Multiple DDE

[Yixiao-uncle]

Hi

I have to write a routine in order to aquire data from a DDE server.

Becouse of large amount of data, more than hundred, I have to use DDE Advise checkMulti.vi.

In the attached file You can find something Im thinking about (Excel is not my DDE server, just to check it)

With that design I meet  at least 2  problems:

1) I am not able to close DDE conncections for each channel;

2) It seems DDE Advice CheckMulti.vi outputs only changed variables, but I need to record all data even they didnt change.

Does anybody have solution for these problems?

Of course I will appreciate other design of routine, but they have beeen based on DDE protocol.

Thank You very much

Antonio

[tbd]

Hi Antonio,

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1) I am not able to close DDE conncections for each channel;

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I looked at these functions and noticed that the [1st] call to Advise Stop returns the one and only Conversation# which is then Closed.  Subsequently, Advise Stop returns the Advise Refnum (since the Conversation is no longer valid.)

While it's appropriate to STOP each Advise Refnum, Close [Conversation] should only be called once - in fact, the first call to Close succeeds without error!.   

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2) It seems DDE Advice CheckMulti.vi outputs only changed variables, but I need to record all data even they didnt change.

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It appears that this is normal/expected for "DDE Advise CheckMulti.vi ".  You can retrieve an arbitrary list of cells by calling DDE Request in a loop (see attached).

Note that it's possible to retrieve an Excel "Range" with a single call to DDE Request by specifying the Item as a "Range" such as "R1C1:R10C2".

Cheers!