Data types determine what kind of value the variable can have. Data types define the initial value, range of possible values, and the number of bits.
To fulfill the requirements of the IEC 61508 standard and as an extension to the IEC 61131 standard, safety-related and standard code is strictly distinguished in EcoStruxure Machine Expert - Safety. Therefore, also safety-related and standard variables, or more precise, safety-related and standard data types are distinguished.
Representation of safety-related and standard data types in the code
For easier distinction of standard and safety-related data types in code worksheets, they are represented different:
FBD/LD code: safety-related variables are displayed with a red background. Variables of standard data types are shown without background.
ST code: safety-related variables are underlined in red, standard variables are not underlined.
IEC 61131-3 data types and safety-related data types
In EcoStruxure Machine Expert - Safety, the following IEC 61131-3 defined elementary data types and special safety-related data types are available:
IEC 61131-3 data types
|
Data type |
Description |
Size/Bit |
Range |
Default initial value |
|
BOOL |
Boolean |
1 |
0...1 |
BOOL#0 |
|
INT |
Integer |
16 |
-32,768 up to 32,767 |
INT#0 |
|
DINT |
Double Integer |
32 |
-2,147,483,648 up to 2,147,483,647 |
DINT#0 |
|
TIME |
Duration |
32 |
0 up to 2,147,483,647ms |
TIME#0ms |
|
BYTE |
Bit string of length 8 |
8 |
0...255(16#00...16#FF) |
BYTE#0 |
|
WORD |
Bit string of length 16 |
16 |
0...65,535(16#00...16#FFFF) |
WORD#0 |
|
DWORD |
DoubleWordBit string of length 32 |
32 |
0...4,294,967,295(16#00....16#FFFFFFFF) |
DWORD#0 |
Safety-related data types
|
Data type |
Description |
Size/Bit |
Range |
Default initial value |
|
SAFEBOOL |
Safety-related Boolean |
1 |
0...1 |
SAFEBOOL#0 |
|
SAFEINT |
Safety-related Integer |
16 |
-32,768 up to 32,767 |
SAFEINT#0 |
|
SAFEDINT |
Safety-related Double Integer |
32 |
-2,147,483,648 up to 2,147,483,647 |
SAFEDINT#0 |
|
SAFETIME |
Safety-related duration |
32 |
0 up to 2,147,483,647ms |
SAFETIME#0ms |
|
SAFEBYTE |
Safety-related bit string of length 8 |
8 |
0...255(16#00...16#FF) |
SAFEBYTE#0 |
|
SAFEWORD |
Safety-related bit string of length 16 |
16 |
0...65,535(16#00...16#FFFF) |
SAFEWORD#0 |
|
SAFEDWORD |
Safety-related doubleWordBit string of length 32 |
32 |
0...4,294,967,295(16#00....16#FFFFFFFF) |
SAFEDWORD#0 |
Generic data types
Generic data types are used to group elementary data types by forming a hierarchical structure. The generic data type ANY_SAFEBIT, for example, includes the elementary data types SAFEDWORD, SAFEWORD, SAFEBYTE and SAFEBOOL. If a formal parameter can be connected to ANY_SAFEBIT, this means that variables of the data types SAFEDWORD, SAFEWORD, SAFEBYTE, and SAFEBOOL can be applied to it.
Structure of generic data types and safety-related generic data types supported by EcoStruxure Machine Expert - Safety
NOTE:
Generic data types which are not supported by EcoStruxure Machine Expert - Safety are not listed below (REAL and LREAL, for example). Also refer to your hardware documentation for further restrictions concerning supported generic data types.
ANY_(SAFE)ELEMENTARY
ANY_(SAFE)MAGNITUDE
ANY_(SAFE)NUM
ANY_(SAFE)INT
(SAFE)INT, (SAFE)DINT
ANY_(SAFE)BIT
(SAFE)DWORD, (SAFE)WORD, (SAFE)BYTE, (SAFE)BOOL
(SAFE)TIME
