Campbell Scientific CR1000KD CR1000 Measurement and Control System - Page 122

Section 7. Installation 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. 187) or functions (p. 525) 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. 442) ). Note Using all uppercase for constant names may make them easier to recognize. 122