Roche cobas b 221 system User Manual

Roche Diagnostics May 2009
A-24 Service Manual · Version 9.0
2 Fluid actions cobas b 221 system
Measurement
Positioning BG and
separating ISE:
This aspiration process assumes that the sample column tip is at SS1. It is aspirated
via VBI and VBO with the main pump. The start of the sample movement is detected
by the conductivity (breaking of the calibration solution column in the measuring
chamber). If this does not occur at the right time, an aspiration error is displayed. The
positioning of the sample is controlled by the MCI-MCO contact path. If a timeout
occurs because an excessively low signal or a non-reproducible conductivity signal, an
aspiration error is displayed. During the aspiration the sample is "observed" with SS1;
if the volume of the sample is too small, this interferes with the aspiration process.
After closing the VBI the ratio of the conductivities of MCI-MCO to MCI-MCC is
checked. If there are air bubbles in the MCI-MCO area, this can result is the
aspiration process restarting and the VBI opening again. When the corresponding
conductivity level is reached, the positioning of the sample is complete.
During the BG positioning ISE is separated between SS2 and SS1.
Positioning ISE: This aspiration process is similar to positioning BG. If an ISE measurement is not
required, the remainder of the sample is aspirated to VII through the sample
distributor to establish the required initial state for a subsequent MSS positioning.
Separating MSS and
washing rail:
A sample segment is aspirated to the SS4.
Positioning MSS: The sample is aspirated by turning the MSS output pump and opening the VSI. The
tearing of the standby solution and the start of the sample is detected by the
conductivity at the MSS input. Then it must also be possible to detect the tearing of
the standby solution and the sample start, at which the MSS output pump is stopped.
The completed sample positioning is checked again for freedom from bubbles via the
conductivity distances.
Positioning tHb/SO
2
or COOX: The sample segment for measurement of tHb/SO
2
or COOX is positioned last. The
valves V2, V4, V17 and V16 are opened and aspirated with the main pump. The
sample is still hemolyzed in the event of a COOX measurement.

Roche cobas b 221 system Specifications

General

Brand	Roche
Model	cobas b 221 system
Category	Medical Equipment
Language	English