21
Note: The electrode should be submerged
approximately 4 cm (1½") into the
solution with the temperature probe
located as close to it as possible.
• Select the second buffer value on the secondary display by
pressing the
Ï
°C or Ð
CC
CC
C key.
• When the “READY” and “CON” symbols blink on the display,
the reading is stable and the calibration can be confirmed.
• Press the CFM key. If the reading is not close to the selected
buffer solution, “WRONG
2
BUF
” and “WRONG ” will blink
alternatively. If the reading is close to the selected buffer, the
slope and the offset are calibrated. The values will be stored in
memory and the meter will return to the operating mode.
Note: The meter will automatically skip the buffer that was used
for the first calibration to avoid erroneous calibration. At
least 1 full pH unit is required between the two buffers used
for the offset and slope calibration. As a result, once
calibrated at either pH 6.86 or 7.01, the microprocessor will
automatically ignore the other one for the second point
calibration. It will do likewise for pH 9.18 and 10.01
Note: During calibration, the secondary LCD displays the selected
buffer value. With HI 9025C, press the RANGE key to display
the buffer temperature during calibration.
PROCEDURE FOR HI 9110, HI 9210 & HI 9210N:
Manual Temperature Compensation
Note: The pH/C electrode of HI 9210N incorporates a tempera-
ture sensor which performs automatic temperature
compensation. Consequently, the following 5 paragraphs
are irrelevant to HI 9210N and you can just proceed with
pH calibration below.
READY
CON
CFM
WRONG
WRONG
2
BUF
pH
°C
SET
RANGE
°C
22
• Press pH/C SET key for HI 9110 or
the RANGE key for HI 9210 to select the
manual temperature setting. The "C"
symbol will be displayed to indicate the
temperature setting mode.
• Remove the protective cap on the top of the meter to have
access to the calibration trimmers.
• Record the temperature of the buffer with a Checktemp C or
an accurate thermometer (e.g.20C).
• Using the screwdriver, turn the temperature trimmer (# 5
pages 9-10) to display the recorded temperature value.
• Press the pH/C SET key for HI 9110
or the RANGE key for HI 9210 to read
pH.
pH Calibration
All three meters provide for manual pH cali-
bration. As a result, you can perform
one or two point calibration at a buffer
of your choice. The instructions below
explain a typical calibration procedure at
pH 7 and then 4 or 10.
• Remove the protective cap from the elec-
trode, rinse it with some pH 7.01 solution, then dip in pH
7.01 buffer. Stir briefly and wait for one minute for the
reading to stabilize.
Note: The electrode should be submerged approximately 4 cm
°C
°C
pH
°C
SET
RANGE
°C
HI 7007
pH
