Pous (Program Organization Units); What Are Pous - Omron NJ-series User Manual

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POUs (Program Organization Units)

The user program that runs on an NJ-series CPU Unit is made from a combination of POUs (program
organization units).
This section describes the configuration and specifications of POUs.
Refer to the Sysmac Studio Version 1 Operation Manual (Cat. No. W504) for details on creating POUs
in the Sysmac Studio.
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What Are POUs?

A POU (program organization unit) is a unit that is defined in the IEC 61131-3 user program execution
model. A POU includes a local variable table and an algorithm (i.e., a series of code or logic). It is the
basic unit used to build the user program.
You combine POUs to build a complete user program.
There are three types of POUs, as described below.
• Programs
A program corresponds to a main routine. It is the main type of POU that is used for algorithms.
You can place any instruction, function, or function block in the algorithm of a program.
• Function Blocks (FBs)
A function block can output different values even with the same inputs. Function blocks are executed
when they are called from a program or another function block.
• Functions (FUNs)
A function always outputs the same values for the same inputs. Functions are executed when they
are called from a program, another function, or a function block.
The POUs consists of a combination of these three types of POUs. You can create many POUs.
You assign the programs to tasks to execute them.
NJ-series CPU Unit Software User's Manual (W501)
6 Programming
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