Number detection and/or reset?

[rpierce000]

I have purchased a Digitrax Super Chief Xtra (only for the business, of course...)

I have several engines that have DCC installed by others that I have not been able to figure out the address on and some that are still at address 3.

3 questions:
1) Is there a way to DETECT a locomotive number if it is the only one on the track?
2) Can you change a locomotive's number without knowing the current one?
3) Can you wipe a decoder number back to 3 WITHOUT wiping all of the function settings?

Thank you!

[KenS]

CV reading depends on the command station.  The Super Chief Xtra has a DCS100 or DCS200, both of which can do this, as can their Zephyr.  The DB150 used as a command station can only write CVs.  Reading does however require a load on the decoder (it works by sensing current), so it won't work with things like Kato's headlight/taillight decoders, as the LEDs don't provide enough load.  Typically this only works on motor decoders. Also, this only works on a programming track, not when programming on the main.

However, you can reset an address using a programming track.  Programming on the main ("Ops Mode Programming") requires sending commands to an address, which only programs decoders with that one address.  Programming on the programming track ("Service Mode Programming") programs any and all decoders on the programming track (generally just one, as programming tracks are limited and may not have enough power to do more).

So, set CV01 to "3" and set CV29 to some value that doesn't have bit 5 set.  Zero is a good value, the only downside is that if the decoder was programmed to use a speed table, or to run in "reverse" (typical of A-A coupled sets where one loco is always backwards) then you just cleared the bit that says to use that feature.

Alternatively, don't touch CV29.  Set CV01 to "3" and set CV17 to "192" (which oddly means zero) and CV18 to "128" (the lowest value it can take). Now put the loco on the main and try running it at address 3 and address 128.  It will only respond to one of them, and which it does will tell you if CV29 was programmed for one-byte (bit 5 clear) or two byte (bit 5 set) operation.  You won't be able to change from one to the other without changing CV29, and if you don't have the ability to read it, that means wiping it, but you can at least run with the kind of address it used to use.

And if you can read CV29, then you just need to change bit 5 (subtract 32 from the value of CV29 to go from "4-digit" (128+) to "2-digit" (2-127) or add 32 to go the other way).

[The_Ghan]

Bob,

That'll teach you to ask three questions at once !!!

You can read CV08 to discover the manufacturer.  Here is a list of manufacturers:
http://www.nmra.org/standards/DCC/mfgnumbers.html

For example, a Digitrax decoder will return the value 129.  Go to the manufacturer's website and follow their reset instructions.

Here's links on how to reset Digitrax Decoders:
http://tsd.digitrax.com/index.php?a=1518
http://tsd.digitrax.com/index.php?a=614

As KenS said, all settings will be set back to factory default, which will mean CV01 will be set to 3.  Any special settings will be deleted.

Cheers

The_Ghan

[Webskipper]

Maybe you could get the Digitrax PR3 and program the decoders on your desktop (just for the business of course).

http://www.digitrax.com/prd_compint_pr3.php

The PR3 is a dual-purpose USB 2.0 device - In Programmer Mode, along with SoundLoaderTM software on a PC or Mac computer, the Digitrax PR3 Programmer lets users create, manage, test, and download Digitrax sound projects to SoundFX decoders.

In MS100 Mode, the PR3 interfaces from a Windows-compatible or Mac personal computer to the Digitrax LocoNet system for use by 3rd party software such as Decoder Pro, Railroad and Co*., etc.

Ipad coming soon.

[KenS]

As KenS said, all settings will be set back to factory default, which will mean CV01 will be set to 3.  Any special settings will be deleted.

Actually, I didn't say that.

You can do a reset on many decoders, but that wasn't the question he asked.

On a Digitrax decoder, setting CV08 to "8" will not change the CV (it's read only) but will cause the decoder to reset of writeable CVs to their factory default.  It's a good thing to do with a new decoder to ensure nothing was left in it from factory testing or a prior customer who returned it.  And this will also reset the address to 3.

But the question was how to change the address from an unknown one without affecting any programming someone might have done for an existing installed decoder. My answer (most of it, anyway) was about how to do that.

[The_Ghan]

Yes, sorry KenS, you didn't say that at all.

Bob, my solution is to simply reset the decoder to it's factory defaults.

Cheers

The_Ghan