The PLUS transceiver provides a communication interface which is applicable also for further applications where high reliability and functional safety are key.
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Aircraft data networks – less wires – from avionics to cabin

Aircraft Wiring = Significant Weight and Complexity

Aircraft wiring contributes significantly to the weight and complexity of the overall aircraft. Today’s passenger aircraft will typically contain between 200 and 500 km of cables. On the A380, there are more than 100’000 wires constituting 470 km and weighing 5’700kg along with 40’300 connectors. Not included in these figures are the harness-to-structure fixation components such as hooks and cable ties (ca. 30% additional weight). Today’s traditional avionics systems consist of separate power and data networks with data networks accounting for about 40% of the overall electrical wiring in an aircraft.

Less Wires = Lower Costs

Besides the lower procurement costs for less wires, as jet fuel accounts for about 30% of airline costs , a reduction in weight will lead to a significant fuel cost savings over time. E.g., a 100 kg weight reduction will lead for an A320 aircraft to yearly fuel cost savings in the range of 20’000 $ and over a 25 years lifetime of the aircraft to 0.5 Mio $.

Less Wires = Less Emissions

Aircraft emissions can be directly attributed to fuel burn. Each kilogram of fuel saved reduces carbon dioxide (CO2) emissions by 3.16 kg. For an A320 aircraft a 100 kg weight reduction will lead to CO2 reductions of 75 tons per year and for a 25 years lifetime to 1’875 tons.

Less Wires = Faster and Lower Cost Aircraft Manufacturing

As less wires have to be installed this reduces the work effort both in time and costs for the installation of the aircraft wiring and thus the manufacturing of the aircraft. Wiring-related costs during fabrication and installation are estimated at 2’200 $ per kg of wires.

Less Wires = Less Maintenance

Most avionics equipment can be quickly and easily exchanged as soon as the problem has been isolated to a single device. However, when the problem is related to wiring it can mean extended hours of troubleshooting in order to determine the problem.

Less Wires

A means is required in order to reduce the overall amount and therefore weight and costs of wiring in the aircraft.

Power Line Communications = Less Wires

= Lower Costs
= Less Emissions
= Faster Aircraft Manufacturing
= Less Maintenance


Power Line Communications 

An innovative solution reducing the number of wires in the aircraft is the use of Power Line Communications (PLC). With PLC data is transmitted over the existing aircraft Power Distribution Network. The general concept for PLC in an aircraft is shown on the right side and consists of the following main points:

• Data network completely removed
• Single connector for power + data
• Data transmission independent of the underlying power signal
• Communications protocol designed for transmission in harsh environments
PLC provides the following benefits
• Lowers operational costs and emissions through a reduction in aircraft wiring weight
• Lowers the required wiring design and routing effort due to the reduced wiring complexity
• Reduces life-cycle costs of airplane wiring as less maintenance is required.


The PLUS AVIONICS data bus is a PLC protocol and technology platform specifically targeting safety-critical, real-time systems in aerospace applications. It has been designed around:

• A proven standard from other industries for the physical layer (IEEE 1901)
• A proven avionics standard for bus arbitration (ARINC 629)
• Custom optimizations and additional protocol layers

One of the main design goals has been to use the available bandwidth from the broadband transmission in order to optimize the data availability and integrity rather than simply increasing the data rate.

The PLUS AVIONICS protocol works on top of any power distribution network without requiring any modifications to the existing wiring. The signal is modulated independently of the underlying power signal. PLUS AVIONICS fullfils the main challenges for the use of PLC within the aircraft:

• Achieving availability and integrity requirements by providing robust communications
• Fulfilling Electromagnetic Compatibility (EMC) requirements for both emissions and susceptibility

Cooperations and Projects

Diehl Aerospace
For aeronautics applications Diehl Aviation and plc-tec AG have entered into an exclusive cooperation for the further development, certification and industrialization of PLUS AVIONICS. This agreement opens the door for Diehl Aviation to use the PLUS technology for the transmission of data over power distribution networks to be integrated into their aerospace products. This also enables customers and partners of Diehl Aviation to utilize the benefits of PLC AVIONICS for their own products and solutions.


