Wiring for DCS on 3-Rail Layouts

[rtimma]

For our Bed and Breakfast, I'm getting ready to wire a medium size layout - mainline of about 250 feet long - and I want to use DCS; plus have the track divided into blocks as on my older layouts. Has anyone had experience doing this and will the DCS signal go through a switch such as a SPDT (just isolating the centr rail) or DPDT ( islolating both ground and center rail). Do I have to use one or the other. THese dtails aren;t really covered on the mannufacturers or outside source DCS instruction videos. The OGA video really covers most other operations well but stops at complex layout wiring, using multiple interfaces (ITUs) and multiple transformers, etc. Is there a need have either solid or stranded wire and does it have to be twsited between each joint. Because of the lenght I was planning on using 14 ga. I was thinking about having the blocks on siding, tec for non-DCS equipmed engines - especially older Lionel equipmnet.

Thanks - Ron Timma [?]

[spankybird]

Hi Ron,
Welcome to the world of DCS. It really isn’t that hard to do. You don’t say if you are planning on running all PS2 engines or a combination of conventional and command engines. The wiring will be the same for both, the only difference is how you program the TIU.

First you should have a feeder line for every 25 feet of track, it does not have to be a different block. If you use different blocks, you can use a different power source, for more overall wattage, thus running more trains on the same track at one time.

Each block will require one channel of the TIU, which has four. They can be reprogrammed to all fixed or all variable or as the factory setting is 2 fixed, and 2 variable.

To connect more than one TIU together, requires a phone cable, and renaming the second one “TIU 2”. This is all done with the remote.

As for putting in your switches, it would be best to keep both wires as close as possible.

I would use the 14 gauge twisted pair wire.

Hope this helps


tom

[Anonymous]

Ron

Just wire up DCS as usual without any changes in your layout wiring at present. It may work. Otherwise do as Tom suggests.

With DCS you are sending both power and a control signal thru the track, as a result you want all tracks to rec'v the signal at about the same time with the same strength. You don’t want your layout to create any other impedance on the signal by "looking" to far a way to complete the signal. So by sending the signal from the TIU in a spoke fashion with both wires to each section of track, you reduce the problems. You can also add a light across the signal as suggested by MTH to improve the signal.


Alan

[Anonymous]

Ron,

I agree with Alan's advice:

Wire DCS to your existing layout exactly like it is. In most cases, it will work just fine. If it does not, try the "light bulb trick" first.

If the "light bulb trick" does not work, see below:

I have great respect for Spankybird, but disagree with him a little here.

With appologies to Spanky:

1) "First you should have a feeder line for every 25 feet of track, it does not have to be a different block. If you use different blocks, you can use a different power source, for more overall wattage, thus running more trains on the same track at one time.

Each block will require one channel of the TIU, which has four. They can be reprogrammed to all fixed or all variable or as the factory setting is 2 fixed, and 2 variable."

I agree about the separate feeder for each block (I actually run two to each block, one to the extreme end of each block). Each block does not require a separate TIU channel. The issue here is one of preventing standing waves. If a loop of track is too large, the DCS Signal coming around one side of the loop may arrive "out of phase" with the signal coming around from the other direction. This will show first with repeated commands (press the whistle once, and hear the engine respond with two whistles, etc.), then, as the loop grows larger, the signal strength will continue to drop until you get check track messages (note Alan's comment regarding the signal reaching the track with the same strength, at the same time).

We have successfully run almost 100 foot circumference loops of track off of one TIU channel--break ing the loop into four blocks by insulating the center rail and running separate feeds to each block works wonders. Lighted lock-ons work wonders here.

One Power Supply per channel is a very good idea. Make sure that the power supplies are phased properly (especially if running an older TIU-Pre-Rev. H1). Older TIU's have the black terminal (commons) tied together internally and people have been known to damage them by connecting multiple transformers out of phase through the TIU.

