15
14
Connect the pH electrode with the built-in
temperature sensor to the meter and press
ON/OFF to power on the instrument.
The meter automatically checks that the stored calibration data
correspond to the connected electrode. The pH range will be auto-
matically set.
If the pH electrode is not connected, the LCD will display the "no
probe" message and then dashed lines in place of the readings.
For greatest accuracy, it is recommended to set
the Calibration alarm time-out to the value
appropriate to your specific use and calibrate
the meter as soon as the "DATE" warning
symbol blinks on LCD (see page 25).
To take pH measurements, simply submerge
the bottom 4 cm (1½") of the electrode in
the solution to be tested, stir gently and
allow for the reading to stabilize. The tem-
perature is displayed in the lower LCD without
the decimal digit.
The pH reading is automatically temperature compensated (ATC).
If the pH reading blinks it means that the electrode is "dead" and
readings are not reliable.
By continuously pressing the RANGE key the follow-
ing information will be displayed on the upper LCD:
• mV reading (
HI 98240
only)
The mV scale is autoranging, when the
reading is outside ±400 mV the deci-
mal point automatically disappears.
• Temperature reading
If the temperature reading is out of
range, a dashed line will be displayed.
• Date
• Time
Pressing RANGE again, the meter returns to pH reading.
If measurements are taken successively in different samples, it is
recommended to rinse the electrode thoroughly with deionized water
or, if not available, tap water first and then with some of the next
sample to condition the electrode before immersing it in the sample.
TAKING pH MEASUREMENTS
b - last pH calibration date
c - last pH calibration time
d - pH electrode offset
e - pH electrode slope
f
- 1
st
point pH calibration buffer
g - 2
nd
point pH calibration buffer
(if present)
h - last mV calibration date
(
HI98240
only)
i
- last mV calibration time
(
HI98240
only)
l
- 1
st
point mV calibration (
HI98240
only)
m - 2
nd
point mV calibration (
HI98240
only)
n - 3
rd
point mV calibration (if present;
HI98240
only).
Note:
If the pH is followed by a set of * or -, it means that the
pH electrode is old or dead respectively.
A dashed line indicates that the calibration has never been
performed.
If the calibration date is followed by the symbol "Dt", it means
that the calibration alarm time-out period has been exceeded.
CODE 13 - Setting the Identification (ID) Code
When using several identical meters it may be useful to uniquely
identify them by assigning an ID code to each meter.
• Select code 13. The message "Instrument ID code" will scroll across
LCD.
• Enter a 4-digit value using the arrow keys.
• Press ALT and CFM to confirm the value.
TESTING BATTERY LEVEL
• Select code 41. The message "Battery test" will scroll across LCD.
• If the meter is connected to an external power adapter, the LCD
will display "LINE", otherwise it will display bAtt on the upper
display, and the remaining percentage
of battery charge (100% means fully
charged battery and 0% corresponds to
the minimum battery voltage that al-
lows the meter to operate).
