BACnet

The BACnet Device component is a Building Automation and Control Networks (BACnet) over IP client. It connects to one BACnet device on your network and polls the present-value of the objects you list in its point map. It publishes each one as a Profinity tag. BACnet is used for building automation and heating, ventilation, and air conditioning (HVAC) systems.

flowchart LR
    Device["BACnet device"]
    subgraph Profinity
        Component["BACnet Device"] --> Tags
    end
    Device --> Component

The BACnet Device component in Profinity polls the objects in its point map from one BACnet device and publishes each as a Profinity tag

Licence required

The BACnet plugin requires the Industrial Protocols licensed component group, and Install an industrial protocol plugin explains how to obtain, install, and licence it.

Add a BACnet Device to your Profile from the Industrial Protocols group in the component catalogue, as described in How to add a component to your profile. Add one component for each BACnet device you want to read. You can change the settings in the Communications settings section later from the component's Change Settings menu action.

The component supports BACnet/IP only, not BACnet MS/TP (Master-Slave/Token-Passing). It reads and writes the device at the Remote host address you configure. It does not discover devices on the network with the BACnet Who-Is request.

Communications settings

Setting	Description
Name	The name of the component. Must be unique within the profile.
Local UDP port	The User Datagram Protocol (UDP) port Profinity uses locally. Between `1` and `65535`. The default is `47808`, the standard BACnet/IP port (`0xBAC0` in hexadecimal).
Remote host	The IP address of the BACnet device. Required, and it is the address Profinity sends every request to. The default is `127.0.0.1`.
Device instance	The BACnet device instance number, as held in the device's own Device object. Between `0` and `4194302`. The default is `0`.
Poll interval (ms)	How often the point map is read, in milliseconds. Between `50` and `600000`. The default is `1000`.
Request timeout (ms)	How long Profinity waits for the device to answer a request, in milliseconds. Between `50` and `60000`. The default is `1000`.
Reconnect delay (ms)	How long Profinity waits between connection attempts, in milliseconds. Between `0` and `600000`. The default is `2000`.
Auto Connect	Connects to the device automatically when the profile is loaded. Off by default, as described in Connections and reconnecting.

Set Device instance to the instance of the device you are connecting to, even when that instance is 0. A BACnet configuration tool or the device's own display shows the instance. Profinity sends every request to the Remote host. Each time it connects, it reads the Device object of the device at that address and compares the two numbers. It does not connect while they differ, so a changed address never leads to another device being read.

Profinity keeps trying to connect when the device is down at start and after a connection is lost, as described in Connections and reconnecting.

Point map

The point map lists the BACnet objects to read. Each row becomes one tag.

Column	Description
Name	The name of the tag, published under the component's `Points` tags. Use a unique name for each row.
Object type	The type of BACnet object: `AnalogInput`, `AnalogOutput`, `AnalogValue` (the default), `BinaryInput`, `BinaryOutput` or `BinaryValue`.
Instance	The BACnet object instance number.
Writable	Allows Profinity to write to the object's present-value from the tag. Off by default.
Unit	An optional unit label for the tag.

Analog objects are published as number tags, and binary objects are published as boolean tags. Profinity reads and writes the object's present-value property, and it polls each object on the Poll interval (ms) rather than subscribing to changes.

Writing to a device

A write can change how the building plant behaves, so turn Writable on only for points that must be controlled from Profinity.

Dashboard

The component dashboard shows the connection STATUS and whether the device is CONNECTED. It also shows the number of values read (RECEIVED) and values written (SENT). Use the Connect / Disconnect menu action to start or stop polling manually. Viewing the dashboard requires the Security administration permission, described under Roles and permissions.

Polled values behave like any other tag, so they can be shown on a dashboard, logged, watched by a rule, or read by a script.

If a point shows bad quality

If a point cannot be read, its tag is marked as bad quality. Check the usual causes in this table before reading the Log.

Cause	Fix
Remote host is wrong.	Set it to the IP address of the BACnet device.
The device does not have the Object type or Instance.	Correct the point map row to an object that exists in the device.
The device does not answer within the Request timeout (ms).	Check that the device answers at the Remote host, or raise the Request timeout (ms).

Refer to Connections and reconnecting for how the Log records failed reads and recovery.

A Device instance that differs from the device at the Remote host puts the component in the Error status and marks every point as bad quality. The component shows and logs a message of the form The device at 192.168.1.20 reports Device instance 1234, but Device instance is set to 0. Profinity tries again every Reconnect delay, so correcting the setting or the device connects it without a restart. Set Device instance to the number in the message, or correct the Remote host if the address now belongs to a different device.

Profinity reads the Device object to check the instance. BACnet requires every device from protocol revision 4 (2004) onwards to answer this read. A device older than that, or one that does not allow its Device object to be read, answers with a BACnet error. The component shows that error as the reason. A device that does not answer the read puts the component in Error in the same way, with a message that the device did not answer. Profinity tries again every Reconnect delay. A device that is replaced on the same address after it was connected is caught at the next failed read, and the component then shows Error until the instance matches.