Diehl Aerospace together with partner HSLU have won the 2017 Crystal Cabin Award for Cabin Systems for “Power Line Communication (PLC) for Aircraft.”

Lucerne University of Applied Sciences and Arts (HSLU)
The Competence Center Intelligent Sensors and Networks is the major research partner of the plc-tec, e.g. in cooperations in several EC and LUFO (German aerospace research program) projects.


EC Project TAUPE
Project Description: Demonstrate a TRL of 4 for PLC and Power over Data (PoD) technology using the Cabin Lighting and Communication System (PLC), the Cockpit Display System (PoD) and optimizing the architecture of the system for power and data transmission in terms of topologies, EMC, security, integrity of data, etc. Members of plc-tec defined an optimized solution for arc fault detection using additional sensing components within the PLC coupling module. This solution has since been patented.

Project Description: Consolidate and extend the efforts of several independent projects by improving the IMA2G Distributed Platform Solution (modular data architecture). The application of PLC was one of two new technologies that was additionally evaluated within the project. Members of plc-tec were responsible for providing the PLC technology within the project (PLUS technology). PLUS AVIONICS was used to enable communications for the Ventilation Control System. Control between RPC (Diehl Aerospace) and FANs (Nord Micro) was realized with PLUS. The PLC technology was seen as a major success story by both the project partners and the EC.


Project description: Design, develop, manufacture and validate the advanced electrical power distribution system (EPDS) based on Multifunctional Power Network with Electrical Switching. This will be a key component in the creation and demonstration of the Multifunctional Fuselage demonstrator being developed within Clean Sky 2 LPA IADP platform 2. The technical areas of work will cover advanced architectures for the Electric Power Systems (EPS) including Power Electronic Switches based on Solid-State Devices, onboard communication networks and Power Line Communication (PLC). plc-tec’s research partner HSLU is responsible as a work package leader for providing the PLC (PLUS AVIONICS) technology.


Project Description: More Electric and Connected Aircraft (MECA) is one of the most promising enablers to reach Flightpath 2050. But MECA asks for more electrical systems, which exchange more data that can be safety critical, and consume more electrical power leading to higher thermal dissipation. This leads to complexity, weight penalty and increased exposure to intended (cybersecurity) and unintended (ElectroMagnetic Compatibility) interference. Overcoming these barriers requires an interdisciplinary cooperation and, in this context, the ADENEAS project emerged, aiming at paving the way for a safe, light, self-configuring, autonomous and modular power and data distribution network that is scalable to all aircraft sizes. ADENEAS stands for Advanced Data and power Electrical NEtwork Architectures and Systems. It is a H2020 project funded by Europe, which started in February 2021 and will run for 36 months. It has a budget of more than 4M€ and a consortium of 9 partners led by Fokker Elmo. plc-tec leads work package 3 which aims to develop a scalable data bus solution for communicating data over the aircraft power distribution network using Power Line Communication (PLUS AVIONICS) technology.

University of Applied Sciences and Arts North Western Switzerland – FHNW

Project Description: plc-tec partners with FHNW Institute of Automation in this project funded by the FORSCHUNGSFONDS AARGAU. The goal of this project is to optimize the analog circuits of the PLUS modem prototype for Electromagnetic Compatibility (EMC) while investigating new circuits for reducing the size, weight

PLUS Avionics Whitepaper


Lorem ipsum dolor sit amet, Power Line Communication for Safety Critical Applications (EC ASHLEY Project 2017)
PLUS Avionics Wing Flap Demonstrator (2019)
Diehl Power Line Communication for Avionics

PLC Train Backbone (PTB)

Reliable train communications backbone for the intelligent freight train

Eco-friendly Transportation

To encourage eco-friendly transportation and achieve climate neutrality by 2050, the European Commission (EC) has declared 2021 the European year of rail. This is motivated by the fact that transport represents 25% of the European Union (EU) greenhouse gas emissions with rail being responsible for only 0.4%. The goal is to massively shift road transport, which currently carries 75% of inland freight, onto rail transport.

