C-Arm Interface Board; Continuity Daisy Chain; Power - Hologic QDR 4500 Technical Manual

C-ARM INTERFACE BOARD

The C-Arm Interface board distributes DC power and signals to the Data Acquisition System
(DAS) and provides control electronics for the devices located in the C-Arm assembly. It passes
several signal and power lines from the Distribution board directly to the DAS. It also provides
buffering for various signal lines. The C-Arm Interface board is located near the rear of the C-
Arm's horizontal shelf.
Note: The Data Acquisition System (DAS) consists of the Analog to Digital Converter,
Integrator/Multiplexor, and Solid State Detector boards.
The C-Arm Interface provides circuitry to:
Control and monitor operation of the X-ray Controller board. Four LEDs (two red, one
green, and one yellow), on this board, provide visual indication of the status of the X-Ray
Controller and the X-ray control circuitry of this board.
Generate timing references to the DAS and Communications Controller.
Control power to the Positioning laser.
Actuate the Aperture stepper motor and monitor its mechanically linked position sensing
device.
Actuate the stepper motor of the Reference Drum device and monitor the encoded signals
returned from each drum of the device. Two green LEDs, on this board, provide visual
indication of the Reference Drum operation.
Generate +7VDC for the DAS system.

Continuity Daisy Chain

The C-Arm Interface board is part of two linked chains of boards. Removing any of these boards
conveys an alarm message to the host computer indicating that the electrical integrity of the
system is compromised. The message can be decoded by the host computer to detect the extent of
the damage.

Power

The C-Arm Interface board receives +28, +24 and +/- 15VDC from the Distribution board. The
+ 28VDC powers the Aperture and Reference Drum stepper motor driver circuitry. The +/-15V
is passed through this board to the DAS. The +24VDC is reduced to +5 and +7VDC. The
+5VDC powers the digital section of this board and the laser while the +7VDC is applied to the
DAS.
Three green LEDs, on this board, provide visual indication of the +28, +24 and +5VDC power
(ON indicates the respective voltage is present).
Section 2 - Functional Description
2-15