Possible Error Messages; Self-Freezing Of The Sample - Knauer K-7400 Benutzerhandbuch

Using the Osmometer K-7400

Possible Error Messages

Table 2

Self-Freezing of the Sample

Table 3
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.
Message
FREEZE
NO FREEZE
OUT OF RANGE
NOT CALIBRATED
COOLER TIMEOUT
MEASUREMENT
TIMEOUT
If the sample does not super-cool but freezes continuously without any
external agent there are three possible causes:
Error reason
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.
Scratches or contaminations at the
thermistor or measuring vial nucleate
inducing premature freezing.
Solutions saturated with air or gases are
sometimes difficult to super-cool.
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.
Cause
The crystallisation took
place or another fault
occurred before the start
of the vibrator
No crystallisation took
place after the
automatically start of the
vibrator
The measured value is
outside the acceptable
range
No calibration points are
available
Timeout due to too slow
cooling.: >3 minutes
Timeout due to too long
measurement.: >5
minutes from START
Solution
Use exact the required
sample volume of
0.15 ml
Exchange of the
measuring vial and
cleaning the thermistor
with cleaning solution.
Degas the sample
solution by ultra sound
17
Removal
See Table 3
On page 16
SeeTable 4
on page 18
Usually
malfunction of the
thermistor
See SOP 3
on page 14