Hanna Instruments HI 254 User Manual

Page 11

If necessary, press the ARROW keys to select a different buffer value.

The tag will blink on the LCD until the reading is

stable.

When the reading is stable and close to the selected buffer, the

READY tag will be displayed and the CFM tag will blink.

Press CFM to confirm calibration.

If the fifth calibration point is reached, the instrument

stores the calibration value and returns to normal mea-

surement mode, or else it goes to the next calibration point.

Note: If the value measured by the instrument is not close to the

selected buffer, WRONG

BUF

and WRONG tags will

blink alternately. In this case, check if the correct buffer has been

used or regenerate the electrode by following the Cleaning Proce-

dure (see page 30). If necessary, change the buffer or the

electrode.

If WRONG, Buffer pH tags and Old tag on the secondary LCD

are displayed blinking, an inconsistency between new and previous

(old) calibration is detected. Clear calibration parameters by

pressing SET/CLR and proceed with calibration from the current

calibration point (the instrument will keep all confirmed values

during current calibration).

The WRONG tag and temperature value are displayed blinking

if temperature reading is out of the defined temperature range of

the buffer. Calibration cannot be confirmed in this situation.

Press RANGE to toggle between pH buffer, buffer

number and temperature reading on the secondary

LCD during calibration.

Note: Calibration parameters are evaluated taking in consideration the new

values for the confirmed buffers in current calibration and the old

values, if existing, for the other buffers. To clear old calibration values,

press SET/CLR before exiting calibration.