DCS & Legacy on Modular Layout

 I wonder if the club is using a power bar ? We know weird things can happen with TMCC and some power bars with surge protectors.  yep just another wild guess.

I'm bringing a power bar with the MOV's stripped out that will make it into a simple extension cord.

 

Rev L TIU and Lionel 180 watt Powerhouses - you can't do any better than that.

 

What does your wiring look like? For our 32 X 18 modular layout each mainline has a paired hot and common with a drop at each module. The mainline buss loops around the layout and the ends are connected together. The power from the TIU channel taps into the loop. It's nothing like a star wiring setup but not quite a traditional buss layout either.

 

Do you have a Cab 1L base you can try?

 

Ken

The Trackers used passive mode for a long period of time, we found that the signal was much improved when the power went through the TIU.

 

Steve

Made a little progress, but ran into a wiring issue that explains some of the issues we were having.  I ended up using active mode, but somehow the two mainlines were crossed, so we had two DCS signals fighting it out, not a good scenario.  However, even with that happening, I had positive control of a DCS locomotive almost all the way around the loop except for the place where they actually crossed, and I had the Legacy connected through my low pass filter.  By the time we sorted out what was wired wrong, it was time to pack it in, so I'll be back on it Sunday and maybe I can actually get everything working.  FWIW, the track signal test doesn't work at all with two DCS channels connected together, no surprise there.  Also, the old Rev. G TIU worked a lot better than the new Rev. L with the two shorted, can't wait to try it with the wiring right on Sunday!

 

Morbid curiousity keeps me reading threads like these, since I no longer have a dog in this fight.  I'm in the process of converting all of my DCS and TMCC locomotives into cash.

 

I truly hope that this works out for you.  Honestly, if somebody with your skill set can't figure out how to make these two systems co-exist, I don't know who can. 

 

Regards,

Jerry

 

I think I "may" be close to a solution.  Things were running better than ever before with Legacy connected, and that was before I discovered we still had a crossed wire in one of the new modules shorting two channels together!  I hope when I get back Sunday to have them both running together.  Of course, that will still leave us with the issue of some Legacy and certain TMCC locomotives killing the signal, but I can't really do anything about that with track wiring.

I like to push a lighted car on track that is suppose to be dead, if it lights up something's  amiss.( Pretty easy). On a existing layout  I check out phasing between   transformers  by measuring   the voltage on each side of the center rail insulated pin separating transformer zones.. (center rail to center rail.) There shouldn't be any or very low.   Yep nothing new here.

 

 

 

 

Glad you're making progress. 

Guns,

   Yep as Marty indicated glad you are making head way, especially with your wiring set up, this may be as good as you are going to achieve unless you decide to completely rewire.

PCRR/Dave

Dave, there's going to be no total rewiring!  

 

Gregg, I know how to check tracks, that cropped up after we did our initial testing because that module wasn't connected yet.  It was the last to go in for the "full scale test", then we noticed we had a wiring issue.

 

 

Isn't connecting two DCS channels similar to 'crossing the streams'?

 

Anyway, glad to hear you found the culprit and have him on the run. A good and probably difficult find and probably also a big relief. Sounds like you have the problem solved and will have a system that now works very well for your display. Good luck on Sunday.

Really curious how your latest run worked out. 

Regards,

Jerry

 

Thats what I accidentally did which essentially gave my layout a DCS lobotomy. Its exactly like crossing the stream. Old Testament, real wrath of God type stuff.
Fire and brimstone coming down from the skies! Rivers and seas boiling! Forty years of darkness! Earthquakes, volcanoes...The dead rising from the grave! Human sacrifice, dogs and cats living together... mass hysteria!

 

The question that came to mind when reading this and previously, the published story of National Capital Trackers wiring standard change, is What's the difference between table layouts and modular layouts?

 

Alex and Marty Fitz ( and others) have been able to have DCS and Legacy play together.

 

The difference is that table layouts do not have the DCS signal running back on itself through the use of blocks.

 

Why not leave one module to module connector disconnected and create one block?

 

This would prevent the DCS signal from running back on to itself on the center rail.

 

It should not cause any other issues.

 

Whichever module has the power and command device connections, the last one adjacent to it after the loop around should not have the bus connected.

