AltcarBob
I have just fitted a Zen mini black decoder to a Heljan BO-BO chassis and because I am still a noob I had problems with the loco address.  It would run sweet on address 03 lights worked and it crept on power setting 1. I changed the long address as I have always done in the past to the last 3 numbers of the loco number in this case 119 and nothing deader than a Norwegian Parrot spent a few minutes checking wiring on the track and decoder socket.

Do a factory reset and it worked on address 03, reset long address to 119 and nothing. Head now bleeding from scratching its late and I decided to do the sensible thing for once in my life and give up and try again in the morning.  I spoke to Chris at DCCconcepts this morning and he told me to set the short address to loco address and TADAAH the loco ran.

It was explained to me that any address lower than 125 is read as a short address and above 125 is read as a long address which was news to me.  Quite by chance the 17 locos I had chipped before last night had numbers above 125.

Probably every experienced modeller on this forum knew all about short and long addresses but it had me panicking for a night.
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Bunkerbarge
News to me so thanks for sharing the information.  I use the last four digits of the loco running number so haven't come across the issue as yet. 
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AltcarBob
I have only been doing DCC for about 9 months and really panicked that I had blown the chip and or the controller. I see that ESU do a chip tester and for my own peace of mind I might invest in one next  month.  I have blown  my monthly budget for August already.
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Ruffnut Thorston
I am glad that you got the problem sorted.

Something that could easily happen, so good to know the reasoning...

So far I have stuck to two digit, short addresses.

I don't think I will get over 99 DCC locos!

But I have a couple of locos with the same last two numbers ...so, as that is the general way I allocate addresses, the duplicates use the first two numbers!  Confusion may happen...but not a problem so far.
Best wishes,

Ruff...
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Ron Solly Sol
I know with NCE, their manual indicates that short address are 1-127   and the NCE DCC forum often has it that you can have a short address of 127  and a long address of 0127 - the zero makes the difference.
Ron
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AltcarBob
I know with NCE, their manual indicates that short address are 1-127   and the NCE DCC forum often has it that you can have a short address of 127  and a long address of 0127 - the zero makes the difference.


Interesting I thought the rule was don't start an address with zero.

I have only been doing DCC for less than a year so much to learn. My next stage is to motorise the turntable and get it running on DCC
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AHJAY
Bob - we should have said 127 not 125 the other day - sorry.

Re long vs short or 1 vs 2 byte addressing it is awkward to explain which is usually why we let the controller make all of the decisions when programming.
If you DO read all of the manual you should be OK - but do NOT just assume what works on one controller brand will work with another.

To qualify this.
* Long and Short addresses do not exist in the context of the usual 2 or 4 digit addressing really.
* There are ONE BYTE addresses (1 to 127 - habitually called short) and TWO BYTE addresses (128 to 9999 + a bit - Habitually called long)
* Those controllers that allow other things to indicate a loco such as image or description work exacly the same, but they "associate" the picture/description to the number internally as a form of "Alias"

ALL decoders are configured to use 1 and 2 byte addresses: It is only the controller brands that have variants in the way they treat them.

To add to the confusion... (It may be useful to ask google to look up "Byte")
* Some controller brands artificially limit 1-byte addresses to 1~99 however a single byte actually goes up to 127 so they cannot really call everything above 99 "long" either as the second byte starts at 128.... leaving a big confusion hole in their addressing.
* Some brands use addresses in the "Confusion zone" as automatically assigned "advanced consist" addresses (100~126 etc)

It can be annoying - set a decoder to address 101 on one brand and it MAY need readdressing on another brand.
Sort of makes a mockery of standards, doesn't it.

However - Zeros can help - Basically in digital ZERO has a value. So - if you actually add a zero anywhere in the number you set into the decoder or request from the controller then it will change what happens
ie:
enter 3 and it is a short address.
enter 0003 and it is a long address.
enter 127 and it is a short address
enter 0127 and it is a long address

(ignore leading zeros that may be reproduced by default on a digital display (unless YOU entered them - they are there x default in most digital displays, so if you enter just 3 and it may well show as 0003).

--------------------------------------------

The good thing is that you do not really need to worry about all of this too much. Your controller can make most of the decisions if you let it.

Personally - if I really needed to use 1 and 2 byte addresses (I usually use all 2-byte or long)  I'd make any number up to 99 a short address, ignore 100 to 999 totally and make all others 4 digit by adding a leading zero to any 3 digit numbers.

Still confused? 
Search "CV29 calculator" in google. There are several and the 2mm scale association one works well if you need a pointer. It also explains things quite well. Have fun.

regards, Ahjay
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AltcarBob
AHJAY wrote:


erm yeah but no but yeah I think I got it

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The good thing is that you do not really need to worry about all of this too much. Your controller can make most of the decisions if you let it.


I will go by this
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Bunkerbarge
AltcarBob wrote:


I will go by this


That's you and the rest of us!!
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