User manual

Windows Server Program
ComTec GmbH 5-28
5.5. Controlling the MPA-3 Windows Server via DDE
The MPA3 program can be a server for a DDE (Dynamic Data Exchange). Many Windows
software packages can use the DDE standard protocols to communicate with other Windows
programs, for example GRAMS, FAMOS or LabVIEW. In the following the DDE capabilities of the
MPA3 program are described together with a demo VI („Virtual Instrument“) for LabVIEW. It is not
recommended to use the DDE protocol for LabVIEW, as a DLL interface is (optionally) available
which works much faster. The following should be seen as a general description of the DDE
conversation capabilities of the MPA3 program.
5.5.1. Open Conversation
application: MPA3
topic: MPA3-
Any application that wants to be a client of a DDE server, must first open the conversation by
specifying an application and a topic name. The application name is MPA3 and the topic is
MPA3-.
5.5.2. DDE Execute
The DDE Execute command can be used to perform any action of the MPA3 program. Any of the
Control command lines described in chapter 5.2 can be used. For example a sequence of control
commands saved in a file TEST.CTL can be executed by specifying the command:
RUN TEST.CTL
The MPA3 program then executes the command and, after finishing, it sends an Acknowledge
message to the DDE client. This can be used for synchronizing the actions in both applications.
Figure 5.23: Opening the DDE conversation with the MPA3 server in LabVIEW