Axis-Shield NycoCard Reader II Manual

Introduction to NycoCard
®
The NycoCard READER II is a small battery powered
instrument, designed to measure all NycoCard
products. The coloured responses of the NycoCard
products are measured by spectral reflectance in three
parts of the visible spectrum.
Description of NycoCard
®
The NycoCard READER II kit consists of:
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NycoCard READER II
Battery charger
Batteries (rechargeable)
A1 Calibration devices
A2 Pen tips
A3 Pen rings
A4 Battery clips
Pad
Instruction manual
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The NycoCard READER II consists of two units: the
instrument box (1), which is the operational and calcu-
lating unit, and the Reader pen (5), which is the mea-
surement unit. The main components of the instrument
box are the microprocessor, the LCD display (3) and
the push buttons (2) for operation. The key elements of
the Reader pen are the Light Emitting Diodes (LED's)
(11), a photodiode (12), a light/dark detector (10) and
the functional design. A pen cable (4) connects these
two units together. The penholder (8) is located to the
right of the display on the instrument box. The pen is
placed in the holder to protect it when not in use. In
front of this holder, there is a lid (6), and on the rear
side of the lid a white calibration device (9) is placed.
Basic theory
The Reader pen contains three pairs of LED's: red,
green and blue. Reflected light from the test sample
is measured, relative to a white sample, by a light-
sensitive photodiode circuit. When a specific test from
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the NycoCard READER II test menu is chosen, the
required LED's illuminate the sample to be measured.
The sample will reflect some of the light and give rise
to a constant current in the photodiode, which will
discharge a capacitor linearly from the voltage V
a lower voltage V . When V
2 2
given to the microprocessor. The microprocessor
measures the time (T) it takes to change the voltage
from V to V . The intensity of reflected light (I) is then
1 2
inversely proportional to T, and the microprocessor
converts the time to a concentration value, which will
then be displayed.
READER II
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READER II
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1 unit
1 unit
3 units
10 units
10 units
10 units
3 units
1 unit
1 unit
to
1
is reached, a signal is
5
When the pen is placed over the sample and the pen
sleeve is pushed down, the light/dark detector regis-
ters that the environment has changed from light to
dark and the measurement is automatically started.
The sleeve will ensure that the pen is held stable in
a vertical position, and that external light is excluded
from the sample.
Adjusting
This procedure compensates for the contribution of
reflected light from the inside of the pen tip (14) and
slight electrical current leakage in the electronic circuit.
Adjusting is performed when the pen is placed in the
penholder, i.e. in a dark chamber without any sample
present. It is important to adjust the instrument each
time the instrument is turned on and when the pen tip
is replaced.
White calibration
White calibration adjusts for any differences in
measuring conditions and variation of pen tips. The
white calibration is performed on a special calibration
device, which is stored under the lid, protected from
light and dust. The NycoCard
be calibrated prior to each series of measurements
(max 20 measurements per series) and prior to each
single, sporadic measurement.
Installation and environment
Check that all components listed in the section
®
Description of NycoCard READER II are included in
the package and that no components are damaged.
Make sure that the instrument is acclimatised to room
temperature before use. Recommended ambient
temperature is 18 – 25°C and humidity must not be
condensing. Ensure that the instrument is protected
from dirt and direct sunlight.
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Your NycoCard READER II is supplied with 3 rechar-
geable NiMH batteries (1.2 V) (16). Before using the
new instrument the batteries should be charged for 18
hours. The connection plug of the battery charger (18)
is inserted into the outlet (19) located at the rear side
of the instrument box. The Reader pen has a modular
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plug (20). The NycoCard READER II is equipped
with RS 232 port for PC-connection (21).
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READER II should
GB