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7 Programming
NX-series Safety Control Unit User’s Manual (Z930)
7-2 Variables
7
7-2-5 Data Types
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 vari-
able. 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 data
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. You cannot use
user-defined derivative data types, such as structures, unions, and enumerations, or array specifica-
tions.
The basic data types that you can use with the Safety Control Unit are listed below.
The Safety Control Unit classifies the following two data types to distinguish between safety data and
standard data.
• Safety data types: These data types represent data related to safety control.
• Standard data types: These data types represent data related to standard control.
The safety data type variables are prefixed with the “SAFE” before the name of the standard data type,
as in SAFEBOOL and SAFEBYTE.
You can input a signal for a safety data type variable to a standard data type variable. You cannot input
a signal for a standard data type variable to a safety data type variable. A building error will occur.
7-2-5 Data Types
Basic Data Types
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.
Integer A data type that represents an integer value.
Duration
A data type that represents a time duration (days, hours, minutes, seconds, and
milliseconds).
Safety Data Types and Standard Data Types
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