DDE_Client is a project designed to show how to use the DDE protocol to exchange data between two Reliance projects. The DDE_Client project needs to be started in the Reliance Control software (and, simultaneously, the DDE_Server project needs to be started in the Reliance Control Server software). If both projects are running successfully, you can set a value in the DDE_Server project and the change is instantly visible in the DDE_Client project (and vice versa).

A DDE device named R_CtlSrv_DDEServer is defined through the Device Manager. The DDE server property is set to R_CtlSrv (it is the DDE server's filename without an extension). Within the DDE device, there are tags defined in the Tags folder. These tags correspond to the tags defined in the DDE_Server project. For clarity's sake, the tags are divided into the T0 and T1 folders. For each tag, the DDE Item property is configured so that it corresponds to the configuration of the same property in the DDE_Server project. The R_CtlSrv_DDEServer device is connected to the DDEClient computer via the Project Structure Manager. The DDE topic property is set to DdeServer (this is if the DDE server is the Reliance runtime software, i.e., Reliance View, Reliance Control, Reliance Server, or Reliance Control Server).