X-Ray & ABS
9
Manual mA/mAs Control
The manual mA/mAs control key on the X-Ray Control Console allows manual setting of the mA/mAs value by the operator for
film or fluoroscopy. When pressed, the button code is sensed by the X-Ray Console Switch Matrix. The code to increase or
decrease the mA/mAs value is sent to the X-Ray Control Console Interface PCB and is delivered to the X-Ray Control Console
CPU card plugged into the X-Ray Control Console backplane.
The output command from the CPU card via the X-Ray Control Interface PCB is then sent via ARCnet to the Table/Generator
Interface Card.
The mA/mAs change command is then relayed by CAN bus to the Generator Power Module Generic Interface card. This
“standard” interface PCB provides a CAN bus communication line for command signals between the generator and the system.
The Generic Interface card passes the command to the kV Control PCB.
The mA/mAs command is received by the card CPU along with the kV and exposure time commands. When the CPU receives
the exposure enable signal, it calculates the acquisition filament drive to apply to the tube filament to match the required tube mA.
This calculation is based on the filament drive values stored in the tube database and the interpolation required to calculate the
filament drive for the kV and mA point selected manually by the operator. In addition, the CPU takes into consideration a
correction for aging of the filament.
The CPU then calculates the filament boost required and applies a 400 ms boost duration, followed by the acquisition command
to the filament heater function.
The CPU sends a new filament drive to the heater function each 1ms and updates the mA command if it has been changed by
the operator or a generator algorithm (ABS mode, falling load mode, or variable mA mode). The CPU also checks the accuracy
of the mA value.
When the exposure command goes into the inactive state, the CPU either stays with the last filament drive command value, goes
into a preheat mode for the next exposure or stops filament drive to allow filament cooling before preheating starts. The state of
the CPU depends upon the application called for by the operator from the X-Ray Control Console.
Summary of Contents for OEC UroView 2800
Page 19: ...X Ray ABS 19 Service Periodic Maintenance Contents Schematics Illustrated Parts Installation ...
Page 37: ...X Ray ABS 37 Service Periodic Maintenance Contents Schematics Illustrated Parts Installation ...
Page 42: ...X Ray ABS 42 Service Periodic Maintenance Contents Schematics Illustrated Parts Installation ...