The freight train has hardly changed in the last decades. The high degree of manual processes and the low level of automation leads to competitive disadvantages, including high shunting costs (last mile) and long unproductive downtimes. In addition, the transport structure changes due to deindustrialization: smaller units to be transported have to travel over shorter transport routes.

A continuous power supply and data communication in freight trains is a prerequisite to enable intelligent train applications and innovation leaps with automation, telematics and digitization. The coupling between the wagons is a crucial component here, since it must couple power and data lines of the wagons, besides the mechanics and the compressed-air lines.

Therefore, the key element for the future Intelligent Freight Train (IFT) is the Digital Automatic Coupler (DAC) which will couple automatically not only the mechanics and the air brake pipes but also the power and data lines. With power and data lines across the whole freight train the DAC is key for enabling the digitalization and automation of the freight train and thus the rail freight traffic.

DACs must work reliably in the harsh freight train operational environment. A key element in providing a reliable electric coupling of the DAC is to reduce the number of electric contacts that need to be coupled. For achieving this goal, a PLC solution can provide a unique advantage as the electric power contacts can be used for data communications.

Power Line Communication Train Backbone

The Power Line Communication Train Backbone (PTB) based on plc-tec’s PLUS technology has been designed as a train backbone network in which PLC is used for data communication via the power distribution network on the freight train. As PTB transmits data over the power line of the train and the respective electric power pin contacts in the e-coupler of the DAC there is no need for any additional data pin contacts in the DAC. This represents a major advantage regarding the reliability of the data communication because fewer pin contacts in the DAC means lower susceptibility to faults, lower maintenance costs and longer life cycle.

PTB has been designed to incorporate ALL signals of the IFT, including control and monitoring signals of the (electro-pneumatic EP) brake, automatic brake test, train energy system, multiple traction, and on-board train integrity monitoring. New protocols for PTB have been designed on top of the PLUS technology taking these requirements into consideration. 

The PLUS Train Topology Discovery (PLUS-TTD) protocol is used to automatically detect the order and orientation of all the wagons in the train for the train inauguration. The PLUS-TOKEN protocol enables deterministic access control using a master-slave based token passing protocol. It is optimized for the linear train topology and provides low latency, and high reliability with no single point of failure. PTB provides a Quality of Service (QoS)-based solution for safety-critical multiplexing to enable the coexistence of safety-critical and non-critical applications.

Cooperations and Projects


HSLU and plc-tec participate in the DAC4EU project where the PTB technology is one of the communication technologies for the train backbone is currently tested. PTB modem prototypes have been integrated into the wagons.

European DAC Delivery Programme EDDP

HSLU and plc-tec participate in the expert groups in workpackage WP1, e.g. in the assessment of the communication technologies for the train backbone and of the power distribution system. The PTB technology is on the short list of technology candidates for the train backbone.



PLUS PTB Whitepaper


PLC Train Backbone (PTB) Demo with VOITH and HVLE (2021)

PLC Train Consist Network PCN

Reduced costs for the passenger train consist data network due to less wires and connectors

Ethernet networks are used today for networking passenger information devices on trains. However, these are expensive and require a large amount of cable with corresponding space requirements and weight. This can be improved by using Power Line Communication (PLC) to transmit data via power supply cables.

There is continuous price pressure in the rail industry. A further reduction in costs in on-board passenger information seems only possible with new concepts.

Passenger Information Systems (PIS) in today’s trains consist, among other things, of audio components (amplifiers, emergency call stations) and an increasing number of displays in various technologies (TFT, LED, OLED, …). Today, these devices are typically interconnected via a train-consist internal Ethernet network (Figure 1). A modern train has several hundred PIS devices. The length of the required network cables can be over 50 km per consist. Together with the required Ethernet switches, this is a significant cost, space, maintenance and increasingly weight factor.

With data transmission using Power Line Communication via existing power supply cables to the individual PIS devices within a train consist, a considerable part of the Ethernet network can be eliminated, which would significantly reduce costs and cable space.

With plc-tec’s PLC Consist Network (PLUS-PCN) solution, based on the Power Line data bUS technology and developed in close cooperation with the research partner HSLU and the leading PIS vendor ANNAX-Wabtec, the existing switch Ethernet-based PIS network can be completely removed for intra-consist communication. The Ethernet-based backbone network remains, but interfaces directly to the PLC modems via the power supply, eliminating the need for Ethernet switches. This provides a cost-effective solution using the existing power distribution cabling.