If you are going to run TMCC also (TMCC is a cheap add-on to DCS-about $50.00 and well spent), tie all of the phased "commons" together BEFORE connecting them to the "Black" inputs of the TIU, and tie the Command Base antenna wire to that point also. Run four wires from this common point to the Black TIU inputs. You will now have the DCS and the TMCC signals available on all four TIU Channels-this combined with the fact that two of the TIU channels are "Variable" in voltage, will allow you to run just about anything ever made for the A/C O gauge, three rail market.


A search on the OGR DCS Forum for "Barry's Commandments" would be a very useful thing for you to do at this point.

2) "To connect more than one TIU together, requires a phone cable, and renaming the second one “TIU 2”. This is all done with the remote."


Running in "Super TIU" mode, the TIU's are not physically connected. The phone cords (3 pair/RJ25 type jack) are used when connecting a TIU to an AIU (Accessory Interface Controller).

Back to the wiring:

14 gauge stranded, paired wire with lugs soldered at each end for the feeders.

MTH Power Distribution Blocks for the point to tie all of the feeders together.

14 gauge stranded, paired wire with lugs soldered at one end and banana plugs soldered to the other for the lead from the MTH Power Distribution Block to the TIU-make this lead as short as possible (mine are 5 feet long).

Mount the TIU in the center of the layout, mounted vertically, with adequate air circulation.

Again, I would stress the search of the OGR DCS Forum for Barry's Commandments-these are tried and true, and have resolved/prevented wiring/signal issues for many O guage modelers.

I appoligize that I do not have any information regarding the use of toggle switches. The only ones that I have used are the "knife switches" mounted on the back of a repro Lionel ("MTH") 437 switch Tower-these work great.

Please let us know how things turn out.

[spankybird]

I would like to thank RAK for helping out. [:D]It seems that my vacation was getting to me. [:P] He is correct with the phone line is to connect the AUI to the TUI and not two TUI together.

I think he miss understood me with saying that each block would require a separate channel of the TUI. For each power supply, you should use one channel of the TUI. If your blocks share the same power source, then one channel and one power supply is good. We are both agreeing on the same thing, just saying it differently. [;)]


tom

[FJ and G]

My understanding of DCS is that you can wire it with a bus line in the traditional way or use the recommended approach, star wiring, which requires more wires but basically has the hot and common going to each power block that you designate. However, on some layouts, the bus wiring method does not work with DCS and on others it does. To my knowledge, no one has ever discovered why this is so. If you have the answer, please cough it up.

Dave Vergun

[Anonymous]

Dave

THE ANSWER IS: infinite diversity infinite possibilities..

Each layout design has a different electrical characteristic or impedance. How can MTH know or foresee the way your layout is set up? Except for a simple circle, there are a myriad of layout designs. Add in switches and you have created a layout that changes its characteristic impedance every time you throw a switch or a combination of switches.

Maybe by passing the signal thru the track MTH created its own problem for us, unlike Lionel where the signal passes thru the air. So to overcome the inherent difficulties with MTH’s system on existing layouts, they suggest wiring in a spoke pattern from the TIU without intervening terminal blocks, so that the wiring to each block uses the same (relatively) length of wire for both the positive and negative (which of course is a bit silly with AC as the power source , but oh well!) This way the signal reaches each track section in about the same time. Recall that electricity thru a wire moves ( energizes the wire’s atoms) fast but slower than the speed of light, with the same impedance.

I block mine from switch to switch instead of 25 foot long sections.

Alan

[spankybird]

I can also add to NOT Following All The Rules. On my large layout, 10 ft. x 20 ft. I use my DCS with three blocks and three channels of the TUI.

This leave me one unused channel. So I tried to added my Circus layout to the DCS, as both circus engines that I have are PS2. This layout is in a smaller room off the main layout room. This would mean that I would have to run a line from the TUI to the layout of 25 feet or so. I had the wire, so what the heck, I will give it a try.

