To connect the probe
With the instrument OFF, connect the
HI 1291D
probe to the DIN connector on the rear panel of
the instrument by aligning the pins and pushing it
in the plug. Tighten the nut to ensure a good con-
nection. Remove the protective cap from the probe
before taking any measurements.
To turn the meter ON
Plug the 12 Vdc adapter into the appropriate
socket or use a 9V alkaline battery to power on
the instrument.
Press the ON/OFF/MODE key until the display
lights up. At start up, all the LCD segments are
displayed for one second, then the percentage
of the remaining battery life is shown for an-
other second (e.g. % 98 BATT). The instrument
then enters normal measurement mode.
Note
: If the display needs to be checked, keep
the ON key pressed while turning the
meter on. The meter will display all seg-
ments as long as the key is pressed.
Note
: If using a battery and its percentage is
under 15%, the stirrer will not work.
To freeze the display
While in measurement mode, press the HOLD/
SET key. The "HOLD" message will appear on
the secondary display and the reading will be fro-
zen on the LCD (e.g. pH 5.73 HOLD). Press any
key to return to normal measurement mode.
To turn the meter OFF
While in normal measurement mode, press the
ON/OFF/MODE key. The "OFF" message will ap-
pear on the secondary display. Release the key.
Note
: The instrument is provided with an
acoustic signal feature, which is heard
every time a key is pressed.
Note
: When the instrument detects the absence
of the probe, the "ATC" tag turns off and the
secondary display shows a default tem-
perature value of 25 °C (77 °F) blinking.
When the probe is connected, the instrument
automatically returns to the Automatic Tem-
perature Compensation mode, the "ATC" tag
turns on, and the measured temperature is
shown on the secondary display.
INSTRUMENT SETUP
The SETUP mode allows the selection of the
temperature unit and the pH buffer set.
To enter SETUP mode, press and hold the ON/
OFF/MODE key until "CAL" message on the
secondary display is replaced by "TEMP" and
the current temperature unit (e.g. TEMP °C).
Then:
•
for °C/°F selection
, use the HOLD/SET key. After
the temperature unit has been selected, press
the ON/OFF/MODE key to enter the buffer set
selection mode; press ON/OFF/MODE twice to
return to normal measurement mode.
•
to change the calibration buffer set
, after setting
the temperature unit, the instrument will show the
current buffer set: "pH 7.01 BUFF" (for 4.01/7.01/
10.01) or "pH 6.86 BUFF" (for 4.01/6.86/9.18).
Change the set with the HOLD/SET key, then press
ON/OFF/MODE to return to normal mode.
• Make sure the instrument has been calibrated
before use.
• If the probe is dry, soak it in
HI 70300
storage
solution for one hour to reactivate it.
• Make sure that the stirrer LED is off or press the
STIR ON/OFF key to stop the stirrer (
HI 208
only).
• Place the beaker with the solution to be tested
into the beaker holder and attach the electrode
holder.
• Insert the probe in the electrode holder and use
the supplied rubber O-ring for probe in order to
immerse the probe tip approximately 4 cm (1½")
into the sample to be measured.
• Press STIR ON/OFF to start the stirrer (
HI 208
only) and wait until the stability indicator turns off.
While the stirrer is on, the stirrer LED also is on.
• The LCD shows the pH value automatically
compensated for temperature variations and
the temperature of the solution.
• If measurements are taken in different samples
successively, rinse the probe tip thoroughly to
eliminate cross-contamination. After cleaning,
rinse the probe tip with some of the sample to
be measured.
pH calibration
For better accuracy, frequent calibration of the
instrument is recommended. In addition, the
instrument must be recalibrated whenever:
a) The pH electrode is replaced.
b) After testing aggressive chemicals.
c) Where high accuracy is required.
d) At least once a week.
• From normal mode press and hold the ON/OFF/
MODE key until "OFF" message on the second-
ary display is replaced by "CAL". Release the key.
• The LCD enters the calibration mode, displaying
"pH 7.01 USE" (or "pH 6.86 USE" if the NIST buffer
set was selected) and "CAL" tag blinking. After 1
second the instrument activates the automatic
buffer recognition feature. If a valid buffer is de-
tected, then its value is shown on the primary dis-
play, and "REC" message appears on the sec-
ondary display. If no valid buffer is detected, the
instrument keeps the "USE" message active for
12 seconds, and then replaces it with "WRNG", to
indicate an invalid buffer.
HI 1291D
pH/Temperature probe with DIN
connector and 0.5 m (1.6’) cable
HI 7004
pH 4.01 buffer solution, 500 mL
HI 7006
pH 6.86 buffer solution, 500 mL
HI 7007
pH 7.01 buffer solution, 500 mL
HI 7009
pH 9.18 buffer solution, 500 mL
HI 7010
pH 10.01 buffer solution, 500 mL
HI 70300L
Storage solution, 500 mL
HI 7061L
Cleaning solution, 500 mL
ACCESSORIES
BATTERY REPLACEMENT
Battery replacement must only take place in a
non-hazardous area and using the battery type
specified in this instruction manual.
Simply rotate the battery cover from the bottom of
the instrument as shown in the figure, and replace
the battery while paying attention to the correct po-
larity. Replace the cover.
OP
EN
CL
OS
E
OPERATIONAL GUIDE
pH MEASUREMENT & CALIBRATION
• For a
single-point calibration
with pH 4.01, 9.18
or 10.01 buffer, the meter automatically accepts
the calibration when the reading is stable; the
meter will show the accepted buffer, with the "OK
1" message, and an audible signal is produced.
After 1 second the meter automatically returns to
normal measurement mode.
If a single-point calibration with pH 7.01 or 6.86
buffer is desired, then after the calibration point
has been accepted, the ON/OFF/MODE key
must be pressed in order to return to normal
measurement mode. After the key is pressed,
the instrument shows "7.01" (or "6.86") - "OK 1",
and an audible signal is produced. After 1 second,
the instrument automatically returns to normal
measurement mode.
Note
: For better accuracy it is always recom-
mended to carry out a two-point calibration.
• For a
two-point calibration
, place the probe in
pH 7.01 (or pH 6.86) buffer. After the 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 recognized, then the "WRNG"
message is displayed. If a valid buffer (pH 4.01,
pH 10.01 or pH 9.18) is detected, then the in-
strument completes the calibration procedure.
When the buffer is accepted, the LCD shows its
value with the "OK 2" message. The instrument
then returns to normal measurement mode.
Note
: When the calibration procedure is completed,
the "CAL" tag turns on.
To quit calibration and to reset to the default
values
• After entering the calibration mode and before the
first point is accepted, it is possible to quit the
procedure and return to the last calibration data by
pressing the ON/OFF/MODE key. The secondary
display shows "ESC" message for 1 second and
the instrument returns to normal mode.
• To reset to the default values and clear a previ-
ous calibration, press the HOLD/SET key after
entering calibration mode and before the first
point is accepted.
The secondary display shows "CLR" message
for 1 second, the instrument resets to the de-
fault calibration and the "CAL" tag turns off.
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