THORLABS BSC202, Руководство пользователя

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6 HA0278T Rev H Dec 2016
Chapter 2
Stepper motors give excellent low speed performance an d positioning stability
compared with DC servo motors. A wide range of 2-phase bipolar stepper motors and
associated actuators are commercially available, each with its own characteristics,
such as step resolution, peak phase current or voltage, and lead screw pitch. For this
reason the apt™ stepper unit operation is fully configurable (parameterized) with key
settings exposed through the associated graphical interface panels.
Motor step resolution, and lead screw pitch can be set for a particular motor/actuator
combination, phase currents can be limited to suitable peak powers as required, and
limit switch configuration is accommodated through a flexible set of limit switch logic
settings. Moreover, relative and absolute moves can be initiated with move profiles
set using velocity profile parameters. Similarly, home sequences have a full set of
associated parameters that can b e adjusted for a particular stage or actuator. Fo r
simplicity of operation, the apt™ software incorporates pre-configured settings for
each of th e Thorlabs stages an d actuators, while still exp osing all parameters
individually for use with other stepper motor driven systems.
For convenience and ease of use, adjustment of many key parameters is possible
through direct interaction with the graphical panel. For example a move to the n ext
position can be initiated by clicking directly on the position display and entering a new
value (see the tutorial in Chapter for further details). Furthermore, all such settings
and parameters are also accessible through the ActiveX® programmable interfaces
for automated alignment sequences.
The apt™ stepper unit also supports encoder feedback through dedicated quadrature
encoded pulse (QEP) inputs, one for each channel of operation. Through conversion
routines, the apt™ software is able to use this feedback signal to generate encoder
position for access either through the GUI or via programmable interfaces for custom
closed loop algorithms. A “built in” a lgorithm can be enabled to allow the stepper
system to reach and maintain an encoded position through an iterative move
sequence. Please see the APTServer on line helpfile or the handbook supplied with
your linear encoded stage for further details.
In the remainder of this handbook, the Tutorial section (Chapter ) provides a good
initial understanding on using the unit, and the reference sections (Chapter 5) covers
all operating modes and parameters in detail.