3D
AEC Calibration
CPI Canada Inc.
Page 3D-16
Rev. D Millenia / Indico 100 Series Service Manual Ch # 740904-06
3D.2.6 AEC Board (Ion Chambers) Cont
The following potentiometers are used for short AEC exposure time compensation:
•
R11 is used for channel 1 short exposure time compensation.
•
R12 is used for channel 2 short exposure time compensation.
•
R13 is used for channel 3 short exposure time compensation.
•
R14 is used for channel 4 short exposure time compensation.
R79 adjusts the output of the high voltage bias supply. This is only fitted on versions of this board intended for
use with ion chambers which require a separate high voltage bias supply. R79 adjusts the value of the +300
and/or the +500 and the +45 VDC outputs, and should be set as per the ion chamber manufacturer
specifications.
The following tables show the pinouts for both the 15 pin D connectors and for the 12 pin in-line connectors
on the AEC board in figure 3D-9.
FUNCTION PIN
NOTE
+300 or +500 VDC output
1
+500 and/or +300, and +45 VDC outputs are
provided on configurations of this board
Not used
2
designed to interface to ion chambers requiring
Right field select
3
these voltage outputs only. Pin 1 will be wired
Start command output
4
to 300 VDC OR +500 VDC, as per the
+45 VDC output
5
AEC chanber requirements.
-24 VDC output
6
Signal input
7
Ground 8
Not used
9
Not used
10
Left field select
11
Middle field select
12
Ground 13
+12 VDC output
14
-12 VDC output
15
Table 3D-6: Pinouts for 15 pin D connector
FUNCTION PIN
NOTE
+500 VDC output
1
+500, +300, +45 VDC outputs are provided on
+300 VDC output
2
configurations of this board designed to
+45 VDC output
3
interface to ion chambers requiring these
+12 VDC output
4
voltage outputs only.
-12 VDC output
5
-24 VDC output
6
+12, -12, -24 VDC outputs are typically used as
Ground
7
the DC supply for a pre-amplifier, often part of
Start command output
8
the ion chamber.
Left field select
9
Middle field select
10
Right field select
11
Signal input
12
Table 3D-7: Pinouts for 12 pin in-line connector
