Applies To:
  • CitectSCADA

I am using Citect as an OPC Client, however I cannot get the communication to my OPC Server to work. This OPC Server only supports OPC DA (Data Access) V2.0. 

Make sure that you use Citect's OPC driver (opc.dll) version or later. This version supports OPC DA2 connection methods via the following parameter.


(0=disable (use OPC DA 1.0a), 1=enable (use OPC DA 2.0), default=0)

You can also override the global setting of UseOPC2 and individually specify the use of OPC DA 1.0a or 2.0 for each IODevice and Status Tag Group.


(0=disable, 1=enable, default=value of UseOPC2)


(0=disable, 1=enable, default=value of UseOPC2)

Another issue is to make sure that you have registered the correct version of the opcproxy.dll. This is the 'OPC Foundation Data Access Proxy'. When you install Citect, a version of the opcproxy.dll (from 24/3/1998, size 85.504 bytes) gets registered and copied in to the Citect\Bin folder.

This is however not the correct version to support OPC DA 2.0. Please register the opcproxy.dll (version, size 77824 bytes) from the Winnt\system32 directory. (Go to the command prompt, then to the winnt\system32 directory and type: regsvr32.exe opcproxy.dll).