APX 525/625 Generator Revision C Diagnostics
©
2005 Del Medical Imaging Corporation
7/5/2005 Page 176
Selection data for mAs, commutation capacitors, and AEC settings are streamed
from the Data Board to the mAs Board (124-0145G1). AEC data is then streamed on
through the mAs Board to the AEC Main Board.
When an exposure is taking place, the mAs Board sends a stream of mAs pulses
back up to the CPU Board in the Operator’s Console, which are used to provide an
indication of the mAs of the last exposure. When an exposure has reached the
desired mAs, an exposure stop signal is sent from the mAs Control Board to the
Logic Board, terminating the exposure. The actual measurement of mAs will only
begin to take place when a signal is received from the kV Regulator Board,
indicating that the kV has reached 75% of its selected value.
During exposures, the kV Regulator Board and the mA/Rotor Board monitor and
control the high voltage, tube current, and filament current in the system, and send
back fault signals to the Logic Board, if an error is detected. Either of these fault
signals will automatically terminate an exposure. The Logic Board will then report the
fault to the CPU Board, which will latch the error and inhibit any further exposures
without operator intervention.
In the AEC mode, exposures are photo timed and terminated by the AEC Main
Board, which sends an exposure stop signal to the Logic Board. Generator backup
faults are reported by the AEC Main Board to the CPU Board through the hardwire
interface.
PREP / PREP READY Cycle: (see illustration X2)
The /PREP REQUEST (LOW TRUE) is decoded from serial data at the Data Board
and sent to the Logic Board (124-0096G1). The PREP Request is then activated on
the Logic Board. A simple RC network between two of the gates of IC8 creates a self
canceling PREP state that will remain active for no longer than 20 seconds or
whenever the operator releases the PREP button on the operator’s console. The
/PREP output from the Logic Board is then sent to several other boards in the
system.
• On the mAs Regulator Board
, the PREP Command is used to clear and reset
the mAs counters.
• On the I/O Board
, IF the thermal interlock of the x-ray tube is closed THEN
the PREP command will close the K3 relay AND initiate the Rotor Boost and
Run signals to the Logic Board, which will then activate the K2 and K1 relays
in alternate sequence to provide the Boost and run voltages to the x-ray tube
stator.
• On the mA/Rotor Board, the PREP Command activates one of four preheat
adjustment potentiometers, based upon the selected combination of x-ray
tube and focal spot. The selected potentiometer is used to fine tune the
filament preheat reference voltage, in order to compensate for slight
differences found in individual x-ray tube filaments.
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