# SUBSCRIBE isn´t working - OPC UA-Client with node-red-contrib-opcua

**URL:** <https://discourse.nodered.org/t/subscribe-isn-t-working-opc-ua-client-with-node-red-contrib-opcua/98765>\
**Category:** General\
**Created:** [21 August 2025 13:31 UTC](https://discourse.nodered.org/t/subscribe-isn-t-working-opc-ua-client-with-node-red-contrib-opcua/98765 "2025-08-21T13:31:43Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![gregoor001](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/gregoor001/32/102851_2.png) [@gregoor001](https://discourse.nodered.org/u/gregoor001)\
**Post date:** [21 August 2025 13:31 UTC](https://discourse.nodered.org/t/subscribe-isn-t-working-opc-ua-client-with-node-red-contrib-opcua/98765/1 "2025-08-21T13:31:43Z")

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Hi guys,  
I’m using node-red-contrib-opcua version 0.2.340 on a Raspberry Pi5.  
An OPC UA node is updating it´s value (float) every 5s. I confirmed that, using an OPC UA Client with READ Action and an inject node with a 5s repeat interval.  
Now I want to get the value with a subscription instead of polling.

In order to do that I´ve tested two flows as it was described here in the forum.  
**First one:**

![flow 1](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/d/d/ddb87cc586be2cadf2f7356c75db06a17568be3f.png)

**Inject node:**  
“empty”, injecting once after 1s.  
**OPC UA Item:**  
Item filed: ns=1;s=my.value  
Type: Float  
Value and Name: Empty

**OPC UA Client:**  
Endpoint: my endpoint, which is working fine  
Action: Subscribe  
Interval: 5s  
Keep session alive = yes

**Second one:**

![flow 2](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/1/b/1b5d1266e5cbec0180fae2f7573ec12fd82137e5.png)

**Inject node:  
msg.topic:** ns=1;s=my.value (also tried with msg.payload: ns=1;s=my.value)  
injecting once after 1s.

**OPC UA Client:**  
Endpoint: my endpoint, which is working fine  
Action: Subscribe  
Interval: 5s  
Keep session alive = yes

With both ways I am getting a subscription error.  
Thanks for your help  
Gregor

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<div class="post-metadata">

**Author:** ![sumitshinde-84](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/sumitshinde-84/32/83795_2.png) [@sumitshinde-84](https://discourse.nodered.org/u/sumitshinde-84)\
**Post date:** [22 August 2025 13:14 UTC](https://discourse.nodered.org/t/subscribe-isn-t-working-opc-ua-client-with-node-red-contrib-opcua/98765/2 "2025-08-22T13:14:06Z")

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Welcome @gregoor001,

This might help: [Advanced OPC-UA: Real-Time Subscriptions, Alarms, and Historical Data](https://flowfuse.com/blog/2025/08/advanced-opcua-real-time-subscriptions-alarms-historical-data/)

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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:** [20 November 2025 13:14 UTC](https://discourse.nodered.org/t/subscribe-isn-t-working-opc-ua-client-with-node-red-contrib-opcua/98765/3 "2025-11-20T13:14:26Z")

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