9600 Service Manual - gmecorp-usa.com

Image System 25
CAMERA ROTATION MOTOR
The operator drives the camera rotation motor by pressing the desired key on the control
panel. The Technique Processor receives this information from the Control Panel
Processor PCB and communicates it via U17 to microcontroller U16 on the Image
Function PCB. U16 in turn communicates over its data bus to U11, the Motor Driver PLD
(programmable logic device). U11 then enables and drives the rotation motor in the
desired direction via U3, the motor driver IC for the camera. See Table 8 and Figure 16
for details of the drive logic.
The rotation motor physically rotates the prism optics assembly inside the camera to
achieve the image rotation. One degree of optics rotation will accomplish two degrees of
image rotation. The camera motors are not PWM driven like the collimator motors due to
the potential for noise in the high gain camera circuits. Motor driver U3 on the Image
Function PCB supplies direct current to the camera motors.
The potentiometer linked to the rotation motor is provided with a +10V supply from
voltage regulator U1 on the Image Function PCB. As the camera rotation motor turns,
the voltage signal (CAMERA _ROT_WIPER) from the wiper of the potentiometer will
vary between 0 and 6.8 VDC. This voltage is routed to sample mux U3 on the Analog
Interface PCB.
It is then converted to a digital value and the Technique Processor communicates this
information via serial communications to the image processor on the Workstation. The
image processor uses this information to generate the position of the camera rotation
icons on the left monitor of the Workstation.