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glossary:glossary_r [2017/02/16 10:10] – external edit 127.0.0.1 | glossary:glossary_r [2020/03/10 17:43] – [RailCom] michael_smith |
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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. |
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RailCom works by having the command-station/booster stop driving the rails between DCC packets, during the inter-message idle packets, and 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, during the inter-message idle packets known as the "cutout", and then the decoder generates a 20 mA serial encoded signal on to the track. The data output by the decoder can be 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 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 in only transmitted out by the decoder in response to a command sent by the command station. this data is received and decoded by the one and only "global" detector on the layout. The data in channel 2 can be up to 36 bits in size. |
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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. |
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| ===== Reversed Linked Section Control ====== |
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| 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\\ |
[[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 ====== |
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