I try to communicate with an OPC Client having problems...
There are two ways to do that:
First way:
Simply create a shared variable in my project file which I can use per drag & drop after deploying it. The shared variable uses the Labview Variable Engine (LVE) and the NI-PS-Protocol. If I have read it correctly, these shared variables can also be OPC items. And yes, it works but limited.
Second way:
Each control / indicator has a data binding tab under properties. There I can select data socket and pass manually the OPC protocoll reference (e.g. opc://localhost/National Instruments.Variable Engine/\\.\test\SGL Array) which is not very comfortable but it works unlimited.
Is problem is that the second way works fine for Labview 8.0 and 8.2 but the first way works in a curios manner on Labview 8.0.
That means: In labview 8.0 I can use the shared variables as OPC items without problems but only for non-array data types. Each array type (SGL,DBL, Waveform,...) does not work. We used the shared variables as simple OPC items a long time and now intented to add an array realizing that it does not work. Than someone told us to install DSC Modul wich adds the OPC functionallity to LabView, seeming to solve the problem.
The remaining fact is that LabView 8.2 has no need for the addionally OPC functionally of the DSC Modul. Way 1 and 2 works without problems in 8.2.
Ok, we have an unlimited license of using LabView in all versions and with all toolkits. But we want to use LabView 8.0, because our vis are programmed there and we do not to intend and vesion upgrade.
If there is no solution here, we can use way to, but I am really interested, why shared variable arrays are not supporting OPC compatibility while non-array data types do.
THX for an answer, best regards from Berlin
