28 Publication 1756-PM004C-EN-P - October 2009
Chapter 2 Organize Tags
The minimum memory allocation for a tag is four bytes. When you create a tag
that stores data that requires less than four bytes, the controller allocates four
bytes, but the data only fills the part it needs.
The COUNTER and TIMER data types are examples of commonly used
structures.
To copy data to a structure, use the COP instruction.
Refer to the Logix5000 Controllers General Instructions Reference Manual,
publication 1756-RM003
.
Data type Bits
31 16 15 8 7 1 0
BOOL
Not used 0 or 1
SINT
Not used -128…+127
INT
Not used -32,768…+32,767
DINT -2,147,483,648…+2,147,483,647
REAL
-3.40282347E
38
…-1.17549435E
-38
(negative values)
0
1.17549435E
-38
…3.40282347E
38
(positive values)
42365
To expand a structure and
display its members, click
the + sign.
To collapse a structure
and hide its members,
click the – sign.
COUNTER Structure
TIMER Structure
Data Type MembersMembers of
running_seconds