  Industrial plants suffer from a high degree of complexity and incompatibility
in their communication infrastructure, caused by a wild mix of proprietary
technologies. This prevents transformation towards Industry 4.0 and the
Industrial Internet of Things. Open Platform Communications Unified
Architecture (OPC UA) is a standardized protocol that addresses these problems
with uniform and semantic communication across all levels of the hierarchy.
However, its adoption in embedded field devices, such as sensors and actors, is
still lacking due to prohibitive memory and power requirements of software
implementations. We have developed a dedicated hardware engine that offloads
processing of the OPC UA protocol and enables realization of compact and
low-power field devices with OPC UA support. As part of a proof-of-concept
embedded system we have implemented this engine in a 22 nm FDSOI technology. We
measured performance, power consumption, and memory footprint of our test chip
and compared it with a software implementation based on open62541 and a
Raspberry Pi 2B. Our OPC UA hardware engine is 50 times more energy efficient
and only requires 36 KiB of memory. The complete chip consumes only 24 mW under
full load, making it suitable for low-power embedded applications.
