Hi Bob; Remember that the "power" wires are also transferring the control packets to the DCC decoder in the locomotive. Also, you probably have an insulated "joint" somewhere in the track, so it is not a complete loop.
If a packet starts from the DCC base unit and goes both ways around a looped wire bus, the two copies of the packet will "collide" about half way around the loop. The result is probably unreadable gibberish as far as the system is concerned, which is somewhat OK as any decoder that wants the packet probably already has seen it. The one remaining problem is that the "junk" packets resulting from the collision may prevent any new packets until they each complete their journey around the loop. Unless you have a lot of decoders needing packets sent, still probably not an issue, but a large layout with many trains would definitely NOT want looped wiring. The same issue with "terminating" open ends of the bus. This prevents a packet from "reflecting" off the open end and colliding with a following packet (or preventing the packet from being sent in a timely manner). Pieter E. Roos --- On Wed, 1/26/11, Bob Werre <[email protected]> wrote: > Chris, that's interesting, but are > you talking about the actual wires > that power the trains or are we talking the control wires > (Digitrax > calls theirs Loconet) to the throttles and remote plugs? > > I can certainly understand not looping the Loconet > cables,however if one > is running a circle of track regardless of the number of > feeders, the > rail itself makes a loop. > > Bob Werre > BobWphoto.com > > > > I always thought the DCC recommendation for longer > (whatever that > > means) runs was to twist the wires together. Not > possible with bare > > wire. :) > > > > You should not have closed loops in your DCC wiring as > it can lead to > > the situation where the same packet arrives at the > decoder at two > > different times. Computer networks are really designed > to work in a > > star wired configuration not in a loop. Packets should > not be > > crossing over themselves within a network. > > > > Chris Borgmeyer > > > > > > > > [Non-text portions of this message have been removed] > > > > ------------------------------------ > > Yahoo! Groups Links > > > [email protected] > > > ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/S-Scale/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/S-Scale/join (Yahoo! ID required) <*> To change settings via email: [email protected] [email protected] <*> To unsubscribe from this group, send an email to: [email protected] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
