The CDW attribute setting to enable CDW in SmartPlant Foundation is located in the web.config file for SmartPlant Foundation version 2009 R3 SP2 and service packs, and in the SPFAppServer.config file for SmartPlant Foundation version 2009 R4 and later.
The CDWEnabled attribute can also be set to True from SmartPlant Foundation Server Manager.
More information on the CDW attribute setting is covered under the section Configuring SmartPlant Foundation to use the CDW.