node-red-ads-eventlogger

Node-RED nodes for subscribing to Beckhoff TwinCAT 3 EventLogger events and alarms via ADS protocol.

Uses ads-client (v2.x) in raw mode to communicate directly with the EventLogger Publisher V2 on ADS port 132.

TwinCAT 3 Build 4022+ required.

Features

• Subscribe to EventLogger notifications (events and alarms)
• Automatic binary parsing of event data (GUIDs, timestamps, UTF-16LE strings)
• Configurable severity filter (Verbose / Info / Warning / Error / Critical)
• Event history storage in Node-RED global context (survives dashboard reloads)
• Automatic deduplication: cleared events update existing raised entries
• Auto-reconnect with configurable retry interval
• Shared connection config node (multiple subscriber nodes can share one connection)

Installation

From a local folder (development)

cd ~/.node-red
npm install /path/to/node-red-ads-eventlogger

From npm (once published)

cd ~/.node-red
npm install node-red-ads-eventlogger

Then restart Node-RED.

Nodes

ads-eventlogger-connection (config node)

Manages the ADS connection to the TwinCAT system.

| Setting | Description | Default | | ------------------- | ------------------------------------------------------- | -------- | | Target AmsNetId | AMS Net ID of the TwinCAT target (e.g. 192.168.1.1.1.1) | required | | Target ADS Port | ADS port of the EventLogger service | 132 | | Router Address | IP/hostname of the ADS router (empty = local) | — | | Router TCP Port | TCP port of the ADS router | 48898 | | Local AmsNetId | Override local AMS Net ID (empty = auto) | — | | Local ADS Port | Override local ADS port (empty = auto) | — | | Auto Reconnect | Reconnect automatically on disconnect | true | | Reconnect Interval | Milliseconds between reconnection attempts | 2000 | | Timeout | ADS request timeout in milliseconds | 5000 |

ads-eventlogger-subscribe

Subscribes to EventLogger notifications and outputs parsed event messages.

| Setting | Description | Default | | ------------- | -------------------------------------------------- | -------------- | | Connection | Reference to an ads-eventlogger-connection node | required | | Min. Severity | Only output events at or above this severity level | Verbose (all) |

Output msg.payload

{
  "eventClass":     "160d9f14-d97e-4462-afad-ea4cd48296b4",
  "eventId":        1,
  "severity":       "Verbose",        // human-readable
  "severityLevel":  0,               // numeric (0-4)
  "timeRaised":     "2026-02-26T09:36:22.400Z",
  "timeCleared":    null,            // null until alarm is cleared
  "timeConfirmed":  null,            // null until alarm is confirmed
  "alarmState":     "Raised",        // Raised | Cleared
  "isAlarm":        true,
  "sourceName":     "MAIN.fbEventTester",
  "message":        ""
}

• msg.topic is always "eventlogger".

Input

Send msg.payload = "resubscribe" to drop and re-create the subscription.

ads-eventlogger-history

Stores events in Node-RED's global context so they survive dashboard reloads and (optionally) Node-RED restarts.

| Setting | Description | Default | | -------------- | ------------------------------------------------------------- | ---------------------- | | Max Events | Maximum events to keep (oldest discarded first) | 1000 | | Context Key | Global context key name | eventlogger_history | | Context Store | Context store ("" = default memory, "file" = persistent) | "" (default) | | Pass through | Forward incoming events to the output | false |

Wiring

Wire the output of an eventlogger subscribe node into this node. Events are stored automatically and deduplicated — when a cleared event arrives matching an existing raised event (same eventClass + eventId + timeRaised), the entry is updated in-place.

Query interface

Send a message to the input to query the history:

| msg.payload | Response | | ------------------------------------------ | ---------------------------------------- | | "getAll" / "getHistory" | All stored events | | "clear" | Clears all stored events | | "count" | Number of stored events | | { severity: "Warning" } | Events ≥ Warning severity | | { sourceName: "MAIN" } | Events matching source (substring) | | { alarmState: "Raised" } | Only raised events | | { last: 50 } | Last 50 events | | { since: "2026-02-26T10:00:00Z" } | Events after timestamp |

Filters can be combined: { severity: "Warning", sourceName: "MAIN", last: 100 }

Dashboard integration

Because events are stored in global context, dashboard nodes can read them directly:

// In a function node:
const events = global.get("eventlogger_history") || [];

Status Indicators

| Colour / Shape | Meaning | | ----------------- | ----------------------------- | | 🟢 green dot | Subscribed, receiving events | | 🟡 yellow dot | Subscribing in progress | | 🟢 green ring | Connected, not yet subscribed | | 🔴 red ring | Disconnected | | 🔴 red dot | Subscription failed |

Notes

• ADS Port 132 is the EventLogger Publisher V2 port. This is different from port 100 (TwinCAT Logger for system text messages) and port 110 (EventLogger V1, which does not accept subscriptions).
• The subscription uses Index Group 1, Index Offset 0xFFFF with cyclic mode and 0ms cycle time (immediate delivery). These values were determined through packet capture analysis.
• The binary event structure was reverse-engineered from live TwinCAT 3.1 Build 4026 traffic. It may vary between TwinCAT versions. The parser handles minor variations defensively.
• The EventLogger sends periodic 16-byte heartbeat notifications which are automatically filtered out.
• For remote connections (Node-RED running on a different machine than TwinCAT), configure the Router Address to point to the TwinCAT system's ADS router and ensure the ADS route is set up on both sides.

References

• Beckhoff TwinCAT 3 EventLogger Documentation
• ads-client library (GitHub)
• node-red-contrib-ads-client (reference)

License

MIT