Hello,
It is kind of hard to answer. You say 'our applicon client is not working' but not what part is not working. Is 'applicon client' an OPC client?
You say 'can i purcahse only client' but not the type of client.
If you want to know if you can purchase an OPC client the answer is yes.
PeakHMI has an OPC client.
Good luck,
Mark
http://www.peakhmi.com/