Configuring a DDE Client connection to a DDE Server

The DDE Client task/worksheet is used to configure a DDE Client connection to a DDE Server application such as Microsoft Excel (or any other Windows program supporting this interface).

Dynamic Data Exchange (DDE) is a protocol for dynamic data exchange between Windows applications, such as Excel. A DDE conversation is an interaction between server and client programs. IWS provides interfaces that run as clients or as servers. See DDE Client Runtime and DDE Server in the Runtime Tasks (Tasks on the Home tab of the ribbon).
Network Dynamic Data Exchange (NetDDE) is an extension of DDE that works across computers on a network.
Note: When running NetDDE, IWS accepts the WRITE triggers only. To read data, you must configure a write command on the server computer.

To open a new DDE worksheet, right-click on the DDE folder and click the prompt screen.

A new DDE worksheet displays, as in the following figure.
Figure 1. DDE Worksheet

The DDE worksheet dialog is divided into two areas:
Every DDE interface is based on addressing an application using the following three structures:

The first task is to find these identifiers in the DDE Server application.

Use the parameters in the DDE client worksheet Header area as follows:
Use the DDE client Body area parameters as follows:

Configuring a NetDDE connection is similar to configuring a DDE connection, except for the Header Application name and topic. Before starting your tests, verify that you enable the DDE Server on the station with which you want to exchange data.

Note: When connecting to servers other than IWS, please refer to the server documentation for information about the proper syntax of APP, TOPIC, and ITEM.
Use the NetDDE Client worksheet Header parameters to define the tags that start reading and writing, and tags that receive the connection status, as follows:
Use the DDE client worksheet Body parameters to relate each tag to each ITEM part of the DDE server address, as follows:
Note: By default, the DDE Client module supports DDE Servers that handle string data in the UNICODE format. If the DDE Server handles string data in the ASCII ANSI format, the following setting must be configured manually in the project_name.app file (you can use Notepad to edit this file):
[Options]
DDEANSI=1