User guide

21
VTB USER GUIDE
6.2 Internal Variable
These variables are allocated in the VOLATILE MEMORY (RAM) of the system and are zeroed at reset.
The possible types managed by VTB reflects the main types defined in a lot of programming languages and they are
the following:
TYPE
DIMENSION
RANGE
BIT
1 bit
From 0 to 1
CHAR
8 bit signed
From –128 to +127
UCHAR
8 bit unsigned
From 0 to 255
INT
16 bit signed
From –32.768 to +32.767
UINT
16 bit unsigned
From 0 to 65.535
LONG
32 bit signed
From –2.147.483.648
to +2.147.483.647
FLOAT
64 bit (standard DOUBLE format IEEE 75)
From -1,79769313486232e308
to +1,79769313486232e308
STRING
Supported only as constant
VETTORE
Single dimension for all variable types
except BIT type
STRUCTURE
Standard declaration
POINTER
Char, Uchar, Int, Uint, Long, Float
32 bit
DELEGATE
Pointer to FUNCTIONS
32 bit
It's appropriate using variables according to the minimum an maximum value they have to contain choosing the best
appropriate. INTERNAL VARIABLES can be declared PAGE LOCAL or GLOBAL.
PAGE LOCAL VARIABLES declared inside the PAGE TASK and visible only to it
GLOBAL VARIABLES declare in MAIN TASK and visible to all the others
VTB doesn't make any control on dimension of the variables and on its assigned value.