Ethernet Advanced Physical Layer (Ethernet-APL) describes a

physical layer In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer: the layer most closely associated with the physical connection between devices. The physical layer provides an electrical, mechani ...

for the

Ethernet Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

communication technology which is especially developed for the requirements of the

process industries Process manufacturing is a branch of manufacturing that is associated with formulas and manufacturing recipes,

. The development of Ethernet-APL was determined by the need for communication at high speeds and over long distances, the supply of power and communications signals via common single,

twisted-pair Twisted pair cabling is a type of communications cable in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted balanced ...

(2-wire) cable as well as protective measures for the safe use within explosion hazardous areas. Because it was created specifically for demanding industrial applications, Ethernet-APL, as a subset of the widely adopted Ethernet standard, offers a high level of robustness for extremely reliable operation. Ethernet has long become the standard communication solution in the information technology field, while

Industrial Ethernet Industrial Ethernet (IE) is the use of Ethernet in an industrial environment with protocols that provide determinism and real-time control. Protocols for industrial Ethernet include EtherCAT, EtherNet/IP, PROFINET, POWERLINK, SERCOS III, CC- ...

is the common description of the variant of this standard for the manufacturing and process industries. Ethernet-APL provides the missing link, extending unified Ethernet communication all the way down to field

instrumentation Instrumentation is a collective term for measuring instruments, used for indicating, measuring, and recording physical quantities. It is also a field of study about the art and science about making measurement instruments, involving the related ...

Structure

Being a physical layer, Ethernet-APL is independent of any protocol or communications stack and designed for wide adoption and application in process automation.

Ethernet as basis for APL

Ethernet-APL is a specific, single-pair Ethernet based on 10BASE-T1L as defined in IEEE 802.3cg,IEEE Standards Association:''802.3cg-2019 - IEEE Standard for Ethernet - Amendment 5:Physical Layer Specifications and Management Parameters for 10 Mb/s Operation and Associated Power Delivery over a Single Balanced Pair of Conductors'' available a

/ref> with additional provisions for process industries. The Ethernet-APL communication is thus part of and fully compatible with the IEEE 802.3 Ethernet specification. Ethernet-APL communication relies on 10 Mbit/s

full duplex A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow ...

communication transported via one

twisted pair Twisted pair cabling is a type of communications cable in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted balanced ...

cable. It supports all major

network topologies Network topology is the arrangement of the elements ( links, nodes, etc.) of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and cont ...

including the well known

trunk Trunk may refer to: Biology * Trunk (anatomy), synonym for torso * Trunk (botany), a tree's central superstructure, and the stem of woody plants * Trunk of corpus callosum, in neuroanatomy * Elephant trunk, the proboscis of an elephant Comput ...

& spur topology which is widely utilized in process industries. The maximum trunk length is 1000 meters into Zone 1, Div 2. The maximum spur length is specified as 200 m into Zone 0, Div. 1. Ethernet-APL incorporates a number of enhancements especially tailored to the demanding requirements of process and other industries like

Intrinsic safety Intrinsic safety (IS) is a protection technique for safe operation of electrical equipment in hazardous areas by limiting the energy, electrical and thermal, available for ignition. In signal and control circuits that can operate with low curren ...

and adds port profiles for optional power supply and hazardous area protection.

Intrinsic safety

is a vital requirement especially by the worldwide

process industries Process manufacturing is a branch of manufacturing that is associated with formulas and manufacturing recipes,

which demand an easy to implement solution to control and power field instruments in explosion hazardous areas. For this reason, optional intrinsic safety is fully integrated into the definitions of the Ethernet-APL communication standard. In the technical specification 2-WISE the 2-wire intrinsically safe Ethernet is defined. The intrinsic safety barrier is an electronic circuit at each output or input of a switch or instrument. It prevents ignitable electric energy from reaching the connector. The intrinsic safety barrier is separate from the communications circuit (PHY). This design principle ensures: * Chip manufacturers can build commercially available PHY in quantities also available for applications not requiring intrinsic safety * Device vendors can easily build intrinsically safe devices Ethernet-APL is designed to support easy planning, validation, installation, documentation and implementation of the intrinsically safe operation of field instruments in hazardous areas. This includes among other aspects live work on cables and instruments without a

hot work __NOTOC__ Hot work refers to operations which can produce a flame or spark. Common hot work processes involve welding, soldering, cutting, brazing and the use of Powder-actuated tool, powder-actuated tools or similar fire producing operations. Th ...

permit. All suitable products carry an approval by a notified body.

Port profile specifications

Part of the standards for Ethernet-APL include the definition of port profiles for interoperability in various application scenarios. This includes aspects such as segment type, differentiating a trunk-to-trunk port from a spur-to-spur port. Other specifications refer to the power characteristics, differentiating between source-to-load and unpowered-to-unpowered ports. Another provision is the definition of power classes. This includes the limitation of the maximum supply voltage and supply current for

intrinsically safe Intrinsic safety (IS) is a protection technique for safe operation of electrical equipment in hazardous areas by limiting the energy, electrical and thermal, available for ignition. In signal and control circuits that can operate with low current ...

power supply A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, electric current, current, and frequency to power ...

. Further topics that are specified in the port profile specification are wiring rules, pin assignments for terminals and connectors as well as shielding and grounding rules.

Structure

Ethernet as basis for APL

Intrinsic safety

Port profile specifications

References

Further reading