Villa Rotograph EVO, Руководство по обслуживанию

Страница: 29 / 223

SERVICE MANUAL
Description
Rotograph EVO (Rev. 1) 3-10
3.3.2. CPU Board (A5 and A6)
It is located in the arm movement assembly on top of the unit.
Main tasks are:
•
General controlling of the unit, receiving the signals from the
keyboard and from the different microswitches.
• Driving of the 3 stepper motors which compose the system.
•
Monitoring the functioning of the motors through the analysis of the
signals coming from the positioning sensors.
• Driving of the HF group (Generator board and tubehead) in order to
provide the X-ray doses set by the operator on the keyboard (kV and
mA set point) and in the meantime, check the functioning of this
group through the managing of the relevant alarm signals.
• Activation of the 2 luminous centering devices.
• Managing of the alarms that can be generated by anomalous
conditions present in the unit and caused by the operator or by a
fault. These signals are sensed by the local CPUs and signalled using
specific CANBus messages.
The CPU board is based on a 32 bit Motorola Microprocessor MCF5232,
mounted on a piggy-back PCB (A6), which also includes the Flash
EPROM, the RAM and other logic and passive components.
The CPU board also includes a number of input/output channels
necessary for the functioning of the system and 3 stepper motor driving
stages based on integrated motor drivers. Each of these motors is
associated to positioning sensors that monitor their functioning. The
signals of these sensors are fed back to the CPU board.
The number and the type of sensors depend on the function of each
motor. In general, optical switches are used.
Depending on the physical location of the motors on the machine, their
signals and the ones of the relevant positioning sensors are routed
directly to the CPU through dedicated cables, or passing through
interconnection boards located nearby.
The transmission of the motion from the motor to the relevant movement
assemblies is achieved through toothed belts (rotation motor, Y axis
motor and cassette holder motor) or through actuators (column motor),
while the rotating collimator is mounted directly on the motor shaft.
The functioning of the different motors and relevant positioning sensors
can be tested through the use of the Service Programs (Passwords). For
more details, please refer to paragraph 8.3.
The circuits of the CPU board are supplied starting from the +24Vdc
(LED H12) provided by the Power supply assembly and generating on
board the requested voltages (+5V, +3.3V and +1.5V). Three LED's on the
board indicate the presence of these 3 voltages (+5V=LED H2, +3.3V=LED
H3, +1.5V=LED H5).