POUspecific

POUspecific is a term used in the context of PLC programming and the IEC 61131-3 standard to describe a Program Organization Unit (POU) that is intended to be used within a single project, subsystem, or module rather than as a reusable component across multiple projects. It denotes a POU whose design, data access, and interface are aligned with a particular scope and are not expected to be imported or reused in different contexts.

In practice, a POUspecific designation may be conveyed through documentation, naming conventions, or tooling constraints that emphasize locality and restricted visibility. A POU labeled POUspecific typically focuses on encapsulating functionality within a defined boundary, often interacting with project-local data structures and interfaces. This designation can be complemented by module boundaries, versioning notes, and access rules that discourage cross-project reuse.

Benefits of the POUspecific approach include improved encapsulation, clearer module ownership, and reduced risk of unintended dependencies that can arise from broader reuse. It can also simplify testing and maintenance within a defined subsystem. However, it may lead to code duplication if similar functionality is needed elsewhere, and it can limit reuse opportunities across projects, potentially increasing integration effort when similar capabilities are required in new contexts.

POUspecific contrasts with broader POU reuse practices, where POUs are designed and implemented with cross-project applicability in mind. See also: Program Organization Unit, function, function block, and modular software design.