The Ethernet Advanced Physical Layer
Technology for IIoT in the Field of Process Plants
The Industrial Internet of Things (IIoT) and Industry 4.0 represent the future of industrial communication. However, implementing them requires fast, reliable communication from the field level to mobile, cloud-based applications.
Nowadays, field devices and sensors in process plants supply large amounts of data that could be collected, processed, and analyzed in the spirit of IIoT, but much of it remains unused. Ethernet enables the rapid transmission of this data and seamless communication between field devices, the process control system, and the cloud. For this reason, Ethernet has become the communication standard in factory automation.
In partnership with leading companies and associations, Pepperl+Fuchs was laying the foundation for future IoT applications in the process industry through the Ethernet advanced physical layer (Ethernet-APL). It fulfills all of the central requirements for process plants, such as two-wire cables with long cable runs and interoperability. For the first time ever, modern Ethernet technology will be applicable in hazardous areas up to Zone 0 / Class 1, Div. 1.
From Hazardous Areas to the Cloud—Barrier-Free and Highly Efficient Communication
Fast and efficient communication
Ethernet-APL enables fast and efficient communication of large data volumes at a rate of 10 Mbit/s. The two-wire cable transmits up to 92 W of data and power of simultaneously. It also sets new standards in terms of range, because trunk lengths of up to 1,000 meters are just as feasible as 200 meters at the spur to the field device.
Intrinsic Safety with Ethernet-APL
For the first time, Ethernet can be applied in hazardous areas up to Zone 0 / Class 1, Div. 1 with the high degree of interoperability that users expect. The spur lines from the field switch to the field device can be designed to be intrinsically safe. A chapter for two-wire Ethernet (2-wire Intrinsically Safe Ethernet, or 2-WISE for short) is currently being added to the well-known IEC standard for intrinsic safety in explosion protection. Inspired by FISCO, the new standard ensures simple planning and validation without calculation.
Transparency across all hierarchical levels
Installation in the field is simple with screw-type or spring-clamp terminals. It is possible to transmit more than one process value and all device parameters, which allows easy plant asset management, predictive maintenance, configuration, and parameterization. A common physical layer for all devices and data enables seamless, transparent communication across all hierarchical levels—from hazardous areas to the cloud. This makes data accessible anytime and anywhere. The interoperability of the installation is ensured by certification of protocol and physical layer. This means that devices work together easily, even where technology from different manufacturers is in operation.
Simple, cost-effective plant modernization
Ethernet-APL supports the trunk-and-spur technology established in the process industry and is applicable to any industrial Ethernet protocol such as EtherNet/IP, HART-IP, and PROFINET. This simplifies integration for planners, plant designers, and plant operators since existing installations and infrastructures can still be used and investments are protected.
How to Provide Interoperability with Ethernet-APL
Four aspects must be precisely defined to create a completely open infrastructure that provides the interoperability that users expect from Ethernet. First,IEEE 802.3 cg defines data communication as 10BASE-T1L. The Ethernet-APL Port Profile Specification defines power supply second and connections, cables, and accessories such as surge protection third. The port profile will be published in an IEC standard. Intrinsic safety is the fourth aspect, where a new chapter to the well-known standard for explosion protection defines the same simple approach to planning and validation that users appreciate with FISCO, see IEC TS60079-47, 2-WISE.
Terminology
The Ethernet Advanced Physical Layer (APL) defines switched architecture. Cross talk between instruments is impossible, which enhances communication stability and has a long-lasting positive effect on availability.
Segment is the name for each connection between switches or between switches and instruments. Trunk is the long-reach cable between switches. It has high power and signal strength and can be up to 1000 m long. Spur is the connection cable for an instrument. It can be up to 200 m and has lower power and signal strength. Spurs can be selected as intrinsically safe.
Topology—Compact Plant Layout
The Ethernet-APL rail field switch provides functionality and connections for the star topology. Each instrument connects to a spur line. The backbone can be configured as a redundant ring. Users choose this topology to meet the following features and requirements:
- Indoor installations as seen in chemical or pharmaceutical industries or in food and beverage installations
- Switches installed in junction boxes or control panels
- Cable lengths of up to 200 m to the instrument
- Ethernet redundancy often required at the plant level or inside the control cabinet
- Explosion protection for any hazardous area
Topology—Long Reach Plant Layout
Ethernet-APL for long-reach plants utilizes the trunk-and-spur topology. This topology can serve outdoor installations as seen in the oil and gas or wastewater industries. Ethernet-APL connects to the top level inside the control cabinet via the Ethernet-APL power switch. It supports ring redundancy for high availability. The Ethernet-APL field switch provides the intrinsically safe barrier for the spur outputs and receives power from the trunk. This is similar to today’s FieldConnex® solutions with Power Hubs, FieldBarriers, and Segment Protectors.
Users select the trunk-and-spur topology to serve the following features and requirements:
- Cable lengths of 1000 m to the field
- Field switches powered via the two-wire cable
- Distribution to multiple instruments via junction box in the field
- Ethernet redundancy at the plant level
- Explosion protection for any hazardous area
This layout is 100 % compatible with the trunk-and-spur topology popular in fieldbus installations. It provides a path for migration projects because the installed cable can be reused.
Product Concepts
There are two types of switches to support the Ethernet-APL infrastructure and just three principle product concepts that enable any type of topology for the field of the process plant. The switches that connect to the Ethernet backbone support redundancy and resiliency concepts for high availability.
Ethernet-APL Rail Field Switch
The Ethernet-APL rail field switch from FieldConnex® is a field switch for installation in a control cabinet or junction box. It connects Ethernet-APL spurs to the plant’s Ethernet backbone. It draws power for itself and the spurs from external auxiliary power.
Ethernet-APL Field Switches
Ethernet-APL fField switches provide power to the spur line where the instrument is connected. The spur has lower requirements for signal strength and power. Two types of field switches enable any kind of topology—the Ethernet-APL field switch and the Ethernet-APL rail field switch for DIN rail mounting.
The Ethernet-APL field switch for Zone 1 / Div. 2 installation receives power from the trunk. It connects APL spurs to the trunk. Outputs are intrinsically safe, supporting connections into Zone 0 / Div. 1.
Ethernet-APL Power Switch
The Ethernet-APL power switch connects the Ethernet-APL network to the facility Ethernet or backbone. It also provides power to the trunk line. This power switch is typically installed in the cabinet inside the control room and is externally powered.
At a Glance
- Cable lengths of up to 1,000 m: spur up to 200 m, trunk up to 1,000 m
- Power supply of up to 50 field devices. Up to 90 W possible.
- High transfer rates: 10 Mbit/s, full-duplex
- Download approx. 100 configuration parameters per field device in only a few seconds
- Intrinsic safety protection easy to apply
- Simultaneous transmission of data and power along the same two-wire cable
Technical Facts
- Connection: Screw-type, spring-clamp, M12, RJ45 (in cabinet only)
- Reference cable type: IEC 61158-2, Type A for intrinsic safety
- Cable cross section: 0.324 ... 2.5 mm2 / AWG 22-14
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