This architecture involves the use of two PLUS-PCN Concentrators per consist (one at each end) connected to the Ethernet backbone network. This provides equivalent redundancy to an Ethernet-based solution. A PLUS-PCN modem including coupler and power supply unit for the 36 V DC train PDN is integrated in each application terminal. The power supply and coupler versions meet all relevant relevant railroad standards for electronic devices and EMC. Suitable interfaces to the existing application devices have been developed, which support the VLAN/IP address support.

Consist Control Cabinet

For a field test, a prototype system consisting of four PLUS-PCN prototypes was integrated into a BLS passenger train (MUTZ Stadler). A PLUS-PCN concentrator was connected to an existing PIS switch. One PLUS-PCN modem each was installed on a TFT display, a side indicator and an audio amplifier.

The applications that run on PLUS-PCN are audio announcements, TFT display updates, and page display updates.
The PLUS-PCN prototype system has been running in normal train operation since January 2019, in temperatures below 0 °C in winter and above 40 °C in summer. Through a combination of remote monitoring of the passenger information system in conjunction with the connection to the PLUS-PCN modem prototypes, the system is constantly monitored.

Tests have shown that the total throughput of the new PLUS-PCN network is approximately 20 Mbit/s. While this is less than the 100 Mbit/s specified for Ethernet, it is sufficient to support the necessary PIS applications (including streaming applications expected in the future).


Key Benefits of PLUS PCN


Savings from PLUS PCN by eliminating Ethernet cables and some of the Ethernet switches


• Less material costs due to fewer cables, connectors and switches
• Less installation costs when laying the cables and devices in the train
• Less maintenance costs

Space requirements
• Less space required for the data network due to fewer cables, connectors, brackets, etc.

• Less weight: The weight of a vehicle influences the wear and tear of the infrastructure (rails and switches) and has thus become an important purchasing criterion for rail operators. The maximum weight of components such as PIS systems is specified in tenders. Exceeding this limit is penalized.

Smart Grid

PLUS Smart Grid for cost-effective data communication for monitoring, protection and automation of the Medium Voltage Grid

Worldwide pressure is increasing on the Distribution Grids with the rapid introduction of Distributed Renewable Energy Resources such as wind/solar farms, and loads such as electric vehicles. Future grids must be kept robust to accommodate new energy flow patterns with a high time dynamic characteristic due to the vast amount of spatially distributed sources with time-varying generation. This calls for smart monitoring, protection and automation (MPA) techniques which have been proven successfully already for the Transmission Grid. However, some MPA applications demand high (Mission- & Time Critical – MTC) communication requirements in terms of latency, reliability, etc. which are today only fulfilled by costly broadband networks e.g. fiber optic.

PLUS Smart Grid enables such a cost-effective communication network by transmitting MTC MPA data over the existing medium voltage grid cables and wires (underground and overhead) between MPA devices, e.g. in the Secondary Substations.

PLUS Smart Grid integrates in addition a highly accurate external reference time PLUS Time Sync in order to support e.g. synchrophasor applications. GPS is generally not seen as suitable in the Distribution Grid as it is often not possible to install the necessary antenna within all Secondary Substations and there are major concerns with the susceptibility of the GPS signal to attacks and spoofing.

PLUS Smart Grid has been installed and tested in a SS cluster in a distribution grid of Bernische Kraftwerke BKW near Berne.


Mission-and-Time-Critical robustness, determinism, low latency

• Robust real-time transmission between SSs with physical data rates of several Mbps, low packet loss and latency down to the range of 5 ms.
• Bus arbitration based on a deterministic protocol
• Peer-to-peer architecture with no single point-of-failure
• Stateless connections minimize setup and recovery times
• Multiplexing of multiple data services onto a single bus

Further information
• PLUS Smart Grid: Smart Grid Multi-Service Communication Network Pilot
• PLUS Time Sync: Precise Time Synchronization of Phasor Measurement Units with Broadband Power Line Communications