NCE decoder issue

MRLdave Sep 23, 2021

  1. MRLdave

    MRLdave TrainBoard Member

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    I have 3 N scale Atlas SD7's with factory installed decoders.....the decoders all appear identical, but only one has an NCE label. I originally thought there was a programming issue because they would only run if set to the default address (3) , but then I figured out the problem is actually they won't take an address above 500, and I'm trying to use 501,509 and 510. I've done resets on the decoders, and they'll take any address I want, as long as its 500 or less. Any ideas on the max 500 address thing?
     
  2. BigJake

    BigJake TrainBoard Member

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    I assume you are trying to stay in the short address range...

    Some DCC command stations have different upper limits for the short decoder address range. Consult the documentation for your system.
     
  3. MRLdave

    MRLdave TrainBoard Member

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    I don't think it's a system/command station issue. I have locos with Digtrax decoders that are set above 500 and on the same night as the NCE, I set a new BLI NW2 with an ESU to address 665.......it seems to be a NCE issue, but you may be right that it's a limit issue. I'm not necessarily trying to stay in the short address range, I've just never run into a situation where I couldn't program a 3 digit address with the default setting on a decoder. I'll also check my system manual, but as I said, other brands of decoders don't seem to have an issue. Thanks for the reply
     
  4. woodone

    woodone TrainBoard Member

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    What DCC system are you using has a command station?
    I know most systems use 1 to 127 has a short address- any thing above 128 is considered a long address.
     
  5. MRLdave

    MRLdave TrainBoard Member

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    I'm using an MRC Prodigy system. Not sure on the system, but I think the decoder manual showed the 0-127 range. The odd thing is the limit seems to be 500, not 127. Initially I was trying to use 501, 509, and 510 for the addresses........none of them worked, but when I'd try to program them, the loco would flash that it was taking a change, and afterwards, the locos would not run on 3, so they WERE getting the address change. They would only run if I set the address back to 3. It finally dawned on me to try something different.........everything works up to and including 500. And I have other locos that are set to 500+ addresses, so I don't think it's a system limit. NCE is not my decoder of choice, but it's what came in the locos. The only other NCE decoders I have are 3 in a set of Atlas H16-44s. I got those because it was the only decoder that included the marker lights of the factory DC boards. Those program fine, but the addresses are in the low 400 range. It seems odd that Atlas would put a decoder in knowing you couldn't program it to the loco number, but I noticed the las SD7 I bought has a different board in it.
     
  6. Pieter

    Pieter TrainBoard Member

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    Try and change CV 29 to include long address (calculators online). Sometime it like to stick to short address. If you are programming manually you will also have to re-calculate CV 17 & 18 (long address). 501 = 17 - 193 & 18 -245.
     
  7. MRLdave

    MRLdave TrainBoard Member

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    I'll give it a try....thanks
     
  8. BigJake

    BigJake TrainBoard Member

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    Your decoder is capable of being addressed with your locomotive's road number. You just need to use what's called "extended addressing," rather than standard (short) addressing, to give your locomotives addresses above 127. All NMRA-compliant DCC locomotive decoders allow extended addressing. Your Prodigy system manual tells you how to enable and configure extended addressing on DCC decoders.

    The NMRA DCC specification does not cover user interfaces, so there is ample diversity in how different DCC systems allow/require the user to select an extended-addressed locomotive vs a short-addressed locomotive. Note that some DCC systems require you to enter a 4 digit address for an extended-addressed locomotive (even for addresses between 128 and 999, inclusive) so in your case, you may have to enter 0500, etc. on the throttle to address your extended-addressed locomotive. All of my locomotives are configured for extended addressing. Some systems do not allow extended addressing for addresses less than 128.

    Note, a free, computer-based DCC decoder programming application called JMRI Decoder Pro is extremely useful, and makes programming decoders much easier and and more intuitive than command stations or throttles. It handles all the binary/hexadecimal to decimal conversions, breaks out individual control bits into check boxes, etc., with clear English (or other language of your choice) names and descriptions of the various registers, bits and fields. The entire JMRI suite is available for free, but generally requires a computer interface accessory for the command station you use (available from the command station vendor). JMRI runs on Windows, Linux (including Raspberry Pi), and Apple computers. JMRI also includes applications besides Decoder Pro to run trains, automate layouts, etc.

    See JMRI.org for more information. The official JMRI user group is on groups.io.
     
    Sepp K likes this.

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