OPC UA read data only when it changes

Industrial
#1

Hi, I want to read data only when it get changes in PLCs.
Anyone have the idea?

#2

Have a look at the "Filter" node. You can set it to only pass a message if the message has changed.

#3

Which type of PLC had been connected？

#4

Hi,

I am using "Filter" node to read data only when it gets changes in PLCs .

Now I am trying to read data at least one time every hour (even if the data does not change), I did not find a way to do it.

Does someone know how to do it ?

#5

Not at computer right now. But probably a couple of trigger nodes. One set to repeat every hour and one set to rate limit to once per hour.

#6

OPC UA provides monitoring with deadband/absolute filter. Better to use it!

Inside client node, select action: monitor then you have option Deadband with parameters:

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