Canon CXDI-80C, Service Manual

Page: 71 / 164

2. Installation procedures
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38
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7.3.2 Signals and their functions for connection with the X-ray generator
<X-ray sync signals>
Signal Description of function
RX_REQ
X-ray exposure signal
This signal indicates that the X-ray exposure command has been issued at
the X-ray generator.
The signal must be held for at least the T
PREP
period.
If it is held less than the T
PREP
period, the X-ray release signal
(RX_COM) will not be output. If RX_REQ has been negated during this
period, approximately one second will be required in a worst-case
scenario until operation is enabled again.
Time taken for RX_COM to be asserted after RX_REQ has been received
from the X-ray generator:
T
PREP
………………………………………………min.0 max.300ms
Since the images taken are read from the sensor using the RX_REQ
negation (or RX_COM timeout) as the trigger, the RX_COM timeout will
serve as the trigger if RX_REQ is not negated. This means a delay in the
start of reading and, as a result, it also means a delay in the image display
timing.
It is recommended that the specifications call for RX_REQ to be
negated in tandem with the completion of X-ray exposure.
Time taken for RX_REQ to be negated after X-ray exposure is
completed:
T
RX_REQ_NEG
…………………………………...min.0 max.100ms
* If this is not satisfied, the image display timing will be delayed.
RX_COM
X-ray exposure enable signal
After the X-ray exposure signal (RX_REQ) has been received from the
X-ray generator, the CXDI system checks whether the preparations for
imaging have been completed, and if they have been completed, it
outputs this signal to the X-ray generator.
Time taken for X-ray exposure after RX_COM assertion:
T
PRE_DELAY
…………………………………….min.0 max.100ms
* If this is not satisfied, the imaging time is reduced.
Time taken for X-ray exposure to stop after RX_COM stop:
T
POST_DELAY
……………………………………min.0 max.100ms
* If this is not satisfied, the images will be adversely affected by shading
and other trouble.