Star wiring

if it were me I  would NOT get DCS.  The TMCC/Legacy system seems much easier to wire although in tunnels there is some special wiring technique that is needed. I think it is called a ground plane.  I'm not much of a fan of DCS.  Or maybe you could skip everything except the LionMaster control by Lionel.  With that you may run three engines.

  whatever you choose....do the homework.  I have a friend who has a layout on the order of 8ft x 24 ft and he just uses the LionMaster ...or is it LionChief system.  

I love the DCS.  The Remote is easier for me to carry.  I can't diagram but I can tell you this: Star Wiring means the wire both positive and negative start from "Point A" and go directly to Points "B" "C" and so on.  In other words, sets of wire go directly from the primary source to all the other points on your layout.  To save wire, people have used "bus" wiring meaning the wires start at Point A same as above HOWEVER the next connect would be from B to C, then C to D.  Each point would have a different originating source.

I wired my layout with bus wiring.  When I got my DCS 6 months ago, it wouldn't work.  I changed my wires into a star pattern.

You will get advice on whether or not you need to use star wiring vs. bus wiring getting a solid mix of conflicting advice.  All I can say is that no matter how you choose to proceed test 1 wire at a time.  Then when you add a second wire, test it and re-test the first wire and so on.

DO DIVIDE your layout into a series of isolated electrical blocks, because WHEN (notice I didn't write "if") you have an electrical issue it will be easier to locate the source of the problem.

Above all else, Smile!!!  Remember that model railroading is fun!  :-) (most of the time)

PS:  I have a huge basement layout that works perfectly with one DCS system powered by one Z4000.  It starts at 3 feet off the ground and climbs to 5 feet and I have tracks that cross over each other.  I've had zero issues with DCS.  It works very well.  

Hello Jerry, I have been running MTH DCS system for some time and for me I think it is one of the best things that has happen to this hobby.

My suggestion is this, purchase a copy of the MTH DCS OGauge Companion Book.

Mr. Barry Broskowitz has written this guide in simple terms thats easy to understand and follow.

The book will cover all your wiring questions and any other questions you may have about DCS.

I don't need to use the DCS  OGauge Companion much, but when something comes up thats unusual on my layout I can easily find the answer in DCS Guide.

I believe you can purchase from MTH on their web site.

Good luck and have fun !!!!!!!

The term 'star-wiring' is a bit misleading as to the actual goal here.  That goal is to insure that any block of track only has one path for power, and more importantly the DCS signal, to flow through.  It doesn't matter if you use home runs to a central location, or a bus that delivers power through feeders, as long as any section of track only has power supplied from one place.  Basically, you want to use center rail isolators every 10-12 track joints and run only one feeder to each of these blocks.  

You can also access pretty much every feature the cab1L offers through the DCS remote if you connect the systems with a serial cable.  

On to less technical information: (my opinion only)

If you have conventional engines, and want to run them through a command system, I think the DCS system offers the most bang for your buck when getting started, however...   Over all, I find the TMCC/Legacy systems to be better made, more adaptable, and use superior (if still obsolete) technology.  The command protocol for TMCC/Legacy is also available to the public allowing folks to build their own devices that can talk to the command system if they wish to.  This is not a big deal for some folks, but for me, not being able to speak to the DCS system is a deal breaker on ever purchasing it...   At least at retail cost, I'd pick one up if the deal was good enough.   

The question to ask is what do you expect out of the system?  If you are looking to run conventional engines, and you already have the cab1L/base, you can add a legacy powermaster or use a ZW-C to get good control of your conventional engines for less money.  On the other hand, if you own, or plan to own DSC PS2/3 engines, you'll want the DCS system to have control of all their features.  For me, I have no desire to purchase PS2/3 engines over TMCC/Legacy ones, so no need for a DCS system.  

JGL

Everything that the others wrote was very good.  In addition to define 'star' wiring, think of the star as an asterisk, like the 'star' button on a touch tone phone.  Each connection to track, as described above, is the end of one of the points on the end of the asterisk or star.  They wire back to the center of the asterisk where you DCS system is.  

