Advanced Instruments 3900, User Manual, Page: 94 / 131

Stir amplitude with low range and glass sample tubes
It has been found that the use of glass sample tubes can increase the
risk of sample pre-freezing errors. It is recommended that the stir
amplitude be set to between 25 and 30 for most instruments if glass
tubes are to be used in low range.
7. Sample-Probe Bin Setting:
a. Make sure the Supervisor/operator keyswitch is in the Supervisor
position while using the TEST and CALIB menus (see Chapter
2).
b. With the 3900 power turned on and “ Press START to
Continue ”, “ Osmometer Ready ”, “ Reset Probe
Configuration ” or the date and time on the display, press the
TEST button. The display will change to “ Select Test Item ”.
c. At “ Select Test Item ”, repeatedly press the > button until the dis-
play reads “ Probe Bin Test ”.
d. At “ Probe Bin Test ”, press START. The display will change to
“ [Start] Ready? ”.
e. At “ [Start] Ready? ”, pipet or measure samples of bin-setting
fluid into three clean sample tubes and place them in the first
three positions of a cassette.
f. Place the cassette in the left (input) deck and press the START
button. The 3900 will run special freezing point tests to deter-
mine the sample probe resistance and bin number.
NOTE In emergency, H
2
O may be used in place of bin-setting fluid
for this test. The bin number thus determined will be accept-
able for bin setting, though the probe resistance displayed is
that at the freezing point of the H
2
O sample used and will
be different from that for bin-setting fluid.
76
The Advanced
®
Osmometer Model 3900 User’s Guide