Tube Voltage; Tube Current; Dead Man" Function; X-Ray Tube Protection - Gendex ORTHORALIX 9200 Service Manual

A.5.4.8

Tube voltage

The kV range is 60-84 kV, with steps of 2 kV.
For legal / homologation requirements, in certain countries
the kV range can be restricted to:
max kV value = 80
via internal firmware configuration (see Section F of this
Service Manual, Service Programs paragraph).
The high tension converter includes the following chain of com-
ponents: rectifier, filter, regulating chopper, inverter, high tension
transformer.
The chopper unit operates at high frequency with the PWM prin-
ciple, providing modulation of the DC supply to the inverter unit,
depending on the kV selected by the operator.
The high tension transformer is driven by the impressed current
inverter, operating at high freqeuncy with fixed duty factor.
The high voltage is monitored by means of a voltage divider built
into the high tension transformer, which provides direct feedback
to the control loop circuit of the converter.
For measurement and accuracy details please refer to section D.
A.5.4.9

Tube current

The mA range is 3-15 mA, with steps of 1 mA.
For legal / homologation requirements, in certain countries
the mA range can be restricted to:
via internal firmware configuration (see Section F of this
Service Manual, Service Programs paragraph).
The power to the filament is controlled by a separate impressed
voltage inverter, operating at high frequency with variable am-
plitude and fixed duty factor.
The filament is continuously preheated when the equipment
is switched on, and additionally heated-up for 0.8 s before the
exposure is initiated.
For details about measurement and accuracies refer to section D.
A.5.4.10

"Dead man" function

The exposure handswitch operates in "dead man" function, stop-
ping exposure and movements as soon as the X-ray pushbutton
is released.
A.5.4.11

X-ray tube protection

A heat storage calculator continuously checks the thermal state
of the anode, inhibiting X-ray exposure when the maximum
tube load is exceeded. The maximum duty factor is 1:20, giving
a maximum wait time of 4 minutes.
Gendex Dental Systems 4519-190-71193-7
from 4 to 14
Printed on: 20 Apr 2012, 04:59:40 pm; Printed by: UWE.ZELLER
A.5.4.12

Anatomical programs

Both for Pan and Ceph operation modes several sets of pre-pro-
grammed exposure factors are available, selected by patient size
and projection mode keys, and by the film/screen speed setting:
please refer to the Operator's Manual for further information.
A.5.4.13

Exposure time

The exposure time is controlled by the microprocessor.
For the applicable exposure times refer to the table below:
PROJECTION
Standard
Dentition only
Child
Right jaw
Left jaw
Maxillary sinus, frontal view
Frontal dentition
Half orthogonal right/left
Right maxillary sinus, lateral view
Left maxillary sinus, lateral view
TMJ lateral view, central
TMJ lateral view, external
TMJ frontal view
Transcan
Transcan DDE
Ceph (selectable)
Ceph DDE:
LL max / AP max / PA max / LL H
Ceph DDE
AP V / PA V / LL V:
For measurement and accuracy details please refer to section D.
A.5.4.14

Back-up timer

If the supply to the tubehead is not switched off by the main timer
after completion of the preset exposure time, a back-up timer will
terminate the X-rays.
The back-up timer operates after the selected exposure time
plus 20%.
The back-up timer circuit is independent from the main timer
circuit and is on the converter board PQ1.
Whenever the back-up timer intervenes, a diagnostic message
"BACK UP TIMER" is displayed.
A-9
ORTHORALIX 9200 Service Manual
EXPOSURE TIME (SEC)
12
9.6
11
8
8
6.2
6.4
6
2.5
2.5
8
8
6
4.6
5.2
0.16 - 0.20 - 0.25 - 0.32 -
0.40 - 0.50 - 0.63 - 0.80 -1.00 -
1.25 - 1.60 - 2.00 -2.50
8
6
(06.0)E