Lens Control Modes; Servomotor Mode; Motor Mode; Pan And Tilt Control - AMX AXB-PT15 POSITRACK CAMERA CONTROLLER Instruction Manual

Lens Control Modes

The Servomotor and Motor modes are two Analog Voltage Control methods available on the
PosiTrack units.

Servomotor Mode

This method is generally used in broadcast or videoconference-style lenses. The voltage range used
for servomotor style lenses is +2.5 to +7.5 VDC. These lenses can be controlled in two different
modes: positional mode and speed mode.

Motor Mode

Motor mode is used when the lens requires the motors be directly driven from an external source.
The standard voltage ranges are ± 6 VDC or ± 12 VDC with a center (no motion) of 0 VDC. Unlike
servomotor lenses, these only operate in speed mode.
The lens moves in relation to the voltage offset from zero. The farther the voltage moves away from
the center point, the faster the lens motor moves. The lens must have POT outputs when recalling a
preset in this mode, these outputs are then passed to the PosiTrack unit. When the received voltage
level matches the level stored in the preset, the voltage returns to zero. Motor mode lenses not
having POT outputs do not have preset recall capability.

Pan and Tilt Control

Presets and travel limit stops are based on encoder counts from a home position index, located at
the center of each axis' range of motion.

Zoom, Focus, and Iris Control

Each PosiTrack unit delivers a low voltage pulse-width-modulated output for zoom, focus, and iris
functions for motor mode lenses. These units are also capable of receiving reference voltage rails
and sending zoom, focus, and iris control signals in response to these rails. In this setting
(slide-switch configured), no active control signals will reach the lens before power (+ 12 VDC and
GND) is supplied to the lens. This motor mode applies to the control of the Fujinon and Canon
teleconferencing lenses. During preset recall operation, these outputs are synchronized with the pan
and tilt motions.
AXB-PT15 PosiTrack Camera Controller
Positional mode is the most common Servomotor mode. When voltage changes, the lens
moves and remains still until the voltage changes again. For example, if a lens receives a
voltage of +3 VDC, the lens moves to the corresponding position and stays there as long
as the voltage remains at +3 VDC. The movement speed of the lens motor is a function of
the PosiTrack unit's analog output. The lens servomotor receives the preset voltage when
a preset is recalled in the positional mode.
Speed mode moves the lens when the voltage deviates from the center point of its range.
The farther the voltage moves away from the center point of reference, the faster the lens
motor moves. The lens must have POT outputs when recalling a preset in this mode,. The
outputs pass to the PosiTrack unit, and when the received voltage level matches the level
stored in the preset, the voltage returns to zero. Servomotor speed mode lenses not having
POT outputs do not have preset recall capability.
Introduction
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