How does this help me?
Well, I always think that knowledge of inner workings and his-
tory helps, but only if you know how to apply it.
Let’s look at a situation I had recently. One of my garden locos
(2) was running just fine. There was a derailment and I re-railed
rolling stock. Must have had a static discharge to the track that
corrupted the decoder. The loco refused to run on its address
(268) afterward. When I read CV 19 and found a non-zero num-
ber (166), I knew why I couldn’t control it. It had changed its
name and wanted to be talked to as 38 and run backwards (38
+ 128 = 166). Just for fun, I did run it on 38 before I reset CV 19
to zero. If your loco isn’t responding to direction, speed and
function commands and it is not intended to be in a consist, try
setting CV 19 to zero and see if order is restored.
System by system
The rest of this information becomes a bit system-specific, so
let’s talk about some systems. I’m not going to cover the entire
history of DCC systems, but just discuss the current (2013)
status of several systems. I’m not going to tell you how to set
up your decoders for each system; just how they treat the
addresses you set. Modern systems set CV 29 appropriately
when you use them to set the address.
As frequent readers know, I favor DecoderPro to set up my
locomotives. It will allow you to program any address from 1
to 127 as short, and any from 0 to 10239 as long in the same
DCC Impulses Column - 4
“If your loco isn’t responding to direction,
speed and function commands, try setting
CV 19 to zero and see if order is restored.”
decoder at the same time. You then tell it which address you
want to use and it will set CV 29 accordingly.
Here we go, alphabetically.
Digitrax
Digitrax reserves address zero for running locos without decod-
ers. While this mode is not recommended, it is still there.
No matter how you select an address on a Digitrax throttle,
if it is between 1 and 127, the system will speak to it as a
short address. You cannot override this behavior. Similarly,
an address between 128 and 9983 will be spoken to as a long
address. Addresses from 9984 to 10239 are not accessible.
4: DecoderPro screen shot for the loco from figure 2. This
is the basic panel setting short and long addresses and
selecting the long (extended) address. The loco direction is
reversed, as this is an Aristo-Craft garden loco, where the
direction of motion is reversed from the NMRA standards.
4
MRH-Feb 2014
