1.5 Aec Calibration Range - CPI Indico 100 Series Service And Installation Manual

3D
AEC Calibration
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.
Page 3D-6
Figure 3D-4: Film/screen speed vs. D/A output
Rev. D Millenia / Indico 100 Series Service Manual
CPI Canada Inc.
Ch # 740904-06