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Chapter 2
Overview and Setup
2.1
Introduction
The TPA101 beam position aligner T-Cube is designed to work with the Thorlabs PDP
and PDQ series detector heads. As a member of the T-Cube family of controllers this
unit benefits from a unified ActiveX software interface, USB connectivity, very
compact footprint and compatibility with the T-Cube Hub System. It is particularly
useful in laser beam alignment, position monitoring and beam stabilization
applications.
The detector head outputs signals that sense the position and intensity of the light
beam hitting the photo detector array. The TPA101 allows monitoring of these signals
and gives a visual indication of the position of the beam, both via the top panel LED
display and the software Graphical User Interface (GUI).
The unit features three main operating modes - Monitor, Open loop and Closed loop.
In Monitor mode, the unit outputs the XDiff, YDiff and Sum signals from the detector
array for use in a monitoring application. In open loop the XOut and YOut position
demand output signals can be turned off, to allow the mirrors to be positioned
manually.
This position aligner T-Cube also benefits from a closed loop mode. In closed loop
operation the unit can be configured to drive out a pair of position demand analog
signals. In typical applications these signals can be used to control the positioning of
a motorized or piezo driven turning mirror in an optical system. The DSP processor
within the unit runs two independent feedback loops, one for each axis of the detector
head. These feedback loops attempt to zero out the X and Y difference signals by
manipulating the position of the turning mirror to centre the beam on the quad detector
head. Full PID parametisation of these feedback loops allow the system to be tuned
to a wide variety of beam alignment applications. Furthermore, it is possible to
configure 2 TPZ001 piezo T-Cubes as slave amplifiers in order to drive piezo products
such as the KC1-PZ mirror mount and PGM100 piezo gimbal mount.
Fig. 2.1 T-Cube position aligner (shown without base plate fitted)
