PMX MANUAL
29
118164-001 REV. A
See below the Timing.
Prep
Exposu
re
Ready
AEC
(X-Ray Disable)
X-Ray Enabled
X-Ray Disabled
HSS
STOP
BOOST
RUN
STOP
X-Ray On
Fig 16 - AEC Timing
4.4.3
Smart AEC Exposure
The main character of this mode is that pre-
exposure is followed by the main exposure at
different parameter settings defined by the
system.
This mode has the ability to change
parameters during an “exposure sequence”.
Exposure sequence is defined a number of
Exposures whereby the System gates the
generator ON and OFF by the AEC
Shutdown signal input. The end of each
individual exposure would be normally
terminated by seconds or mAs programming.
In Smart AEC Mode (S-MAC) the exposure is
split into two parts. Both parts of the exposure
are required to use the same filament and
HSS speed, but the kV / mA / exposure time
are allowed to change between the first part
of the exposure and the second part. The
Prep, Exposure Control, X-Ray On (status),
and AEC signals, along with the serial
command port are all involved with Smart
AEC mode. The sequence of events for doing
a Smart AEC exposure is as follows:
1. The host sends the required commands
to set up the exposure. These are HSS
Speed, Filament, kV, mA, and exposure
time for 3 point mode, or Filament, kV
and mAs for 2 point mode. (Note that in
smart AEC, 2 point mode HSS Speed is
automatically set to Fast).
2. The host sets Prep “On”. The unit will go
into the Boost / Preheat phase on the
filament. (See Note 1).
3. The host sets exposure control ON and
AEC control ON to enable X-Rays. AEC
may be set ON before or simultaneous
with exposure control ON.
4. The unit will turn High voltage ON. High
voltage will remain ON until the
programmed exposure time has
elapsed. The host should monitor the X-
Ray On status.
5. After the X-Ray On status transitions
from ON to OFF the Host should set the
AEC control to the X-Ray disabled state
(Low). The host must also leave the
exposure control ON during this time.
6. The host must now send the settings for
the 2
nd
part of the exposure over the
serial interface. Any combination of kV,
mA, exposure time if in 3-point mode, or
kV and mAs if in 2-point mode may be
changed. HSS Speed and Filament may
not be changed.