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22
PHO
TOMETER MODE
Discard the sample immediately after the reading is taken, or the glass might become permanently
stained.
All the reaction times reported in this manual are at 25 °C (77 °F). In general, the reaction time
should be increased for temperatures lower than 20 °C (68 °F) and decreased for temperatures higher
than 25 °C (77 °F).
Interferences
In the method measurement section the most common interferences that may be present in a typical
water sample have been reported. It is possible that a particular application could introduce other
compounds that will also interfere.
8.4. TIMERS & MEASUREMENT FUNCTIONS
Each method requires a different preparation procedure, reaction times and sample preparations. If a
timer or timers are necessary for proper sample preparation, the
Timer
will be available.
To use a reaction timer, press
Timer
. The default timer will start immediately. To stop and reset the
timer, press
Stop
.
If the selected method requires more than one timer, the meter will automatically select each timer
in the appropriate order. To bypass the default order, you may press the desired key to activate a
different timer (only while the current timer is stopped). Press
Continue
to start the active timer.
For some methods, the timer is only necessary after a Zero measurement has been performed. In this
case, the timer key will only be available after the Zero measurement has been performed.
If the method requires a Zero or Read measurement after a timer has expired, the meter will
automatically perform the appropriate action. Follow the instructions in the method procedure.
To perform a Zero or Read measurement, insert the prepared cuvette, then press
Zero
or
Read
. A Zero
measurement must be conducted before a Read measurement.
8.5. CHEMICAL FORMULA & UNIT CONVERSION
Chemical formula and unit conversion factors are pre-programmed into the instrument and are
method specific. In order to view the displayed result in the desired chemical formula press the
keys to access the second level function and then press
Chem Frm
to toggle between the available
chemical formulas for the selected method.