NI-DAQmx vs. old NI-DAQ programming for Visual C++

[Igor Rumanov]

Are there functions for Visual C++ in NI-DAQmx library analogous to the functions in old NI-DAQ library ? In particular, does there exist an analogue of DAQ_Monitor function in NI-DAQmx allowing to check just received data under continuing input operation through a (M Series) Multifunction DAQ board ?

[Jason W]

Hey Igor Rumanov,

Thanks for the post.  The functions for Visual C++ in the NI-DAQmx library are not analogous to the functions in the old NI-DAQ library.  Therefore, there is not a direct analogy for DAQ_Monitor, but you can have DAQmx functions do the same thing.  The daqmx function call that is equivalent to setting the DAQ_Monitor sequential=1 is the DAQmx_Val_CurrReadPos.  The equivalent for setting the DAQ_Monitor sequential=0 is DAQmx_Val_MostRecentSamp.  What these calls do is they set the read position (just like the DAQ_Monitor funciton does except they don't read the data).  In daqmx, once the read position is set then you still have to have a read function that extracts the data.  That daqmx function is called DAQmxReadAnalogF64.  For a detailed description for the function calls I talked about above go to Start>>Program Files>>National Instruments>>NI-DAQ>>NI-DAQmx C Reference Help.  From there go to NI-DAQmx C Properties>>List of read propeties.  Then click on RelativeTo. 
The daqmx read function calls are located in the same help file under NI-DAQmx C Functions>>Read Functions. 
I recommend taking a look at the following link.  It talks about the Terminology Changes from traditional daq to NI-DAQmx.  The C daqmx calls are identical to the C++ daqmx calls, so you don't have to worry there being a difference there.  If you have any further questions, feel free to let us know.

http://digital.ni.com/public.nsf/websearch/7759B0D2A8A392DF86256D21001B452E?OpenDocument

Thanks,
Jason W
Application Engineer
National Instruments