The use of equipment digital twins of standardized, multi-purpose units can accelerate process development and reduce experimental effort. Experimental data are essential not only for identifying critical process parameters and enabling model-based methods within a Quality by Design framework, but also for constructing and validating the simulation models that describe digital twin behavior. To achieve high-fidelity and robust predictive models, structured concepts are required to manage metadata and process-, product-, and resource-specific information exchanged between physical and digital twins. Electronic lab notebooks (ELNs), which contextualize experimental data, must therefore be structured and standardized to ensure interoperability and seamless data exchange. For integration into digital twin workflows and process transfer between equipment instances of the same category, ELNs must comply with FAIR (Findable, Accessible, Interoperable, Reusable) data principles. This work proposes a Semantic Integration Pattern for FAIR-compliant ELNs to document simulated experiments using domain-specific, vendor-independent standards such as DEXPI 2.0 and ISA 88/IEC 61512-1. DEXPI 2.0 supports standardized descriptions of equipment and process steps, while ISA 88/IEC 61512-1 structures experimental recipes. The resulting FAIR ELN Semantic Integration Pattern enables standardized data exchange between ELNs and digital twin tools. Its applicability is demonstrated through an illustrative example documenting simulated saponification experiments in gPROMS® using simple batch reactor model. The results will support subsequent real experiments conducted in a 2L stirred tank unit.