I'll be doing the testing tonight, didn't have access to the building last night.  I'll report on my progress.

Wiring a Modular layout is so different than a fixed layout especially when it comes to having command control work properly. The star wiring pattern as suggested by MTH can be implemented on a modular layout but it really isn't practical or efficient. One of the first the National Capital Trackers attempted was a single path feed to each module, by using insulating pins between modules, it didn't work. We tried having one module bus connection open on various spots in the layout, it didn't work. We tried the same thing with light bulbs and/or filters at the ends and the TIU, it didn't work. Our current harness has a continuity circuit that works in conjunction with an indicator light in our power cabinet. If the light doesn't come on, you do not have all of the modules connected. One of our most recent shows the crew setting up and running didn't bother getting a light, for the most part they ran OK. Another member that came to the show and brought a train to run, he placed it on the track and could not start it. He ended up moving next to where the power was plugged into the layout in order to get it running. This same person has told me that this is the first time he has been unable to get a locomotive running on a random spot since the implementation of the new harness. Ours is designed to work in a dual path circuit if you will. This is 100% counter to the way the manufacturer tells you wire a layout, but again a modular layout isn't a home layout. You don't believe it? Find out for yourself at fall 2016 York when the Trackers are in the Black Hall. We have gone to great lengths to make sure all command systems work, work reliably, coexist with each other, and operate seamlessly with conventional.

 

Steve

I'm curious how many tiu are used on some of the modular layout?  Are  more signal generators(channels)  better? . I also  understand if  running conventional things can get really complicated.

Most shows we only use 2. One is for the layout (3 tracks), the other is strictly for programming with tether only. Bigger layouts may have 2 for running mainlines, 2 or more programming/yard, and the one I use to run my timesaver puzzle. The Trackers do not block wire layouts, we usually don't have enough time to set something like that up. Each loop/circuit of track gets its own TIU output That's it.

 

Steve

No conventional running, strictly command for our modular shows.  We use one signal generator for each of the two mainline loops, one for all the sidings.  We're still working out how to get DCS to the yard, that is a work in progress.

 

Refresh my memory, how many signal generators stevia a TIU

Four channels, each has a signal generator.  Right now I'm just trying to get good signal to the whole set of mainlines and have the Legacy connected without killing the signal.

 

Thanks John, I was stuck between 2 and 4 and it has been so long since I heard that information. I feel your pain, DCS signal issues are not something one wants to troubleshoot

I'm thinking we're on the home stretch, we'll see...

 

Steve,

 

I seem to recall that NCT were using a capacitor on the Legacy wire at one point (in addition to the Susan Deats filters?)

 

-Bill

John are you going to be there tonight?

You betcha' Bill, I'll be there.

 

It was looking pretty good until we put the last module in and it had all the wires crossed up.  I think when we get that fixed, you may be ready.  I had good control all the way around, even with the two channels shorted together.  The odd thing was, the track signal didn't work at all, obviously the two carriers fighting didn't allow the return conversation.  I was using your Rev. G TIU, it seems to like shorted channels much better than my Rev. L did.  I suspect the Rev. L will work much better now that the short is gone. 

 

The Legacy being connected didn't seem to affect it after I installed my Chebyshev low-pass filter, so maybe that's actually doing it's job.  When I put it on the 'scope after building it, I had about a 30db roll-off from 455khz to 3.27mhz, so it's doing what I intended in stomping on any harmonics from the Legacy.  Tonight is the acid test!

 

Bill,

 

We may have briefly tried something back in the dark ages of TMCC, but since Legacy has been installed it has been a direct connection. There was some discussion with another group about the natural capacitance of parallel run wire degrading the Legacy signal. That hasn't been an issue.

 

At one time we had a goal of every module having filters on every track. We probably reached 95-98% of that goal. Some times DCS worked some times not. When the engineering analysis was performed on the new harness, the filters were found to impede the performance of the DCS signal. With the new harness we do not use filters or magic light bulbs.

 

Steve

Well John what was the out come from the other night.
Did you get it working right with the legacy.
An did you guys get the stub yard working.

He was  last seen entering  under the layout 2 days ago with a volt meter.. He hasn't come out yet.