Jmri /dcc++ and Reading Cvs From Nce Decoders
Motor turning The way reading values out of a decoder works is really surprisingly archaic. The command station basically guesses CV values one at a fourth dimension (due east.grand. Is the address 0? Is information technology 1? Is it two? .... 255) until it guesses right, at which point the decoder answers (Ack - acknowledges) with a pulse of current draw that the command station can detect. Typically information technology does that past very briefly turning on the motor. So, the fact that you saw the motor pulse a few times ways the decoder was trying to acknowledge a correct approximate. But it sounds like since you got zero dorsum in JMRI, the command station was unable to find the ack. Is there annihilation in the RDC that's always wired across the rails that might constantly be drawing electric current? Like lights perhaps? If so, then the deviation between the current with the motor off and briefly on might non be enough for the command station to observe.
Thanks, Ken As I stated in my update, the command station doesn't get the proper values either using the NCE controller. I don't believe there would be any electric current draw every bit there are no extraneous lights and the directional headlights are under control of the decoder. This may only take to remain one of those "deep, dark secrets of DCC"! lol Edit: Thanks for the the technical explanation of the motor pulses. I was not enlightened of the crusade of that action. Bud (aka John), The Old Curmudgeon Fan of Northern Pacific and the Rock Island
. . . If your NCE system can not read the decoder, neither will JMRI. This could exist a decoder lock condition, if it supports it. 255 is a value dropped into a register. This value gets replaced with the one 'read' from the decoder. Every bit the read fails yous can end upwards with "255" being returned if locked. As the decoder dates from the 90'south, I dubiety it had CV lock. Have you tried both Direct and Page mode to read the decoder. Some of the D104 manuals country PAGE mode only. Others country Direct or Page. Simply then they do non conspicuously state Service mode programming as supported but mention OPS fashion. JMRI definition file mentions an "Advanced Decoder Acknowledgement" in CV29, flake 3.. By default it is Disabled. Could non find whatever reference to this in the D104-eu, D104KRS or D104P2K manuals so accept no thought if this information is valid or was only on Wnagrow decoders. The D104 decoder dates back to 1990's and Wangrow. Marc
@marcfo68 - Hmmm I may disconnect the layout and use a separate piece of runway and endeavour programming on the"primary". btw - through JMRI, I tried both direct and PAGE to no avail. Since I accept only had this NCE system, I must have programmed this on information technology. Whether it was with JMRI, I don't recall, but probably not. Bud (aka John), The Old Curmudgeon Fan of Northern Pacific and the Rock Isle
Might consider replacing the decoder, reduce frustration NCE D104eu on ebay for $xiv in Jan 2020, just search for them. There are also new nine pin decoders of diverse brands for virtually $20. For myself, sometimes it is not worth the time and frustration when I can find a replacement role inside my upkeep. The budget part is important. -- Doug -- Modeling the Norwottuck Railroad, returning trails to rails.
Effort reset If you're non content to just run it equally is and not worry most it until something goes wrong... Before getting desperate, endeavor resetting the decoder. I believe with this decoder that's done by writing a value of 2 to CV30. Then get-go fresh with the programming (the accost volition exist 3). But if it works at present, your best bet may exist to only utilise it and not worry near it.
Having similar bug Mark Charles
Keep alives vs programming Keep alives can crusade problem with reading on the programming track. Since the read works by the command station watching for a quick pulse alter in the current used past the loco, the keep live tends to obscure that quick change. If you put the loco on powered track for a few minutes to let the keep alive fully charge, and then quickly motion to the programming track you may accept better luck. If not, you should still be able to write new values, merely non read them dorsum.
. . . TCS WOW have a characteristic to plow off KA via CV182 bit two. This is in DecoderPro, Advanced tab for the WOW. Now it is non articulate if the KA remains in the circuit and gets charged at power ON. One can not disconnect the KA on the TCS Mother boards so they may use CV182. If the KA is disconnectable, disconnect while programming. A PITA. Marc
Keep alives can cause problem Quote: Go on alives tin cause problem with reading on the programming track. Since the read works by the command station watching for a quick pulse alter in the electric current used past the loco, the keep alive tends to obscure that quick change. Quote: Now it is non articulate if the KA remains in the excursion and gets charged at power ON. The problems with many of the early decoders, especially Sound decoders, and decoders equipped with additional capacitors is due to the "express energy" bachelor during programming. Run into sec. B, iii) NMRA Standard Southward-nine.2.three DCC Service Way. Emphasis added. Quote: 3) Service Mode operations should be performed in an surroundings with limited energy to prevent harm to decoders during programming. For the purposes of this STANDARD, limited energy is defined as 250 mA, sustained for more than 100 ms. A developer may farther limit the free energy via a electric current limiting resistor, if it is clearly documented that not all compatible DCC devices may be programmed by this programmer. So the power is normally OFF when an engine is sitting on a Programming Track. Each fourth dimension a CV is read or written the programmer needs to turn track ability ON, look for some time for the decoder to ability upward, transport DCC Service Mode Commands (read and or write), wait for an Ack, then turn rail power OFF. With only 250 mA available for 100 ms, many early sound decoders, which could easily spike to 250 mA, were not able to stabilize the ability, initialize the microcontroller, receive commands and send an Ack (a load of "sixty mA for half dozen ms +/-1 ms") before power was turned OFF. If this limited free energy is not enough for a decoder adding any additional capacitive load (stay-alives) just made the situation worse. Of course many of the states concluded up buying programming boosters (PowerPax, DB100) which helped but did not solve the bug. Note: When programming on the Main ability should already be ON, and so the decoders are already powered upwards and initialized. New we just demand more systems (many European systems already do) which support Advanced Acknowledgment ( South-nine.3.2 DCC Basic Decoder Transmission) with Acks on the Main. With newer generations of decoders, manufacturers take washed a skilful chore of limiting the turn on power spikes, and some like TCS accept added feature to limit the additional load presented by stay-alive during Service Way programming. Only those with older or less capable decoders installed will have to proceed to deal with the problems. The DCC Specialties PowerPax DCC Programming Booster is still available for apply with recalcitrant decoders and programmers. For some newer programmers it seams that manufactures accept taken the hint from the programming booster manufacturers and fudged the specifications (currents to a higher place 250 mA for more than 100 ms) to improve operation. There are also some DIY alternatives and hacks. If you accept admission to a SPROG or DCC++ arrangement running JMRI DecoderPro, you can often fudge by opening a Throttle and turning the Track power ON earlier attempting to read or write. With SPROG systems y'all will demand to ensure that your are in programming mode, and for DCC++ systems you will nevertheless demand to identify your engine on the Programming Rails. Hitting the Ability Button volition apply power to the Programming Track, allowing the decoder to power up and initialize, and will oftentimes permit DecoderPro to read all of a decoders CVs. At present at the cease of whatsoever read of write sequence DecoderPro will turn the power off, just only hit the Power Push again and go along reading or writing. I take used this hack to deal with the old Quasi-nami decoders installed in Large Scale Bachmann engines with adequately big cap banks. Ken K
Certain early decoders may not be readable The decoder may not have been setup for read back. Your decoder may have marketed for Factory installs,MRC manufacturing plant installed decoders Will NOT readback.!!!! Fifty-fifty MRC "Aftermarket" decoders didn't readback. That the way it was back in the early years of DCC.
Source: https://forum.mrhmag.com/post/unable-to-read-decoder-12214678