Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 66)

L-force | PLC Designer
Concepts and Base Components
64 DMS 4.1 EN 03/2011 TD29
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3.6 What is a Program Organization Unit Object "POU"
Do not get puzzled with the term "POU":
It is basically used for all objects which are used to create a PLC program.
POU = Program Organization Unit
POUs which are managed in the "POUs" view are not device-specific but they might be
instantiated for the use on a device (application). For this purpose program POUs must
be called by a task of the respective application.
POUs, which are ONLY managed in the Devices view, i.e. which are inserted in the
"device tree" explicitly below an application, can only be instantiated by applications
indented below this application ("child" application). For further information see the
descriptions of the device tree and of the Application object.
BUT "POU" also is the name of a certain sub-category of these objects in the Add
Object menu, at this place just comprising programs, function blocks and functions!
So, a Program Organization Unit object in general is a programming unit, an object
which is managed either non-device-specifically in the "POUs" window or device-
specifically in the "Devices" window and can be viewed and edited in an editor
window. A POU object can be a program, function, function block as well as a method,
action, interface, DUT (Data Unit Type) or an external file of any format.
Regard the possibility to set certain properties (like e.g. build conditions etc.) for each
particular POU object.
In order to add a programming object to the project use command 'Add Object'.
The following POU object types can be used per default:
• Action
• DUT (Data Type Unit)
• External File
• Global Variable List
• Global Network Variables List
• Image pool
• Interface
• Library Manager
• Method
• Property
• POU
• Textlist
• Visualization
Besides the Program Organization Unit objects there are Device objects used for
running the program on the target system (Resource, Application, Task Configuration
etc...). Those are managed in the "Devices" view.