Omron NJ-series User Manual page 200

Function Block Definitions and Instances
A function block consists of a function block definition that is made in advance and instances that are
then used in the actual programs. All instances of a function block are based on the function block defi-
nition.
A function block definition consists of an algorithm and a local variable table.
 Function Block Instance
When you place an instance of a function block definition in a program or another function block, the
function block definition is treated as a part of that program or function block.
Function block definitions that are called from a program or another function block are called
instances.
Every instance of a function block has an identifier known as an instance name associated with it,
and every instance uses memory.
You can create instances of a function block definition to process different I/O data in the same way.
Instance name
Function block definition name
Instance name
Function block definition name
Instances cannot be read from other programs or function blocks. If an instance with the same name
as another instance is placed in a different program or another function block, that instance will oper-
ate as a completely separate instance.
NJ-series CPU Unit Software User's Manual (W501)
Program POU
FB1_1
FB1
Variable Memory area
declarations
reserved.
Algorithm
FB1_2
FB1
Variable
declarations
Memory area reserved.
Algorithm
6 Programming
Memory area
Memory for
instance
FB1_1
Memory for
instance
FB1_2
6
6-13