Attribute Description Specification Default
Initial Value Specify a value for the variable for
one of the following situations:
• When the power supply is turned
ON
• When the mode is changed to
RUN mode or DEBUG mode.
This setting is re-
quired.
FALSE for BOOL and
SAFEBOOL variables,
and 0 for numeric vari-
ables.
Constant If you set the Constant attribute, you
can set the initial value of the variable
when it is downloaded, but you can-
not overwrite the value afterward.
Specify making the
value a constant or not
a constant.
Do not specify a con-
stant.
Comment You can add comments to variables. UTF-8 format
127 bytes max.
None (empty).
l
Attributes Supported by Each Type of Variable
Type of variable Variable Name Data Type Initial Value Constant Comment
Global variables Supported. Supported. Supported. Supported. Supported.
Programs Internal variables Supported. Supported. Supported. Supported. Supported.
External variables Not supported. Not supported. Not supported. Supported. Supported.
Function
blocks
Internal variables Supported. Supported. Supported. Supported. Supported.
Input variables Supported. Supported. Supported. Not supported. Supported.
Output variables Supported. Supported. Supported. Not supported. Supported.
Additional Information
The following comments are linked. If you change a comment, the comment for the correspond-
ing parameter is also changed.
• Device variable comments in I/O mappings
•
Global variable comments
• I/O terminal comments in the Parameters Tab Page
6-2-5
Data Type
The Data Type attribute defines the type of data and range of data that is expressed by a variable.
The amount of memory that is allocated when you declare a variable depends on the data type of that
variable. The more memory allocated, the larger the range of values that the variable can express.
The data types for the input and output variables of instructions depend on the instruction. Set the da-
ta types of input and output parameters for the instruction arguments according to the data types of
the input and output variables for that instruction.
The Safety Control Unit allows the use of only pre-defined basic data types. Y
ou cannot use user-de-
fined derivative data types, such as structures, unions, and enumerations, or array specifications.
Basic Data Types
The basic data types that you can use with the Safety Control Unit are listed below.
Type Definition
Boolean A data type with a value of either TRUE or FALSE.
Bit string A data type that represents a value as a bit string.
Integers A data type that represents an integer value.
6 Programming
6 - 14
NX-series Safety Control Unit User's Manual (Z930)
To Next Page
Loading...
Need help?
General
