Large Scale Central

DCC address

Electronics DCC
#1

I was trying to program an address into my HO Bachmann 10 wheeler tonight and I had issues. I know I am talking HO here, but DCC is DCC right? Anyway the number on the locomotive is 27. When I programmed 0027 into the decoder, I could not run the locomotive with the controller set to 0027. I reset the decoder and reprogrammed it at least 3 times.

Its a Digitrax DH126, programmed through JMRI on a DCC++ system.

When I programmed the address as 1127, I can now run the locomotive just fine with the throttle set to 1127. So, why didn’t 0027 work? Why did 0004 work on the other 10 wheeler? I am cornfused.

#2

Gee, I thought one of the DCC “experts” here in large scale land would know why.

#3

David Maynard said:

Gee, I thought one of the DCC “experts” here in large scale land would know why.

Perhaps I can help.

The DCC Specification allows for short addresses from 1 to 127 and a long address from 0 to 10239.

Note that 3 as a short address and 3 as a long address are two completely different addresses.

This subtle point has confused many experts over the years. That is why most systems do not allow all addresses. Some for example only use short addresses from 1-99 and long addresses from 100-9999.

Others differentiate short and long addresses by using a 0 before the number to indicate a long address.

Remove the leading 0s from your address and you will likey get a proper short address which should work fine on your system.

Hope that helps

Stan

#4

David Maynard said:

Gee, I thought one of the DCC “experts” here in large scale land would know why.

We figured it was a bait and trap as you have an answer/response to most everything else?

Glad to see Stan hooked you up though !

#5

My clubs use a Digitrax system, and I have a simple throttle where I dial in 4 numbers for the address. So if I program a short address, my controller will still control it?

#6

David Maynard said:

My clubs use a Digitrax system, and I have a simple throttle where I dial in 4 numbers for the address. So if I program a short address, my controller will still control it?

It should.

If not, try programming the decoder with a short address of 27 – I know that I’ve had issues trying to program a long address of 100 on Digitrax.

#7

David Maynard said:

My clubs use a Digitrax system, and I have a simple throttle where I dial in 4 numbers for the address. So if I program a short address, my controller will still control it?

Digitrax supports short addresses from 1 to 127 and long addresses from 128 to 9999. So yes if you program a short address less then 128 your Digitrax controller will control the locomotive.

If you program a long address with a value of 01 to 0127 your Digitrax controller will NOT control it. You can always look at CV29 to determine if the address in the locomotive is a long or short address.

Stan

#8

Ok. Thanks. JMRI interfaced through DCC++ makes it real easy to read and set the CVs. So, when I get back to my side of the state of insanity, um, I mean, Pennsylvania, I will try programming it with a short address and see if that works.

#9

For short addresses, the number for the loco is in CV1. max value would be 255, but few systems can do this. less than 128 or even 100 is more common.

For long addresses the loco number is in CV 17 (high order) and cv 18 (low order) My system goes from 2 to 10,239.

High order number is address divided by 256 and added to 192. The the remainder goes in cv18.

So for long addressing address 27 you would set cv17 to 192 and cv 18 to 27. Works for me on my Zimo system.

CV 29 bit 5 selects short addressing if 0 and long addressing if a 1.

PS: it is very easy to me to program this directly as I have worked with 4 number systems most of my life (Binary, octal, decimal and hex).

Note that a system spec for the numbers can be different than the decoder spec for numbers.

For example the older LGB MTS I system could only do 1-8 for addresses but the decoders could do 1-99.

I can do short addresses between 128 to 255 with my Zimo MX1 but only with the later hand held controllers.

#10

So the Digitrax will let you set a long address that you cannot control from the same system…

cute.

Greg

#11

Greg, I do not have the Digitax at home to find out if what I set will or will not work. That is part of why I asked the question. I have JMRI on my computer, talking to an Ardweno (sp) that is hooked up with a motor driver board to act as a DCC controller/programmer. Search DCC++ on the web and you should be able to see what I am talking about. Anyway, I don’t want to program the thing on my DCC++ system, get to the show, and have the darn locomotive just sit there because Digitrax cant talk to it. I have heard that Digitrax can be a bit goofy and it doesn’t “like” certain addresses. I do not know if its true or not, it’s just what I have heard.

#12

I’m taking what Stan said, not many people around know more than Stan about DCC or Digitrax, he was a dealer for many years.

I try to stay away from using loco numbers under 127, but I do fully comprehend that many LS steam locos have one or 2 digit road numbers.

I run everything on long addresses.

Greg

#13

Greg

Never a dealer, to much work. Wife was though. I did however create the group that developed DCC, was the editor for most of the standards and RPs and co-authored the original DCC book.

Almost all systems have a usable address range. When you program a decoder with the system you use you generally will have no problems. When you program a decoder with a general purpose programmer you need to know if your system supports the address you desire.

For example a the Bachmann EZ Command only supports short addresses 1-10 If you use a general purpose programmer to program an address of 75 it will not work.

Stan

#14

When you program a decoder with a general purpose programmer you need to know if your system supports the address you desire.

Yes, and that is my concern.

#15

I guess I am very fortunate to have a system that is very flexible in what I can program for addresses short and long. Also be careful about what speed steps are set in the control station vs the limits of a decoder. I just has an engine that would not do 128 speed steps, needed 28 steps set on my station in order to work properly. Same for old LGB MTS, these engines could be 14 steps only.

#16

Dan, I do not know the quirks and limitations of Digitrax. Many of the NMRA guys don’t like Digitrax because they believe its too quirky. But, all the clubs around here use Digitrax. That confuses me. If its that bad of a system, then why is it the defacto standard among the local clubs?

#17

Sometimes it is not whether a system is good or bad, it is what a local guru has and offers help to others.

When club members ask if they should go to DCC, I ask who programs your cable TV remote.Interesting answers result, but it tells me how much I need to help get a new DCC user going. Same for Radio control DC users/battery users.

#18

Dan, I program the remote. At work I load drivers on customer’s computers, update firmware on printers/copiers, set up scanning and remote folders, and sometimes I have no clue why something doesn’t work. At home, I only call Dave Bodner, when all else fails on my home computer. But usually I can tweak that thang too.

So tonight I think I have had enough of installing decoders for a while. I put my HO Riverrossi Hiawatha Pacific on the programming track and got her programmed, but the headlight would not come on. It seams I got the polarity reversed on the headlight LED. Its working now.

So for the 2 day show, in a week an a half, I will have my choice of 2 Mantua Pacifics, A Mehano Pacific, A Riverrossi Pacific (is there a theme here?), a Mehano Mountain, 2 Bachmann Moguls, a Bachmann 4-4-0 , a Bachmann 4-6-0, a Clyde (my favorite), a Penn Central Bachmann GP something and 2 Blue box Athern Penn Central F7s. Now to see how many cars I can fix. Fix, I broke a few when I dropped the box they were in.

I never did reprogram the 4-4-0. I will just have to remember its address is 1127. Just like I have to remember the Clyde is 0186. The number on the side of the Clyde, embossed on a (simulated) polished brass plate is B86. That’s them Aussies for ya.

#19

I’d make it 1186 (B is decimal 11 in hex code)…

Greg

#20

Yes, and B is the second letter of the alphabet. So 0286 could have worked. I didn’t program it. Mr Know it all (Denny) programmed it. He is the DCC guru, and he hates Digitrax. But that club too uses Digitrax. Again, I am confused as to why.