Reading values from OPC-UA server|OPC UA Standard|Forum|OPC Foundation

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Reading values from OPC-UA server
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Anders Pedersen
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03/12/2020
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03/12/2020 - 03:23
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Hello, unpaid intern here trying to collect data.

I have to read multiple values coming from a plc, and I have to do it through a hardly documented thirdparty webportal.

I have recieved a pdf with documentation from the PLC running the OPC-UA sever. I have name spaces, identifier types, and identifiers.

 

I think I need to format the variable ID like so:

ns=4;s=P_OPC_UA.weight

 

but the weight node appears to be an array of stuff, 0-6 values. Do I just add a [] at the end after weight;

ns=4;s=P_OPC_UA.weight[4]

like so?

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Randy Armstrong
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03/12/2020 - 07:25
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NodeIds are structures - not strings. Any string format depends on the s/w doing the parsing.

That said 'ns=4;s=P_OPC_UA.weight' is a UA defined syntax.

If the value is an array there is a separate parameter called IndexRange which is a comma separated list of ranges.

i.e. 2:3,4:5,2:3

where there is 1 entry in the list for each dimension in the array.

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