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Would a dual mode decoder run on address zero?

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  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Tuesday, April 30, 2019 4:56 PM

My first DCC system was a MRC2K that had three trottles on a panel and two on a lanyard. Throttle one on the panel was for DCC or a DC loco by design.

On the Bachmann EZ Command you press button ten for a DC loco.

I gave the system away and bought a NCE Power Cab that does not run DC locos.

Running a DC loco on stretch zero is hard on the motor. I did temp measurments with an infrared scanner with the loco in a test stand some years ago. Motor brushes where they contact the armature get hotter when the motor is stopped and DCC still applied.

https://sites.google.com/site/markgurries/home/technical-discussions/dc-loco-on-dcc

Motor and light decoders are about $20.00 each depending on place you get them.

Many just do not want to seem to do any research but make assumptions. The Internet is loaded with info on this subject.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Tuesday, April 30, 2019 4:46 PM

 That's exactly what it's doing - stretiching out the positive half oor the negative half of the 0 bits in the DCC signal (since the definition of a 1 bit is a bit time less than some value, and a zero is any bit time over some other value, with a dead space in the middle). Assuming a loco wired per NMRA DC standards, positive on engineer's side is forward, if the phase of the 0 bit on the right rail is longer than the phase of the 0 bit on the left rail, there is a net positive DC offset to the right rail and the loco moves forward.

 You can;t remove the negative somponent completely, or DCC decoders will not work, and DCC decoder equipped locos would only be able to move in one directions. So the DC motor still sees an AC voltage, just one that is more positive in one direction or the other. Hence the buzzing Stopped, there is an equal amount of postive side and negative side, so the armature doesn;t turn, but just vibrated back and forth. No airflow, basically a short through the windings , Depending on the motor, it will burn up in seconds (a coreless motor) to hours (a big heavy massive open frame motor) if left sitting there.

 It's OK for a quick test run (except coreless motos) but not really suitable for long term running. Decoders are cheap, just put a decoder in it.  Also, by extending the 0 bits to make the DC offset, it increases the time required to transmit full DCC packets to decoder equipped locos, slowing the response to throttle, direction change, and function control.

                                   --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    July 2006
  • From: Sebring FL
  • 842 posts
Posted by floridaflyer on Tuesday, April 30, 2019 4:38 PM

Correct on all counts Greg.

  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Tuesday, April 30, 2019 4:16 PM

SPSOT fan
Now most DCC systems can become ‘DC’ systems by running with address one. When running with address 0 the layout becomes DC and the DCC equipped locomotives don’t run at al

i don't believe a DCC sytem "can become a DC system".

I don't believe the layout becomes DC when address 0 (or 1) is used.

A DCC system can control a single DC locomotive using address 0 by skewing the DCC signal to have a DC offset.

i doubt any decoder can be programmed with address 0.   You would select loco address 0 in the controller to control a single DC loco and can continue to control other DCC equiped locos using their assigned addresses.

or am i confused (not the first time)?

greg - Philadelphia & Reading / Reading

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Tuesday, April 30, 2019 3:05 PM

 No, the decoder will not run on address 0, because as soon as you set it on the rails, it will see the DCC signal and be in DCC mode. At most, you might confuse it and have it take off at full speed, which is one of the reasons I disable DC operation in all my decoders.

 There are few if any decoders made today that are not "dual mode" and will work on DC or DCC.

                                          --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    May 2010
  • From: SE. WI.
  • 8,253 posts
Posted by mbinsewi on Tuesday, April 30, 2019 12:58 PM

I have 4 locos with dual mode decoders.  3 Atlas, and 1 Bachmann Spectrum.  Since I turned my lay out over to DCC, I've never set it back to DC to try these locos on DC, to see how they work.

It's an easy switch for me, flip a switch, unplug one power system, and plug in another, and I can go from DCC back to DC.

I have run locos (analog) with out decoders on the DCC lay out, and my Digitrax manual says to set the address of an anolog loco at "00".

If I were to go to DC mode with the lay out, I don't know what the address of the dual mode decoders would set to, as acording to the instructions, there is nothing I need to do to the locos to run on DC.  Their default address for DCC is "03".

I don't know if JMRI reads anything, or even works with DC.  I have it, but it's not actively connected to the lay out, I use it as a "stand-alone" for decoder work, sometimes.

I would think that a dual mode loco, placed on a DCC system, would read only the DCC signal, and an address change to "0", the loco probably wouldn't work.  But I don't know that for sure.

Not sure if I contributed to an answer to your question, or just rambled on with some thoughts on it all.  Confused

Mike.

  • Member since
    April 2019
  • From: Pacific Northwest
  • 780 posts
Posted by SPSOT fan on Tuesday, April 30, 2019 12:55 PM

MisterBeasley

Note that only some DCC systems support the address zero feature.  My Lenz system does, but many do not.

Duly noted!

I am most firmiliar with Digitrax systems for the information of those replying.

Regards, Isaac

I model my railroad and you model yours! I model my way and you model yours!

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,483 posts
Posted by MisterBeasley on Tuesday, April 30, 2019 12:53 PM

Note that only some DCC systems support the address zero feature.  My Lenz system does, but many do not.

It takes an iron man to play with a toy iron horse. 

  • Member since
    April 2019
  • From: Pacific Northwest
  • 780 posts
Would a dual mode decoder run on address zero?
Posted by SPSOT fan on Tuesday, April 30, 2019 12:24 PM

This question is just be cause I am feeling curious, I really can think why I would be important but I’ll ask anyway!

So today many DCC decoders are dual mode, meaning they run on but DC and DCC. Now most DCC systems can become ‘DC’ systems by running with address one. When running with address 0 the layout becomes DC and the DCC equipped locomotives don’t run at all. What I’m wondering is what a dual mode decoder will do when you run address 0. Will it run as a DC loco, or will it ignore the DC signal and sit still doing nothing.

Again just a curiosity, I don’t actually have a DCC system at the moment, though I do run on others systems.

Regards, Isaac

I model my railroad and you model yours! I model my way and you model yours!

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