Accessing variables from PLC with OPC using DSC Module failes due to wrong node path

[ZMK16]

Hello LabVIEW enthusiasts,

I am connected to a PLC of a milling machine with an installed OPC server inside using the DSC Module. I would like to collect data during the running process. For most of the variables this is already working, but for some of them labVIEW is giving the following error

LabVIEW:  (Hex 0xFFFA8EBB) The node path refers to a node that does not exist in the server address space.

At first I thought this is happening when I type in an address that contains more then one variable like the address for the axis prosition...actToolBasePos. I already tried to set up my OPC function to ask for an array, but it still gives the same error. If you want to ask for a specific variable in an address that contains various variables you have to write ....actToolBasePos[u1,1]. Using this I can access the single variables in UA Expert and in the NI OPC Server, though in my application were I connect to the OPC Server programatically it leads to the stated error. Also for some addresses that contain different variables it works to read them without a specification like [u1,1]. In this case LabVIEW is displaying the first variable in the address.

I tried to find a pattern behind the addresses that work and those which don't work, but i was not able to. I have the feeling that in the node path that leads to the OPC Read function the specification like [u1,1] hast to be written down in a different way, more like actToolBasePos.u1.1, but I tried a lot of things and nothing works, I am always getting the same error.

Does somebody has an idea why I can access some variables and others not?

[ikelli]

Have you made sure that all of your variables are configured with Read enabled? It might be that you are configuring some but not all, which would explain why in the read stage you are not getting consistent behavior.  Where are you doing your enabling?  It might be that you are calling it to enable in that location and it never sets correctly but the error isn't propagating.  This would be a good place to look next.  Also, is this a new set-up that you are completing or was the system working previously and is now showing an error?

[ZMK16]

Hello Kelli,

Thank you very much for your answer, I almost lost hope.

This is a new set-up we want to install for monitoring a milling process.

I have never configured any variable with read or not read. We are connected directly to the controller of the machine via Ethernet. But I think all the variables are readable, because I can read them in any other software like UA Exper or even the NI OPC Server. I can't see a pattern in the addresses that are accessable and those which are not. I would not know where to configure single variables.