Toshiba LC531 Series Instruction Manual page 66

Chapter 3 Software Functions
(2) Classification of variables depending on definition method
(3) Classification depending on usage
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There are variables that allow the user to freely define their names and types
(user variables), and variables that have predetermined names and data
types depending on their use (standard variables).
Variables that allow the user to define their names and types include the
instance variables and temporary variable that are classified as local
variables, and the user variables that are classified as controller global
variables.
Variables have various data types depending on their use. The table below
shows different data types.
Notation Type
BOOL Boolean type
INT Integer type
DINT Double-precision
integer type
UINT Unsigned integer
type
REAL Real type
TIME Timer type
WORD Word type
DWORD Double word
type
Controller global variables and local variables can be classified as follows
depending on the usage.
■
Classification of controller global variables
Controller global variables are classified into system variables for
referring to clock information and error information, tag instrument
variables for referring to parameters and data of tag instruments, and
user variables that the user can use for any purpose, etc.
■
Classification of local variables
Local variables are classified into temporary variables that are reserved
temporarily during program execution and instance variables that are
reserved permanently for the program.
Instance variables are zeroed when the power is turned off and on.
Temporary variables become undefined without being zeroed. Make
sure to write data before using them.
Table 3-3 Variable types
Number
of bits
1 0,1
16 -32768 to 32767
32 -2147483648 to 2147483647
16 0 to 65535
32 -3.40282×10
The data type complies with IEEE754.
32 0 to 2147483647ms(24d20h31m23s647ms)
16 0000 to FFFF
32 00000000 to FFFFFFFF
Effective data range
38 38
to 3.40282×10