Rockwell Automation 2708-NBD VBASIC Language Development Kit - Manual (Page 38)

A–B
5
Chapter
5–1
A-B VBASIC Application Library
The BASIC Language Development Kit (Catalog No. 2708-NBD) consists of
a set of BASIC source files which you may use to decrease your
development time and enhance the quality of your A-B VBASIC
applications.
Note: Subroutines for the A-B VBASIC Application Library can be found in
Appendix C of this manual.
The core of the library is the module ENV.BAS.
ENV.BAS provides a set of I/O routines for access to the workstation devices
such as the bar code port, comm ports, network, and so on. Since virtually all
workstation applications are driven by external events from multiple devices,
ENV provides a simple mechanism for reading from more than one I/O
device at once with timeouts.
In order to speed developoment on IBM PC compatible computers, we have
provided a second library of subroutines (ENVPC.BAS) with names identical
to those in ENV.BAS, but which use standard PC devices to emulate
2708-DH5XX workstations. This allows testing of A-B VBASIC
applications under MicroSoft’s Visual BASIC. ENVPC allows you to
simulate input from slot readers, comm ports, and the network all on your
development PC without needing an actual workstation.
READ.BAS provides a library of field oriented I/O subroutines. You may
read string fields, autoexit fields, numeric fields, secured (password) fields,
and fields with default values using the routines. The FORMEX.BAS
example program demonstrates forms style entry using READ.BAS.
MENU.BAS subroutines allow you to create visually oriented selection
menus for easy-to-use application programs. This is also demonstrated by the
example program FORMEX.BAS.
The IOTEST directory contains examples for A-B VBASIC Low Level I/O.
Scientific math support for process control applications is provided with
MATH.BAS, TRIG.BAS, and HYP.BAS.
Introduction