GB2407013A - Signalling via mains wiring - Google Patents

Signalling via mains wiring Download PDF

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Publication number
GB2407013A
GB2407013A GB0322785A GB0322785A GB2407013A GB 2407013 A GB2407013 A GB 2407013A GB 0322785 A GB0322785 A GB 0322785A GB 0322785 A GB0322785 A GB 0322785A GB 2407013 A GB2407013 A GB 2407013A
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GB
United Kingdom
Prior art keywords
neutral
live
earth
mains
wires
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB0322785A
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GB0322785D0 (en
Inventor
Peter John Jones
Philip Williams
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Individual
Original Assignee
Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to GB0322785A priority Critical patent/GB2407013A/en
Publication of GB0322785D0 publication Critical patent/GB0322785D0/en
Publication of GB2407013A publication Critical patent/GB2407013A/en
Withdrawn legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B3/00Line transmission systems
    • H04B3/54Systems for transmission via power distribution lines
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B2203/00Indexing scheme relating to line transmission systems
    • H04B2203/54Aspects of powerline communications not already covered by H04B3/54 and its subgroups
    • H04B2203/5429Applications for powerline communications
    • H04B2203/545Audio/video application, e.g. interphone

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)

Abstract

Sending signals over the live and neutral wires of domestic wiring, encounters problems associated with appliance switching and varying impedance due to changes in the load. These problems are reduced by using the neutral and earth wires. A switch or sensor A actuates encoder B, which has a user set code e.g. of 12 bits, which modulates an FM modulator C. The modulator uses two different frequencies to represent binary values and the pulse width may also be different for the binary values. The RF pulses are impressed across the neutral and earth conductors of the mains wiring, via a capacitor G. Additionally the signal may also be applied to the live conductor via capacitor R.

