EasyData 2.0 contains a bug that prevents the proper calibration of an Ion Selective Electrode. The calibration equation for an ISE in EasyData is "power(ba^x)". The calibration procedure works as expected, but at the end of the routine the values for b and a are accidentally reversed. The resulting readings are extremely high values (e.g. 9.8 x 10^19).
This issue has been resolved in EasyData v2.1 (and newer) available on the Vernier web site http://www.vernier.com/easydata).
Alternative work around:
When the second calibration point has been collected, the Sensor Calibration screen is displayed.
Write down the values for a & b as they are shown on the screen.
Select OK to exit the calibration routine.
Select Calib and then select Edit.
Select Manual Entry...
Enter the values you recorded earlier. Type in the value of b for A and the value of a for B.
This will put the values in the proper place in the equation and the sensor will now be calibrated properly.