A/D programming

[PPLLC]

If you know C or Visual Basic, and the card shipped with code examples, I have found the most useful thing I can do when programming using a dll is to have the sample code open in another window. The sample code provided with a card will show the correct initialization procedure and calls you have to make. A word of caution: not all dlls are LabVIEW friendly, so you may want to read up on using dlls in the LabVIEW documentation as well as here in the discussion forums. One thing that can get very involved is a dll that has a structure to be passed in that contains an array.

Good luck!

[Dennis_Knutson]

A DLL is a Dynamic Link Library. It's a type of executable for windows programs. DLLs are used in a lot of different ways. One way for a DAQ board vendor to provide a software interface to it's board is to provide a DLL that can be called from a number of different program environments (i.e. LabVIEW, Visual Basic, C++). For details on how LabVIEW can access DLLs go to Help>Search the LabVIEW Bookshelf and when it opens, select Using External Code in LabVIEW. In order to use a DLL, you'll have to know the name of the DLL that the vendor provides and then know the details of all of the functions that are in the DLL. Without any of that, you can't do much of anything. See what kind of programming support Meilhaus provides.

[Dennis_Knutson]

Stop what you're doing with trying to access the DLL. I downloaded the LabVIEW drivers from Meilhaus and they done all of that for you. It looks loke they provide a lot of examples. Open one up that might pertain to what you need to do and read the provided help. Turn on Context Help and move your cursor oven the VI's icon.

[JohnGalt]

OK. So I won't use the Call Library Node. I will use the Meilhaus drivers, but one question, what would be the best way to learn how to use them, I can look at the examples, but are there other ways that might be a little easier to understand so i don't have to stare at it for an hour trying to figure out what each example is doing? I might try using this same idea for the serial communication I am doing, but I don't know whether it has drivers like this. BTW: How do I determine which wire to read from on the board using those drivers? Dennis said he had them, I will look them over as well, but so far have not found how to do that.

Thanks again,
Cole

[Dennis_Knutson]

Well, now you're getting into what kind of information does Meilhaus provides and I can't answer that. I only downloaded the drivers so I don't have any documentation that might have come with the boards. Based on the few examples I looked at, each VI does have some documentation built-in. Turn on Context Help and as you move your cursor over a VI in a diagram or the icon in the upper right corner of a VI, you'll see a description of the VI.

I'm not sure what you mean by wire to read from. Because the topic is A/D programming, I assumed you wanted to acquire analog data and not output an analog signal. You should have some information as to how to physically wire up to channel 0, channel 1, etc. Looking at the example called AIScan, if you wanted to acquire from channels 0,1,2, then you would enter 3 into the Count of Channels control. It uses me4000AIMakeChannelListEntry so look at that.

Do not use this driver as an example for serial communication. Serial and DAQ programming are two completely different things.

[JohnGalt]

OK. I think that solves my problem. Thanks for all the help. I should be able to program this now.