Python OPC-UA client stops reading after a while

user_15702417 0
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I’m writing a code that reads data from an OPC server. This is a summary:

url = opc.tcpXXXXX

client = Client(url)

client.connect()

And then in a while loop I want to read data from the server for several days:

While True:

Data1 =client.get_node(“ns=4;i=3”)

Data1_Val = Data1.get_value()

#write it to sql table

time.sleep(120)

I’m reading 20 nodes the same way in the same while loop. At first, all works fine. But, after a while the script would still be running but without any data acquisition! What I mean is that after about 2 hours, I will no longer get data from the server.

What could possibly be the problem?

Thanks!

opc-ua python
2 Answers

That will be really difficult to say with so less information…

Anyway if you want to often read the value of a bunch of nodes from the server, you should use the OPC UA subscription.

This will be more efficient and you shouldn’t miss any value

user_17165830

What is your opc server ?

1-) Ex. in kepserverex opc server runtime has 2 hour for a free version. then it ill stoped read data and publish to opc server. Maybe other opc servers are like this.

2-) OPC servers include some config settings like connection time or alive time or someting like that. Check your server settings.

3-) Some Opc servers need certificate, if u connect wihout certificate it ill close session after a while for security.

4-) Sometimes our request failed from server , because server cant read data of your wish. This error can lead to logging out, it can also be in the configuration settings of this server.

U should check them, if u can say your opc server name i can search

user_191810180
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