Exposing all variables over OPCUA

Ask Questions B&R Software & Runtime
1

It seems like AS Code watch window has access to all the variables on the PLC even if they aren’t enabled in the UA Map. Is there a way to access them with OPCUA not using AS Code?

I’ve had projects where enabling all the variables makes the node list file too big and fail to load, but that doesn’t seem to be an issue with AS Code. Does it have special access to everything?

2

Hello

AS can access the variable using PVI, which is not OPCUa, if my memory serve me right, it’s the same protocol that RUC uses to access the variables. If you want to access to OPCua variables without AS, you can use other opcUa tool, like UaExpert.

If you are can share a bit more of information of what are trying to achieve, it would be easier for us to help.

Best regards

3

Hi,

I’m absolutely not sure about, but I assume that AS Code uses a different access service exclusively usable for B&R software? → that’s really just a guess, but I could imagine that it’s the same thing compared to mappCockpit, where I can trace PLC variables also without having them enabled in the UA default view.

Maybe someone here knows more / knows it better.
Best regards!

4

Hi,

As @alexander.hefner said, I don’t know if this is intended to be used by other third-party software, but please have a look here:

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I have able to read and write non OPC UA Tag like the ASC watch is doing by

  1. using the method Register to add the pv
  2. rebrowse the VariableSet folder to see the added pv
  3. I don’t know how to use the Query Method and what to expect with it (maybe to get the complete list of pv?)

Again as it’s a fairly new feature that is mainly used for the B&R tool, it’s probably not publicly documented yet and may change in future to address other needs.

5

In the end query is an interface to browse through the PLC variable list tree with additonal filtering.

Call is something like this if you want to use this in your code:

query({
  filter: EncodedFilter,    //{ Global: true (Bit 0), Local: true (Bit 1), Dynamic: true (Bit 2), Constant: false (Bit 3) }
  scope: "::ProgramName",   // variable scope/path prefix
  startIndex: 0,            // pagination start
  MaxResultCount: 100       // page size
})

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This is what you get with the call. Then with using the Name that gets returned you can register it into the VariableSet folder. So in theory you can very easily build your own mappView widget that does OpcUa watch or write some application that enables interaction with the whole system using OpcUa