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glossary:glossary_r [2017/02/16 10:07]
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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 [[https://www.raspberrypi.org/|RASPBERRY PI FOUNDATION]] provide low-cost, high-performance computers that people use to learn, solve problems and have fun.  [[https://www.raspberrypi.org/|RASPBERRY PI FOUNDATION]] provide low-cost, high-performance computers that people use to learn, solve problems and have fun. 
  
-Two current models of single board computer...+Two current models of single board computer running LINUX based system with several development environments...
  
-Raspberry Pi Zero (aka Pi0) +Pi Zero (aka Pi0)  
 + 1 GHz single-core CPU, 512 MB RAM, HDMI, USB and 40 pin GPIO (~ £4)
  
-- 1 GHz single-core CPU, 512 MB RAM, HDMI, micro USB and 40 pin GPIO (~ £4) +Pi 3 B (aka Pi3) 
- + 1.2 GHz quad-core CPU, 1 GB RAM, Ethernet, Wireless, Bluetooth, HDMI, 4 x USB and 40 pin GPIO (~ £35)
-Raspberry Pi 3 B (aka Pi3) +
- +
-1.2 GHz quad-core CPU, 1 GB RAM, Ethernet, Wireless, Bluetooth, HDMI, 4 x USB and 40 pin GPIO (~ £35)+
  
  
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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.1487239622.txt.gz · Last modified: 2017/02/16 10:07 by WortingUK