Turn the meter on
• Press and hold the ON/OFF/MODE button
until the LCD lights up. All the used segments
will be visible for one second (or as long as
the button is pressed).
Freeze the display
• While in measurement mode, press the SET/
HOLD button. The reading will be frozen on
the LCD. Press any button to return to nor-
mal mode.
Turn the meter off
• While in measurement mode, press the ON/
OFF/MODE button. OFF will appear on the
secondary display. Release the button.
Note:
If measurements are taken in differ-
ent samples successively, rinse the
probe thoroughly to eliminate cross-
contamination. After cleaning, rinse
the probe with some of the sample to
be measured.
OPERATIONAL GUIDE
pH MEASUREMENT &
CALIBRATION
Taking Measurement
• Submerge the electrode in the solution to be
tested while stirring it gently.
• Measurements should be taken when the sta-
bility indicator (hourglass) disappears.
• The pH value automatically compensated for
temperature is shown on the primary LCD
level while the secondary one shows the
sample temperature.
Note:
Before taking any pH measurement,
make sure the meter has been cali-
brated (CAL tag is displayed).
pH Calibration
For better accuracy, frequent calibration of the
instrument is recommended. In addition, the
instrument must be recalibrated whenever:
SETUP
Setup mode allows the selection of tempera-
ture unit and pH buffer set.
To enter the setup mode, press the ON/OFF/
MODE button until CAL on the secondary dis-
play is replaced by TEMP and the current tem-
perature unit (e.g. TEMP °C). Then:
For °C/°F selection:
• Use the SET/HOLD button. After the tem-
perature unit has been selected, press the
ON/OFF/MODE button to enter the buffer
set selection mode.
• Press the ON/OFF/MODE button again to re-
turn to the normal measuring mode.
To change the calibration buffer set:
• After setting the temperature unit, the meter
will show the current buffer set: “pH 7.01
BUFF” (for 4.01/7.01/10.01) or “pH 6.86
BUFF” (for NIST 4.01/6.86/*9.18).
• Change the set with the SET/HOLD button,
then press ON/OFF/MODE to return to the
normal measurement mode.
ELECTRODE MAINTENANCE
When not in use, rinse the electrode with water
and store it with a few drops of pH4
solution in the protective cap.
NEVER STORE THE ELECTRODE IN DIS-
TILLED OR DEIONIZED WATER!
• If the electrode has been left dry, soak the tip
in pH4 for at least one hour to
reactivate it.
• To prolong the electrode life, it is recom-
mended to clean it monthly by immersing the
tip in
deionized water
for
30 minutes. Afterwards, rinse it thoroughly
with tap water and recalibrate the meter.
• The electrode can be easily replaced by un-
screwing the body as shown below.
a)
The pH electrode is replaced.
b)
After testing aggressive chemicals.
c)
Where high accuracy is required.
d)
At least once a month.
Calibration Procedure
• From normal measuring mode, press and hold
the ON/OFF/MODE button until OFF on the
secondary LCD is replaced by CAL.
• Release the button. The LCD enters the cali-
bration mode displaying “pH 7.01 USE” (or
“pH 6.86 USE” if the NIST buffer set was
selected).
• The meter automatically recognizes buffers:
if a valid buffer is detected then its value is
shown on the primary display and REC ap-
pears on the secondary LCD level. If no valid
buffer is detected, the meter keeps the USE
indication active for 12 seconds, followed by
WRNG, indicating the buffer being measured
is not a valid calibration value.
Single-Point Calibration
• For a single-point calibration with buffers
pH 4.01, 9.18 or 10.01, the meter automati-
cally accepts the calibration when the read-
ing is stable. The accepted buffer is displayed
together with the message “OK 1” for one
second, then the meter automatically returns
to the normal measuring mode.
• If a single-point calibration with buffer pH
7.01 (or pH 6.86) is desired, then after the
calibration point has been accepted, press
the ON/OFF/MODE button to return to nor-
mal mode. The meter shows “7.01” (or
“6.86”) and “OK 1” for one second, then it
automatically returns to the normal mode.
Note:
For better accuracy, it is recommended
to perform a 2-point calibration.
Two-Point Calibration
• For a two-point calibration, place the elec-
trode in pH 7.01 (or pH 6.86) buffer. After
the first calibration point has been accepted,
the “pH 4.01 USE” message appears. The
message is held for 12 seconds, unless a valid
buffer is recognized. If no valid buffer is rec-
ognized, then the WRNG message is shown.
If a valid buffer (pH 4.01, 10.01, or 9.18) is
detected, then the meter completes the cali-
bration procedure. The LCD shows the ac-
cepted value with the “OK 2” message, and
then the meter returns to the normal mode.
Note:
When the calibration procedure is
completed, the CAL tag is turned on.
To quit calibration & reset to default values
• After entering the calibration mode and be-
fore the first point is accepted, you can quit
the procedure and return to the last calibra-
tion data by pressing the ON/OFF/MODE
button. The secondary LCD displays “ESC”
for one second and then the meter returns to
the normal measuring mode.
• To reset to the default calibration values,
press SET/HOLD after entering the calibra-
tion mode and before the first point is ac-
cepted. The secondary LCD displays “CLR”
for one second, the meter resets to the de-
fault calibration and the CAL tag disappears.
BATTERY REPLACEMENT
When the batteries become weak, the battery
symbol on the LCD lights up to indicate a low
battery condition. Batteries should be replaced
soon.
To change the batteries, unscrew and release
the electrode body. Take
out the battery compart-
ment and carefully re-
place all four batteries
while paying attention to
their polarity.
Reattach and tighten the
electrode body properly
to ensure a watertight
seal.
