21
CALIBRA
TION
pH CALIBRATION ERROR MESSAGES
If the meter does not accept a pH calibration point, a short message is displayed to indicate the
possible error source.
Problems which arise during calibration can have different sources: the sensor, measuring temperature,
buffer solutions etc. Special note should be taken of the symptoms of the problem as these are useful
for locating the source of the problem.
• “Input out of scale”: the pH value is out of range. The pH sensor may require replacement.
• “Check sensor”: the electrode may be broken, very dirty or the user has attempted to calibrate the
same buffer value twice.
• “Wrong buffer”: the displayed pH reading is too far from the selected buffer value. This is often
seen immediately after a buffer calibration has been completed but before the pH sensor has been
moved to the next buffer. Check if the correct calibration buffer has been selected.
• “Invalid temperature”: the buffer temperature is outside the acceptable range.
• “Wrong buffer” / “Contaminated buffer” / “Check electrode”: the buffer is contaminated or the
sensor is broken or very dirty.
• “Check sensor” / “Clean sensor”: the electrode is broken or very dirty.
• “Wrong” / “Clear old calibration”: erroneous slope condition. These messages appear if the slope
difference between the current and previous calibration exceeds the slope window (80% to 110%).
Press the
Clear
softkey to clear the previous calibration data and continue the calibration, or press
ESC
to quit the pH calibration mode.
RESTORING FACTORY CALIBRATION
When a new pH probe is being used, some of the error and warning messages are based on the
previous calibration. Restoring factory calibration will delete the user calibration and restore the
factory default calibration. Use the
/
keys to highlight
Restore factory calib.
and then press
Select
.
