Navigator 600 Phosphate
Multi-stream
3 Principle of Operation
10
IM/NAV6P/MS–EN Rev. F
3.3 Multi-Stream Operation
Between 2 and 6 sample streams can be fitted to the analyzer
depending on the version. The sample streams are connected
to constant head units and a solenoid valve connected to each
constant head unit selects the stream to be sampled by the
analyzer.
The analyzer samples the streams in a sequence that is defined
in the
Configuration
menu (see Section 5, page 22). The
sampling time is set to a minimum of 14 minutes for upscale and
for downscale changes. Sampling times are user-configurable
up to 60 minutes and may need to be increased from the default
values of 14 minutes if carry-over effects become significant.
The upscale time should be equal to, or less than, the
downscale time.
The analyzer uses the value of the maximum measurement
range set in
Configuration
to determine whether to utilize the
upscale or downscale sampling time. When switching from one
stream to the next, if the maximum range value:
decreases – the downscale time is used
increases – the upscale time is used
does not change – the upscale time is used.
The analyzer dead time (the time between the stream valve
energizing and the corresponding response on the analyzer
display) is approximately 12 minutes. This dead time is utilized in
the analyzer to minimize the stream sampling time (refer to
Fig. 3.3, page 10). The stream valve (stream 1) is on for the
allotted sampling time, it then switches off and the next stream
valve in the sequence switches on. The reading for stream 1 is
not taken for another 11 minutes; this enables a stable reading
of stream 1 to be taken in the shortest duration.
Soon after the reading for stream 1 has been updated, the next
stream in the sequence begins to enter the cuvette.
Fig. 3.3 Multi-Stream Timing
Stream 1
Solenoid Valve Open
Stream 2
Solenoid Valve Open
Stream 3
Solenoid Valve Open
Stream 4
Solenoid Valve Open
Reading Taken for
Stream 2
Reading Taken for
Stream 3
Reading Taken for
Stream 1
Yellow Sampling
Symbol Displayed
Blue Update
Symbol Displayed
Dead Time 11.5 minutes.
Dead Time 11.5 minutes.
Sampling Interval
Nominal 12 minutes.
Update Time
10 minutes.
Toggles between time left to end of update
and time of last update
Sampling period and amount of time left
(the period the stream solenoid is
energized)
Update period – time left before
the stream value is updated
