DCS Signal Strength?

Bob,

Too many engines means too much of a power demand. This can cause problems with signal strength.

I have each engine on a power-switched siding and only power on those than I'm actually using in an operating session.

Barry, even if the engines haven't gone thru the start up procedure?

One other thing I've noticed, with all these engines on the layout I sometimes get one that starts up on its own.  I can usually press shut-down for that engine and it'll stop, but sometimes I have to turn off the power and remove the engine.

I knew I needed to add toggle switches anyway, so maybe that'll fix it, thanks!

The only reason I was keeping so many engines on the layout was that I don't have enough shelf space to store them.  Maybe I'll cut it down to 3 and see if that fixes things.

Bob,

 

even if the engines haven't gone thru the start up procedure?

Yes.

One other thing I've noticed, with all these engines on the layout I sometimes get one that starts up on its own.  I can usually press shut-down for that engine and it'll stop, but sometimes I have to turn off the power and remove the engine.

Same issue.

I just tried adding engines back onto the layout, one at a time.  I now have 3 on the layout and no issues with track signal strength, all 10 and no unwanted start ups.  I may add one more, but 4 will be my limit until I can install some toggle switches.  I still may run some wires over to the east side of the layout (let me see if I can add the photo now):

Thanks again Barry

nope

something's up with my browser this morning and I can't see any pictures or attachments, so I don't see the diagrams posted.

 When I added my engine yard, I got the same results at first. I added another TIU channel and just used a jumper on the input side because I didn't have another power brick. I connected this new channel to the yard tracks.

 The signal went right back to tens everywhere. My mainline is so large, that adding the yard tracks full of engines, stole the signal strength. Once another channel was added on the same brick, all was well. I have since changed to a version L TIU and removed the bulbs to the yards.

 When I get more than twelve ten or so engines in the engine yard terminal, I still get some missed watchdog startups and lower signal problems. I added switches to kill some yard tracks to solve. Adding more channels would have helped.

Bob, for your diagnosis, place a loco, stopped but powered up, in an area where the signal issue seems to be greatest.  Turn off, with the toggles, all sidings.  Set the engine to give signal strength.  Turn the toggles on, one at a time, and see what happens to the signal strength.  If turning on a toggle causes signal strength to drop, place a bulb across the end of that siding. 

This is what I did when I built/expanded the layout to add an area with many sidings and had signal problems; cured all signal problems.

Note I did not say to put the loco on the suspect siding.  I have found that turning on power to some sidings, even with nothing on them, can pull down signal strength elsewhere.

Another possibility is that if any of these locos are not DCS, they may have constant voltage boards which kill DCS signal.  Some cars also have these boards for lighting.

I strongly recommend against tackling rewiring, unless you layout uses #18 gauge wire or smaller.  My layout was built long before DCS, using 14-gauge feeds and common buss ground.  Tweaking as described above solved all signal problems.

What part of VA are you in?

RJR,

Haven't installed toggles yet, but will and will try what you suggest.

All of the engines on the layout are PS2, no lighted cars currently on either.

It didn't occur until I added the TT and changed the trackage around it, before it was about the same amount of trackage and close to the original locations.

I can see the layout plan now so maybe they fixed whatever was going on this morning.

I'm fairly sure that your problem is what I encountered when I expanded and added sidings.  It's weird, some sidings had major effect and needed a bulb, while an adjoiinng siding would have no effect when turned on.

By any chance, are using Rev L TIU?

Rev L is the one I have.

I knew I should have bought some toggle switches at the local NMRA train show last month

Buying standard electric components is like buying something at a marine supply house; price is multiplied.  Try online at Mouser.

For our yard on our modular display layout, I installed a 13A RF choke in series with the common switched power for each track.  I have a rotary switch to select the track that will connect to a TIU channel to provide DCS capability to that yard track.  The TIU is run in passive mode for the yard so there is no input side power to the channels.

To energize a track, we set the rotary switch to the track and turn on the power to that track.  Works great, we get the DCS watchdog and power to the track.  The choke prevents interference between TIU channels.

That may be why I didn't buy any!

John, is the TIU you're using only tied to the yard or is it used elsewhere on the layout?  In other words, could 1 channel of the TIU be used in passive mode and the other(s) used normally?

