BACnet/IP Nodes

Read property values from BACnet/IP building automation devices and integrate building data into your orchestration pipelines. Two nodes are available: the BACnet Read node for a single read function, and the BACnet Read Group node for reading many functions from one device in a single node.

Configuration Quick Reference

Field	What you choose	Details
Parameters	Connection, Function, Function Parameters, Timeout Override	Select the BACnet connection profile, choose a read function, configure function parameters with expression support, and optionally override timeout.
Settings	Description, Timeout (seconds), Retry on Timeout, Retry on Fail, On Error	Node description, maximum execution time, retry behavior on timeout or failure, and error handling strategy. All execution settings default to pipeline-level values.

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BACnet Read Node

BACnet Read Node

Read one or more property values from BACnet objects using ReadPropertyMultiple. Each read item is identified by a user-defined name, which becomes the key in the result output.

Supported Function Types:

Function Name	Purpose	Common Use Cases
Read Properties (bacnet.read)	Read property values from one or more BACnet objects in a single request	Temperature readings, HVAC status, energy meters, alarm states

Node Configuration

Parameter	Type	Required	Description
Connection	Selection	Yes	BACnet/IP connection profile to use
Function	Selection	Yes	Read function from the selected connection
Function Parameters	Dynamic	Varies	Auto-populated from the function schema. See your BACnet/IP connection functions for full parameter details.
Timeout Override	Number (seconds)	No	Override the default function timeout

All function parameters support expression syntax ({{ expression }}) for dynamic values from the pipeline context.

Input

The node receives the output of the previous node as input. Input data can be referenced in function parameter expressions using $input.

Output Structure

On success the node produces:

{
  "result": { ... },
  "_metadata": { "success": true, "functionId": "<function-id>", "durationMs": 42, "timestamp": "2026-01-15T08:30:00Z" }
}

Field	Type	Description
_metadata.success	boolean	true when the function executed without errors
_metadata.functionId	string	ID of the executed function
result	object	Function-specific result data (see below)
_metadata.durationMs	number	Execution time in milliseconds
_metadata.timestamp	string	ISO 8601 / RFC 3339 UTC timestamp

Function-Specific Output Data

Read Properties (bacnet.read) — the node's result, one item per Item Name under result.results:

{
  "results": {
    "Zone Temperature": {
      "object_type": 0,
      "object_instance": 1,
      "property_id": 85,
      "value": 72.5
    },
    "Damper Position": {
      "object_type": 1,
      "object_instance": 10,
      "property_id": 85,
      "value": 45.0
    },
    "Occupancy Sensor": {
      "object_type": 3,
      "object_instance": 5,
      "property_id": 85,
      "value": 1
    }
  }
}

Each result entry is keyed by the Item Name defined in the read function:

Field	Type	Description
object_type	number	BACnet object type code that was read
object_instance	number	Object instance number
property_id	number	BACnet property ID that was read
value	any	The property value returned by the device
error	string	Error message (present only if the individual item failed)
quality	string	The item's verdict: bad when the item failed or the device reports fault / out-of-service, uncertain when overridden, good otherwise. Pass it to a UNS Publish node's Quality parameter.
status_flags	object	Present for Present_Value reads on analog, binary and multi-state objects: the device's Status_Flags as in_alarm, fault, overridden, out_of_service booleans. The read fetches them in the same ReadPropertyMultiple round-trip.