DCS was our chosen command control and I researched it compulsively. In short, star pattern (or home run) wiring is a great idea especially for troubleshooting. I also found that many folks here who claim to have followed DCS wiring protocol have no idea what they are talking about.  One drop per track block is what's called for.  But it is impossible to wire turnouts and follow all the DCS wiring rules - if you plan to keep the turnout's existing wiring, not create three discrete track blocks at each turnout and want to follow good power practices by putting power drops at all three legs.  Wiring for DCS and putting a power drop for each turnout leg has so far resulted in each power drop on that track block carrying an independent data package to the locomotive, so I've had the situation of pressing the whistle button once and the locomotive responding by blowing the whistle 2-3 times.  For me, it's a non-issue, but thought you'd want to know.  While I love the immense number of DCS features, it is temperamental and have found Legacy to be much more trouble-free and robust. 

Thank you very much all,

At this point I only have 2 ps2 engines and how about 10 legacy engines. I have a  CAB 1l , TPC 300 and I'm using a postwar Lionel ZW transformer. Everything seems to work pretty good. If I only have a few ps2 engines. Can I get the most out of them, sound wise or anything else with my current Lionel set up? Please advise, looking forward to your advice.

Thank you very much again for your input it is much much appreciated, Jerry

Jerry,

    I will advise you the same way Barry advised me long ago, before you rewire anything, just try adding DCS to your original layout, and see what actually happens. Especially now with the new Rev L, it is very forgiving as to signal strength.  I also strongly recommend the purchase of the DCS O Gauge Companion 3rd addition.  Also pick up a copy of the OGR Video Guide to DCS, both formats are great education for building and running a DCS/Legacy layout.

PCRR/Dave

In spite of what "REDJIMMY1955" says, our layout is "star wired" specifically for DCS, plus we have Legacy and TMCC, all of which operate concurrently at any time. Do it correctly, and you shouldn't have any issues. Just remember to KEEP THE TRACK CLEAN!!!!

Again, thank you all for your replies. It helps very much when you are a novice like me, believe me. Jerry

I took a short cut with my DCS and jumped some wires to power feed some of my Atlas turnouts.  It took me a while to figure out why Legacy engines (run on DCS) would spontaneously uncouple at times.  I finally asked myself (a while after I had done it and had forgotten) if I had followed the star wiring to these turnouts.  Well, as stated I didn't.  I rewired the turnouts in a star pattern and guess what?  No more spontaneous uncoupling.  It was my error, but I thought that there were design defects in the Legacy uncoupling system.  I actually posted a whole big post about it a while ago.

Also, despite sound advise from knowledgeable people I have no blocks on my layout (other than for sidings).  My runs can be up to 76 feet.  I have not encountered problems with this.  I do star wire feeder wires about every 6-8 feet.

Alan

Alan,

Just to clarify for the OP, while you may have star pattern wired correctly, you didn't follow DCS wiring protocol.  It requires electrically isolated track blocks comprised of approximately 10 sections of track, with one set of wires per track block located approximately in the middle of each given track block.

I've surmised that the key reasons for this protocol are basically two-fold: (a) to propagate a strong signal everywhere on the layout, as each DCS command only needs to be carried over (relatively) short distances of track; and (b) the track block isolation avoids a given DCS command from being communicated to the same engine multiple times via multiple power drops.  Again, this is the likely reason why my track blocks with turnouts and 3 drops cause my "one command" to trigger 2-3 responses from the MTH engine in that block  

Peter

PJB posted:

Alan,

Just to clarify for the OP, while you may have star pattern wired correctly, you didn't follow DCS wiring protocol.  It requires electrically isolated track blocks comprised of approximately 10 sections of track, with one set of wires per track block located approximately in the middle of each given track block.

I've surmised that the key reasons for this protocol are basically two-fold: (a) to propagate a strong signal everywhere on the layout, as each DCS command only needs to be carried over (relatively) short distances of track; and (b) the track block isolation avoids a given DCS command from being communicated to the same engine multiple times via multiple power drops.  Again, this is the likely reason why my track blocks with turnouts and 3 drops cause my "one command" to trigger 2-3 responses from the MTH engine in that block  

Peter

 

Thanks for the information, Peter.  I will use this information when I next wire a layout.  Meanwhile, my DCS locomotives are doing well so I can't complain.

