Hanna Instruments HI 2550 User Manual

Page 16

ONE-POINT CALIBRATION

ONE-POINT CALIBRATION
Two SETUP selectable options are available: “Pnt” and “OFFS”.
If the “Pnt” option is selected, the new calibration point overrides an
existing one. The adjacent slopes will be reevaluated.
If the “OFFS” option is selected, an electrode offset correction is performed.
The adjacent slopes will remain unchanged.
• Proceed as described in “FOUR, THREE or TWO-POINT CALIBRATION”

section.

• Press CAL after the first calibration point was confirmed. The

instruments will memorize the one-point calibration data and
return to measurement mode.

Notes: • If the value measured by the instrument is not close to the

selected buffer, “WRONG” “ ” and “WRONG” “ ” tags
will blink alternately. Check if the correct buffer has been
used, or clean the electrode by following the Cleaning
Procedure (see page 53). If necessary, change the buffer or
the electrode.

• When a custom buffer is displayed, the “BUFFER pH” tag

blinks. To change the custom buffer value in accordance with
the buffer temperature proceed as described in “WORKING
WITH CUSTOM BUFFERS” (see page 17).

• If the buffer temperature or the manual temperature

exceeds the temperature limits of the buffer, “WRONG” tag
and temperature reading will blink.

• If “WRONG”, “BUFFER pH” tags and “OLD” message are

displayed blinking on the secondary LCD line, an inconsistency
between new and previous (old) calibration is detected.
Clear calibration parameters and proceed with calibration
from the current calibration point. The instrument will keep
all confirmed values during current calibration.

• To clear calibration parameters for all uncalibrated buffers

starting with current buffer, press CLR. The calibration will
continue from the current point. If this procedure is
performed while calibrating in the first calibration point,
the instrument returns to measurement mode.

• Press RANGE to toggle between pH buffer,

calibration buffer number and temperature
reading.