Chapter 4, Calibration
4-5
Example:
Calibrate the optics to 2891 digital units or +3.53 VDC:
Correction Factor printed on the back of the gray card = 0.829
Optic
Digital Gain to be Adjusted = 0.829 x 2891 =
2397 digital units
or
Optic
Voltage Gain to be Adjusted = 0.829 x 3.53 VDC =
2.926 VDC
Note:
The bowl optics signal
calibration
range differs from the bowl
optics signal
test
(operational) range. The optics
calibration
range
is utilized to adjust the optics gain if it is found to be outside the
acceptable optic calibration
test
range.
12. Adjust the photoelectric transceiver to attain the desired optic value
determined from the calculation in step 11.
13. Remove the optics fixture from the centrifuge.
14. Adjust R24 potentiometer on the Processor Card until the average
optics offset value is 1 to 66 digital units (as displayed on the screen)
or 0.0 ± 0.08 VDC.
15. Replace the optics fixture in the centrifuge, rotating it until the optic
beam is centered on the gray card.
16. Close the centrifuge cover to allow the cover’s bowl collars to lock
around the optic fixture’s square alignment tabs.
17. Ensure the optic gain is within the specification range in step 11. Re-
adjust if necessary.
18. Repeat the above steps until both the optics gain and offset are within
the specified ranges.
Note:
When documenting the optics signal calibration value, ensure the
value recorded is the bowl optics calibration value, not the actual
gray card reading. In the above example in step 9, the value
recorded would be 2891 digital or +3.53 VDC.
Warning!
The Correction Factors used in the above calculation are example
values only. Each gray card is individually indexed and the
Correction Factor may vary for each card. The Correction Factor
from the actual card being used must be incorporated into the
optics signal calibration and testing calculations.
!
