15MC_VAR

[sinatiras]

Merhabalar.
15 Mc ile programlama yapıyoruz ama kafama takılan bi nokta var. Resimlerdeki;
VAR,
VAR_GLOBAL,
VAR_INPUT,
VAR_OUTPUT,
VAR_STATIC,
VAR_RETAIN arasındaki farklar nelerdir? Neye göre tanımlama yapmalıyım? Yardımcı olursanız sevinirim.
Teşekkürler.

[Uğur]

Kod: Tümünü seç

l  VAR
The variable of scope VAR is a general variable, usually a local variable.

l  VAR_INPUT
The variable of scope VAR_INPU means an input variable. When a POU calls an FB or FC, the variable of VAR_INPUT scope can be observed as an input pin parameter. 
Max. 30 variables of scope VAR_INPUT can be defined for an FB or FC. Otherwise, an error will occur during download if there are more than 30.

l  VAR_OUTPUT
The variable of scope VAR_OUTPUT is an output variable. The variable of scope VAR_OUTPUT is not allowed to define for an FC.
Max. 32 variables of scope VAR_OUTPUT can be defined. Otherwise, an error will occur during download if there are more than 32.

l  VAR_GLOBAL
The variable of scope VAR_GLOBAL is a global variable. Global variables can be defined only in the global variable table and can not be defined in the variable table of a POU. 

l  STATIC
The variable of scope STATIC has the static attribute. The variable can be used only in the POU where the variable is defined. When the variable for an FC is of STATIC, the system will assign a fixed address to the variable so that when the controller works, the value of the variable can be stored.

l  RETAIN
The variable of scope RETAIN has the attribute that data are retained when power off.