Description

Sicnallin via the mains wiring The domestic mains wiring consists of 3
cables, Live Neutral and Earth and there exists examples of utilising these cables for communication purposes. The best known being the voice intercom frequently in the form of a baby alarm.
These intercoms could be plugged into any mains sockeyes and used Live and Neutral Lines onto which was superimposed the audio signal either as plain audio or in more elaborate arrangements the audio was incorporated as part of a modulated signal.
The disadvantages of this arrangement were twofold, both mains sockets must be wired to the same phase of the mains suppler, and the ever present 50 or 100 hz hum had to be eliminated from the audio circuits.
Nowadays there is a lot more noise superimposed on the mains wiring due to the huge increase in domestic appliances which rely on switch-mode power supplies. Examples are light dimmers, fluorescent lights, motor speed controls and computer power supplies as well as thermostats all of which can superimpose high amplitude spikes on the mains. The mains wiring is therefore much noisier now than it was when the mains intercoms were introduced. In addition, the X10 protocol addresses the use of Zero (grossing techniques when signalling via mains wiring using Lisle and Neutral.
The arrangement, which is the subject of this application, adopts the significant step of using the Neutral and Earth wires of the mains. This has the following advantages.
1) The amplitude noise mentioned before is mainly associated with the Live wire as it is the live circuit which is switched by Thyristors and switch-mode power supplies.
2) The RF Impedance of the Neutral and Earth wire tends to remain constant w hen compared with the Live-Neutral circuits. This allows a superior impedance match to be achieved. The:RF Impedance of the live and neutral circuits will vary during the course of a da: as equipment is switched on. and off and plugged in and out, This particularly applies to the modem use of E.MC Filters which often have fixed capacitors fitted across these lines.
3) In a building such as a school or an office block it is likely that a 3-phase supply is provided. The Neutral and Earth wires are common to a 3phase installation and signals flail] be present in all parts regardless of the phase to vhch the individual socket is connected. This means that it is not necessary, to provide a means of linking the phases together to allow RF signals to pass as would be required in a system using the Live wire.
A further enhancement of the operation can be achieved by coupling a part of the signal to the Live wire as well as the Neutral wire. This reduces the series inductance of the transmission path thus improving signal levels at the receiving end. It also helps overcome the attenuation encountered by the presence of Earth Leakage Trips and Miniature Circuit Breakers as these are frequency double wound and their impedances are equal and opposite.
The system to be described is not for voice transmission but is intended for, but not restricted tot the data necessary to identify a. particular sending station. In its basic form one sender and one receiver is used but a combination of many senders and rno,-e than one receiver is possible.
With reference to Fig 1 and Fig 2 where Fig 1 is the sender and Fig 2 the receiver.
A means of actuation - A - can be a switch, or external sensor initiates the Encoder -B- which generates a code according to its settings. Typically such encoders have address lines which are set by links or slide switches so that the code may be selected by the user thus enabling each sender in a system to have its over code.
The Modulator - C - consists of an oscillator with transmission being initiated by the actuator - A. The data Tom the encoder is used to frequency modulate the modulator such that the frequency shifts in accordance with the l's and O s become fl and f2. In practice these frequencies can be anything from audio to RF.
The modulated signal is sent to the output stage - D - which amplifies and matches the signal to the mains wiring.
The power supply - H - feeds all stages and is fed by transforn:er - F -. The output of the sender is coupled to the Earth wire - E - and the neutra! line - I] - via a capacitor -G-- which should be a good quality mains rated component. In addition the signal is also coupled to the Live conductor via capacitor R -, and this can be shown to provide advantages.
With reference to Fig 2 The signal across Neutral and Earth is passed to the receiver via Capacitor - O - The input stage - I - comprises an amplifier and discriminator which filters out the wanted FM signal and feeds this to the decoder - .T - . The decoder generates an output reflecting the encoder switch or link settings in a form that can be shown by the display unit - K - . This unit might be a numerical or indicator panel as appropriate. In practice the display unit can be latching and provide additional outputs to initiate actions as appropriate to the application.
The power supply -- M - powers the receiver, although it should be noted that the system will work in the event of a power failure as the Neutral and Earth wires will still be intact. It is assumed that a battery backup facility is provided in this case.
The enhancement which uses the Live wire mentioned earlier is connected to the receiver via Capacitor- P - . It has been mentioned that the noise on the mains causes problems for such arrangements but the system described here has immunity to such noise as follows.
Firstly the noise interference is of a pulsed amplitude nature and the use of FM allows the receiver to discriminate between AM and FM signals by conventional amplitude limiting techniques but an additional level of immunity can be provided by the choice olpulse widths as follows.
Noise interference from, say, a light dirnrrer is tied to the mains frequency of 50hz or 1 OOhz in the case of rectified mains and the switch spikes w 11 occur at this rate typically every 1 Om S. By making the bit rate period of the data signify cantly longer than thelOmS noise pulse period, the receiver can be made to ignore any signals either of an amplitude nature or with a pulse repetition rate of this value.
The pulse length representing O is 50mS and I is 1 OOmS both of these pulses is therefore many times longer than any mains related noise.
Pulse width and.FM applies all to improve noise immunity In the working version a 12 bit code is adopted and the pulse width set to 15mS Which gives a word length of 1 80mS meaning some 15 repetitions will talce place in the 3 second transmission.

Claims (3)

  1. Claims i) A communication system using the Neutra] and Earth wires in an
    electrical installation to eliminate the distributed loads and the noise found on the Live to Neutral circuits.
  2. 2) A conrwication system as in 1 and 2 which couples the live and neutral wires together at the same RF potential and phase to eliminate common mode and differential inductance and reduce series inductance.
  3. 3) A communication system using the main Neutral and Earth independent of the live phase in a 3 phase installation 4) A communication system as in I to 4 which utilises pulse widths longer than the maximum duration of noise spikes found on the live to neutral. s
GB0322785A 2003-09-30 2003-09-30 Signalling via mains wiring Withdrawn GB2407013A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0322785A GB2407013A (en) 2003-09-30 2003-09-30 Signalling via mains wiring

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0322785A GB2407013A (en) 2003-09-30 2003-09-30 Signalling via mains wiring

Publications (2)

Publication Number Publication Date
GB0322785D0 GB0322785D0 (en) 2003-10-29
GB2407013A true GB2407013A (en) 2005-04-13

Family

ID=29287056

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0322785A Withdrawn GB2407013A (en) 2003-09-30 2003-09-30 Signalling via mains wiring

Country Status (1)

Country Link
GB (1) GB2407013A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1892843A1 (en) 2006-08-24 2008-02-27 Sony Deutschland GmbH Method for transmitting a signal on a power line network, transmitting unit, receiving unit and system
DE102007062957A1 (en) * 2007-12-21 2009-07-02 Rp-Technik E.K. Power supply line and lighting fixture e.g. lamp, communication providing method, for e.g. building automation, involves executing control sequence based on potential sequence, while maintaining protective conductor at constant potential
EP2280493A2 (en) 2009-06-18 2011-02-02 RP-Technik e. K. Security related communication process on power supply lines and an appropriate network
WO2013143868A2 (en) * 2012-03-30 2013-10-03 Leica Geosystems Ag Buried service detection
CN105575099A (en) * 2015-12-17 2016-05-11 广州市雅江光电设备有限公司 Ground differential signal transmission circuit

