wtw OxiTop Control OC 110, Operating Manual

Page: 64 / 102

GLP/TOOLS OxiTop
®
Control OC 110
64
ba31116e05 07/2014
T
Incubator
, is smaller than 1% of the selected measurement range final
value.
The AutoTemp function The AutoTemp function is made up of the adaptation phase and the
test phase .
Adaptation phase
The phase without evaluation of the pressure process. The duration of
the adaptation phase is defined for the various measuring times
according to the table. The adaptation of the microbiology to the char-
acteristics of the sample is made in this phase and small temperature
deviations, too high and too low temperatures of the sample, can be
compensated for. The measuring system is zeroed after the adaptation
phase has expired.
Test phase
The phase in which the further pressure process direction in the sample
bottle is checked. The test phase is defined for the various measuring
times according to the table.
In this phase, the continuing temperature deviation can be compen-
sated if the temperature of the sample is too low.
Sequence of the test
phase:
With a further drop in pressure (consumption) or constant pressure
after the adaptation phase, the pressure value at the end of the adap-
tation phase is the starting point of the measurement.
On a further increase of pressure following the adaptation phase (the
sample is still too cold), the turning point of the pressure process at
which the pressure increase changes into a pressure drop, is the
starting point of the measurement. If the sample is too warm the test
phase is dropped (temper the sample according to the table on the last
page).
If no starting point is found (according to the procedure given in points
1 and 2) after the termination of the
AutoTemp phase (time limit
exceeded), the last measuring point of the AutoTemp phase forms the
starting point.
This means that the BOD curve in the graphical evaluation does not
emerge from the coordinate origin at the zero time point. A sample that
was too cold was started.
Measuring time
of the measure-
ment Recommended sample temper-
ature at the start of the mea-
surement
1 day
T
Incubator
-0.5K ... T
Incubator
2 days
T
Incubator
-1K ... T
Incubator
3 days
T
Incubator
-2K ... T
Incubator
4 days
T
Incubator
-3K ... T
Incubator
5 ... 99 days
T
Incubator
-5K ... T
Incubator
BOD5 15°C ... 20°C