About DDE Client Communications

Important: Net DDE Communications is obsolete, starting CIMPLICITY 7.5. DDE client Communications (Local only) is an As-Is product.

The CIMPLICITY DDE Client Communication enabler acts as a DDE Client and is able to communicate with standard DDE Servers. A DDE Server uses a three-level hierarchy:

  • Application (or Service) Name
  • Topic Name
  • Item Name

to uniquely identify a unit of data the Server can exchange during a conversation with a Client. Conforming to this hierarchy:

  • A CIMPLICITY device is associated with the Application and the Topic Name.
  • A CIMPLICITY point is associated with an Item Name.

Typically, you must first configure a Topic through a configuration tool that is specific to the type of Server being used (usually the Topic identifies the physical address of the device). You then use that Topic Name, along with the Application Name, to configure the CIMPLCITY Device (see the DDE Device Properties screen below). The CIMPLICITY Device Point Address is the Item Name whose format is dictated by the specific Server being used.

The DDE Client Communications enabler is able to communicate with multiple DDE Servers at one time. Each server is defined as a separate CIMPLICITY device.

The DDE Client Communications enabler provides the following features:

  • Communication with multiple DDE Servers at the same time.
  • Access to multiple Topics under a single Server at the same time.
  • Communication with DDE or NetDDE Servers.
  • Alarm generation when a communication failure occurs.
  • Read and write accessible Items.
  • A utility program, dde_diag.exe, which can be used to validate a DDE Server's Service, Topic and Item names.