7
A microprocessor controlled special tungsten lamp emits radiation which is first optically conditioned
and beamed to the sample contained in the cuvet. The optical path is fixed by the diameter of the
cuvet. Then the light is spectrally filtered to a narrow spectral bandwidth, to obtain a light beam of
intensity
I
o
or
I.
The photoelectric cell collects the radiation
I
that is not absorbed by the sample and converts it
into an electric current, producing a potential in the mV range.
The microprocessor uses this potential to convert the incoming value into the desired measuring
unit and to display it on the LCD.
The measurement process is carried out in two phases: first the meter is zeroed and then the actual
measurement is performed.
The cuvet has a very important role because it is an optical element and thus requires particular
attention. It is important that both the measurement and the calibration (zeroing) cuvets are
optically identical to provide the same measurement conditions. Whenever possible use the same
cuvet for both. It is necessary that the surface of the cuvet is clean and not scratched. This to avoid
measurement interference due to unwanted reflection and absorption of light. It is recommended
not to touch the cuvet walls with hands.
Furthermore, in order to maintain the same conditions during the zeroing and the measuring
phases, it is necessary to close the cuvet to prevent any contamination.
1) Liquid Crystal Display
2) Cuvet Holder
3) Cuvet alignment indicator
4) ON/OFF key
5) ZERO/SET key
6) READ/TIMER key
7) CAL CHECK key
FUNCTIONAL DESCRIPTION
18
or
• Press READ/TIMER and “SIP” will blink on the
display.
• The instrument will show for three seconds the
CAL CHECK™ standard value.
Then the date of last calibration (e.g.: “01.08”)
appears on the display, or “01.01” if the factory
calibration was selected. In both cases the
number of the month is blinking, ready for date
input.
Note
: if display will show “ERR” the
calibration procedure failed. Verify that the right
CAL CHECK™ Standard Cuvet
B
is inserted, that
both
A
and
B
cuvets are free from fingerprints or
dirt and that they are inserted correctly.
DATE INPUT
• Keep READ/TIMER pressed to scroll to the desired
month number (01-12).
• When the correct month has been set, press ZERO
to confirm. Now the display will show the day
number blinking. Keep READ/TIMER pressed to
scroll to the desired day number (01-31).
Note
: it is possible to change from
day
to
month
and vice versa by pressing ZERO.
• When both the day and month have been selected,
hold CAL CHECK for three seconds to store date
and calibration values. The instrument will show
for one second “Stor”, to confirm that the new
calibration data has been accepted.
• The instrument will return automatically to the
measurement mode by displaying the parameter
code (“701” or “711”) on the LCD.
or
