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glossary:glossary_r [2017/02/16 10:10]
WortingUK [Raspberry Pi]
glossary:glossary_r [2020/03/12 05:27] (current)
michael_smith [RailCom]
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 A relatively new DCC standard to implement return messages from a train/​decoder. ​ It was originally developed by Lenz, and is now a NMRA standard. ​ Further development is in progress by European companies, and this extension is called RailComPlus.  ​ A relatively new DCC standard to implement return messages from a train/​decoder. ​ It was originally developed by Lenz, and is now a NMRA standard. ​ Further development is in progress by European companies, and this extension is called RailComPlus.  ​
  
-RailCom works by having the command-station/​booster stop driving the rails between DCC packets, during the inter-message idle packetsand then the decoder generates a 20 mA serial encoded signal. ​ ​This ​is decoded by the command-station and/or other RailCom decoder(s).   +RailCom works by having the command-station/​booster stop driving the rails between DCC packets ​and placing a short circuit across the track for approx.470uS, during the inter-message idle packets and is known as the "​cutout", ​then the decoder generates a 30 mA serial encoded signal ​on to the trackThe data output by the decoder can be in either 1 or 2 "​channels"​ or both, Channel 1 is for the loco address that the decoder will respond to. Channel 1 data is unsolicited data 2 (6 bit) bytes in size called datagrams, that is to say the data is sent out without being requested and is received and decoded ​by "​local"​ detectors around the layout in track "​blocks"​. Channel 2 data can be up to 6 (6 bit) bytes and is only transmitted out by the decoder in response to a command sent by the command station. this data is received ​and decoded by only one "​global"​ detector on the layout. Therefore the maximum data transmitted in the DCC cutout period for CH1 and CH2 is 8 bytes (datagrams).     ​ 
 +  
 RailCom/​Plus allows: the identification of unknown trains; block occupancy; transmission of train information,​ such as its actual speed; and more efficient '​on-the-main'​ programming. ​ See: [[http://​www.nmra.org/​sites/​default/​files/​s-9.3.2_2012_12_10.pdf|NMRA standard]] and [[http://​www.esu.eu/​en/​support/​white-papers/​railcomplusr/​|ESU RailCom Plus]].  ​ RailCom/​Plus allows: the identification of unknown trains; block occupancy; transmission of train information,​ such as its actual speed; and more efficient '​on-the-main'​ programming. ​ See: [[http://​www.nmra.org/​sites/​default/​files/​s-9.3.2_2012_12_10.pdf|NMRA standard]] and [[http://​www.esu.eu/​en/​support/​white-papers/​railcomplusr/​|ESU RailCom Plus]].  ​
  
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 The Positive voltage goes to the Negative part of a circuit and vice versa. ​    \\ Used to reverse DC motors in trains. The Positive voltage goes to the Negative part of a circuit and vice versa. ​    \\ Used to reverse DC motors in trains.
  
 +
 +===== Reversed Linked Section Control ======
 +
 +This is a method for the control of the switching of power to sections of track on a model railway layout. ​ It is described in Technical Bulletin T32/1 of April 2002.\\ Also see [[public:​morag:​start#​files_from_morag_yahoo_group|here]] for articles on the subject.
 ===== RFID ===== ===== RFID =====
 **R**adio **F**requency **ID**entification\\ ​ **R**adio **F**requency **ID**entification\\ ​
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 [[http://​en.wikipedia.org/​wiki/​RFID|Wikipedea article]]\\ ​ [[http://​en.wikipedia.org/​wiki/​RFID|Wikipedea article]]\\ ​
 [[glossary:​thomasrfid|MERG Demonstration]]\\ ​ [[glossary:​thomasrfid|MERG Demonstration]]\\ ​
 +**MERG RFID systems**\\ ​
 +The tags generally used in MERG RFID systems have a 40 bit ID number, that is 5 bytes, when transmitted there is then a sixth byte added which is a checksum for data integrity. The tag readers transmit the data over a serial link using [[glossary_h#​ascii_hex|ASCII Hex]]. The start of a message is STX <​0x02>​ this is followed by the 12 ASCII Hex characters of the data plus checksum, some readers then send LF <​0x0A>​ CR <​0x0D>,​ and finally ETX <​0x03>​. This makes a message of either 14 or 16 bytes in total.\\ ​
 +The MERG Concentrator replaces the STX with a reader identification letter, A to H or I to P. For CBUS the incoming data is converted back to its original 5 bytes and checked against the checksum. These 5 bytes are then transmitted as bytes 3 to 7 of an 8 byte message. <​Opcode><​DN/​NN Hi><​DN/​NN Lo><​data0><​data1><​data2><​data3><​data4>​
 ===== Risk assessment ====== ===== Risk assessment ======
  
glossary/glossary_r.1487239849.txt.gz · Last modified: 2017/02/16 10:10 (external edit)