PRONOVA Stelzner EC 2000, Technical Instructions

Page: 28 / 158

30
GB
1. Technical instruction pH AGRAR 2000
Starting up the pH AGRAR 2000
for the first time
Open the cover on the rear side of the de-
vice and insert the nine-volt battery. Put the
cover back on. Turn on the device by briefly
pressing the ON/OFF button. Connect the pH
electrode to the device and then carefully
remove the protective cap from the elec-
trode. Clean the pH electrode with pulp-tis-
sue paper or a dry cloth. The device is now
ready to be used. The pH electrode should be
submerged into the material to be measured,
such as a substratum suspension or soil so-
lution. The measured value can then be read
after the display has stabilized.
Attention: When making a direct measure-
ment into the soil or substratum, be sure to
always first prepare a hole with the enclosed
dibble! The pH electrode is made of glass and
can break when used improperly. Repeat the
measurement several times and then take
the average result.
Be sure to clean the electrode after you are
done measuring. The electrode tip should
always be stored in a moist condition. A
few drops of 3-mole KCl solution should be
put into the protective cap before the cap is
placed back on the electrode. Never store
the pH electrode in deionised water – this
would shorten the life of the electrode signi-
ficantly!
Short guide to the pH meter AGRAR 2000
Taking measurements
Press the “on/off” button (at first, the elec-
trode slope of the previous calibration will be
displayed)
Calibration
During the measuring cycle, press the
“on/off” button for five seconds until the LED
illuminates. Immerse the glass soil-insertion
electrode into a buffer solution pH 7. Press
button “cal pH 7”; when display shows 7.00,
rinse glass soil-insertion electrode with deio-
nised water and immerse it into a buffer so-
lution pH 4. Press button “cal pH 4”. When
display shows 4.00, the LED goes out and the
measuring cycle starts again.
Calibrating the pH meter AGRAR 2000
Press “on/off” button (at first, the glass soil-
insertion electrode slope of the previous
calibration will be shortly displayed, then
you will see the measured pH value). The
pH meter AGRAR 2000 now operates in the
measurement mode.
To change from measurement mode to cali-
bration mode, press “on/off” button for about
5 sec. (until LED illuminates).
Then remove the protective cover of the
glass soil-insertion electrode, rinse the glass
soil-insertion electrode with deionised water
and immerse it into a buffer solution pH 7.
Wait until the value displayed has stabilised.
Now, shortly press button “pH 7 cal”. The
displayed values will alternate between C. 7
(cal 7.00) and the measured value; wait until
display shows pH = 7.00. Afterwards, rinse
glass soil-insertion electrode well with deio-
nised water, immerse it into a buffer solution
pH 4.00 and shortly press button “pH 4 cal”.
The values displayed will change between
C. 4 and the measured value; wait until the
target value of the buffer solution = 4.00 is
displayed.
The meter will then automatically change
from the calibration mode to the measure-
ment mode and the red LED will go out.
Take the glass soil-insertion electrode out
of the buffer solution, rinse it well with deio-
nised water and immerse it into the sample
solution you would like to measure. The
electrode slope1 of the pH electrode calibra-
tion will be saved automatically; it may dis-
played again after switching off the pH me-
ter AGRAR 2000 (press “on/off” button) and
switching it back on (press and hold “on/off”
button). If you do not switch off the pH meter
AGRAR 2000 by pressing the “on/off” button,
it will automatically switch itself off after 10
minutes (A1 mode active). When purchasing
the pH meter AGRAR 2000, the A1 mode will
be active.
If you do not wish that the pH meter AGRAR
2000 automatically switches itself off, you
have to proceed as follows: switch on the
pH meter AGRAR 2000 and simultaneously
press the buttons “pH 4 cal” and “pH 7 cal”
for about five seconds until you see “A 0” on
the display.
When you repeat these steps, the pH meter
AGRAR 2000 will turn back into the “A 1”
mode.
pH AGRAR 2000