2.8 Aec Board (Universal Aec Board With Short Aec Time Compensation) - CPI Indico 100 Series Service And Installation Manual

CPI Canada Inc.
3D.2.7 AEC Board (Universal AEC Board) Cont
R10, R19 and R24 adjust the output voltage from the high voltage power supply on the AEC interface board
(the upper board on the universal AEC board assembly in figure 3D-10 and 3D-11). This high voltage supply
generates the PMT high voltage, up to approximately -1000 VDC available at J7, and also the nominal +500,
+300 and +50 VDC supplies noted in table 3D-8. The +500, +300 and +50 VDC supplies are available to bias
ion chambers if needed and are adjustable as defined below.
These potentiometers are switched into the circuit electronically by logic circuits connected to the
AEC channel select commands. Only one potentiometer will be active at any given time, the condition under
which each potentiometer is active is described below, along with the function of that potentiometer.
•
R10 adjusts the high voltage supply output for the PMT when ABS operation is selected. This is
described in chapter 3E.
•
R24 adjusts the high voltage supply output when AEC channel 1, 2, or 3 is selected. AEC channels 1, 2,
3 are normally used with an AEC chamber.
R24 will be used to adjust the +500, +300 and +50 VDC bias voltage outputs if required for ion
chamber(s) connected to AEC channels 1, 2 or 3.
•
R19 adjusts the high voltage supply output when AEC channel 4 is selected. AEC channel 4 is normally
used for digital acquisition or spot film work using a PMT pickup for AEC control. This will typically be the
same PMT used for ABS control during fluoroscopy operation.
Refer to 3D.2.9 for further details if using a PMT for AEC control on AEC channel 4.
3D.2.8 AEC Board (Universal AEC Board With Short AEC Time Compensation)
The AEC board shown below has short AEC time compensation, and is factory configured to be compatible
with most makes/models of AEC chambers (ion and solid state) on the market. This assembly also contains
a low current, high voltage supply for a photomultiplier tube (PMT). The PMT supply is located on the upper
board, which also contains the connectors to interface to the AEC pickup device(s).
Figure 3D-11: Universal AEC board with short AEC time compensation
Millenia / Indico 100 Series Service Manual Ch # 740904-06 Rev. D
3D
AEC Calibration
Page 3D-19