What is Ethernet APL?

Stefan Ditting: In simple terms, digital data transmission requires a protocol and a physical transmission medium. Both can be combined (almost) arbitrarily and both are available for different applications. A well-known protocol in industry is the combination of Profinet and Profisafe. Well-known transmission media are the widely used, low-cost copper cable, fiber optic cables for bridging large distances, or radio to reach places that are difficult to access. Ethernet-APL is a transmission medium that has been specially developed for use in the field level of process automation.

What can APL do?

Stefan Ditting: Ethernet-APL was developed specifically for use in the field level of process automation. For this application it combines many positive features of which only a few are mentioned here. It can transmit digital data with 10 Mbit and energy via two wires, it can be used in areas with interference and explosion hazards, and it can be used in a future-proof manner due to the disclosed technology and standardization.

And where exactly are the advantages (for the plant operator), where are the limitations?

Stefan Ditting: Ethernet-APL has been developed to enable the advantages of digitization throughout the field level, economically and over the entire life cycle. The gain is to be measured depending on the application. Measured values can be transmitted with high precision and enriched with additional information such as device states, digital interfaces can enable simple device replacement, and consistent safety and security concepts can be set up. The more intelligent the devices used, the greater the benefit of Ethernet APL. However, the use of Ethernet APL is likely to be too expensive in the foreseeable future for simple, binary-controlled end devices.

What about the availability of APL? Where do we stand today? After all, the specifications should be completed in 2021, after which the Ethernet APL infrastructure and compatible field devices will be available.

Stefan Ditting: Indeed, users need a comprehensive portfolio of devices in order to realize different applications and make an individual selection (best of breed). Currently, there are already some pioneers offering Ethernet-APL devices. Companies like Pepperl + Fuchs supply media converters, companies like Endress + Hauser supply sensors. Other companies, including manufacturers of actuators, are known to already offer devices or are currently developing them - also for functionally safe applications.

Ethernet-APL enables continuous digital communication throughout the entire plant. Which products along this communication path does Hima already offer or are currently in development?

Stefan Ditting: As described, Ethernet-APL is an excellent transmission medium for connecting the field level. Since Hima systems are not in the field, they do not require direct integration of Ethernet-APL. In addition to the transmission medium, a protocol is needed (as described in answer 1). Hima has therefore pioneered safe control systems and provides Profinet/Profisafe, an open and safe protocol for connecting field devices. Thus, Hima already enables fully digital end-to-end safety using Profinet/Profisafe over Ethernet APL. (agry.)