How can I use datasocket to read OPC quality attribute?

[Helene]

I use the read datasocket VI to read data from an OPC server. How can I get the quality attribute of the data I read?

[Andrey_Dmitriev]

May be it help:

Using DataSocket to Read OPC Quality and Timestamp Attributes
http://sine.ni.com/apps/we/niepd_web_display.DISPLAY_EPD4?p_guid=B45EACE3E1E756A4E034080020E74861&p_node=DZ52000&p_submitted=N&p_rank=&p_answer=&p_source=External

[Helene]

Thanks for your answer, but it doesn't help much : I don't use Labwindows CVI, but Labview.

[Andrey_Dmitriev]

Upss, sorry...
But LabVIEW have one sample with illustration how it possible. Look in examples:
Help->Find Examples->
Communicating with External Applications->OLE for Process Control (OPC)->OPC Quality and Timestamp Attributes.vi
(located in LabVIEW\Examples\comm\opc.llb

[JRA]

You may want to start by looking at the two examples DS Writer with Attributes.vi and DS Reader with Attributes.vi. They ship with LabVIEW and do exactly what you are wanting to do. If you're reading from Datasocket it doesn't matter what type of server you're using because it's the same high-level interface for all of them. Therefore, what you see in these examples is what you will do with the data from the OPC server.

[Helene]

Thanks a lot, it answers perfectly to my problem.

I am just suprised that all the dataskt.llb VIs are not directly reachable through the function palette.

[Helene]

Well, thanks for yoour anxwer, but the exact answer to my problem is given in the "datasocket OPC" example. In this example, it says that : "This example uses the DataSocket VIs that shipped with versions of LabVIEW prior to version 6i. These VIs are provided with LabVIEW 6i for compatibility. The DataSocket primitives shipping with LabVIEW 6i are not currently fully compatible with OPC. When using DataSocket to connect to OPC Servers, use the older compatibility DataSocket VIs."

This comment explains why I couldn't find (in the current 6.1 LV version) a datasocket read vi allowing me to read the OPC quality status. The required VI exists in prior versions, and is given in dataskt.llb.