PRONOVA Stelzner EC 2000, Technical Instructions

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5. Technical instructions for the NITRAT 2000
Starting up the NITRAT 2000 for the first time
Open the cover on the rear side of the device
and insert the nine-volt battery. Put the cover
back on. Turn on the device by briefly pres-
sing the ON/OFF button. Connect the nitrate
electrode to the device and then carefully
remove the protective cap on the electrode.
Clean the nitrate electrode with pulp-tissue
paper or a dry cloth. The NITRAT 2000 is
now ready to be used. The nitrate electrode
should be submerged into the material to be
measured, such as a substratum suspension
or soil mixture. The measured value can then
be read after the display has stabilized.
Turn off the device after you have finished
the measurement. Disconnect the nitrate
electrode from the device and clean it. The
electrode is best cleaned by spraying it
gently with distilled water and then carefully
drying it with a pulp-tissue paper or dry cloth.
The nitrate electrode should then be stored
in its dry protective cap. If the electrode will
be used daily, it can be stored in the condi-
tioning solution that comes with the device.
Quick guide for the NITRAT 2000
Taking measurements
Press the ON/OFF button (initially, the elec-
trode’s conductive slope for the previous
calibration will be displayed). Submerge the
nitrate electrode in the mixture which you
wish to measure.
Calibration (dual-point calibration)
During the measuring cycle, press the ON/
OFF button for five seconds until the LED illu-
minates to get to the calibration mode. Sub-
merge the cleaned and dry electrode into a
calibration solution of Cal 1 = 50 mg/l NO
3
and
gently sway the electrode through the solu-
tion. Then press the CAL 1 button. The display
will alternate between the number 50 and the
relative measured value in mV. After a few
minutes, a stable value will be displayed. The
electrode can then be taken out of the cali-
bration solution, cleaned with distilled water
and carefully dried.
Now submerge the electrode in the Cal 2 =
500 mg/l NO
3
calibration solution. Sway it
gently in the solution and press the CAL 2
button. The display will alternate between
the number 500 and the relative measured
value in mV. The device switches automati-
cally into the measurement cycle and the red
LED goes out after the electrode has reached
a stable value.
From these two calibrated values, the device
calculates the conductive slope of the nitrate
electrode and saves this value.
If no stable value is reached after several
minutes of calibration, then the nitrate elec-
trode should be immersed in the conditioning
solution for several hours so that it can rep-
lenish itself. The device can be turned off by
pressing all three buttons (CAL 1, CAL 2 und
ON/OFF) for at least ten seconds long.
Calibration (single-point calibration)
Normally, before each series of measure-
ments, a single-point calibration with CAL
2 is sufficient. To do this, first turn on the
device and press the ON/OFF button for
several seconds until the LED is illuminated
indicating calibration mode. Submerge the
cleaned and dry electrode into a calibration
solution of CAL 2 = 500 mg/l NO
3
and gently
sway electrode through the solution. Then
press the CAL 2 button. The device will alter-
nate between flashing the number 500 and
mV display. The device will then automati-
cally change from the calibration mode to
the measurement mode and the red LED will
go out.
Nitrate electrode
Depending on the degree of use (anywhere
from one to three years), the nitrate electrode
can gradually lose its ability to measure pro-
perly. This measure of a nitrate electrode’s
usability is called the electrode conducti-
vity slope. New electrodes exhibit a voltage
change of 57 +/- 2 mV. If the slope decreases
to under 45 mV/p NO
3
, then the device will
display the “E 1” error warning. If the slope
is still too low following a re-calibration, then
you should replace the nitrate electrode.
A used nitrate electrode can also be reple-
nished at our factory at a charge of about
one-third of the original sales price.
NITRAT 2000