Quantum ODYSSEY HF Series User Manual

Chapter 4 Theory of Operation
HF Series X-ray Generators - Service Manual Revision W
Quantum Medical Imaging 4-17
chamber and the detectors within the selected ion chamber. The AEC board
receives the voltage input from selected ion chamber, and processes the sig-
nal. The processed signal is compared continuously with a set reference volt-
age produced by KVP Board A2 AY40-003S. The reference voltage is a
function of kVp and the film/screen combination type. When the processed
signal is equal to the reference voltage, the exposure is terminated.
The AEC Board A11 AY40-031S "fine" gain adjustment potentiometers are as
follows:
• A11R22 Table gain adjustment
• A11R23 Wall 1 gain adjustment
• A11R24 Wall 2 gain adjustment (currently not used)
The above potentiometers provide fine gain adjustments for each of the ion
chamber detectors, coarse gain adjustment is performed by adjusting the
MASTER GAIN potentiometer located on the ion chamber. A11R12 provides
AEC dV/dT adjustment as described in the AEC calibration instructions in
Chapter 3. The following major test points and a brief description are:
• TP1- Wall 1 input from ion chamber
• TP2- Wall 2 input from ion chamber
• TP5- +15V supply to ion camber
• TP6- -15V supply to ion camber
• TP7- Table input from ion chamber
• TP9- Inverted polarity slope of selected ion chamber signal
• TP12- AEC output to KVP board
Universal Type AEC
The "universal" AEC Board A11 (AY40-027S) has the capability to work with
two ion chambers (four in the future), and provides necessary interface to
connect to the Siemens tomography system (or any other tomography sys-
tem having similar hand-shake protocol as Siemens). The universal AEC
Board is capable of working with ion cambers that have different type of out-
puts (Slop / Level), polarity (Positive / Negative), or logic levels. (active low,
active high.) The ion chamber configuration/ setting can be set through
setup menus in the calibration setup mode. The settings options to ion cham-
ber type that can be programmed are:
• Ion chamber cell selection
• Type of the ion chamber output slope/level
• Polarity of the AEC output signal
• The level of ion detectors selection signal (active low/active high). The
ion chamber ON (Reset) is always active low.

Quantum ODYSSEY HF Series Specifications

General

Brand	Quantum
Model	ODYSSEY HF Series
Category	Medical Equipment
Language	English