9600 Service Manual - gmecorp-usa.com

Image System 27
CAMERA IRIS MOTOR
The camera iris motor is driven by software only during boot-up and when the system is
in the Pulsed Fluorography mode (boosted pulse). In this mode, the mA can reach as
high as 40 mA. To accommodate the extra light output from the image intensifier at this
time, the Technique Processor will stop down the iris during the exposure and then open
it back up at the termination of the exposure. During boot-up the software will drive the
motor to ensure the iris is in its fully open position.
The Technique Processor communicates the instructions 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 iris
motor in the desired direction via U3, the motor driver IC for the camera. See Table 9
and Figure 17 for details of the drive logic.
The voltage signal (CAM_IRIS_WIPER) from the wiper of the iris motor potentiometer is
not used at this time.