Read Item Configuration

Each read item in the function is configured with:

Field	Type	Required	Default	Description
name	String	Yes	—	Unique name for this item — used as the key in results
object_type	Number	Yes	—	BACnet object type code (e.g., 0 = AnalogInput, 3 = BinaryInput)
object_instance	Number	Yes	—	Object instance number
property_id	Number	No	85 (Present_Value)	BACnet property to read

Supported Object Types

Code	Name	Typical Use
0	AnalogInput	Temperature sensors, pressure sensors, flow meters
1	AnalogOutput	Valve positions, damper commands, setpoints
2	AnalogValue	Internal calculated values, configurable setpoints
3	BinaryInput	Occupancy sensors, switch states, alarms
4	BinaryOutput	Relay commands, on/off controls
5	BinaryValue	Internal binary states, mode flags
8	Device	The device itself (instance = Device ID)
12	Loop	PID control loops
13	MultiStateInput	Multi-position switches, fan speed states
14	MultiStateOutput	Multi-position actuator commands
17	Schedule	Weekly schedules
20	TrendLog	Historical data logs

Common Property IDs

ID	Name	Description
85	Present_Value	Current value — the most commonly read property
77	Object_Name	Human-readable name of the object
28	Description	Text description of the object
36	Event_State	Current alarm/event state
103	Reliability	Reliability status of the object
111	Status_Flags	Bitmask: in-alarm, fault, overridden, out-of-service
117	Units	Engineering units (e.g., degrees-Fahrenheit, percent)

ReadPropertyMultiple

The BACnet Read node uses the ReadPropertyMultiple service to read all configured items in a single BACnet request. This is more efficient than reading properties one at a time, especially when acquiring data from many objects on the same device. If a function holds more items than fit in the device's APDU size, the connector automatically splits them into multiple requests (and halves a chunk that still comes back too large), so large functions never fail outright — failed items are reported individually.

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BACnet Read Group Node

The BACnet Read Group node reads many objects from a single BACnet device across multiple read functions in one node — the efficient way to acquire hundreds to thousands of points without wiring a separate Read node per function. It supports selective function lists, an All Functions mode, label-based selection, and parallel or sequential execution.

Each function's items are automatically split to fit the device's APDU size (see the Read node's ReadPropertyMultiple note above), and reads are bounded by the connection's Max Concurrent Reads setting so the device is never flooded.

Node Configuration

Parameter	Type	Required	Default	Description
Connection	Selection	Yes	—	BACnet/IP connection profile
Function Selection	Selection	No	Select Functions	Select Functions reads the functions you list. All Functions reads every read function on the connection. By Labels reads every function whose labels match the labels you pick.
Functions	Array of {functionId, alias}	When Function Selection is Select Functions	[]	List of specific functions to execute. Each entry requires a functionId; alias is optional and becomes the result key.
Execution Mode	Selection	No	parallel	parallel — functions run concurrently (bounded by Max Concurrent Reads). sequential — functions run one after another.
Continue on Error	Toggle	No	true	When enabled, the node continues executing remaining functions even if one fails
Debug Mode	Toggle	No	false	Enable detailed logging for troubleshooting

Functions can also be selected dynamically by label instead of a fixed list — useful when the set of points grows over time. Set Function Selection to By Labels and choose the label values to include.

All Functions Mode

When Function Selection is All Functions, the function list is ignored. The node automatically discovers and executes every read function defined on the selected connection.

Function Type	Description
bacnet.read	Read Properties (ReadPropertyMultiple)

Input

The node receives the output of the previous node as input.

Output Structure

The node output is the canonical {result, _metadata} envelope: result holds one entry per function read, keyed by the function's output key; _metadata holds the group's accounting.

{
  "result": {
    "Floor 1 Sensors": {
      "value": { "results": { "Zone Temperature": { "object_type": 0, "object_instance": 1, "property_id": 85, "value": 72.5 } } },
      "success": true,
      "error": "",
      "duration": 48,
      "timestamp": "2026-09-07T08:30:00Z"
    },
    "Floor 2 Sensors": {
      "value": { "results": { "Zone Temperature": { "object_type": 0, "object_instance": 2, "property_id": 85, "value": 70.1 } } },
      "success": true,
      "error": "",
      "duration": 41,
      "timestamp": "2026-09-07T08:30:00Z"
    }
  },
  "_metadata": {
    "connectionId": "conn-123",
    "connectionName": "AHU-1 Controller",
    "total": 2,
    "successful": 2,
    "failed": 0,
    "totalDuration": 83,
    "executionMode": "parallel",
    "originalRequests": 2
  }
}

