MN00178
1359
SECTION III THEORY OF OPERATION
General:
This manual provides information expected to be used in installing, adjusting, and operating the EXO HD GeminEye™ System.
OVERVIEW
The EXO GeminEye system is fundamentally different than previous GeminEye models in that it provides streaming video and control through an IP connection. Unlike
previous models, there is no serial communication method, and there are no analog video outputs.
Each camera housing has a video server, also known as an encoder, which converts the video directly from the camera to streaming internet video. The two RJ45 IP con-
nectors on the cable are connected directly to the encoder, and provide the pathway for both video and control. The video for the visible camera is on the cable labeled
"Camera 1", and the video for the thermal camera (if equipped) is on "Camera 2". Both encoders in a two camera GeminEye have a separate control signal path to control
and position the GeminEye, and either encoder can control and position the unit.
The center section camera positioning system consists of stepper motors with their respective motor drivers controlled by a power supply and logic circuit boards. The unit
is powered by 10 to 30 VDC. Control communication from the encoders is processed on the logic circuit board, providing control and status information on the command
signal. Also connected to the control board are two positions sensing optical boards (one for the pan axis of motion, and one for tilt); these are referenced during a power
up condition to determine position of the system. During the power up cycle, the GeminEye will move to determine its position, and once the sensors are read, the unit will
return to the centered position.
LOGIC CONTROL BOARD
The logic control board is located inside the pan & tilt cabinet in the front heat sink. The control board processes all communication, and position information.
OPTO POSITION DETECTORS
There are 2 detection circuits used for detecting position and dynamic re-calibration. The pan uses a 4 channel optical system to read absolute sector position (16 sectors
of 22.5 degrees) and 17 transition points of pan movement. These are encoded using reflected binary code for absolute sector position. The tilt uses a 2 channel optical
system to read absolute sector position (4 sectors of 45 degrees) and 3 transition points. The positioner recalibrates "on the fly" when moving "right" and "down" directions.
The system counts motor pulses to the stepper motors to define position. Each micro step is equal to 0.01 degrees of movement in both the pan and tilt axis. These are
readout in 0.01º increments. If for any reason, the system is stalled during motion; the microcontroller will know what sector the system is in and will recalibrate the system
if sufficiently out of calibration.
DRIVE SYSTEM
The drive system consists of:
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Two 0.9º stepper motors, each driven by a 16x micro step motor driver.
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A high torque timing belt drive system with a 5.625:1 mechanical reduction ratio
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The motor drivers generate a holding current which holds the motors in position when they are not being commanded to move.
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The dual camera system uses 3 ball bearings, 3 thrust bearings, 3 rotary seals, 2 timing belts, and drive pulleys.
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The stepper motor drive circuits divide each 0.9º step of the motor into 16 microsteps, providing for very fine motion control, with each microstep equating
to 0.01 degree of movement. The QuickShift® technology introduces an additional division of speed, changing the speed range for pan and tilt independently.
This allows a very wide dynamic range of speeds from fast to extremely slow movements.
COMMUNICATIONS & CONTROL BOARD
All communication to the EXO GeminEye model is through a Moog Video encoder, which is an IP connection only. There is one video encoder for each camera module, and
either can provide motion control of the positioner.
