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Variables Section 1-3
Refer to Variable Definitions in 2-1-2 Function Block Elements for details on
AT settings and 2-5-3 AT Settings for Internal Variables for details on using AT
settings.
Array Settings A variable can be treated as a single array of data with the same properties.
To convert a variable to an array, specify that it is an array and specify the
maximum number of elements.
This property can be set for internal variables and input-output variables only.
Only one-dimensional arrays are supported by the CX-Programmer Ver. 5.0
and later versions.
• Setting Procedure
Click the Advanced Button, select the Array Variable option, and input the
maximum number of elements.
• When entering an array variable name in the algorithm in a function block
definition, enter the array index number in square brackets after the vari-
able number.
For details on array settings, refer to Variable Definitions in
2-1-2 Function
Block Elements
.
Initial Value This is the initial value set in a variable before the instance is executed for the
first time. Afterwards, the value may be changed as the instance is executed.
For example, set a boolean (BOOL) variable (bit) to either 1 (TRUE) or 0
(FALSE). Set a WORD variable to a value between 0 and 65,535 (between
0000 and FFFF hex).
If an initial value is not set, the variable will be set to 0. For example, a bool-
ean variable would be 0 (FALSE) and a WORD variable would be 0000 hex.
Retain Select the Retain Option if you want a variable’s data to be retained when the
PLC is turned ON again and when the PLC starts operating.
• Setting Procedure
Select the Retain Option.
Size When a STRING variable is used, the size required to store the text string can
be set to between 1 and 255 characters.
1-3-4 Variable Properties and Variable Usage
The following table shows which properties must be set, can be set, and can-
not be set, based on the variable usage.
(1) The value of the input parameter will be given.
(2) Valid only for STRING variables.
Property Variable usage
Internals Inputs Outputs In Out
Name Must be set. Must be set. Must be set. Must be set.
Data Type Must be set. Must be set. Must be set. Must be set.
AT (specified
address)
Can be set. Cannot be set. Cannot be set. Cannot be set.
Array specification Must be set. Cannot be set. Cannot be set. Must be set.
Initial Value Can be set. Cannot be set.
(See note 1.)
Can be set. Cannot be set.
Retained Can be set. Cannot be set.
(See note 1.)
Can be set. Cannot be set.
Size Can be set.
(See note 2.)
Cannot be set. Cannot be set. Cannot be set.
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