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T-Cube Position Aligner
4.5.6
Using the Target Display
The ‘target’ display shows the horizontal and vertical position of the laser beam within
the detector sensor array. When used in conjunction with the display on the piezo
cubes, it can also be used to show when the piezo actuators are near the ends of their
travel and need re-centering. This will require manual adjustments to the turning
mirror actuators.
For example, consider the situation shown below, when the unit is in open loop mode
and the red LEDs are lit. This indicates that the laser beam is in the upper right hand
quadrant of the detector array. Let’s also assume that the piezo drivers controlling the
piezo mirror show around 10V.
Fig. 4.11 TARGET and VOLTS Displays Showing Values Near Travel Limit
When the unit is switched to closed loop mode, the amber LEDs light up, as the piezo
units drive the piezo mirror to reposition the laser beam.
Fig. 4.12 Repositioning the Laser Beam
But the piezo units now show 0V which means that the piezos are at the limit of their
travel and cannot drive the piezo mirror further. The piezo actuators must be
recentered (i.e. OUTPUT pot adjusted for 37.5V display), and the position error taken
up by manual adjustment.
1) Press the MODE button on the position aligner to select ‘Open Loop’ mode.
