Ethernet Advanced Physical Layer (APL) is a type of Single Pair Ethernet (SPE), which uses the IEC 60079 Two-Wire Intrinsically Safe Ethernet (2-WISE) technical specification to render it safe for applications in hazardous environments. SPE is two-wire Ethernet with a maximum length of 1,000 meters, full-duplex communication capabilities, and a bandwidth of up to 10 Mbit/second. These qualities make it ideal for pulling complex datasets from smart instruments in expansive process industry environments such as those seen in oil and gas or wastewater management.
APL (and SPE) are making a stir, particularly in the process industries, by promising to bring Ethernet to the field level, enabling top-to-bottom connectivity without the need for network gateways or protocol conversion.
These benefits and others were discussed at a customer panel session of the recent Ethernet-APL virtual workshop, during which standards development organizations FieldComm Group, ODVA, OPC Foundation, and Profibus and Profinet International presented alongside 12 industrial project partners currently deploying the technology.
Intelligent device applications
According to Sven Seintsch, a consultant from industrial services provider Bilfinger Engineering and Maintenance, the most fundamental advantage that APL provides is the ability to extract more data from intelligent devices and instrumentation. Due to its high bandwidth, APL can more easily pull maintenance information and other data out of these field devices in real-time without cluttering a network.
“APL is about 300 times faster than communication technologies that we are using in our plants today; and with this high bandwidth, many new use cases are enabled,” Seintsch said. “Getting information out of these devices is only possible with the high speed and bandwidth APL offers.”
Reduced integration complexity
APL can also reduce complexity during the integration and commissioning of devices. When devices are connected to an APL network, a repository of data such as field device integration (FDI) packages, operating instructions, and security certificates can be stored on the devices themselves and transmitted over the local APL network, rather than being downloaded from the internet or otherwise acquired externally. As a result, plant operators can commission and install new equipment without a pre-existing internet connection. This also helps in identifying individual devices on the network, reducing the commissioning time for projects that could involve the integration of hundreds of devices.
“It is very important to be able to work without an online connection to the internet because you may not have this during the startup of new plants,” Seintsch said. “It just makes life much easier to be able to connect the devices to the local network and upload the device integration files to set up your system.”
To be compatible with APL, devices must be manufactured with the appropriate physical transceiver (PHY), though pre-existing Fieldbus Type A cabling can remain in use. This means installations with buried or difficult-to-reach cabling can more easily make the transition by updating devices and connectors without needing to replace their entire cabling infrastructure. The first APL-compatible devices went into production this year.