This is off topic (I can do that on my own thread right?) I tried my 2 Variable channels again in Fixed mode and neither worked (the engine starts automatically after a couple of seconds with sound and lights) but I can't change speed (it just sits there) and no other pushes of any buttons make a change.  I'll get hold of George later to see if he'll take a look.

What part of VA are you in?

Portsmouth, across from Norfolk.

Yep, no problem using a channel in passive mode and others powered.  I settled on switching the TIU just to the individual tracks so that I could be sure of a good DCS signal to add engines in the yard before we drive them out onto the mainlines.  Since the channel gets powered as the track is powered, I get the watchdog signal for the track when power comes on.

Just a possibility: Did you set the DCS Channels To All On for this? With the Variable Channels, the DCS signal may be turned off.

Russell, if the variable channels are turned up full, they output the same waveform as when they're in fixed mode.  However, if they're not at 100% voltage, you would indeed get a more "chopped" waveform.

Russell,

I followed Barry's instructions (down near the bottom) from this topic:

https://ogrforum.ogaugerr.com/topic/power-to-tiu-1

I've had this problem for at least a year, thought I'd try again for "S's & G's".  They work fine in conventional (if I recall correctly, I no longer have any conventional engines), just not in command.

 On both my older tiu and the new L that replaced it, I followed Barry's instructions and turned the variable channel to fixed. I jumpered the inputs from fixed one or fixed two to the variable 1 or 2 (set fixed) and it worked.

 I just would guess that something's being overlooked. Unless somehow the generators for both variables got cooked? I would bet something got messed up with the remote changes to the tiu, somehow??

Bob, re your "off-topic" issue.  Try a conventional reset:  TIU off; track connected to transformer; turn on power; press whistle once and bell 5 times at 1/2 second intervals; whistle should toot twice.  This cannot be done with DCS/TIU on.

See recent thread: "Proto3 Engine will not run in conventional"

Are these recent PS3 locos by any chance?

Unless somehow the generators for both variables got cooked?

Joe, That's basically it, here's a post I made to a topic (2013) on my TIU failure:

The constant here is this:  The ability to control the engine is lost, when a Variable channel is jumpered to a Fixed channel, when this problem occurs.

This is either a design issue and/or we've been told to operate the system in a way that it shouldn't have been (jumpering Variable channels to Fixed channels in order to run command control and conventional engines from the handheld), not operator error.

When mine stopped working correctly, the only thing I was doing was letting the engine run around the layout at a constant speed (10 mph), didn't even have the handheld in my hand.  There were no apparent power fluctuations, interruptions, orderailments.

I bought my system in Sept 2011 (the day the earthquake rattled southeastern VA, I was at Davis Hobby Supplies buying the set when it hit), 13-14 months later I had VAR 1 go out as mentioned above, then VAR 2 died a couple of months after under the same conditions.

Bob, why do you say you jumper FIXED & VARIABLE to control command and conventional locos?  Absolutely not necessary.  My layout uses 6 channels, and a command or conventional loco can go anywhere at any time, under control from the remote.

Your statement gets me to wondering:  Do you have the outputs from FIXED AND VARIABLE also connected together to to the same track?  This should not be done.

It's a major no-no to ever jumper the outputs together, though for a short period it won't hurt anything.  The inputs can be jumpered together, mine have been jumpered since I got the TIU.  Four channels, two bricks.

Bob,

There is absolutely nothing wrong with jumpering Fixed #1 IN to any other TIU input channel. However, it's only necessary to do so when all of the following are true:

• The TIU is not being powered via the Aux. Power port
• Fixed #1 In is not being powered
• It is desired to operate DCS engines on a channel other than Fixed #1.

To use a variable channel to operate a DCS engine, do the following first:

• Power the TIU either via the Aux. Power port or via Fixed #1 Input orby jumpering the variable cxhnnel to be used to Fixed #1 Input
• Make sure that the DCS signal is turned on for all channels: Menu/System/DCS Setup and press the AON soft key
• Make sure that the variable channels are in fixed mode of operation: Menu/System/DCS Setup, select each variable channel individually and press the FXD soft key until the message comes up saying that the channel is in fixed mode.

This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!

Barry, there is no need to set a VARIABLE to FIXED to run a DCS engine.  Simply scroll the voltage to an appropriate level, say 18 volts.  I know, for that's what I've been doing since DCS came out.

