Valliappan-
Do you already have an OPC server for your PLC setup? If so, then the LabVIEW DSC module can read its OPC items and bind them to shared variables. I was also taking a look at teh list of drivers included on the Industrial Automation OPC servers disk, but it doesn't look like the Fara is supported:
http://www.ni.com/opc/opcservers.htm
If you do not have the DSC module, you can read OPC items through a datasocket connection. There's an example on this knowledgebase:
http://digital.ni.com/public.nsf/websearch/F92C1F2F7B35105B86256DB200628B24?OpenDocument
Xaq