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HA0277T Rev H Dec 2016
Chapter 2
2.2.4
APT Server (ActiveX Controls)
ActiveX Controls are re -usable compiled software components that supp ly both a
graphical user interface and a pro grammable interface. Many such Co ntrols are
available for Windows applications development, providing a large range of re-usable
functionality. For example, there are Controls available that can be used to
manipulate image files, connect to the intern et or simply pro vide user in terface
components such as buttons and list boxes.
With the APT system, ActiveX Controls are deployed to allow direct control over (and
also reflect the status of) the range of electronic controller units, including the BSC201
stepper motor controller. Software applications that use ActiveX Controls are often
referred to as 'client applications'. Based on ActiveX interfacing technology, an
ActiveX Control is a l anguage independent software component. Consequently
ActiveX Controls can be in corporated into a wide range of softwa re development
environments for use by client application developers. Development environments
supported include Visual Basic, Labview, Visual C++, C++ Builder, HPVEE, Matlab,
VB.NET, C#.NET and, via VBA, Microsoft Office applications such as Excel and Word.
Consider the ActiveX Control supplied for the BSC201 APT stepper controller unit.
This Control provides a complete user graphical instrument panel to allow the motor
unit to be manually operated, as well as a complete set of software functions (often
called methods) to allow all parameters to be set a nd motor operations to be
automated by a client application. The instrument panel reflects the current operating
state of the controller unit to which it is associated (e.g. such as motor position).
Updates to the p anel take place automatically when a user (client) application is
making software calls into the sa me Control. For example, if a client application
instructs the associated stepper motor Control to move a motor, the progress of that
move is reflected automatical ly by changing position readouts on the graphical
interface, without the need for further programming intervention.