Digitrax SE8C

Having cracked the basics of schedules, I'm now turning my focus
to installing two, three, and three aspect with a feather, signals onto my
small UK exhibition layout.  It's a Digitrax layout with TC Silver. 
I purchased sometime ago, two SE8C units along with a pack of the US style
signal heads. 
To sort out the two aspect was straight forward as the outputs
are either red or green.  You simply cut off the signal mast head and find
the suitable output terminals and solder the contacts. 
However, I can't seem to get my head around how you have the option
of three aspects without using three different addresses.  Can someone
please furnish me with a portion of common sense because I'm clearly not as
smart as I thought!  My fingers are starting to bleed through excessive
head scratching!

I have a number of 3-aspect signals, some with feathers, and controlled by DCC and Traincontroller.  You only need two addresses: one to switch red to yellow, and the other from yellow to green. If you define a 3-aspect signal to TC you will see it requires 2 addresses. To get the right aspect there are three combinations, as both switches have, for example, A and B positions: A+A (red), B+A (yellow) and B+B (green).  This is what allows you to have a 3-aspect signal with two addresses.
 
For my signals I have some DPDT latching relays which I previously used for frog polarity switching on Peco solenoids before I moved to Tortoises. I use two of these for a 3-aspect signal, each switched by a Lenz LS150 decoder port.  The first switch sets the output to red or yellow/green. The yellow/green wire is then the input to the second switch which sets either yellow or green. In TC you define your two addresses, and which combination of the two switches is required for each of the aspects.
  
Feathers are easy: the output from the first switch to yellow/green also goes to the feather. But its wire is routed via the second switch of the Tortoise motor that controls the diverging route. Only if the signal is not red, and the diverging route is set, does the feather come on.  No extra switching required and neither DCC nor TC know of the feather's existence.

Thanks Robert, I think I understand your explanation.  I'll put it to the test this weekend.  Regards Charlie

  Still no joy I'm afraid, I still can't make this work.
  The three aspect signal has four cables, one per aspect and the return.  Whichever way I seem solder them on to the "Plug 'N Play Signal Mast Head" (Page 12 SE8C manual), I can only get the red and green to alternate and the yellow is either on or off or flashing.
  My aim of course is to have either Red or Yellow or Green.
  

Relax Guys,
It's sorted.  The British signal LEDs tend to be common cathode whereas the Digitrax controllers (and no doubt many others) are common anode.
Once it's reprogrammed it appears to work perfectly.

Glad that's sorted!  I did have a look at the SE8C manual and couldn't believe how complicated it was! I just use a pair of latching DPDT relays each with a Lenz LS150 port …

Following the hassle I had in setting up my Digitrax SE8C, today, I've posted a YouTube Video which I hope explains how it's done!
Please take a look and subscribe if you like it.