CPI Canada Inc.
AEC Calibration
3D
3D.5.0 AEC DENSITY CALIBRATION (Cont)
Figure 3D-7a: PC GenWare
®
Figure 3D-7b: Touchscreen GenWare
®
AEC Setup & Calibration window, Density tab
Please note the following points regarding density calibration:
•
Up to eight density plus and eight density minus steps are available. If
±
8 density steps are not required, the unwanted density steps may
be deprogrammed per the procedure below. For example, if only
±
5 density steps are desired, then density steps
±
6, 7, and 8 may be
deprogrammed.
•
Once the desired number of
±
density steps are known, the relative minimum and maximum mAs values must be determined. Typically, the
minimum density step will result in half (50%) of the nominal mAs (dose) and the maximum density step will typically give double (100%
increase) the nominal mAs (dose). The nominal mAs is the value that was recorded at 0 density in table 3D-9.
•
The relative mAs change per density step must be determined next. To do this, note the relative minimum and maximum mAs as
determined above (i.e. 50% at min density and 100% increase at max density), then calculate the number of - density steps and the number
of + density steps that will be required.
The relative mAs change between density steps will then be the minimum density (i.e. 50) divided by the number of density minus steps
or the maximum density (i.e. 100) divided by the number of density plus steps. This will yield the required mAs increment for each density
minus step and for each density plus step respectively.
For
±
8 density steps, this gives a mAs decrease of 6.25% per density minus step (8 steps x 6.25% per step = 50% mAs at -8 density)
or a mAs increase of 12.5% per density plus step (8 steps x 12.5% per step = 100% mAs increase at +8 density).
Use and disclosure is subject to the restrictions on the title page of this CPI document.
CMP 200
®
Service Manual Ch # 901476-05 Rev. A
Page 3D-27
