Use DDE with the Server
Use DDE with the Server
Using DDE in an Application
Dynamic Data Exchange (DDE) is a Microsoft communications protocol that provides a method for exchanging data between applications running on a Windows operating system. The DDE client program opens a channel to the DDE server application and requests item data using a hierarchy of the application (service) name, topic name, and item name.
For DDE clients to connect to the server interface, the runtime must be allowed to interact with the desktop.
For more information, refer to How to Allow Desktop Interactions.Example 1: Accessing a Register Locally (Using the Default Topic)
The syntax is <application>|<topic>!<item> where:
• application DDE service name
• topic _ddedata*
• item Modbus.PLC1.40001
*This is the default topic for all DDE data that does not use an alias map entry.
Note: An example of the syntax is "MyDDE|_ddedata!Modbus.PLC1.40001".Example 2: Accessing a Register Locally (Using an Alias Name as a Topic)
The syntax is <application>|<topic>!<item> where:
• application DDE service name
• topic ModPLC1*
• item 40001
*This is the topic using the alias map entry.
Note: An example of the syntax is "MyDDE|ModPLC1!40001" . For additional possible syntax, refer to the DDE client's specific help documentation. See Also: