Applies To:
  • CitectSCADA 3.00 4.00

How to set up network DDE.

For Network DDE to function, NetDDE.EXE must be running. In Windows for Workgroups this happens by default. In Windows 95 it is necessary to create a shortcut in the Startup folder.

To direct a DDE call over the Network, the Application is \\ComputerName\NDDE$ . Where ComputerName is the Windows Name of the remote computer. The Topic is the DDEShareName on the remote computer. This creates a problem in that there appears to be no way to specify the actual Application and Topic. In fact they are specified under the DDEShareName. The Item can also be specified with the DDEShareName but it more flexible not to do so.

In Windows for Workgroups, this is done in the [DDEShares] section of SYSTEM.INI. For example:-

EXCEL$=EXCEL, DEMO.XLS,,15,,0,,0,0,0
ACCESS$=MSACCESS,TEST;TABLE tblRecipe,,15,,0,,0,0,0

The recommended way to add or edit DDE Shares is to use a DDE Shares Manager application. If one is not available, copy one of the existing entries using a simple text editor and alter as required.

In Windows 95 the DDEShareNames are stored in the Registry under \HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NetDDE\DDE Shares.

Entries can be made using Regedit or using a DDE Shares Manager application.