Radio ripple control technology
The radio ripple control technology is used - similar to the audio frequency ripple control technology - for tariff switching of electricity meters or for load control (demand-side management, DSM for short) of consumers in the supply network of an energy supply company . However, the power grid itself is not used as the transmission path, but a radio frequency. Classic radio ripple control technology uses a long-wave radio frequency . The latest variant of radio ripple control uses a frequency in the VHF range based on pager radio . This article describes the classic radio ripple control based on longwave technology.
development
With the postal reforms carried out from 1989 to 1996 (the postal structure law came into force in mid-1989) and the associated loss of the sovereign rights of the German Federal Post Office , the introduction of a radio ripple control procedure was also possible in the Federal Republic of Germany. Such systems already exist in other countries such as Great Britain (long wave) or the USA ( UHF / VHF band). In Great Britain, the control signals are transmitted in a phase-modulated manner together with amplitude-modulated speech or music signals via public long-wave transmitters .
At the beginning of the 1990s there were efforts in Germany to set up a network control procedure with long-wave transmitters that could be received nationwide. In particular, the pent-up demand for ripple control transmission technology in the new federal states after reunification gave the impetus to set up a central radio ripple control transmission system for all of Germany. Their investment and operating costs would have to be significantly lower than the construction of conventional audio frequency ripple control transmission systems at the individual network operators. The time signal transmitter DCF77 of the former Deutsche Bundespost Telekom , which was already of sufficient reception quality throughout Germany and beyond, served as a model.
In 1992 the VDEW then formed an ad hoc working group "Ripple control over radio", whose task was to prepare a study on the technical feasibility and economic efficiency of radio ripple control. The study proved that radio ripple control technology was technically possible and was even significantly cheaper compared to audio frequency ripple control after a critical mass (approx. 3% of the ripple control receivers installed at that time) was exceeded.
From November 1992 an industry working group set itself the task of defining the system and defining interfaces and technical features. At the same time, Deutsche Telekom carried out a field test in 1992 and 1993 to determine the bit error rate in the intended long-wave channel (Mainflingen transmitter, 129.1 kHz) at various baud rates . The DeTeWe Funkwerk Köpenick GmbH provided radio test receivers for this purpose.
In August 1993 the operating company Europäische Funk-Rundsteuerung GmbH (EFR) was founded. At that time the shareholders were the Berliner Kraft- und Licht AG (BEWAG), the Isar-Amperwerke in Munich, the Franconian overland plant in Nuremberg (now N-ERGIE ) and the overland plant in Lower Franconia in Würzburg. Also from August 1993 field tests were carried out with the first prototype radio ripple control receivers. In the middle of the following year, the first production samples of the radio ripple control receivers were installed at BEWAG. Series delivery started in 1995.
Transmitters
The radio ripple control is currently operated via three long-wave transmitters, the transmission systems in Mainflingen near Frankfurt am Main , the Burg transmitter near Magdeburg and, since 2006, the Lakihegy transmitter near Szigetszentmiklós , Hungary. The two transmitters in Germany - belonging to the Telekom subsidiary T-Systems until the end of 2007 - are now owned by Media Broadcast GmbH and are operated on behalf of Europäische Funk-Rundsteuerung GmbH (EFR).
The ripple control transmitter in the Mainflingen transmitter, where the DCF77 time signal transmitter is also located, works with a nominal power of 100 kW on the frequency 129.1 kHz (DCF49), the Burg transmitter with 50 kW on 139 kHz (DCF39) and the Lakihegy transmitter 100 kW at 135.6 kHz (HGA22).
