Industrial Internet of Things (IIoT) play an important role in the new round of industrial revolution. However, the isolation of Information Technology (IT) networks and Operational Technology (OT) networks impedes the innovations, developments, and disruptive business models applied in IIoT. With the emergence of time-sensitive networking (TSN), it is feasible to interoperate between IT/OT networks with deterministic data transmission. By integrating TSN in IIoT architecture, the article proposes a reference architecture with multi-modal interconnection, endogenous safety and security, and integrated scheduling as the core elements. We believe the design could give a guidance for IIoT system design and development.