How do I get device information via VBA

[illson]

Hi, 

I've written a smal Daqmx-Application for Excel in VBA. Is it possible to get device information about the connected Daq-device? I need to know how many channels the device has in order to enable or disable some functionality of my programm.

With kind regards,

Alex

[illson]

I've found the solution with DAQmxGetDevAIPhysicalChans. One more question How do I have to use the function?

At the moment I tyry the following

Dim tmpStr As String
Dim tmp As Integer
tmp = DAQmxGetDevAIPhysicalChans("Dev1", tmpStr, 0)

But I only get a 79 in tmp and an empty tmpstr. Is the something I have to do first? Is 0 for the buffersize okay? What for do I need the buffersize when I ask for physical chanels? I have a USB 6009 Card

Greatings,

Alex

[RupiDo]

Hi Alex,

the command DAQmxGetDevAIPhysicalChans can be used to show all available AI channels from the device.

DAQmxGetDevAIPhysicalChans(const char device[], char *data, uInt32 bufferSize);

1.The first parameter of the function is a character array (string-array) where you have to transfer the devicename,e.g. "Dev1"

2. The 2nd one is the output value which is also a character array, this is array shows all AI channels

3. buffer size is an integer value, the number specifies the length of the output value array

char result[20000];

int    size = 50;

....

DAQmxGetDevAIPhysicalChans("Dev1", result, size);

Please make sure for basic testing that only one Device exist. Otherwise the function won't work, because an arry of devices is transmitted -

if this happes you need a for-loop around the function;

Kind regards,

Rupert Donauer,

NIG AE

[illson]

Hey Rupert,

Thank you for your reply.

When I use the function, the intellisens says, that the function expects device as a string, result as a string and buffer as an integer. By the way, there is no char in VBA as far as I know. So I do this:

Dim result as String

Dim dummy as Long

dummy = DAQmxGetDevAIPhysicalChans("Dev1", result, 50)

Then the result is "" (empty) and dummy is 79. I'm a bit desperate with this problem. What does 79 mean?

Do you have another idea?

Regards, Alex

[RupiDo]

Hi Alex,

I carried out the functin in LabWindows CVI ( ANSI C development from NI).

I'm not involed in VBA.

Check if the dummy parameter  is required, in CVI the command:

...

DAQmxGetDevAIPhysicalChans("Dev1", result, 50);

...

was allright.

Kind regards,

Rupert

Rupert