SparkPlug B Nodes

SparkPlug B is the MQTT-based interoperability standard for industrial IoT, providing a well-defined topic namespace, payload encoding, and birth/death certificate lifecycle. MaestroHub acts as a SparkPlug B Edge Node, publishing device data to SCADA hosts and IoT platforms.

Publish-Only Protocol

SparkPlug B nodes in MaestroHub publish data outward. There are no read nodes — data ingestion from SparkPlug B is handled through MQTT subscriptions on the connection level.

Configuration Quick Reference

Field	What you choose	Details
Parameters	Connection, Function, Function Parameters, Timeout Override	Select the connection profile, 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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SparkPlug B Publish Node

SparkPlug B Publish Node

Publish device data metrics to a SparkPlug B infrastructure via MQTT.

Supported Function Types:

Function Name	Purpose	Common Use Cases
Publish Device Data (sparkplugb.ddata)	Publish DDATA message with device metrics	Sensor telemetry, machine status updates, periodic data reporting

Node Configuration

Parameter	Type	Required	Description
Connection	Selection	Yes	SparkPlug B connection profile to use
Function	Selection	Yes	Publish function from the selected connection
Function Parameters	Dynamic	Varies	Auto-populated from the function schema. See your SparkPlug B 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:

{
  "success": true,
  "functionId": "<function-id>",
  "data": {
    "topic": "spBv1.0/Plant1/DDATA/EdgeNode1/sensor-001",
    "deviceId": "sensor-001",
    "metricCount": 2,
    "action": "ddata"
  },
  "durationMs": 15,
  "timestamp": "2026-01-15T08:30:00Z"
}

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

data fields:

Field	Type	Description
topic	string	Full MQTT topic the message was published to
deviceId	string	Device identifier used in the message
metricCount	number	Number of metrics included in the payload
action	string	Always "ddata" for device data publishes

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Publish Device Data (DDATA)

The DDATA function publishes device metrics to the SparkPlug B topic namespace.

Function Parameters

Parameter	Type	Required	Description
deviceId	String	Yes	Device identifier. Becomes part of the MQTT topic. Supports template placeholders.
metrics	Object	Yes	Name-value map of metrics to publish. At least one metric is required. Values support template placeholders.

Example metrics:

{
  "temperature": 25.5,
  "humidity": 60,
  "motorRunning": true,
  "status": "ACTIVE"
}

Supported Metric Data Types

Metric types are automatically inferred from the values provided:

Value Type	SparkPlug B Type	Example
Integer	Int32 / Int64	60
Float	Double	25.5
Boolean	Boolean	true
String	String	"ACTIVE"

Topic Structure

Messages are published to the standard SparkPlug B topic namespace:

spBv1.0/{groupId}/DDATA/{edgeNodeId}/{deviceId}

The groupId and edgeNodeId are configured on the connection profile. The deviceId comes from the function parameter.

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Automatic Lifecycle Management

The SparkPlug B connector automatically manages birth and death certificates — you only need to publish DDATA.

Certificate	When Published	Purpose
NBIRTH (Node Birth)	Automatically on connection	Announces the Edge Node to the SCADA host
NDEATH (Node Death)	Automatically on disconnect (also set as MQTT Last Will)	Notifies the host that the Edge Node is offline
DBIRTH (Device Birth)	Automatically on first DDATA for a device	Registers the device and its metric definitions
DDEATH (Device Death)	Automatically on disconnect	Marks all devices as offline

tip

You do not need to publish birth or death certificates manually. The connector handles the full SparkPlug B session lifecycle, including sequence number management and LWT (Last Will and Testament) configuration.

Sequence Numbers

The connector manages two sequence counters per the SparkPlug B specification:

Counter	Scope	Behavior
bdSeq	Birth-death cycle	Increments on each NBIRTH/NDEATH cycle, wraps at 256
seq	Message sequence	Increments per message, resets to 0 on NBIRTH, wraps at 256

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Validation Rules

• deviceId is required and cannot be empty.
• metrics must be a valid object with at least one key-value pair.
• The connection must be active (connected to the MQTT broker) at execution time.

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Settings Tab

The SparkPlug B Publish node uses the standard 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: stop the pipeline, continue to the next node, or follow the error output path

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