Each entry under result is one function's read — keyed by the function's alias, else its name, else its id (see Output Key Resolution):

Field	Type	Description
result.<alias>.value	any	What the function read — its own result.value when it has one (the whole {results} object of a bacnet.read — its read items by Item Name — since that result carries no top-level value), otherwise its whole result. null when the read failed
result.<alias>.success	boolean	true when this function's read succeeded
result.<alias>.error	string	Why the read failed; empty when it succeeded — always present
result.<alias>.duration	number	How long this function's read took, in milliseconds
result.<alias>.timestamp	string	When the read was issued, RFC 3339 UTC

The _metadata object is the group's execution summary:

Field	Type	Description
_metadata.connectionId	string	The connection every function was read on
_metadata.connectionName	string	That connection's display name
_metadata.total	number	How many functions the group ran
_metadata.successful	number	How many read successfully — including the ones onChange then suppressed
_metadata.failed	number	How many failed; successful + failed = total
_metadata.totalDuration	number	Wall-clock time of the whole group, in milliseconds
_metadata.executionMode	string	parallel or sequential
_metadata.originalRequests	number	How many functions were selected to run
_metadata.keyCollisions	string[]	Output keys that two or more functions resolved to — the later read overwrote the earlier under that key. Present only when it happened
_metadata.configWarnings	string[]	Non-fatal problems in the node's config, each saying what was ignored. Present only when there were any
_metadata.outputMode	string	onChange — present only in that mode
_metadata.suppressedCount	number	onChange mode: how many successful reads were unchanged since the last run and left out of result
_metadata.emittedCount	number	onChange mode: how many entries result carries — total − suppressedCount
_metadata.suppressedKeys	string[]	onChange mode: the output keys left out as unchanged. Present only when at least one was
_metadata.reason	string	onChange mode, when every successful read was unchanged: why result is empty — the node buffers instead of waking downstream

Output Key Resolution

Each function result is keyed in the output map using the first available value:

1. Alias — the custom alias set in the function entry
2. Function Name — the name defined on the connection function
3. Function ID — the unique function identifier (fallback)

Execution Modes

Parallel (default)

• Functions execute concurrently, up to the connection's Max Concurrent Reads limit.
• Fastest total execution time, and safe because the per-connection limit caps how many requests hit the device at once.

Sequential

• Functions execute one after another in list order.
• Lowest peak load on the device and the most predictable timing.
• When Continue on Error is off, execution stops at the first failure.

Tuning for the device

BACnet field controllers tolerate only a few simultaneous transactions. The connection's Max Concurrent Reads (default 4, range 1–16) is the ceiling on in-flight requests for both execution modes. If you see dropped packets or timeouts under load, lower it to 1–2; raise it only for robust controllers. See the BACnet connection Advanced settings.

Error Handling

Continue on Error	Behavior
true (default)	The node completes even if individual functions fail. Failed functions include an error field in their result. The node output remains successful.
false	The node fails as soon as any function fails. In sequential mode, remaining functions are skipped. The node result is marked as failed.

Validation Rules

• connectionId is required.
• executionMode must be parallel or sequential.
• With Select Functions, at least one function entry is required; with By Labels, at least one label is required.

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Settings Tab

Setting	Type	Default	Description
Description	Text	—	Optional description displayed on the node
Timeout (seconds)	Number	Pipeline default	Maximum time the node may run before timing out
Retry on Timeout	Toggle	Pipeline default	Automatically retry the node if it times out
Retry on Fail	Toggle	Pipeline default	Automatically retry the node if it fails
On Error	Selection	Pipeline default	Error strategy: Pipeline Default (the pipeline's Error Handling setting), Stop Pipeline or Continue Execution

When left at their defaults, these settings inherit from the pipeline-level execution configuration.