HIMA HIQuad H41X, Системное руководство

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Programming System
Page 68 of 110 HI 803 211 E Rev. 1.01.00
6.1.1 Variable Types
SILworX supports the following variable types:

VAR, a variable within a logic (read and write).

VAR with the CONST attribute, a variable that was defined as constant and cannot be
modified.

VAR with the RETAIN attribute, a variable that retains its value after a power outage.

VAR_EXTERNAL, reference to global variables (read and write).

VAR_GLOBAL, global variable (read and write) to exchange values between programs and
subordinated functions and function blocks.

VAR_INPUT, input variable (read) of a POU. It is also displayed in the interface viewer.

VAR_OUTPUT, output variable (write) of a POU. It is also displayed in the interface viewer.

VAR_TEMP, temporary variable (read and write).

VAR_ACTION, action declaration (read and write).
Which type can be assigned to a variable depends on the hierarchy of the variables in the
structure tree. The following table shows the permissible variable types in connection with the
structure tree nodes.
Type Project Configuration Resource Program
type Function
block
type Function
type
VAR X
VAR_EXTERNAL X
VAR_GLOBAL X X X (1)
VAR_INPUT (1) X X
VAR_OUTPUT (1) X X
VAR_TEMP (2) X
VAR_ACTION (2) X
(1) Contrary to the standard, this function is not supported.
(2) Contrary to the standard, VAR_ACTION is supported.
Table 22: Supported Variable Types
6.1.2 Initial Value
An initial value can be allocated to any variable. The variable adopts this value if no other value
was assigned by the program:

While starting the program

If a fault occurs in one of the following sources from which the variable derived its value.
Examples:
-
Physical input.
-
Communication interface.
-
User program in the STOP state.
The value that the connected variables should adopt can be set for safe ethernet and
communication protocols.
i
HIMA recommends assigning a safe value as initial value to all the variables that receive their
value from a physical input or from communication!
Variables that have not been assigned an initial value have an initial value of 0 or FALSE if the
variables are of type BOOL.