The Circus layout is 8 ft. x 5 ft.


I used only one feeder to the outside rails on the lower left side.

I am happy to say, it works, with a single strength of 10’s around the whole layout.[tup]



The best thing to do, is hook it up to your layout and try it, before you start changing things.[:D][:D]

tom

[FJ and G]

thanks guys, nice to see others are using DCS

[Anonymous]

Tom (Spankybird),

Sorry if I misunderstood! It does, indeed, sound like we are all on the same page!

Your Circus Layout looks great!

Alan's assessment is quite logical (to follow one Star Trek reference with another). Infinite Diversity-Infinite Possibilities). MTH could not have forseen all of the possibilities in layout design out there. Regardless, should exisiting layout wiring not work (which it does in most cases) there are ways around it.

To David's question, I have often wondered the same thing-Why will DCS work sometimes with Bus type wiring, or in very large applications without blocks. The only thing that I could ever think of is that the length of the track is, in some of these instances, such (by happenstance) that the signal, going around the track, does not overlap or meet in an "out of phase" condition. This is pure conjecture on my part.

One could build larger and larger loops of track, documenting the results as one went (I actually started to do this last summer, after passing the 80 foot loop length barrier and finding my signal results dismal). I did stop my tests after I got the appropriate results for the TCA National Convention Layout last year (that had to work-and had to work perfectly, which, ultimately, it did).

I would be interested in doing more testing of this nature, but time does not permit at the moment. It would also be interesting to test with different types of track and different light bulbs, wire gauges, bus vs. star wiring, etc. to try to better identify the interactions of all of these things.

That being said, Barry's Commandments (I know, I am repeating myself) are still the best place to start.

[ChiefEagles]

On my temp layout with old Lionel track, I hooked up DCS. Running tow PS2's and lots of conventional [sometimes both at the same time]. It is two loops [one inside the other, joined by some old manual swtiches] that are wired using 14 stranded to a point. Then jumpers soldered on from telephone wire [solid 4 connector using a pair for + and one pair for -]. Had heard how finiky DCS was. Figured it would not work. 10 track signal all around. Now this may change when I go to the big layoput that fills the room and two levels using all 14 stranded there]. I think you hook it up and run it. If it works, that is good. Problems, back up and punt. Do the least possible changes until it works.

[rtimma]

[:)] Thanks For the Input[:)]

Thanks to all that send infromation -

The common thread seems to be:

1. Use the 14 GA stranded wire
2. Use feeders at least every 25 feet - or in-between switches if used as blocks
3. Use all 4 outputs of the TIU as fixed - though that's one I still need to figure out.
4. Since I'm just beginning the layout I should use the star wiring configuration
5. No one really knows why the older common ground works some places and not others - I don't know but have had that experience - even on small modular layouts
6. No one seems to have used a DPDT relay at the block connection to switch from DCS to a conventional transformer or for block control.
7. I really liked the photo of the 5 by 8 double loop - think I will use that on the modular layout I do for our Shriner's Steam and Tractor Show in the Fall - supports the Children's Hospital - and is also a lot of fun!


New Question - Does anyone also use one ofthe QSI surge protectors in-line with the circuit breakers on the Z-4000 for additonal protection?

I'll keep everyone posted as to what happens with the wiring I install -

Thanks again

Ron Timma

[FJ and G]

Ron,

I differ slightly with 2 points:

#3. I'd rather have 4 variable as I run Williams conventional; takes very low voltage

#6 I do in fact use dpdts to cut power to certain blocks of my choosing

[ChiefEagles]

I built [easy to do] one of the quick acting circuit breakers from the OGR video. I'm using one of the older KW's and thus wanted the fast protection.

[spankybird]

HI Ron,

I e-mailed you how to set the TIU, but for all here on the forum here it is.

To reprogram the TIU, go to MENU, SYSTEM, SETUP, point at your Variable
channel and hit the FXD softkey (it is bottom row, right side of display).

