Bio-Rad BioFrac™ Fraction Collector - Manual (Page 57)

Calibration Screen
User Guide | 49
Calibration Screen
Use the Calibration screen to adjust the drophead calibration, screen contrast, sleep
mode, and to zero the analog-to-digital converter (AtoD). Refer to Table 14 for more
information about the use of each function key.
Table 14. Calibration screen function keys
Function Key Function
Done Returns the display to the Method Library
screen.
Contrst Allows the user to set the display contrast. The
up and down arrow keys are used to increase
and decrease the screen brightness,
respectively.
X–Y axis Places the fraction collector in rack calibration
mode. Allows the user to calibrate the fraction
collector X–Y arm. Calibration should rarely be
required. Calibration is done on an F1 rack that
has 13 x 100 mm glass tubes in positions A1,
A15, and B90 (plastic tubes should not be
used). See
Calibrating the Fraction Collector
X–Y Arm on page 50 .
Caution: Using this function overwrites
the previous calibration.
Zero AD Allows the user to zero any voltage offset in the
analog-to-digital (AtoD) converter. The AtoD is
used to convert the analog UV signal used for
threshold collection to a digital signal. In the
event of an offset in the AtoD voltage, the
Current UV signal (see
Figure 16 ) displayed on
the run screen may be in error. This calibration
should rarely be required.
To zero the AtoD, press Zero AD, connect a
shorting plug (Combicon connector with the
analog IN(+) and IN(–) pins connected to the
analog IN (ground)), then press Next.