Specifications

RSLinx – Training Guide D - 1
Appendix D: Using Network DDE
Network DDE:
Network DDE, referred to as NetDDE, is an extension of the DDE available in Windows.
It provides information-sharing capabilities by opening two one-way pipes between
applications. Network DDE is an extension of Dynamic Data Exchange (DDE) that can be
used between two computers across the network.
Under Windows 95 or Windows NT, NetDDE allows a DDE client on one computer to
read from and/or write to a DDE server on a different computer.
• For example, RSLinx could be running on one computer, and RSView32 or
Excel could be running on a different computer.
They could exchange data using DDE in much the same way
as if they both resided on the same computer.
NetDDE takes all of the capabilities of DDE and extends this capability across the
Windows network. NetDDE is not a special form of DDE; rather it involves a redirector
that runs in the background on a Windows workstation searching for particular
information contained in a DDE conversation.
One of the advantages of the implementation of NetDDE in Windows is that it requires no
changes to any DDE-aware (compatible) applications (i.e., software programs that can
communicate via DDE). All DDE-aware applications can take advantage of Network
DDE.
Note: For Windows NT systems, Network DDE Services must be set up and
started; they are not automatically started. You must have Windows NT
administrator privileges to complete these procedures.
For a Windows 95 environment, you must manually start NETDDE.EXE
before using Network DDE. Also, Rockwell Software is currently working
on a utility to create DDE shares in Windows 95. For more information on
this utility, contact Technical Support at 440-646-7801.
WARNING: Do not use NetDDE for moderate to heavy data applications.
It is best used to read a group of points every so often,
i.e. end of shift reports.