Sensaphone SCADA 3000 Users manual - Manual (Page 188)

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SCADA 3000 User’s Manual
ARRAYS: This is a more advanced programming type that significantly shortens
and simplifies long programs.
ERROR HANDLING: When a program is compiled, it is scanned for language
related errors. An error message, including the type of error, is displayed.
EDITING TOOL: The SCADA 3000 Windows Software provides an editing
utility that allows you to write, compile, upload, download, run, and start C pro-
grams.
This chapter provides basic instruction in the C language and gives all the commands that
are valid for use with SCADA 3000. Sample programs are included. If you have questions or
problems, please contact our technical support department at (610)558-2700 or via email at
[email protected].
STRUCTURe
Listed below are some examples that will help demonstrate the C language structure. Refer to
the following pages for explanation of the keywords, functions, and commands used within the
sample programs.
1) All programs must begin with the main () function. It must be followed by an open brace {
and closed with an end brace }.
Main ()
{
}
2) A statement is a line of programming code. All statements are placed inside the braces {} and
end with a semicolon (;). For example:
main ()
{
write_uaf(output,0,0,on);
}
This program will turn on output relay 0, on the main board.
3) In the C language, numbers are stored in what are called variables. A variable must be
defined before the main () function. SCADA 3000 allows you to have up to 1024 variables.
intx;
main ()
{
x=12
}
In this program we defined a variable called “x” and set its value equal to 12. Here, x is defined
as an integer. SCADA 3000’s language can define variables as characters (char), integers (int),
or floating point numbers (float). A character can hold a value from -128 to 127 and an integer
can hold a value from -32,768 to 32,767. Both characters and integers must be whole numbers.
A floating point number is one that can have a fractional part (i.e., numbers after the decimal
point). Floating point numbers can be very large or very small, generally between 10-38 and
10+38. Generally speaking, there is no advantage to using variables as int or char types within
the SCADA 3000, and examples from this point on will use only variables of the type float.
The following program will set x equal to the value of input 0 on the main board.
float x;
main ()
{
x=read_uaf(input, 0,0);
}