# OPC UA Event Subscription Lost After Network Disconnection – Need Guidance on Reconnection Strategy

**URL:** <https://discourse.nodered.org/t/opc-ua-event-subscription-lost-after-network-disconnection-need-guidance-on-reconnection-strategy/101139>\
**Category:** Industrial\
**Tags:** opcua\
**Created:** [27 May 2026 09:40 UTC](https://discourse.nodered.org/t/opc-ua-event-subscription-lost-after-network-disconnection-need-guidance-on-reconnection-strategy/101139 "2026-05-27T09:40:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sauvagenicolas](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/sauvagenicolas/32/102972_2.png) [@sauvagenicolas](https://discourse.nodered.org/u/sauvagenicolas)\
**Post date:** [27 May 2026 09:40 UTC](https://discourse.nodered.org/t/opc-ua-event-subscription-lost-after-network-disconnection-need-guidance-on-reconnection-strategy/101139/1 "2026-05-27T09:40:48Z")

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Hello,

I am currently developing a data acquisition system using Node-RED with the `node-red-contrib-opcua` library to connect to an injection moulding machine via OPC UA (EUROMAP 77 / ENGEL CC300 controller).

My goal is to subscribe to **Extended OPC UA Events** — specifically the `EngelCycleParametersEventType` — which is fired after each production cycle and contains injection unit parameters (cushion volume, specific pressure, injection time, dosing time, etc.) as well as barrel temperature zone data.

**The problem I am facing:**

When a network interruption occurs between my OPC UA client (Node-RED) and the machine's OPC UA server, the event subscription is silently dropped. When the network comes back, the TCP connection may be re-established (keepalive is active), but the subscription to the `CycleParametersEventType` events is no longer active, meaning I stop receiving cycle data without any explicit error being raised.

To recover, I currently need to:

1. Explicitly disconnect from the OPC UA server
2. Reconnect
3. Re-inject the monitored node topic to re-establish the event subscription

This manual process is not reliable in a production environment where network interruptions can happen at any time.

**What I am looking for:**

I would appreciate guidance on the recommended approach to handle this scenario automatically, specifically:

- Is there a built-in OPC UA mechanism (e.g. subscription watchdog, keep-alive count, lifetime count) that should handle this transparently?
- Should the client detect the subscription loss via the status output and trigger a full reconnect + resubscribe sequence programmatically?
- Are there any known limitations or specific configuration parameters on the ENGEL CC300 side that affect subscription resilience?

**Environment:**

- Client: Node-RED with `node-red-contrib-opcua`
- Machine: ENGEL injection moulding machine, CC300 controller
- Interface: EUROMAP 77 / OPC UA, port 4840
- Event type: `EngelCycleParametersEventType` (subtype of `CycleParametersEventType`)
- Security: username/password authentication, no encryption

Thank you in advance for your help.

Best regards

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [26 July 2026 09:41 UTC](https://discourse.nodered.org/t/opc-ua-event-subscription-lost-after-network-disconnection-need-guidance-on-reconnection-strategy/101139/2 "2026-07-26T09:41:27Z")

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