14. Blood Leak Detector
Figure 14-4. Blood Leak Detector Block Diagram
Blood Leak Detector Calibration
The calibration of the BLD is performed automatically at a flow
rate of 500 mL/min when the technician selects the sensitivity of
the BLD (see Section 18.5.11). This sensitivity is selected in terms
of mL/min blood leak rate. The I/O Controller varies the LED
light intensity via the I/O Hydraulic Power Board until the signal
from the photocell measures about 2 VDC. The LED voltage
value is stored in the SRAM.
The actual BLD alarm threshold depends on two variables, the
BLD sensitivity selected during customization and the actual
dialysate flow rate used during each treatment.
157-1278-921 Rev A 14-7
April 2004
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