wtw OxiTop Control OC 110 Operating Manual page 90

What to do if...
Display message
undef.
(Display in the curve pre-
sentation or sample sta-
tistics)
10 of 12 
called up
(sample message, no. is
variable)
90
Cause
 The selected measurement range
has been exceeded.
 The sample filled was too warm.
 The AutoTemp function is
switched off.
 The sample filled was very cold
and has a low consumption
behavior (small BOD value).
 The system is not sealed (bottle
internal pressure = atmospheric
pressure).
 Two measuring heads have not
been found by the controller
 The measuring heads are placed
at another location (e.g. other lev-
els in the incubator, other incuba-
tors, further storage locations)
 The measuring heads have no
optical contact with the controller:
- Distance too great, angular posi-
tion imprecise
- IR window of the measuring
head averted from the controller
- Shading by other objects
 The missing measuring heads are
defective.
®
OxiTop
Remedy
 Select the correct measurement
range (see application reports on
the CD-ROM, Principles of measur-
ing technique).
 Pre-temper the sample more pre-
cisely.
 Switch on the AutoTemp function
(only effective with run durations of
more than 1 day).
 Check the system for leaks by
means of a visual check:
Are the sealing surfaces of the bot-
tle and measuring head clean and
fault-free? Are there cracks in the
sleeve, bottle or measuring head?
 Perform a cal-test (see section
9.5.4 - , page 71).
CAL TEST
 Check the incubator temperature.
 Modification of the distances or
angle.
 Search at other storage locations.
 Search for and check measuring
heads (see section 12.3 G
, page 93)
INFORMATION
ba31116e05
Control OC 110
ENERAL
07/2014