices to a BACnet/IP-to-MS/TP router.
2. Configure baud rate, MAC address, max master and network number on the router.
3. Put the router IP into MS/TP router IP.
4. Configure the target objects manually or use discovery if the router exposes the devices correctly.

BACnet/SC

BACnet/SC mode connects as a BACnet/SC thin client to a Secure Connect hub.

Configure:

• Transport: BACnet/SC client
• BACnet/SC hub URL: for example wss://192.168.2.50:47809
• BACnet/SC device UUID: optional persistent local UUID

BACnet/SC mode currently supports client reads, writes and Who-Is/I-Am collection. Server mode is disabled in BACnet/SC mode.

Server mode

Server mode is available for BACnet/IP transport. Configure serverStatesPattern to select ioBroker states. Number states are published as analogValue, boolean states as binaryValue, and all other states as characterStringValue.

The BACnet server answers:

• Who-Is
• ReadProperty
• ReadPropertyMultiple
• WriteProperty for presentValue on writable published objects

Additional manual server data points can be configured in the Admin table serverPoints. Each row defines the BACnet object type and instance that a BACnet client can read from this adapter.

If a row has no stateId, the adapter creates an ioBroker state below:

bacnet-flex.0.server.points.<instance>

If stateId is set, that existing ioBroker state is exposed as the BACnet object. Set writable to allow BACnet WriteProperty presentValue writes for that row.

Troubleshooting

No BACnet/IP devices found

• Check local firewall rules for UDP port 47808.
• Set the correct broadcast address for the subnet.
• Try a specific local bind interface instead of 0.0.0.0.

MS/TP devices are not visible

• Check the router configuration first: baud rate, MAC address, max master and network number.
• Verify that the BACnet/IP side of the router is reachable.
• Some routers do not forward all discovery broadcasts; configure objects manually if needed.

BACnet/SC does not connect

• The hub URL must start with wss://.
• Check TLS trust and certificates on the host.
• Check that the Secure Connect hub accepts this client.

Changelog

0.1.3

• Clean release metadata after the 0.1.2 workflow release.

0.1.2

• Add package and integration smoke tests for the release workflow.

0.1.1

• Add release metadata, German documentation and checker-compatible repository setup.

0.1.0

• Initial BACnet Flex adapter with BACnet/IP client/server, MS/TP router mode and BACnet/SC client mode.

Older entries are stored in CHANGELOG_OLD.md.

License

MIT

Copyright (c) 2026 TheBam1990