DCS Fixed voltage locos start when powered.

@RJT posted:

I have two sidings being feed of my mains which are coming of Fixed 1 & 2. The sidings are controlled by a on off toggle switch. When I turn the switch on any locomotive on the siding starts up but cannot be controlled from the hand held DCS Unit.

That's because those locomotives are NOT seeing the Watchdog Timer signal, which is transmitted by the TIU whenever it is first powered on.

I must first select shutdown which is the only option the works and let the loco shut completely down and then start it to control it.

Try selecting the "Start Up" key, instead of "Shut Down".

My question is why would the locomotives start when the siding is powered on?

Because it did NOT see the "Watchdog Timer", and thus started in conventional.

This only happens when I select the on position with the selector up until that point the siding is dead as in no power.

Right, which means that sideing is NOT seeing the "Watchdog Timer" signal whenever you power on your TIU.

Glad you asked this question Rick.

Glad you replied with this good insight Hot Water.

I've had this happen guys and didn't understand what was going on until now .   Thanks.😉

What HW fails to mention is the watchdog signal is ONLY sent when the input power to the TIU channel comes up.  If you are individually controlling a siding without turning power off on the whole TIU channel that controls it, there will be no watchdog.

The solution is to utilize the DCS-RC Perpetual Barking Watchdog Generator based on the DCS Remote Commander and a custom board.  With one of these connected to the output side of the TIU channel, you have continuous watchdog signals as long as there's power from the channel.  I use three of these, one for every TIU channel except my mainline.  I have individual switches for every siding, and I don't have to worry about the watchdog signal as there's always one on the tracks.

@Dallas Joseph posted:

Glad you asked this question Rick.

Glad you replied with this good insight Hot Water.

I've had this happen guys and didn't understand what was going on until now .   Thanks.😉

Well, it would have been useful for HW to also tell you why you didn't have the WD signal, and maybe how to fix the issue.

@RJT posted:

I have two sidings being feed of my mains which are coming of Fixed 1 & 2. The sidings are controlled by a on off toggle switch. When I turn the switch on any locomotive on the siding starts up but cannot be controlled from the hand held DCS Unit. I must first select shutdown which is the only option the works and let the loco shut completely down and then start it to control it. My question is why would the locomotives start when the siding is powered on? This only happens when I select the on position with the selector up until that point the siding is dead as in no power.

Rick, this topic is clearly discussing DCS and so we are moving it to the appropriate category.  Please help reduce our moderation time by placing posts in the MOST logical category based on the main theme of the topic.

@gunrunnerjohn posted:

Well, it would have been useful for HW to also tell you why you didn't have the WD signal, and maybe how to fix the issue.

So,,,,,,,,,I guess you didn't read my answer carefully, where I stated, "That's because those locomotives are NOT seeing the Watchdog Timer Signal, which is transmitted by the TIU, whenever it is first powered on.".

It's all about reading and comprehension.

@gunrunnerjohn posted:

What HW fails to mention is the watchdog signal is ONLY sent when the input power to the TIU channel comes up.  If you are individually controlling a siding without turning power off on the whole TIU channel that controls it, there will be no watchdog.

The solution is to utilize the DCS-RC Perpetual Barking Watchdog Generator based on the DCS Remote Commander and a custom board.  With one of these connected to the output side of the TIU channel, you have continuous watchdog signals as long as there's power from the channel.  I use three of these, one for every TIU channel except my mainline.  I have individual switches for every siding, and I don't have to worry about the watchdog signal as there's always one on the tracks.

Well, it would have been useful for HW to also tell you why you didn't have the WD signal, and maybe how to fix the issue.

Do you have a diagram of just the TIU and the PBWG  ?  🤓🤔     I have two of the Remote Commander receivers .

At the risk of having my nits picked, but to perhaps further expand for the OP or anyone else interested ....... when the DCS system is first turned on, it sends out a "watchdog" signal to all locos on tracks then being powered up. That "watchdog" signal tells those engine(s) to start in DCS command mode when started up. That "watchdog" signal is only sent out once, within the first few seconds or so of the TIU being turned on. If an engine does not "see" or receive the signal at that time, then whenever it is powered up in the future and even though the TIU is still on, the engine is programmed to start in conventional mode, not command.   

Since, power to the engines on your sidings was not on when the TIU was first turned on, those engines never saw the initial "watchdog" signal and were not "programmed" to start in command mode when power to them was turned on. When the toggle was eventually flipped to power the siding, the engine (having never seen the initial "watchdog" signal), thinks it is supposed to start in conventional and will not respond to commands from the remote.

There are three basic ways to deal with this situation:

1. As you discovered, shut it down and then re-start.

2. Just hit "start" instead of shut down, as per HW.

3. Purchase GRJ's generator which basically puts out a continuous watchdog signal so the engine on the siding sees it when the toggle switch is turned on and you can eliminate 1 and 2.

There are also issues of power initially being turned on too slowly and/or voltage issues that can contribute to the "watchdog" signal not being seen but those are not relevant here and are best left for another day.

@Hot Water posted:

So,,,,,,,,,I guess you didn't read my answer carefully, where I stated, "That's because those locomotives are NOT seeing the Watchdog Timer Signal, which is transmitted by the TIU, whenever it is first powered on.".

It's all about reading and comprehension.

No, it's actually about explaining it clearly, what you said is not really totally true.   Each channel's power will individually send a watchdog when that channel is powered up.  Many layouts power the TIU from aux power, and even if it's powered from fixed #1, you can get watchdog signals on the other channels individually.  So, the TIU is powered up continuously, but each channel can still generate the watchdog when it's input power transitions from off to on.

That's true ...... if an initial non-powered channel is subsequently powered up from when the TIU was first turned on, that individual channel will generate a new initial watchdog signal ( about 45 seconds or so, I believe) for anything powered on that channel even though the TIU is already "on".