Campbell Scientific RTDAQ Software - Manual (Page 266)

Section 9. Calibration and Zeroing
The currently measured value for the sensor will be displayed in the next
screen. Now place the sensor into the first known condition, and enter that
known value into the First calibrated value box. Press Set First Value. Wait
for the calibration process to measure the first value. The word Calibrating
will be visible in the Current Value box until that process is complete. Now
place the sensor into the second known condition, and then enter the
corresponding known value into the Second calibrated value box. Press Set
Second Value. The calibration process measures the second point value. At
that point the datalogger calculates the new multiplier and offset and applies
them within the running program. These values are also written to the
calibration file.
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