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Copper - an outdated technology or power basis for the IIOT?

SPE: Limits o of single-pair cabling
Rainer Schmidt
Business Development Manager Cable Systems, HARTING Electronics
Copper - an outdated technology or power basis for the IIOT?

Are copper-based conductors an outdated technology or are they the basis for IIoT and emerging Ethernet networks? Reutlingen University’s NG200 joint project with HARTING and LEONI explored this question with the aim of demonstrating how well-known and relatively new copper-based transmission solutions compare to WLAN and fibre optic cables. In this context, the focus was on possible data transmission bandwidths with simultaneous power supply, depending on the transmission path.

Powerful data and information networks comprise a basic requirement for the requisite development steps in automation technology and for Industry 4.0 and IIoT. The NG200 joint project of Reutlingen University, in cooperation with HARTING and LEONI, demonstrates just how much power copper-bound communication
technology holds in store.

As far as communication standards go, the beneficiaries are TCP/ IP and Ethernet. For a long time, wireless technologies such as Wi-Fi/WLAN or 5G were favourites in the battle of available communication media. With the advent of Single Pair Ethernet (SPE), the balance of power is shifting substantially once again.

The research was intended to explore the performance limits of copper-wired networks – both for de facto communication in terms of bandwidth in MHz or data transmission capacity in Gbit/s and the coding used, such as PAM16, as well as the simultaneous transmission of supply voltages for end devices. The simultaneous transmission of power and data via Power over Ethernet (PoE) or Power over Data Line (PoDL) are well-known, and the ability to employ remote power supply represents a lasting advantage over wireless and fibre optic transmission.

Specifically, channel models were developed and examined that included all transmission parameters depending on bandwidth (frequency up to 2.5 GHz), transmission reliability (BER of 10-12), the channel length (10-1,000m), the number of pairs in such a channel (here, the smallest unit is a pair = a “twisted pair”/1TP) and the possible power for remote supply (up to 100W).

"With the advent of Single Pair Ethernet (SPE), the balance of power is shifting substantially once again."

Rainer Schmidt, Business Development Manager Cable Systems, HARTING Electronics

The channel models are matrices that can comprehensively describe channel properties by way of mathematical parameters – S-parameters in Touchstone format. This in turn permits simulations of channel behaviour to be run. The simulation results help to minimise the significant effort involved in developing and manufacturing prototypes for cables and connectors and the subsequent tests in the laboratory.

HARTING T1 SPE connector
HARTING T1 SPE connector according to IEC63171-6

The investigations were then completed by calculations and tests with power transmissions of up to 100W and the associated cable heating. The results predicted via channel simulation were largely confirmed in the practical tests. The results of the investigations were summarised in a so-called “NG 200 matrix” and show the correlation between bandwidth, range, line coding and transmission rate for a given cable design and a given number of pairs. 
This turns the NG200 matrix into a dynamic database that can be harnessed to calculate, evaluate or predict any application.

Expanding the NG200 matrix with the symbol error rate also enables conclusions to be drawn about the best coding method (PAM) to be used.

Conclusion: In future, the NG 200 matrix that is created can be used to quickly and reliably predict necessary cabling parameters depending on the bandwidth, length and the coding method employed. This is particularly helpful when developing more powerful Ethernet components and the associated cables and connectors.

High symmetry of the HARTING T1 to ensure 2.5GHz

In the future, cable and connector designs up to 2.5 GHz should be examined more closely to discover their technical possibilities and approach a desired cost/benefit ratio. A good example is the HARTING T1 SPE connector according to IEC63171-6, which already has specifications up to 2GHz and is tested.
In addition to the NG200 matrix, the joint project also yielded practical findings that relate to the performance of data cables and connectors. With the technological means available today, the production of data cables and connectors up to 2.5GHz is possible. And if there is a corresponding demand in the market, it can also be shown to be cost-effective. Again, by way of comparison: Today, for a 4-pair system, there are Cat.7A cables (1000MHz) and correspondingly powerful connectors, e.g. according to IEC 61076-3-104 Tera™ (the RJ45 can no longer be Valuable notes used for this high frequency range). The key to success with these product designs is the special paired shielding. There is PiMF construction (Pair in Metal Foil) for the Cat.7A cable and chamber shielding for the Tera™.
Consequently, a well-shielded 1-pair system set up in a highly symmetrical manner can be operated with more than twice the bandwidth used today. These 1-pair systems are operated using Single Pair Ethernet (SPE) and are in part already available on the market – see the T1 Industrial from HARTING.
The result is a performance boost by a factor of 2.5 of high-speed transmission via shielded copper-bound systems! Combined with 100% availability and remote power supply for devices, copper technology is not outdated at all, but rather a declaration of war on fibre optic cable and wireless in the LAN area – as well as a basis for IIoT!

Valuable notes

  • The results of the joint project and the NG200
    matrix will be incorporated into international
    standardisation. Consequently, preparatory work
    is under way on a standard proposal (NWIP/TS)
    for modelling information technology transmission
    channels for ISO/IEC JTC 1/SC 25/WG 3.
  • ISO/IEC JTC 1/SC 25/WG 3 is the body that
    developed the ISO/IEC 11801 series
    (structured cabling) and, with the amendment
    of ISO/IEC 11801-3, was the first to present a
    comprehensive cabling standard for SPE
    cabling in the industrial sector.
  • The detailed final report for the NG200 joint
    project is available in the TIB (Technical
    Information Library) under the research
    number 03FS15010.
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