Model Railway Forum banner
1 - 3 of 3 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
Hi All
I have what is basically an oval layout (multi tracks) with hidden loops inside hills which are used for storage and to park trains to add to the operational side of the layout.
I am thinking on the lines of having isolated sections at the end of the storage sidings before the points activated by push and hold switches (sections will be longer than the longest Loco) so that there is no mistake when train driven into loop it will stop without the old brain having to remember.
Now assuming the power to the whole layout is not switched off as I understand it the master DCC unit will continue to send signals in the track to the loco as it will assume it is running. Then you start up another loco ( I appreciate the master unit has to support multiple locos at the same time) and resume operations on the main layout.
When ready to bring the loco out of the storage loop (assume points set correctly) if the isolated section is made live I am assuming that the loco will pick up its signal and start up as per the program in the decoder.
I guess the question is does the master keep sending the signals to the Loop engine decoder even though it will not be getting a response from that decoder because it is held on an isolated section of track.
Thanks
Robert
 

·
Registered
Joined
·
293 Posts
QUOTE (Roberth1 @ 12 Mar 2007, 12:13) <{POST_SNAPBACK}>I guess the question is does the master keep sending the signals to the Loop engine decoder even though it will not be getting a response from that decoder because it is held on an isolated section of track.
If you simply leave the first loco setting as it was, and just change address for the next loco, it is likely that the command station will continue to send out commands to the first loco, and add the new commands to its packet queue. In a traditional DCC system the command station does not get a response from the decoder anyway, and has no idea whether the loco has 'heard' it or not, hence the need to continually send commands.
The actual effect you get will depend on the packet queueing methodology your particular command station uses.
My own command station design would not produce the desired response because I have chosen to only allow an individual handset to control one loco at a a time. Even if you can program your decoders to accept an infinite time between commands, the decoder would have lost its settings during the period the track is isolated.
 

·
Administrator
Joined
·
9,844 Posts
If you are not already commited to a large set of decoders, you could consider installing models which support braking when they detect an asymmetric DCC signal. This is called "ABC" by its inventors - Lenz, and is supported by ESU, Zimo and a few others as well. When you want a locomotive to stop automatically in a particular section, you switch on the asymmetric signal, the decoder detects it and comes to a halt within the distance programmed into a CV in the decoder. How you switch on the asymmetric signal is up to you, but you could use a set of contacts from the points.

David
 
1 - 3 of 3 Posts
Top