3D
AEC Calibration
CPI Canada Inc.
Page 3D-30
Rev. D Millenia / Indico 100 Series Service Manual Ch # 740904-06
3D.5.0 AEC CALIBRATION (TABLE BUCKY) Cont
Step
Action
95 KV BREAKPOINT CALIBRATION:
46.
Select the 95 kV breakpoint. Use copper thickness per table 3D-13 for the 95 kV
breakpoint.
47.
Repeat steps 27 to 32 to calibrate the 95 kV breakpoint, substituting 95 kV where
applicable in place of 55 kV.
48.
Select << to return to the AEC CALIBRATION menu.
Step
Action
FILM SCREEN 2 BREAKPOINT CALIBRATION:
49.
Select FILM SCREEN 2.
50.
Repeat steps 16 to 48 as described for film screen 1 except:
WHEN CALIBRATING THE 75 KV KNEE BREAKPOINT FOR FILM SCREEN 2, DO
NOT ADJUST THE AEC BOARD GAIN POT. DOSE ADJUSTMENTS MUST ONLY BE
MADE BY VARYING THE BREAKPOINT CALIBRATION NUMBERS.
FILM SCREEN 2 MUST BE THE NEXT HIGHEST FILM SPEED AFTER FILM
SCREEN 1.
Step
Action
FILM SCREEN 3 BREAKPOINT CALIBRATION:
51.
Select FILM SCREEN 3.
52.
Repeat steps 16 to 48 as described for film screen 1 except:
WHEN CALIBRATING THE 75 KV KNEE BREAKPOINT FOR FILM SCREEN 3, DO
NOT ADJUST THE AEC BOARD GAIN POT. DOSE ADJUSTMENTS MUST ONLY BE
MADE BY VARYING THE BREAKPOINT CALIBRATION NUMBERS.
FILM SCREEN 3 MUST BE THE HIGHEST FILM SPEED.
3D.6.0 SHORT AEC TIME COMPENSATION (IF APPLICABLE)
Step
Action
SECTION 3D.6.0 ONLY APPLIES FOR AEC BOARDS WITH SHORT AEC
EXPOSURE TIME COMPENSATION (FIGURE 3D-9 OR 3D-11)
IF AEC
EXPOSURES LESS THAN APPROXIMATELY 15 MS ARE REQUIRED
.
1.
Select the image receptor to be short AEC time compensated, ie table bucky.
2.
Select the highest film speed used on the selected receptor, then select the 75 kV
breakpoint.
3.
Set the mA per table 3D-13 for the film speed being used. Reinstall the absorber as per
table 3D-13 for the 75 kV breakpoint.
4.
Make an exposure and confirm the dose (or mAs) readings as previously recorded in
table 3D-14.
5.
Reduce the absorber thickness such as to decrease the AEC exposure time to
approximately 10 ms.
6.
Adjust the short AEC time compensation pot for the AEC channel being calibrated such
that the dose (or mAs) is approximately the same as previously recorded (step 4). The
short AEC time compensation potentiometer designations are given in table 3D-11.
