Dataq Active X class

Question

Hello,
I'm new to Labview. Using a Dataq DI-400 ISA card, I'm trying set up
LV 6.0 to do real time calculations (mean, derivative, and frequency)
then save the data to Excel (or ASCII file). Dataq provides two
Active X class methods for accessing their cards. The Windaq Active X
class requires their DAQ software to run in the background (providing
an easy way to calibrate, etc). They also provide a DataqSDK Active X
class to create a VI that does not require their WinDaq software to
run. I've had limited success with creating a graph to display one of
the channels using the Windaq active X class. I'm confused how to
extract the data per channel to input into the mean.vi, etc. Does
anyone have any experience in this area or pointers. I guess
the
confusion is in the limited documentation of how their Active X class
brings the data into LV. Any good hints on using the variant to data
node?
TIA
Chad

Answer 1

Aaron,
Thanks for the suggestion. The Dataq documentation says that the
active X class returns waveform data to a variant. They have another
active X class that returns data in calibrated units. I'll have to
play around to figure out what that means exactly. The variant to
data seems to work for first active X class I mentioned.
Thanks again,
Chad
Aaron Marks wrote in message news:<[email protected]>...
> They have to have some documentation for their activeX classes. If
> you know what data type the method or property is passing, then you
> can just wire that type as a dummy variable to the "type" input of the
> Variant to G Data. Your going to have a very hard time getting valid
> data if you don't
know the type though. You might be able to figure
> it out in LabVIEW by using the Variant to Flattened data VI and then
> using Application note 154 to decode the type descriptor.