Xylem System 5000 BASIC Manual - Manual (Page 12)

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The ‘GROUP: Symbol specifies where the Basic Program will appear in the Input/Output menus.
If not specified or listed without a name, the program will be added to a “Basic Programs”
grouping in the menus. The special case of “None” (case-sensitive and without quotes) may be
used to not add the Program to a group but rather list Program alongside the other Inputs and
Outputs. Any other name used will create and add the Basic Program to the given group name.
The Group may also be modified through the Basic Management screen.
The ‘IO: Symbol accepts the following parameters: Input, Output, Serial, and/or Network. Any
combination of the above may be used to declare where this Basic Program will appear in the
menus. If Input is specified, the program will be available as a selectable Input for a Task.
Output allows the program to be added as an Output. Serial and Network allow the program to
be used as a Listening Ports Program, available only to their respective setting. Once a program
has been installed, these settings may be modified through the Basic Management screen.
The ‘VAR: Symbol accepts up to three parameters with comma’s separating them. The first is
the variable name. If the variable name contains a trailing dollar-sign ($), it is treated as a string.
The optional second parameter is the variable’s default value. If a number variable is intended,
no quotes should be placed around the second parameter, however if a string variable is declared
(with a trailing $), the second parameter should have quotations around the specified value. An
optional third parameter may be specified declaring a variable as STATIC. Unlike standard
(local) variables whose values are defined individually for each run of a program, STATIC
variables maintain the same initial value across all instances of a program. For example, if two
or more Tasks are set to run the same program, local variables may be set differently for each
Task. Static variables, however, will be initialized with the same values independent of the Task
running the program. Changing a static variable’s value within one Task will change that value
for all other Tasks running that same program. Variables declared using the ‘VAR: Symbol can
be manually adjusted through the touch screen interface menus and provide the real flexibility in
creating simple and easily configurable Basic 5000 programs.
BASIC FEATURES & FUNDAMENTALS