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Greetings To All,

I am using a MTH K4000 to power the East/West Main Lines (two separate loops) on my layout.  The East/West mains are accessible via two crossovers (the mains are electronically isolated at the crossovers).  I, additionally, have several sidings that are electronically isolated with SPST switches so I can "park" an engine and not have any power going to that siding.  Here's the problem.  When maintaining a constant 17 to 18 volts on both of the mains, and subsequently  energizing an isolated siding by simply activating the SPST switch, the engine on that siding will begin the start-up sequence without being addressed with the remote.  Power for the sidings is tapped off of the same MTH Power Terminal that powers the mains but is controlled (ON/OFF) via a SPST switch. I am running DCS and both engines are MTH PS-3 Diesels.

 

Here's the conundrum.  I can shut the engines down using the remote and it will remain silent until I address the engine with the remote and initiate the "Start-Up" sequence.  Further, if I gradually increase the power from 0 volts to 18 volts the engine will remain silent until it is addressed with the remote.  The "ghost" start-up only happens when the power is off on the insulated siding and I introduce a full 17-18 volts the instant I energize the siding via the SPST switch.

 

I am inquiring because I am planning to go with two 180 watt bricks instead of the K4000 and it seems that if I do this, any engine on a mainline will start-up without being addressed as a result of the "instant" flow of 18 volts as opposed to a gradual increase via the handles on the K4000 which is how it is done currently.  Whassup with that?

 

Chief Bob (Retired)

Last edited by PUFFRBELLY
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If an engine doesn't get a watchdog signal, it will usually start in conventional, rather than command mode.  The watchdog signal is only sent by the TIU on a channel for about 30 seconds after power is applied to the input of that TIU channel.  When you turn on a toggle switch, there is no watchdog.  If a transformer is turned on to feed a TIU input, that channel sends the watchdog to tell the engine to start in command mode.

I have both a Z4000 and a PH-180 feeding TIU circuits.

The engine is responding properly when no watchdog signal is sent, just as RJR describes above.

To circumvent the problem, do any one of the following:

  • Turn the toggle switch on prior to putting power through the TIU channel.
  • Immediately after the toggle switch is thrown to the on position, press Shut Down on the remote or the DCS App.
  • Prior to turning on the toggle switch, highlight the engine in the remote's engine list, either Active or Inactive. Then, turn on the toggle switch and immediately press the thumbwheel.

DCS Book CoverThis and a whole lot more about DCS is all in MTH’s “The DCS Companion 3rd Edition!"

This book is available from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at MTH's web store!

DCS Book Cover

This and a whole lot more about DCS WiFi is all in MTH’s “The DCS WiFi Companion 2nd Edition!"

This book is available from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at MTH's web store!

Barry Broskowitz posted:

The engine is responding properly when no watchdog signal is sent, just as RJR describes above.

To circumvent the problem, do any one of the following:

  • Turn the toggle switch on prior to putting power through the TIU channel.
  • Immediately after the toggle switch is thrown to the on position, press Shut Down on the remote or the DCS App.
  • Prior to turning on the toggle switch, highlight the engine in the remote's engine list, either Active or Inactive. Then, turn on the toggle switch and immediately press the thumbwheel.

DCS Book CoverThis and a whole lot more about DCS is all in MTH’s “The DCS Companion 3rd Edition!"

This book is available from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at MTH's web store!

DCS Book Cover

This and a whole lot more about DCS WiFi is all in MTH’s “The DCS WiFi Companion 2nd Edition!"

This book is available from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at MTH's web store!

Ladies and Gentleman, We Have A Winner!!!   Thank you Barry!   This is exactly the information I was looking for.   Wanna see my surprised face?    BTW, I have the DCS O Gauge Companion, but it's just easier to ask.

Chief Bob (Retired)

There was a very interesting and detailed discussion about using a circuit added to a dcs rc to create a repeating watchdog after the TIU signal ended.  There were circuits designed. Eventually Gunrunner John built and sold them to be added to avoid this problem on yards that are off at the beginning of the watchdog cycle.

You can find it at this topic

Proposed Solution to DCS Watchdog in Yard Tracks (DCS-RC WD Gerber Files Added to First Post)

You will likely also need to purchase an MTH DCS remote.  I think that the model number is 50-1033

 

willygee posted:

When it does finally start in command at the siding what do you get  when running a dcs signal check?

I get 10's everywhere on my layout. I meticulously followed the wiring protocol outlined in Berry’s book “The DCS O Gauge Companion”. The signal wasn’t the problem. It apparently was the lack of the “Watchdog” signal that caused the “Ghost” start-up.

Chief Bob (Retired)

PUFFRBELLY posted:

Greetings All,

So, Mr. Broskowitz provided the exact information I was looking for.   However, I would like to thank everyone who took the time to read my post and reply!   Your efforts are greatly appreciated.   This is what makes this a GREAT FORUM!!!

Chief Bob (Retired)

 Although I didn't post on this one I really appreciate this post.....Most times, some don't even bother  to say thank you.   (whether you get it right or not)

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