Knauer K-7400, Руководство пользователя, Страница: 16 / 51

Using the Osmometer K-7400 17
Possible Error Messages
Any error message will be deleted simply by pressing any key. The main
screen will be displayed.
In any case the first row shows > ERROR < which is specified in the
second row.
Table 2
Message Cause Removal
FREEZE
The crystallisation took
place or another fault
occurred before the start
of the vibrator
See
Table 3
On page 16
NO FREEZE
No crystallisation took
place after the
automatically start of the
vibrator
See
Table 4
on page 18
OUT OF RANGE
The measured value is
outside the acceptable
range Usually
malfunction of the
thermistor
NOT CALIBRATED
No calibration points are
available See SOP 3
on page 14
COOLER TIMEOUT
Timeout due to too slow
cooling.: >3 minutes
MEASUREMENT
TIMEOUT
Timeout due to too long
measurement.: >5
minutes from START
Self-Freezing of the Sample
If the sample does not super-cool but freezes continuously without any
external agent there are three possible causes:
Table 3
Error reason Solution
Too less sample solution is in the measuring
vial. A very cold zone, which causes self-
freezing of the sample, develops above the
solution on the measuring vial material.
Use exact the required
sample volume of
0.15 ml
Scratches or contaminations at the
thermistor or measuring vial nucleate
inducing premature freezing.
Exchange of the
measuring vial and
cleaning the thermistor
with cleaning solution.
Solutions saturated with air or gases are
sometimes difficult to super-cool. Degas the sample
solution by ultra sound
If these three remedies do not produce the desired result, it is indicated
that the difficulties are caused by the nature of the sample to be
measured and the set cooling temperature is too low. In this case the
freezing temperatures must be set higher. Setting the cooling
temperature see screen 5 COOL in Fig. 8 on page 12.
Calibration and measurement must be performed at the same
setting. After changing the setting, a new calibration is required.