Alan

ajzend posted:

PJB posted:

Alan,

Just to clarify for the OP, while you may have star pattern wired correctly, you didn't follow DCS wiring protocol.  It requires electrically isolated track blocks comprised of approximately 10 sections of track, with one set of wires per track block located approximately in the middle of each given track block.

I've surmised that the key reasons for this protocol are basically two-fold: (a) to propagate a strong signal everywhere on the layout, as each DCS command only needs to be carried over (relatively) short distances of track; and (b) the track block isolation avoids a given DCS command from being communicated to the same engine multiple times via multiple power drops.  Again, this is the likely reason why my track blocks with turnouts and 3 drops cause my "one command" to trigger 2-3 responses from the MTH engine in that block  

Peter

 

Thanks for the information, Peter.  I will use this information when I next wire a layout.  Meanwhile, my DCS locomotives are doing well so I can't complain.

Alan

Alan,

At the end of the day, that's what matters. It's amazing how much peace of mind I get when everything is working properly. 

Peter

Star Wiring when using Passive Mode:

On my DCS system I use Passive Mode. This means that no power is applied to the TIU INPUT channels.

Passive Mode allows me to separately apply AC voltage directly to the track using my Z-4000 transformers completely by- passing the TIU.

Wiring from the transformer to the track is applied using 16 gauge wire. However signals from the TIU to the track is separately applied using 20 gauge wire since very little current flows through this wire.  On my layout every wire from the TIU to the track also includes a series connected 560 ohm 1/2 watt "isolating" resistor.

.

:

What makes you think you need an isolating resistor in passive mode?

Jerry,

Do a Google (image) search for "star wiring for dcs" and you will see many results. This is just one example, and it shows partial wiring (just the inner loop) of the track:

Note that at least the center rails of the individual track sections should be insulated from the adjacent section center rails. I also do strongly recommend Barry's book and Rich's video on DCS, as mentioned above.

Good luck!

Alex

Thank you, 

I have a heavy  12 gauge common ground running around the perimeter of my layout. I then wired  positive  heavy wire to several terminals. From the terminals I wired positive wire to several areas of the layout  center rail and wired common to the heavy common perimeter wire. Is this wiring setup considered star wiring?

Thank you very much Jerry

gunrunnerjohn posted:

What makes you think you need an isolating resistor in passive mode?

To clarify the circuit design:

My unique method of track wiring requires this isolation method. Not necessary if AC power is always applied to all portions of the layout at the same time.

DCS is a great system and I find it very easy to use once you learn it. Other then train operation the feature I use the most is the track signal strength that every 2.0, 3.0 engine will transmit to your hand held remote unit. Nothing will point out a dirty section of track better then that. It will also tell you the run hours of your engine as well as other cool things like set your smoke level.

Let's not forget your accessory interface unit "AIU" it will work off of the DCS to permit operation of switches and accessories. This devices is a very big deal when you are writing a script for repeat demonstration action on your layout.

I also have TMCC and Legacy and I enjoy both of them, though I'm not fully up on it's cool stuff yet.

As for the Lion Chief Plus, wow what I great toy. You can not only run on your engine layout, but it is just as much simple fun on your around the tree loop.

But, as for the star wiring I have to tell you it's the best way to go. I originally had a buss loop when DCS and TMCC first came out and I had a good bit of signal issues so I rewired using the star plan and all my systems are working much better. Also as stated above a ground buss near your track will increase signal on your TMCC/ Legacy right of ways. With out it your TMCC engines will fly like a rocket if it runs through a tunnel or under another loop of track.

Now, go have some fun!

I have 8 years of experience with DCS and Star Wiring. Star Wiring with DCS is a superb operating system. Although it requires more wire, the power and signal continuities, and signal strength in the track attributable to Star Wiring are superior.

The nature of DCS avoids the command radio signal issues you will need to delouse with TMCC.

Follow the guidelines for Star Wiring in Barry Broskowitz's  book,  The DCS O Gauge Companion.

It is a good idea to have power ON-OFF switches for all storage sidings.

Thanks again all for your replies.

Jerry

Pro hobby, I still don't get the purpose of the resistor.

It's to weaken the DCS signal, makes it more sporting to run stuff that may careen out of control.