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 (LCD)
2) Cuvet Holder
3) Cuvet alignment indicator
4) ON/OFF key
5) ZERO key
6) READ/TIMER key
7) CAL CHECK key
FUNCTIONAL DESCRIPTION
14
• Hold READ/TIMER for three seconds. The
display will show the countdown prior to
measurement.
Alternatively, wait for 1 minute and just press
READ/TIMER.
In both cases “SIP” will blink during
measurement.
• The instrument directly displays concentration
in mg/L of free chlorine on the Liquid Crystal
Display.
or
INTERFERENCES
• Alkalinity:
• Acidity:
• Hardness:
• Bromine (Br
2
):
• Chlorine dioxide (ClO
2
):
• Iodine (I
2
):
• Oxidized Manganese
and Chromium:
• Ozone (O
3
):
above 1,000 mg/L CaCO
3
if present as bicarbonate (HCO
3
-
, sample
pH < 8.3); above 250 mg/L CaCO
3
if present as carbonate (CO
3
2-
,
sample pH > 9.0).
In both cases, it will not reliably develop the full amount of color
or it may rapidly fade (negative error). To resolve this, neutralize
the sample with diluted HCl.
above 150 mg/L CaCO
3
. May not reliably develop the full amount
of color or it may rapidly fade (negative error). To resolve this,
neutralize the sample with diluted NaOH.
in case of water with hardness greater than 500 mg/L CaCO
3
,
shake the sample for approximately 2 minutes after adding the
powder reagent.
positive error.
positive error.
positive error.
positive error.
positive error.
