Clear Alarm

Use this node to clear an active alarm when the triggering condition resolves — for example, when temperature drops back below the threshold that created a “High Temperature” alarm. The node finds the active alarm by type and originator (or directly by alarm ID), clears it, updates its details field via a script, and emits the cleared alarm object downstream.

• Alarm type — required. The type of alarm to clear (e.g., High Temperature). Supports templatization — use ${metadata.key} and ${data.key} to build dynamic values.

• Alarm details script — a TBEL or JavaScript function that generates the content for the alarm’s details field when clearing. The function must return a valid JSON value (primitive, array, or object) and has access to:

  • msg — message data
  • metadata — message metadata
  • msgType — message type
  • metadata.prevAlarmDetails — the previous alarm details as a JSON string

1. Resolve alarm type: expand the configured alarm type pattern using the message data and metadata.

2. Find the alarm to clear:

   • If the message originator is an ALARM entity: fetch that alarm directly by ID (the configured alarm type is ignored).
   • Otherwise: query the database for the latest active alarm with the resolved alarm type and the same originator as the message.

3. Clear the alarm:

   • If an active (non-cleared) alarm exists:
     1. Set cleared = true and clearTs to the current system time.
     2. Execute the details builder script (with metadata.prevAlarmDetails containing the previous details JSON).
     3. Update the alarm’s details field with the script result.
     4. Set metadata isClearedAlarm: true.
     5. Replace the message data with the cleared alarm object and change the message type to ALARM.
     6. Route via Cleared.
     7. Emit an ALARM_CLEAR lifecycle event to the originator’s root rule chain.
   • If no active alarm exists, or the alarm is already cleared:
     • Forward the original message unchanged via False. No database changes occur.

Incoming message

Data: { "temperature": 25.0 } | Originator: DEVICE

Node configuration

{
  "scriptLang": "TBEL",
  "alarmDetailsBuildTbel": "return { clearedAt: msg.temperature };",
  "alarmType": "High Temperature"
}

State: an active High Temperature alarm exists for the originator with status ACTIVE_UNACK.

Outgoing message

Data:

{
  "id": { "entityType": "ALARM", "id": "f66e9b38-6f0e-4dc7-ad57-1cb4e014b6fc" },
  "type": "High Temperature",
  "originator": { "entityType": "DEVICE", "id": "3bc2eb60-8d77-11f0-8a6c-59050cd4204f" },
  "severity": "CRITICAL",
  "acknowledged": false,
  "cleared": true,
  "startTs": 1757429087063,
  "endTs": 1757429195123,
  "clearTs": 1757429287456,
  "status": "CLEARED_UNACK",
  "details": { "clearedAt": 25.0 }
}

Metadata: { "isClearedAlarm": "true" } | Message type: ALARM | Connection: Cleared

The alarm status changes from ACTIVE_UNACK to CLEARED_UNACK, the details script runs with access to metadata.prevAlarmDetails, and an ALARM_CLEAR lifecycle event is sent to the device’s root rule chain.

State: no active High Temperature alarm exists for the originator.

Result: original message forwarded unchanged via False. No alarm modifications; no lifecycle events.

Originator: ALARM with ID f66e9b38-6f0e-4dc7-ad57-1cb4e014b6fc

When the message originator is an ALARM entity, the node fetches and clears that specific alarm by ID — the configured alarm type is ignored. The alarm status changes from ACTIVE_ACK to CLEARED_ACK.

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "TbClearAlarmNodeConfiguration",
  "type": "object",
  "properties": {
    "alarmType": {
      "type": "string",
      "description": "Alarm type (supports templatization)."
    },
    "scriptLang": {
      "type": "string",
      "enum": ["TBEL", "JS"],
      "description": "Script language for the details builder function."
    },
    "alarmDetailsBuildJs": {
      "type": "string",
      "description": "JavaScript details builder function body."
    },
    "alarmDetailsBuildTbel": {
      "type": "string",
      "description": "TBEL details builder function body."
    }
  }
}