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB445748A (en) * 1935-08-27 1936-04-17 Radio Systems Inc Improvements in method and system for distributing signal currents
GB474530A (en) * 1936-05-18 1937-11-03 Gen Electric Co Ltd Improvements in or relating to electric systems of remote control
US3810096A (en) * 1972-09-14 1974-05-07 Integrated Syst Co Method and system for transmitting data and indicating room status
GB2039402A (en) * 1979-01-05 1980-08-06 Robertshaw Controls Co Two-way AC power line communications system
DE3146987A1 (en) * 1981-11-26 1983-06-01 Siemens AG, 1000 Berlin und 8000 München Intrinsically wireless communication system
US4408186A (en) * 1981-02-04 1983-10-04 General Electric Co. Power line communication over ground and neutral conductors of plural residential branch circuits
US4433326A (en) * 1981-02-04 1984-02-21 General Electric Company Power line communication system using the neutral and ground conductors of a residential branch circuit
GB2174273A (en) * 1985-02-14 1986-10-29 Verran Micro Maintenance Limit Method and system of and apparatus for computer LED 220 communication along mains wiring
US5066939A (en) * 1989-10-04 1991-11-19 Mansfield Jr Amos R Method and means of operating a power line carrier communication system

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB445748A (en) * 1935-08-27 1936-04-17 Radio Systems Inc Improvements in method and system for distributing signal currents
GB474530A (en) * 1936-05-18 1937-11-03 Gen Electric Co Ltd Improvements in or relating to electric systems of remote control
US3810096A (en) * 1972-09-14 1974-05-07 Integrated Syst Co Method and system for transmitting data and indicating room status
GB2039402A (en) * 1979-01-05 1980-08-06 Robertshaw Controls Co Two-way AC power line communications system
US4408186A (en) * 1981-02-04 1983-10-04 General Electric Co. Power line communication over ground and neutral conductors of plural residential branch circuits
US4433326A (en) * 1981-02-04 1984-02-21 General Electric Company Power line communication system using the neutral and ground conductors of a residential branch circuit
DE3146987A1 (en) * 1981-11-26 1983-06-01 Siemens AG, 1000 Berlin und 8000 München Intrinsically wireless communication system
GB2174273A (en) * 1985-02-14 1986-10-29 Verran Micro Maintenance Limit Method and system of and apparatus for computer LED 220 communication along mains wiring
US5066939A (en) * 1989-10-04 1991-11-19 Mansfield Jr Amos R Method and means of operating a power line carrier communication system

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1892843A1 (en) 2006-08-24 2008-02-27 Sony Deutschland GmbH Method for transmitting a signal on a power line network, transmitting unit, receiving unit and system
US7962118B2 (en) 2006-08-24 2011-06-14 Sony Deutschland Gmbh Method for transmitting a signal on a power line network, transmitting unit, receiving unit and system
EP2800285A3 (en) * 2006-08-24 2014-11-26 Sony Deutschland Gmbh Method for transmitting a signal on a power line network, transmitting unit, receiving unit and system
DE102007062957A1 (en) * 2007-12-21 2009-07-02 Rp-Technik E.K. Power supply line and lighting fixture e.g. lamp, communication providing method, for e.g. building automation, involves executing control sequence based on potential sequence, while maintaining protective conductor at constant potential
EP2280493A2 (en) 2009-06-18 2011-02-02 RP-Technik e. K. Security related communication process on power supply lines and an appropriate network
WO2013143868A2 (en) * 2012-03-30 2013-10-03 Leica Geosystems Ag Buried service detection
WO2013143868A3 (en) * 2012-03-30 2013-12-05 Leica Geosystems Ag Buried service detection
US9594183B2 (en) 2012-03-30 2017-03-14 Leica Geosystems Ag Method for buried service detection using a mains socket
CN105575099A (en) * 2015-12-17 2016-05-11 广州市雅江光电设备有限公司 Ground differential signal transmission circuit

Also Published As

Publication number Publication date
GB0322785D0 (en) 2003-10-29

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)