Rockwell-automation 2708-NBD VBASIC Language Development Kit User Manual download pdf (Page 38)

A–B

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

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Rockwell-automation 2708-NBD VBASIC Language Development Kit User Manual Page 38