4
Chapter 2
Overview
2.1
Introduction
The BSC201 single channel APT Stepper Motor Controller is the next generation of
enhanced controllers using the familiar APTUser interface. Many new fe atures are
provided, including a choice between trapezoidal and S-shaped velocity profiles, a
higher theoretical microstep resolution (409600 for a 200 full step motor) and speeds
more than twice that achieved by its predecessors.
The apt stepper motor controller is supplied with a full suite of software support tools.
An intuitive graphical instrument panel allows immediate control and visualization of
the operation of the stepper controllers, and any other controllers that are installed in
the system. See Chapter 5 for a full description of the apt system software.
Fig. 2.1 APT Single Channel Stepper Motor Controller (BSC201)
Stepper motors g ive excellent low speed performance and po sitioning 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