Rockwell Automation 57C610 Enhanced Basic Language, AutoMax - Manual (Page 24)

4Ć4
4.1.1.4 Boolean Variables
A boolean variable is a named location which represents a
TRUE/FALSE or ON/OFF value. It is named using the rules listed in
section 4.1.1 and terminated with an at" symbol (@).
The following are valid boolean variable names:
REEL_EMPTY@
OVER_TEMP@
TURRET_ENGAGED@
The following are invalid boolean variable names and the reasons
that they are invalid:
SYSTEM_READY (Variable not terminated with @)
WEB_FULL@@ (Two @s backĆtoĆback are illegal)
4TH_READY@ (Variable starts with a digit rather than
Ăa letter or an underscore)
As with integer and real variables, boolean variables form
expressions. With boolean variables you use the boolean operators
NOT, AND, OR, and XOR and boolean constants TRUE, FALSE, ON,
and OFF in forming these expressions:
LINE_DOWN@ = NOT(POWER@ AND RUN@)
RUN _REQUEST@ = TRUE
SECTION_ POWER@ = FALSE
CRT _REFRESH@ = OFF
IF RUN@ OR (STOPPED@ AND FAULT@) THEN 1350
Refer to section 5.3 for more information about boolean
expressions.
4.1.1.5 String Variables
String variables are used to store any alphanumeric sequence of
printable characters, including spaces, tabs, and special characters.
The terminating character is $.
The sequence in a string variable cannot include a line terminator
(<CR>). When defined, the sequence must be enclosed either in
single or double quotes. If one type of quotes is used in the
sequence itself, the other type must be used to enclose the
sequence.
Version 1.0 Executive software allowed a fixed maximum length of
31 characters for string variables. Version 2.0 and later allows string
variables of variable length, from 1 to 255 characters. To specify the
maximum size of a string variable, add a colon and a number
(1Ć255) immediately after the $ character. For example, defining
A$:50 as a local variable in an application task will reserve space for
50 characters. Note that if no length is specified, the default length
is 31.
4.1.2 Subscripted Variables (Arrays)
Array variables are used to store a collection of data all of the same
data type. Arrays are permitted for all data types. Arrays are limited
to four dimensions, or subscripts. The number of elements in each
dimension is limited to 65535. This size is further limited by available
memory. The term array is used to denote the entire collection of
data. Each item in the array is known as an element.