Campbell CR6 Series, Руководство оператора

Страница: 384 / 690

Section 7. Installation
384
Some smart sensors send strings containing NULL characters. To manipulate a
string that has NULL characters within it (in addition to being terminated with
another NULL), use MoveBytes() instruction.
7.7.19.4 Inserting String Characters
Example:
Objective:
Use MoveBytes() to change "123456789" to "123A56789"
Given:
StringVar(7) = "123456789" 'Result is
"123456789"
try (does not work):
StringVar(7,1,4) = "A" 'Result is
"123A<NULL>56789"
Instead, use:
StringVar(7) = MoveBytes(Strings(7,1,4),0,"A",0,1) 'Result is
"123A56789"
7.7.20 Subroutines
A subroutine is a group of programming instructions that is called by, but runs
outside of, the main program. Subroutines are used for the following reasons:
•
To reduce program length. Subroutine code can be executed multiple
times in a program scan.
•
To ease integration of proven code segments into new programs.
•
To compartmentalize programs to improve organization.
By executing the Call() instruction, the main program can call a subroutine from
anywhere in the program.
A subroutine has access to all global variables
(p. 585).
Variables local
(p. 589)
to a
subroutine are declared within the subroutine instruction. Local variables can be
aliased (as of 4/2013; OS 26) but are not displayed in the
Public
table. Global
and local variables can share the same name and not conflict. If global variables
are passed to local variables of different type, the same type conversion rules
apply as apply to conversions among variables declared as Public or Dim . See
Expressions with Numeric Data Types
(p. 222)
for conversion types.
Note To avoid programming conflicts, pass information into local
variables and / or define some global variables and use them exclusively
by a subroutine.