Note the issue of "forbidden" jumpering relates to OUTPUTs, not INPUTs.

None of my Outputs were jumpered together, only inputs, in this case Fixed 1 to Var 1 or Fixed 1 to Var 2.

Barry, there is no need to set a VARIABLE to FIXED to run a DCS engine.  Simply scroll the voltage to an appropriate level, say 18 volts.

How is this done unless the handheld is in Conventional mode?

When my failures occurred, I had a Z750 power supply (21vac, no controller) wired to the TIU, now I have a PH180 power supply (18vac, no controller) wired to the TIU.

Bob, there is no such thing as setting the remote to conventional mode.  Press the ENG button and you can send digital signals to DCS locos, that have no effect on conventionals.  Press TRK, and you can control track voltages.  These are entirely independent.

Let's say I have a section of track connected to VARIABLe and I want to run a conventional loco.  I press TRK, select the track, and use thumbwheel to control track voltage and the direction, whistle and bell to activate those functions.  Changing voltage has no effect on DCS locos unless it's too low to provide enough power, around 13 volts.  Whistle and bell buttons have no effect.  Pressing DIR will cause the DCS loco to lurch briefly, but that's not an issue and won't trigger anything unless you hold it down more nthan 5-7 seconds.

If I want to run DCS, I press TRK and set the voltage to about 18.  Then press ENG and control the loco as usual.

If you want to run both types at the same time, have the conventional loco pull a heavier train than the DCS is pulling.  Press TRK to control it and ENG to control the DCS loco. 

Leave DCS signal turned on at all times; it doesn't affect conventional.

Robert,

 there is no need to set a VARIABLE to FIXED to run a DCS engine

No kidding. You think I don't know that?

However, when someone is having a problem, streamlining assistance is desirable. Setting variable channels to fixed for DCS operation avoids other issues, and does not require setting up TIU tracks.

I know that you know it, but your post says it is necessary.  I see too many posts that convey the impression that a dual-service layout is complex, requiring elaborate wiring or switches..  It is not.  Operating a dual-mode layout is ultimate simplicity.

Robert,

but your post says it is necessary

No, it does not!

It simply says "do this" and "make sure" to eliminate a possible oversight and preclude having to take additional steps, e.g.,

• Click TR
• Select a track
• Press the thumbwheel
• Use the thumbwheel to roll up voltage.

When troubleshooting problems, it's best to provide information that gets the possible correction implemented most easily and with the fewest steps.

What you did by "correcting" my post was to cause confusion.

Feel free to correct me, however, wait until I state something wrong.  

To use a variable channel to operate a DCS engine, do the following first:...

• Make sure that the variable channels are in fixed mode of operation:

ipse dixit.

Robert,

ipse dixit

How is:

"Make sure that the variable channels are in fixed mode of operation"

either arbitrary or dogmatic? What it is, is a good way to eliminate variables that can get in the way of a solution.

If one is going to ever run conventional, one must set up TIU tracks per the DCS instructions.  If one is only going to run DCS, one might as well set the VARIABLES to FIXED.  If one is only going to run conventional occasionally, you might as well set the VARIABLES TO FIXED since, if you want to run conventional, merely moving the thumbwheel when TRK has been pressed will convert to VARIABLE for the session or until emergency stop is pressed, bit it is not necessary.  If one runs conventional often, or ever leaves conventional locos on the track, I wouldn't set the channels to FIXED because that can have unpleasant consequences (speedy takeoff) if one has to repower up, such as after an emergency stop.  When set to VARIABLE, nothing will move until you move the thumbwheel one notch.  When I turn on layout power, within a few seconds VARIABLE channels set to FIXED power up to full voltage.  If I have an old Lionel E-unit loco on the tracks, there's a 50-50 chance it will take off flying.  This has also happened to me with a PS3, which for some reason locked itself into reverse, requiring a conventional reset to cure.

I am trying to think of what problems require channels to be set to FIXED to diagnose.

Robert,

Where does Bob Delbridge say he will ever run conventionally?

Where does he say he shall not?

Goodnight, Robert.

Goodnight, Barry.  [see you next week]

Goodnight Mrs. Calabash, wherever you are.