CPI Indico 100 Series Service And Installation Manual page 166

3D
AEC Calibration
3D.7.0 AEC DENSITY CALIBRATION (Cont)
*TUBE?
+1: 12%
+2: 25%
+3: 37%
+4: 50%
3200MS <<
*TUBE?
+5: 62%
+6: -
+7: -
+8: -
3200MS <<
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 programmed out per the procedure below. For example, if only ± 5
density steps are desired, then density steps ± 6, 7, 8 may be deprogrammed.
•
Once the desired number of ± density steps are known, the relative minimum and maximum dose
values must be determined. Typically the minimum density step will result in half (50%) of the nominal
dose and the maximum density step will typically give double the nominal dose (100% increase). The
nominal dose is the value that was recorded at 0 density in table 3D-14.
•
The relative dose change per density step must be determined next. To do this, note the relative
minimum and maximum dose 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 dose 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 dose increment for each density minus step and for each density
plus step respectively.
For ± 8 density steps, this gives a dose decrease of 6.25% per density minus step (8 steps x 6.25%
per step = 50% dose at -8 density) or a dose increase of 12.5% per density plus step (8 steps x 12.5%
per step = 100% dose increase at +8 density).
Refer to table 3D-15 for two typical examples of density steps vs calibration numbers. For 8 minus
density steps the dose decrease is 6.25% per step, and for 8 + density steps the dose increase is 12.5%
per step as per the example calculation above.
For 5 minus density steps the dose decrease is 10% per step, and for 5 + density steps the dose
increase is 20% per step.
Page 3D-32
0%HU *DENS. SETUP*
0%HU *DENS. SETUP*
Rev. D Millenia / Indico 100 Series Service Manual
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