Today, we can create a DAQmx custom scale in MAX or Labview via the "DAQmx Create Scale" VI. This VI changes a pre-scaled value, e.g. 5Volts, to a scaled value in a physical unit, e.g. 100Newtons. This scale can be Linear, Map Ranges, Polynomial or Table.
For all of these four options, only a mono-channel sensor can be used.
However, multi-channel sensors are not so rare and there is actually no way to scale a 6-components load-cell, for instance. For this kind of transducer, F = M*U where F is a 6-components vector including the 3 forces in Newtons and the 3 moments in Newtons*meters, U is a 6-components pre-scaled vector including the 6 input channels in Volts and M is a 6*6 matrix. M is never diagonal, because the forces affect the moments.
Finally, what I'd like to have is an extension of the "DAQmx Create Scale" VI which could enable a multi-channel pre-scaled input to be scaled in physical units through a matrix.