Which Unscaled Data VI to use

[Dave_Thomson]

   I am acquiring data from a 16 bit M series board.  Right now I am using the unscaled Analog 2D I16 NChan NSamp DAQmx Read vi, but my channel is scaled unipolar from 0 to 10 V.  Being I16, my unscaled data can only go from -32767 to 32767.  So does my 0 to 10V range map into 0 to 32767, or is it mapped internally to 0 to 65336 and then truncated to 0 to 32767?  Using I16's for a unipolar range is basically wrong, but since I am doing it, how is the data being scaled?  I've really only got 15 bits for the 16 bits of the data - am I losing the LSB or the MSB?
   The right way to do this would likely be to use the U16 NChan NSamp Read for a unipolar gain.  But can anyone clarify how the I16 Read is dealt with for data from a Unipolar channel?

Thanks,
   Dave

[Ryan_V[DE]]

Dave,

Actually, all M Series devices are bipolar-input only. Therefore, you are correct to use a signed data type. If you were to use a signed data type, the driver would not map the data into the positive range. Instead, it just casts it to the appropriate data type. So if you were to use the wrong data type, you could just use LabVIEW's "type cast" VI.

Hope this helps,