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3D
AEC Calibration
CPI Canada Inc.
Page 3D-6
Rev. D Millenia / Indico 100 Series Service Manual Ch # 740904-06
3D.1.5 AEC Calibration Range
Since the Millenia and Indico 100 family of generators allow for up to three separate film screen
combinations to be calibrated, the following points must be considered :
•
The AEC board allows for a 0 to a maximum of 10 volt ramp at the comparator input. All AEC signals
must fit within this range (for all film/screens, densities, and techniques).
•
Most x-ray applications require the use of two or more different film screen combinations, all of which will
require different exposure doses.
•
Using the slowest film screen combination, the required film input dose will be determined.
•
Once this value is determined (during AEC calibration) the density calibration is performed to allow 100%
(double the dose) and 50% (half the dose) values. These are typical values and will determine the
maximum required range of the AEC reference voltage (output from the D/A converter).
•
Figure 3D-4 illustrates the different windows required for various film screen combinations.
Figure 3D-4: Film/screen speed vs. D/A output