DDE Rotor Control

[salsero 129]

Hi, I am willing to control an application with DDE and I don t know how to start. I think the application I do have should be as a Server and with LabVIEW, I have to make a Client to use the other application. is there any example to help. thank you in advance. cheers

[IS]

Hello salsero,

there are a couple of LabVIEW examples online which show the principle of DDE. Most of them connect LabVIEW to MS Word or Excel. Use this link to get to the Developer zone code library and search for DDE.
http://www.ni.com/devzone/dev_exchange/ex_search.htm

DDE is quite an old technic of exchanging single values of data between 2 windows applications. If you are programming your server application yourself I would consider using ActiveX to build an interface for data exchange.

I. Schumacher
Application Engineering
National Instruments Germany

[salsero 129]

Hello dear Schumacher,

As I see you are an AE in NI, and I wish that you can help me with it.
I am doing a project on this rotor control issue, my Unversity dpt bought this kind of interface card that should be working via an LPT port, this card has its own software that will be normally the "DDE Server".
This software do accept only DDE protocol and since my supervisor wanted the use of LabVIEW, the only way is using DDE to control it.
I am not a LabVIEW expert, however I did read enough about it and I found out that LabVIEW is an old method but I do have no choice to convince my sup. Moreover, I tried to convince him that DDE LabVIEW is mainly working only between MS applications like Excel, and access and unfortunetly my sup is not ready to underst
and this point.
So, as an expert, what should I do?
I need to find a solution since they want some results for AIRBUS as soon as possible.

Sincerely yours,

Salsero

[IS]

Hi Salsero,

actually, using DDE in LabVIEW (or any other ADE) is not a big deal. If you want to write to a DDE server you onlöy need to know some parameters to reference the server, such as service, topic and item name. The rest can be done with a three-icon VI. All names are passed to the server application via string and must match the servers expectations.

I found an application note exactly describing how to perform DDE communication with LabVIEW. Use this article as a manual and have a look at the examples which are in our database. As long as you know your service, topic and item names you can even use those Excel examples to communicate with your own server.

Hope this helps.

I. Schumacher
Applicatione Engineering
National Instrume
nts Germany

[IS]

Sorry, forgot the link to the article.
Here it comes:

http://zone.ni.com/devzone/conceptd.nsf/webmain/14134D7CE042EDBF86256A3A006BD87C?opendocument

[salsero 129]

Hi Schumacher,

I got your message and I thank you for it.
I have another question about this issue and I hope that you can clarify it for me.
I have the name of the service, I have also the topic name and the item name. I would like now to ask for the data of EXTRA 10 Commands that do belong to the item, which should be first requested.
how can I make it.
anothe question, in the case I want to send some values with the following commands, shoudl I do it with Poke?

cheers

Salsero