Campbell CR850, Operator'S Manual

Page: 122 / 566

Section 7. Installation
122
Variable Initialization
By default, variables are set equal to zero at the time the datalogger program
compiles. Variables can be initialized to non-zero values in the declaration.
Examples of syntax are shown in CRBasic example
Initializing Variables
(p. 122).
CRBasic Example 11. Initializing Variables
Public aaa As Long = 1
Public bbb(2) As String *20 = {"String_1", "String_2"}
Public ccc As Boolean = True
‘Initialize variable ddd elements 1,1 1,2 1,3 & 2,1.
‘Elements (2,2) and (2,3) default to zero.
Dim ddd(2,3)= {1.1, 1.2, 1.3, 2.1}
‘Initialize variable eee
Dim eee = 1.5
Local Variables
Local variables are variables that are reserved for use within the subroutines
(p. 188)
or functions
(p. 503)
in which they are declared as Dim . Names can be identical to
globally declared variables and to variables declared locally in other subroutines
and functions. This feature allows creation of a CRBasic library of reusable
functions and subroutines that will not cause variable name conflicts. If a
program with
Dim variables declared locally attempts to use them globally, the
compile error undeclared variable will occur.
To make locally defined variable public, which makes them displayable, in cases
where making them public will lead to a name conflict with other Public
variables, create a data table to which the local variables are sampled, then display
those sampled data.
When passing the contents of a global variable to a local variable, or local to
global, declare passing / receiving pairs with the same data types and applicable
string lengths.
7.7.3.4.2 Constants
CRBasic example Using the Const Declaration
(p. 123)
shows use of the constant
declaration. A constant can be declared at the beginning of a program to assign an
alphanumeric name to be used in place of a value so the program can refer to the
name rather than the value itself. Using a constant in place of a value can make
the program easier to read and modify, and more secure against unintended
changes. If declared using
ConstTable / EndConstTable , constants can be
changed while the program is running by using the external keyboard / display
menu (
Configure , Settings | Constant Table ) or the C command in a terminal
emulator (see Troubleshooting -- Terminal Emulator
(p. 421)
).
Note Using all uppercase for constant names may make them easier to recognize.