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MTH DCS and Reverse loop

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  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Saturday, November 28, 2020 4:09 PM

 That appears to be the protocol between the handheld and the TIU, or from a computer via the serial port ont he TIU. Perhaps the same packet format gets send on the rails, but the signal format of what's on the rails isn;t shown. I'm not about to buy some DCS equipment and put my scope on it and try to figure it out.

 I did find that ProtoCOund 2 receivers seem to care about the polarity on the rails - unlike DCC where you cna flip the two track wires under a running loco, if it's going forward, ie towards the boiler end, it will just continue on its way, the only interruption being the time it takes to switch the connections. PS2, it seems, if you flipped the polarity, the loco would no longer respond to commands untilt he polarity was put back. ProtoSound 3.0 doesn't have this issue. That sort of tells me they are not using a symmetrical waveform like DCC, and that on the PS2 receivers, they cheaped out and left off components that made the polarity not matter - something they added in for PS3. 

 Since in addition to sound and motion commands, you can actually talk through the DCS system (honestly - anyone still think this was designed with the serious operator in mind?) then they need to be able to encode data packets as well as voice in the carrier signal. Since the track voltage can vary, if you power the system with variable voltage, which allows you to run Grandpa's old Lionel train right alongside a new MTH PS3 loco, though at slower speeds, the top speed of the PS3 equipped loco will be greatly reduced, tells me there is no fixed carrier like DCC, so the control signal must be completely independent, or else is a small magnitude superimposed signal like many pre-DCC command control systems.

 Then there is configuration storage. It seems the engineers at MTH had no idea about EEPROM - the earlier locos actually used a battery to keep RAM alive to store condifuration options. Newer ones still don;t use EEPROM - they have a supercapacitor. So park your locos too long, and they will forget their settings. This is 'superior'?

                                            --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
    September 2003
  • 21,669 posts
Posted by Overmod on Saturday, November 28, 2020 2:16 PM

rrinker
I have no idea what the DCS signal on the track looks like.

Is this of any use to you?

http://www.silogic.com/trains/RTC/Serial%20Data%20Stream%20Decoding.pdf

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Saturday, November 28, 2020 1:51 PM

 I doubt a DCC autoreverser would work. This might need to be done manually with a toggle like with DC layouts. I have no idea what the DCS signal on the track looks like.

 If MTH doesn't have a device to handle this, I'd contact them. 3-railers don't need anything, there is no reverse loop issue with 3 rail track.

 Some Google searched for DCS Reverse Loop turned up a lot of discussion but no answers. The DCS user manual makes no mention of them. My guess - you're on your own here. Just another reason for my suggestion in your other thread to use standard DCC - reverse loop operations are completely automatic, and multiple vendors sell the device needed to do this.

                                     --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
    January 2003
  • From: US
  • 27 posts
MTH DCS and Reverse loop
Posted by krakow on Friday, November 27, 2020 11:41 PM

I am thinking about adding a reverse loop to my planned layout that just started construction, I run all MTH HO with DCS. Is there a specific wiring configuration that needs to be done for this to work with DCS?

Tags: dcs , MTH , reverse loop

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