DCC ImpulsesColumn - 6
OK, nowwehaveaway to tell that theblock isoccupied.What
dowedowith this knowledge?
Signal animator
A signal animator is a relatively simpletimer circuit activated
by theblockdetector.When theblock isoccupied, theanima-
tor sets the signal to the stop (red) aspect.When theblock
clears, theapproach (yellow) aspect is set. After theapproach
aspect hasbeendisplayed for aperiodof time (usuallyuser
adjustable) the signalmoves to clear (green).
Anoperator running a through train and following traffic can
use these signals to knowwith relative certainty that the
block ahead is clear (yellowor green). In the real world, a
greenwould assure that the secondblock aheadwas clear,
aswell.With a signal animator, information from the second
block ahead is not shared. Thus, theengineer doesn’t have
100% certainty that hehas two clear blocks.
As great as the concept
seems, today therearenot a
lot of choices in readybuilt
hardware to implement it. A
tinkerer could always build
his owntimer circuit and
activate itwith anoff-the-
shelf DCCblock detector.
Atlashas anice system that
has even some realistic signal
heads
. This sys-
tem seems tohavebeen lost
in theMade-in-China issues
over the last fewyears. It is
reasonablypriced, but not
7: AzatraxMRD2optical
detector senses twoplaces
in the block. Photo courtesy
of Azatrax.
7
MRH-Apr2014
