Hanna Instruments HI 4221 - Manual (Page 41)

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• When in MTC mode, if pressing after entering
calibration and while a custom pH calibration buffer is
selected, a pop-up menu will be displayed on the LCD
in which the custom buffer and the temperature value
can be ajusted by pressing
and then
or keys. Press to save the modified
value and then / to select next/
previous value to be adjusted.
• When in ATC mode, if pressing after entering
calibration and while a standard pH buffer (with a
x.xxx resolution) or a custom pH buffer is selected, a
pop-up menu will be displayed on the LCD in which
the buffer value can be ajusted using
or
. Press to save the new buffer value.
• If the Automatic buffer entry type has been selected for the calibration procedure, the instrument
will automatically select the closest buffer to the measured pH value from the edit buffer group
(see pH Setup for details, page 20).
• If the Semiautomatic buffer entry type has been selected for the calibration procedure, the instrument
will automatically select the closest buffers to the measured pH value from all the available buffers
and the used buffer value can be selected with
or .
CALIBRATION MESSAGES
• Wrong buffer. Please check the buffer: this message appears when the difference between the pH
reading and the value of the selected calibration buffer is significant. If this message is displayed, check
if you have selected the appropriate calibration buffer.
• Wrong buffer temperature: this message appears if the buffer temperature is out of the defined buffer
temperature range.
• Clean the electrode or check the buffer. Press <Accept> to update calibration: this message alerts the
user that some dirt or deposits could be on the electrode. Refer to the electrode Cleaning Procedure (see page 65).
• Slope too low. Please check the buffer / Slope too high. Please check the buffer: these messages appear
if the current slope is under 80% or over 110% of default slope. Recalibrate the instrument using fresh buffers.
• Slope too low. Press <Clear Cal> to clear old calibration / Slope too high. Press <Clear Cal>
to clear old calibration: these messages appear as a result of an erroneous slope condition. Follow
displayed instructions.