Ethernet-APL Modernizes Process Automation Networks

Ethernet-APL brings all of the familiarity and use of standard Ethernet to the process industries while solving challenges such as using single twisted pair cables rather than 4-pair cables, supporting hazardous area deployment, and supporting cable distances well over 100 meters.  

In order to take advantage of the flexibility, ease and seamless integration Ethernet-APL offers when digitizing your automation network, it’s important to consider your network’s topology. This blog post will provide an overview of the Ethernet-APL standard, some topology factors as well as best practices for planning and structuring a modern automation network.

Ethernet-APL and Its Variants

Developed with the process industry in mind, Ethernet-APL provides a simple, two-wire conductor that can deliver 10 Mbps data rates and power to field devices over long distances —  much faster than the 1200 bit per second rate with HART. But the game changer is making use of the familiarity, architecture, and common components of Ethernet. It also supports safe ignition protection type “i” in Ex Zones 0, 1 and 2. 

This new data exchange standard has been defined at the lowest layer, making it compatible with any Ethernet-based protocols at higher levels. That means expensive gateways between production and company networks down to the field devices are not necessary. Automation protocols can be deployed as required, as can web servers, OPC UA and cloud/edge connectivity. With Ethernet-APL, end users can seamlessly install millions of devices ranging from small sensors to control units or highly complex analytical instruments to create new layout possibilities built with one very familiar topology and protocol — Ethernet. 

Although the Ethernet-APL Engineering Guideline outlines various Ethernet-APL network topologies, keep in mind that the circumstances for the Ethernet-APL spurs are the same for all topologies. Ethernet-APL devices can be connected to a switch by a Category IV cable (no longer than 200 meters). Here are examples of three Ethernet-APL variants:

• Variant 1. APL field switches are connected to a standard industrial Ethernet network, and the installation environment will largely influence the installation location – e.g., a control cabinet or out in the field. Figure 1 shows the APL switch connected directly to the control network using normal Ethernet copper cables or fiber-optic cables. The control network connection is typically around 100 Mbps to accommodate a brownfield plant that must keep step with 21st-century technologies.