Configure the BACnet/IP Connector

Configure BACnet/IP instances and items, discover devices and supported objects, use BBMD registration, and troubleshoot read and write communication.

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The BACnet/IP Connector communicates with BACnet devices over an IP network. You can discover devices and their supported objects automatically, or configure instances and items manually when you already know their BACnet addresses.

This guide explains the connector parameters, device and item discovery, manual configuration, supported object types and data types, and common communication problems.

Prerequisites

Install the BACnet IP Connector.
Connect SIA Connect to the BACnet/IP network.
Allow BACnet traffic on the configured UDP port. The default port is 47808.
For manual configuration, identify the target device instance number and the required object details.
If the device is on another BACnet/IP subnet, obtain the BACnet Broadcast Management Device (BBMD) address, port, and foreign-device registration time-to-live.

The instance address is the BACnet device instance number, not the device's IP address.

Configure an instance manually

Open Workspace > Instances.
Create an instance and select the BACnet IP Connector.
Enter a name for the instance.
Enter the target BACnet device instance number in Address.
Configure the instance parameters described below.
Create the instance.

Instance parameters

Parameter	Required	Default	Description
Address	Yes	None	The BACnet device instance number of the target device. Valid BACnet device instances range from `0` to `4194303`.
Port	Yes	`47808`	The UDP port used for BACnet/IP communication. BACnet port `47808` is also represented as `0xBAC0`.
Timeout	Yes	`5000` ms	How long the Connector waits for BACnet responses. Increase the value on slow or routed networks.
Network interface	Yes	`eth0`	The SIA Connect network interface used for BACnet/IP communication. Select the interface connected to the BACnet network.
Device ID	Yes	`0`	The local BACnet device instance used by SIA Connect. A value of `0` makes the Connector use local device instance `230`.
BBMD address	No	Empty	The IP address or hostname of the BBMD used to register SIA Connect as a BACnet foreign device. Leave empty when BBMD registration is not required.
BBMD port	When using a BBMD	`47808`	The UDP port of the BBMD.
BBMD TTL	When using a BBMD	`300` seconds	The time-to-live used for BACnet foreign-device registration.

Choose a local Device ID that does not conflict with another BACnet device on the network.

Discover BACnet devices

Device discovery sends a BACnet Who-Is request and creates candidates from the devices that respond. The Connector reads each device's object name and description when they are available.

Open Workspace > Instances.
Start instance discovery and select the BACnet IP Connector.
Configure the BACnet/IP discovery parameters.
Start the discovery.
Select the required device candidates.
Import the selected instances.

The imported instance address is the discovered BACnet device instance number. Discovered devices are listed in ascending device-instance order.

Device discovery parameters

Device discovery uses the same Port, Timeout, Network interface, Device ID, and BBMD parameters as an instance. It also provides the following optional filters:

Parameter	Required	Accepted values	Description
Device instance min	No	`0` to `4194303`	The lowest BACnet device instance included in the Who-Is request.
Device instance max	No	`0` to `4194303`	The highest BACnet device instance included in the Who-Is request.

To limit discovery, enter both values and make sure the minimum is not greater than the maximum. If the range is incomplete or invalid, the Connector ignores it and performs discovery without the range.

During discovery, Port accepts values from 1024 to 65535. Timeout must be greater than 0. BBMD port and BBMD TTL accept values from 1 to 65535. Invalid values are replaced with their defaults.

Discover items

Item discovery reads the selected device's BACnet Object_List. It then reads the name, description, Present_Value, data type, and engineering unit of each supported object.

Open the BACnet/IP instance.
Start item discovery.
Wait while the Connector reads the device's Object_List and object properties.
Review the discovered item candidates and any warnings.
Select the required candidates.
Import the selected items.

The Connector configures discovered items to use the Present value property. It also assigns the detected data type and engineering unit. Output and value objects that support writing are marked for read and write access. Input objects are marked as read-only.

Unsupported objects, unsupported Present_Value data types, empty values, and objects that cannot be read are skipped. The discovery result includes a warning for each supported object that could not be imported as a candidate.

Configure an item manually

Open the BACnet/IP instance.
Create an item.
Enter a name for the item.
Select the BACnet Object type.
Enter the Object instance.
Select the Property.
Select the property's Data type.
Configure the item's access and polling settings as required.
Create the item.

