DCC++ Help

MechE-83 Nov 23, 2019

  1. MechE-83

    MechE-83 TrainBoard Member

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    Hello all,

    Mechanical engineer here, trying to workout some EE problems, and build my first layout at the same time.
    Due to the cost savings, I started with a simple DC set, and built a DCC++ base station using an arduino uno and a Flashtree motor shield. (https://www.amazon.com/gp/product/B07VCFQCY8/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1)

    For my first test I tried to program a Digitrax TF4 decoder, however I kept getting a 308 error, that the base station isn't getting a response from the decoder.

    Anyway, looking for some advice for trouble shooting this.
    Thanks all!!
     
  2. wvgca

    wvgca TrainBoard Member

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    i assume that the error is from jmri
    a 308 indicates no response from decoder, and the most common error is the motor shield either does not have current reporting, or the reporting is on different pins from where it assumes it's gong to get the current sense
     
  3. MechE-83

    MechE-83 TrainBoard Member

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    Ah, sorry for forgetting that information, and thanks for the response!

    Yes, the error is from JMRI.
    I checked the pin labels between the Flashtree board and a picture of the Arduino version, and all the pins were labeled the same. But I can't seem to find any documentation to verify the pin out for either board. Is there a good resource for that information?

    Also,
    I can read 12VDC coming into the motor shield board, but I'm not sure what I should be looking for on the programming/main track output.
    I thought I had read somewhere that DCC is an AC signal, is that correct?


    Thanks again!
     
  4. wvgca

    wvgca TrainBoard Member

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    rather than using 12 volt, cut the traces to use a higher voltage .. and run 15 volt to 18 volt, depending on what you have for an adapter ... i -think- mine was 15 volt ?? not sure right now .. i use it mostly to save cv's and programing on my locos .. DCC is a modified dc signal with times pulses going from positive to negative, no sine wave involved at all, all square waves
     
  5. MechE-83

    MechE-83 TrainBoard Member

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    Thanks, will do.

    Would a lack of power result in not getting a response from the decoder?
    I also picked up an actual Arduino Motor Shield on Amazon today.
    So I can try with that Monday or Tuesday.
     
  6. MechE-83

    MechE-83 TrainBoard Member

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    Hey,

    So I got an 18V power supply, but then I double checked the motor shield board. It is rated for 5-12V, have other people run a motor shield at 18V's?
     
  7. wvgca

    wvgca TrainBoard Member

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    yes, there are two [i think] traces to cut on the motor shield board ..
    it's been a few years now, lol
     
  8. MechE-83

    MechE-83 TrainBoard Member

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    A) Thanks for all the help so far!!

    B) Looks like I got my basestation all set up. and it passed the diagnostics tests (https://github.com/DccPlusPlus/BaseStation/wiki/Diagnostics---D---Command). I can also measure about 16 V on my track. However, I'm still getting a 308 error when I try to talk to my loco. Are there any good sources for troubleshooting that error? (currently googling things, but who knows where that will lead!!)


    Thanks!
     
  9. MechE-83

    MechE-83 TrainBoard Member

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    OK,
    Got some more time to play around this morning.

    Looks like I have everything working from the computer side.
    I can read my decoder, reprogrammed it to 4 from 3 (didn't make any other changes). I did read all sheets though, and that worked.

    However, when I then switch over to my main track and try to run this train, it lurches forward for a bit, then stops.
    I've had it run anywhere from a single pulse, to maybe a couple inches.

    This is an old train that I updated to DCC (I think I got it on Ebay for like $16), I cleaned all the wheels with acetone, and the q-tips came away dirty, but that didn't seems to fix the problem.

    Any chance someone's run into this problem before?

    Thanks again!!
     

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