An operational amplifier can be used to provide the following signal conditioning:
The latter is most useful for calibrating a transducer's output signal.
The dynamic range of a signal from an input transducer may be too
large to process through the DAQ system (eg. the ADC is often the
limiting factor).
One can use a linear amplifier and choose to overflow or reduce the
overall gain.
The latter approach will cause a loss in precision.
Another approach is to use a nonlinear amplifier, such as one with a
logarithmic gain, 
.