Intermittent Reading CV DCC++

Bluehat Oct 27, 2016

  1. Bluehat

    Bluehat New Member

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    Hi,

    Im new to DCC++ and very happy to have stumbled across it!

    I have successfully setup my Ardunio Uno with Ardunio Motor Shield, I can control my DCC locos using JMRI or the DCC++ controller.

    However, when im trying to read the CV values from my MERG ACC5.1 accessory decoder im having some issues. In both JMRI and DCC++ controller I have to press read around 1-20 times, before I get a successful read. When running the diagnostics tool it says "unrecognisable reply".

    What could the cause be? Ive seen some forum posts about changing a ACK threshold, could someone recommend some values to see if it improves?

    Thanks,

    Matt
     
    Scott Eric Catalano likes this.
  2. Travis Farmer

    Travis Farmer TrainBoard Member

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    it really depends on what current values your motor shield (or separate current sensor if applicable) reports for values. I don't remember the formula i used for my situation at the moment, but i use the IBT-2 motor controllers. those have an output of 1023 @ 45A. ACK current i think is around 60ma to 100ma, IIRC. whatever the formula is, i set mine to a very low 3 (stock programming is 30). without the formula, i would say to just decrease it little by little, until you have stable readings. another thing to check is how stable your current sense value is. there could be an intermittent open/short causing bad reads.

    Hope this is of some help.

    ~Travis
     
    Scott Eric Catalano likes this.

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