The selected data type must match the BACnet property's actual application data type. A mismatch can cause read or write errors.

Item parameters

Parameter	Required	Default	Description
Object type	Yes	Analog input	The BACnet object type that contains the required property.
Object instance	Yes	`0`	The instance number of the object within the BACnet device.
Property	Yes	Present value	The BACnet property to read or write.
Data type	Yes	Boolean	The BACnet application data type used to interpret the property value and encode writes.

Supported object types

Object type	BACnet object type number	Discovery access
Analog input	`0`	Read
Analog output	`1`	Read and write
Analog value	`2`	Read and write
Binary input	`3`	Read
Binary output	`4`	Read and write
Binary value	`5`	Read and write
Character string value	`40`	Read and write
Integer value	`45`	Read and write
Large analog value	`46`	Read and write
Octet string value	`47`	Read and write
Positive integer value	`48`	Read and write

Supported properties

Property	BACnet property number	Description
Present value	`85`	The current value of the object.
Description	`28`	The object's description.
Object name	`77`	The object's name.
Object type	`79`	The object's BACnet type.
Object identifier	`75`	The combined BACnet object type and instance identifier.
Out of service	`81`	The object's out-of-service state.

Supported data types

Data type	BACnet application tag	Description
Boolean	`1`	A false or true value, represented as `0` or `1`.
Unsigned int	`2`	An unsigned integer.
Signed int	`3`	A signed integer.
Real	`4`	A 32-bit floating-point value.
Double	`5`	A 64-bit floating-point value.
Octet string	`6`	A sequence of bytes.
Character string	`7`	A character string.
Enumerated	`9`	A value selected from a BACnet enumeration.

Verify communication

Enable the BACnet/IP instance and its items.
Open the instance and check its current status.
Confirm that item values update at the configured interval.
For a writable object, perform a controlled write only when it is safe to change the target system.
Confirm that the BACnet device accepts the value and that the item reads back the expected result.

The Connector attempts BACnet ReadPropertyMultiple first. If the target device rejects that service as unrecognized, the Connector automatically switches to individual ReadProperty requests for that device.

Troubleshoot the BACnet/IP Connector

Issue or message	Cause	Action
No devices are discovered	The selected network interface or port is incorrect, BACnet broadcasts are blocked, the timeout is too short, or the devices are on another subnet.	Select the interface connected to the BACnet network. Confirm UDP port `47808` or the configured port. Increase Timeout if necessary. Configure BBMD registration when discovery must cross a BACnet/IP subnet boundary.
`Failed to initialize BACnet/IP on interface ...`	The selected network interface is unavailable or cannot be opened.	Select an active SIA Connect network interface and confirm its network configuration.
`Invalid BBMD address: ...`	The BBMD address cannot be resolved.	Correct the BBMD IP address or hostname and confirm that DNS is available when using a hostname.
`Failed to register as foreign device with BBMD ...`	The BBMD rejected the registration or could not be reached.	Check the BBMD address, port, TTL, routing, firewall rules, and foreign-device configuration.
`Timeout bind request (...s)` or `Timeout binding to BACnet device ...`	The target device instance did not respond to Who-Is and binding requests before the timeout.	Confirm the instance Address, network interface, UDP port, BBMD settings, and network path. Increase Timeout on slower networks.
`Timeout receiving message`	The Connector sent a request but did not receive the expected response.	Confirm that the device is online and that the item uses a valid object type, object instance, and property. Check packet filtering and increase Timeout if required.
`Invalid BACnet target device instance: ...`	The instance address is not a valid BACnet device instance.	Enter the BACnet device instance number from `0` to `4194303`. Do not enter an IP address.
The discovered device has a generic name	The device responded to Who-Is but did not return Object_Name.	Identify the device by its instance number and MAC information, then assign a clear instance name during import.
An expected item is not discovered	The object type or Present_Value data type is unsupported, Present_Value is empty, or an Object_List property request failed.	Review the discovery warnings. Confirm that the device exposes Object_List and Present_Value. Configure the item manually only when its object type and data type are supported.
A read returns an object or property error	The configured object, object instance, property, or data type does not match the target device.	Check the target device's BACnet object list and property definition. Correct the item parameters.
A write is rejected	The property is read-only, the object does not support writing, or the value cannot be encoded as the configured data type.	Confirm that the target property is writable and that the item data type matches the property. Check the BACnet error returned by the device.

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