Javier,
You can access Virtual Channels through the NI-DAQ functions in CVI.
The examples in the "easyio" directory use functions that take char [] values as arguments for the channel string, and hence, may be used to access virtual channels. The examples in the "daq" directory take integers as channel arguments, and hence, may not be used to access virtual channels. Virtual channel names are string data types so the channel string input argument must be able to handle strings. Virtual channels will allow you to apply a linear, table or polynomial scale to your raw data. This would be useful when performing a system calibration or applying a polynomial for a thermocouple.
Hope that helps. Have a good weekend,
Adam Sweet
NI-Wisconsin
