External POU - Editor
The editor for external POUs is used for library development by device manufacturers.
External POUs are external objects for which no code is generated when building the project. An external POU is included only after the project is running on the target system. This means that the external object must exist on the target system (for example, in a library).
External POUs can be included in a safety application only by means of libraries.
They are added to the project in the POUs view () by selecting the project and executing the context menu command .
The POU type is always FUNCTION_BLOCK.
The editor of a Safety External POU consists exclusively of the Declaration part for declaring local variables. There is no implementation part.
Object properties
The properties dialog is opened by selecting the external POU in the POU pool and activating the context menu command Properties. It contains the following tabs:
Common
Build
Safety
Access Control
For a more detailed description of the Common, Build, and Access Control tabs, see the CODESYS Help.
Safety CRC
CRC of this POU
The CRC has to match the implementation of the function block in the controller.
Version (editable)
A version must be entered. It has to match the implementation of the function block in the controller. The version can be used for quickly detecting the object version in the object list of the safety application object.
Comment (editable)
Usage
When the System interface check box is selected, the Single call check box is reset, and the other way around.
For more information about calling POUs with the Single call flag, see: FB Calls