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3.1.3 Resetting User Calibrated Values
The calibrated pH/mV/Ion values can be reset to the factory default using
the procedure below. The temperature off set will not be reset using this
procedure. To abort the reset, press CAL to revert to the measurement
mode.
1. Press and hold CAL while switching the meter on using the ON/
OFF key. The DISPLAY will show "rSt" blinking.
2. Press the ENTER key to confi rm. The meter will automatically
clear all stored pH/Ion calibrations or mV off set values and
revert to the measurement mode.
3.2 Ion Calibration
The meter is capable of a 2 or 3 point ion calibration with standard
solutions. The meter will display "- - -" if the meter has not been
calibrated or if the meter has been reset.
To abort the ion calibration, press CAL to revert to the measurement
mode.
Ion calibration values are not stored in the meter's non-volatile memory.
Ion calibration data is lost once the meter is reset and when the batteries
are removed and replaced.
The error message "Er2" will be displayed after a single point calibration
is completed. Recalibrate using a minimum of 2 points.
Calibration values are successfully stored if the ISE (Ion Selective
Electrode) slope is within the specifi ed tolerance of 15-90mV/decade,
otherwise an error message "Er3" will be displayed.
If any of the calibration points are not within 1 decade of each other, an
error message "Er4" will be shown at the end of calibration process.
The ion calibration options available include 0.1, 1.0, 10.0, 100.0 ppm.
Recalibrate and ensure that consecutive calibration points are 1 decade
apart from each other.
Ensure that new or fresh standard solutions are used during the
calibration. Do not reuse ion standard solutions because they may be
contaminated and aff ect the calibration and accuracy of measurements.
Store standard solutions in a dry, cool environment. Check that electrodes
and ion standard solutions are kept in good condition for best results.
Before use, remove the plastic protective cap at the tip of sensor of
the electrode and refer to the electrode instruction manual for proper
operation. Rinse the electrode before and after each calibration or sample
measurement to avoid cross-contamination.
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