Radio ripple control receiver
With radio ripple control technology, in contrast to audio frequency ripple control technology, not every switching command is necessarily transmitted by the transmission center at the desired switching time. The radio ripple control receivers have the function of a programmable timer , which automatically carries out its switching operations. Only the regular time synchronization of the receiver-internal clock, parameter changes of switching times or time-independent circuits such as e.g. B. the brightness-dependent switching of street lighting systems . The radio ripple control receivers contain a long wave receiver and are legally considered a radio receiver.
protocol
Most telegrams are a few bytes long (approx. 1 second), but a length of 30 bytes is possible. The response time is a few seconds. A telegram is sent asynchronously with 200 baud and 340 Hz shift, with 8 data bits and one even parity bit . The protocol is standardized in IEC 60870-5 or in the 870-5 (old system). A data telegram consists of 7 header bytes, a user data field with up to 16 bytes and a few leading bytes:
- Start 68h (h = hexadecimal)
- L Feld
- L Feld Wiederholung
- Start 68h
- C Feld
- A Feld
- CI Feld
- User data 0-16 Byte
- Prüfsumme
- Stop 16h
After the start character 68 hex , the length field (L) follows, which is sent twice, followed by another start character (68 hex ). This is followed by the C field, the A field and the CI field. The L defines the number of user data bytes plus 3 (for C, A, CI). The C field (control field, function field) specifies the direction of data and is responsible for other tasks. The A field (address field) indicates the recipient address; Addresses from 1 to 250 can be assigned for individual users. Address 255 (FF hex ) is used to send information to all participants (broadcast). This is z. B. used for the time / date update (every 10 seconds). The meaning of the CI field (control information field) is not yet entirely clear. It may be used as an addressing extension. Mostly it is identical to the A-field. The user data field is followed by a checksum, which is formed from the last significant byte of the arithmetic sum of C, A, CI and the last user byte . At the end the stop character 16 hex is sent. Most of the telegrams are sent a second time. Currently the length varies between L = 5 to L = 13. Sometimes the string "DCF49 TEST" is sent in the user data field with L = 13, C = FFh, A = FFh (broadcast), CI = FFh.
A more detailed protocol specification can be found in the associated DIN standard.
With Versacom and Semagyr transmission protocol according to DIN 43861 part 3 and 4 for ripple control => 7 byte header, length of the freely assignable information field 2-15 bytes, 1 byte checksum and stop byte according to FT1.2 generates a total length of 24 bytes per Data telegram.
- Start 68h (h = hexadecimal)
- L Länge Userdaten
- L Wiederholung
- Start Wiederholung 68h
- Telegrammnummer (07-F7h + 10h-Inkrement je Telegramm)
- Anwenderadresse 1.Byte
- Anwenderadresse 2.Byte
- Userdaten 2-15 Bytes
* Funktions- und Adressbyte
* max. 5 Byte Funktionsspezifikation
* Einzel- oder Gruppenadressierungsinformationen und Relaisinfo
- Prüfsumme
- Stop 16h
Individual addressing
3 bytes are available for the address for individual addressing. This means that 16,777,215 recipients can be individually addressed.
Most significant Bit Least significant Bit
||-|-|-|-|-|-|-|-||-|-|-|-|-|-|-|-||-|-|-|-|-|-|-|-||-|-|-|-|-|-|-|-||
1 Byte 2Byte 3Byte 4Byte
||Relaiszuordnung|| Einzeladresse ||
| | | |
| | | RelaisNr.1
| | |
| | |
| |RelaisNr.6
| Nicht benutzt
Nicht benutzt
Wenn Relais Bit=1 dann Relais geschaltet.
* Frame empfangen: Sonntag 10 Jun 17:02:19 2012 Start-Marke: 68 L-Feld: 0a Start-Marke: 68 C-Feld: 65 Telegramm-Nummer: 6 Adresse 1 (A-Field): 00 Adresse 2 (CI-Field): 00 RAW-HEX-DATEN: 00 78 02 91 00000000 01111000 00000010 10010001 . x . . ea 06 0c 11101010 00000110 00001100 . . . Nutzdatenlänge: 7 byte Checksumme: 6c End-Marke: 16 Übertragene Zeit: 17:02 Datum: 10.06.12
costs
At Energieverbrauch.de the monthly costs per radio subscriber / receiver are € 0.65. The radio ripple control receiver costs 100 euros (large numbers). Receiver modules are available for 20 euros (e.g. types FUMx FSK).