Omron NX-SL5500 User Manual

6-1
POUs (Program Organization Units)
The safety program that runs on a Safety CPU Unit is made from a combination of POUs (program
organization units).
This section describes the configuration and specifications of POUs.
Refer to 6-5 Programming Operations on page 6 - 26 for the procedures to create POUs on the Sys-
mac Studio.
Refer to Sysmac Studio Version 1 Operation Manual (Cat. No. W504) for the procedures to create
POUs that are used with an NJ/NX-series CPU Unit.
6-1-1
POU
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 safety program.
You combine POUs to build a complete safety 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 execut-
ed 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 POU consists of a combination of these three types of POUs. You can create many POUs.
You assign the created programs to a safety task to execute them. Only one safety task can be used
by the Safety CPU Unit.
6-1-2
Overview of the Three Types of POUs
Program
l
Executing Programs and Execution Conditions
• You execute a safety task to execute the programs that are assigned to that safety task.
• Programs are always executed.
l
Notation
• The POUs must include at least one program. More than one program can be assigned to the
safety task.
6 Programming
6 - 3
NX-series Safety Control Unit User's Manual (Z930)
6-1 POUs (Program Organization Units)
6
6-1-1 POU

Omron NX-SL5500 Specifications

General

Brand	Omron
Model	NX-SL5500
Category	Controller
Language	English