Applies To:
  • CitectSCADA 5.50 Service Pack B, 5.50 Service Pack C, 6.x, 7.x
  • VijeoCitect v6.x, v7.x

I have installed Unity Pro L, and have created a PLC project. I am trying to link an OPC I/O Device in Citect to the PLC Tag Database using the Unity FastLinx driver (Unity Speedlink in VijeoCitect). But when I configure the link, I receive error:
"Unable to Refresh Tags - Could not open the external database. Check to make sure that the external database is not in use by another application and then try again."

How do I resolve this issue?

Unity FastLinx uses a Unity Pro Server to parse all dynamic and static requests. Therefore it is a requirement that the Unity Pro Server is installed.

Currently the only version of Unity Pro that supports Unity FastLinx is Unity Pro XL. This is because Unity Pro XL contains the Unity Pro Server component.

It is recommended that if you are using Unity Pro M or Unity Pro L, that you upgrade to Unity Pro XL if you wish to use Unity FastLinx.

Unity, FastLinx, XL, L, M, UnityPro Server, API