1. To adjust an apparatus so that it reads values correctly. 2. To determine the number of units of a quantity being measured per scale division of the readout device. 3. To check equipment readings by measuring a known standard. 4. To adjust values so that the integrated traveltime agrees with data from surface sources into a well seismometer in the borehole. 5. To transform a logging tool signal into a quantified physical parameter, or the result of this transformation recorded on a log.