Rockwell Automation 57C610 Enhanced Basic Language, AutoMax - Manual (Page 17)

3Ć1
3.0 STRUCTURE OF AN
AutoMax ENHANCED BASIC
PROGRAM
BASIC programs, or tasks, are created using a text editor.
Note the following naming convention. Application task names in
AutoMax are limited to 8 characters. The initial character must
always be a letter. Following the initial character can be letters (AĆZ),
underscores (ă), and numbers (0Ć9). Spaces and other characters
are not permitted. The file extension is used to identify the task.
Extension .CNF identifies configuration tasks. Extension .BAS is
used for BASIC tasks. AutoMax Control Block tasks use extension
.BLK. UDC Control Block tasks also use extension .BLK. PC/Ladder
Logic tasks have a .PC extension.
An AutoMax Enhanced BASIC program consists of a set of
statements using certain language elements and syntax (rules for
the form of each statement). Each line begins with a number that
identifies the line as a statement and indicates the order of
statement execution. Each statement starts with a word specifying
the type of operation to be performed, such as PRINT, GOTO, and
READ. For a BASIC program to compile correctly, all text except
print list items delimited by quotation marks must be in upper case.
The following symbols have special meaning for the duration of this
manual:
<CR> =
Carriage return, sometimes marked RETURN" or
ENTER" on keyboards. You should assume that
all BASIC statements end with a <CR> unless
otherwise noted. Some statements used in
examples may explicitly use the <CR> notation at
the end of a statement to make the example easier
to understand.
_ = Underscore character used to make variable
names more readable (for example,
MOTOR_SPEED, LINE_REFERENCE).
Note that the underscore is not a dash or minus character, which
appears on the same key as the underscore on most standard
keyboards.
3.1 Line Format
The format of a statement in a BASIC program is as follows:
line statement statement line
number keyword body terminator
10 LET SPEED%=(GAIN%+3) <CR>
The line number is a label that distinguishes one line from another
within a program. Consequently, each line number must be unique.
The line number must be a positive integer within the range of 1 to
32767 inclusive.
Line numbers are required for the following reasons:
1. To determine the order in which to execute the program.