You can even get more complex and give each track a name like ‘track 1’ and set them as variable and the factory ones at fix. This way you could choose between ‘track 1’ and channel 1.

As for the circuit breakers, because I use a post-war ZW (two of them) and Chief uses a KW, both have very slow breakers in them. We have built fast acting circuit breaker boxes. It is the same breaker that is already in the Z-4000. Therefore you don’t need this.

AS for the Surge protectors, the TIU has one in it. Again this is double protection.

tom

[Anonymous]

Ron,

I agree with Dave on the variable issue-sometimes I keep "Variable 1" and "Variable 2" variable, if I am running them on separate tracks-that way I can run conventional locomotives. If I am running all command locomotives I set them for "Fixed". If your layout is large enough that you will be using all four channels on what amounts to the same track (or loop of track) and are running command only, set them for "Fixed".

Tom (Spankybird) is absolutley right-QSI surge protectors are good, but uneccessary as the TIU has surge protection built in.

The breakers in the Z4000 should be fast enough, although many people run external fuses between the transformers and the TIU, just in case. If you have a "Rev. !" TIU, there are internal fuses to protect it, but you do have to take the TIU apart by removing the six small screws in the back and taking the cover off. I am running Lionel 180 Watt power bricks, which, with the exception of one that had a defective breaker, are plenty fast enough. I have also installed screw posts on the inside of my TIU (where the mounting holes are) and removed the six small screws from the back. The TIU is mounted with velcro, and the cover can be removed to change the fuses by removed screws, screwed into the aforementioned mounting posts from the front. Much easier.

Use lighted lock-ons at each point where the wire is connected to the track or, solder to the track and install a lamp accross the terminals of the TIU (I have not tried the second approach, but understand that it works well-I prefer the lock-ons). Solder every place possible.

Use the MTH power distribution blocks for the center of the "Star" pattern. These things work great!

Please tell us how everything works out!

[Anonymous]

One point

I use two 180 LNL bricks wired together to a power block terminal to obtain 360 watts THEN I connect to TWO TIU channel ports from that power block ( between which i have the fuses); this way each channel can command however much of the 360 watts it needs depending on which engines are on which channelled line.

If I have one engine on one line it would take a lower portion of the total 360 watts than the other channel that may have three or more engines on it. Otherwise if you wire the 180 to a single channel you restrict the 180 watts to the one channel and thus wastes wattage if only one engine is on that channel.

Alan

PS there is a 10 amp limitation on each channel of the TIU. However I found that my way the amperage capacity also splits so that the limitation is actually closer to 20 amps ; I have had at most six engines on one channel line at a time and the amp reading has never been greater than about 12 amps.

[ChiefEagles]

Allan, I like that. I get into the bigger layout, I may email you for more indebth conversation on the increased power and amps.

[rtimma]

1. Does anyone know what the commerical equivalent (Beldon, Atlas, tec.) wire is for the wire that is being recommended and sold by OGR for use in wiring for DCS? Possibly more cost efficient in 1000 foot spools.

2. The MTH terminal blocks are great but is there a less expensive commerical terminal block that is available through companies such as Allied Electronics, etc?

3. Has anyone heard whether there will be any commerical O-Gauge companies associated with DCS and related systems at the National Scale O-Gauge Convention in Washingtion D.C. a couple weks from now?

Thanks

[spankybird]

HI Ron,

I guess I can fess up and tell you that I pick up a 1000 ft roll of 18 AWG stranded twin lead wire at a flea market for $6.00. And that is what I have used on my layout.

tom

[spankybird]

OH yea,

The terminal blocks I pick up years ago at a Ham Fest (Ham Radio Flea Market)
tom

[garyseven]

Ron Timma
Have fun, and get the OGR Video. DCS is great!

[spankybird]

Hi Ron,

try this place for your supplies

www.newark.com

tom