FORUM CLINIC: 12 years using DCC - SIGNIFICANT NEW INFO!

[n2mopac]

Sorry I'm a little behind here, but here is one question. Assuming each block is train length, couldn't a person simply wire the bulb into a feeder from the main bus to the track and forgo the 3rd bus wire. I know this may go againsy your standard of supplying feeders to every track section, Joe, but theoretically will this not work?

Ron

[jfugate]

Ron:

Yes, that would work, assuming there is only one track feeder to the train block, and it has an 1156 bulb in it.

[Anonymous]

This is very good information, and applies to both DCC and non-DCC layouts. Keep it coming! It's especially appropriate for guys like me that are building a new layout and getting ready to lay track by this weekend!

Mark in Utah

[jfugate]

TOPIC THIS POST: All about DCC friendly turnouts

So what's the big deal with DCC Friendly turnouts anyway? Actually, it's all about shorting the track, and the most common place a short can occur on a layout is at turnouts.


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A DCC friendly turnout is a turnout with less chance of a short if something doesn't track right. And a DCC friendly turnout can be a key component of good short management, in addition to the 1156 bulb we've already discussed.


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Any time I've seen the DCC friendly turnout discussion come up on boards and forums, there's always a lot of talk about the points end of the turnout, but I don't think that's the real issue. More derailments happen at the frog end of the turnout, and it's also the more likely place you'll see a short.


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So to focus on the frog end, you have two basic choices with how you handle the frog – live (powered) frog or dead (unpowered) frog.


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In both cases, the frog is generally isolated with gaps (unless you use the turnout to do power routing). If you look at a live frog turnout, the polarity of the power to the frog is based on the position of the points.


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But with a live frog turnout, if you run through the turnout from the frog end with it thrown against you, you will get a short. And we don't like shorts on a DCC layout!


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By contrast, with a dead frog turnout, you expect the other wheels of the loco NOT on the frog to pickup the power. Most modern locos have all-wheel pickup and a dead frog is not an issue. Only if you have extremely short wheelbase locos will you have a problem with dead frog. I model the 1980s SP, so dead frogs work fine for me.

I spoke with Gary Siegel recently (owner of the wonderful L&N layout covered in MR back in the late 90s) and asked him which he was using: live frogs or dead frogs? Like me, Gary started out using live frogs but has now gone to dead frogs.

As to the pros and cons of live frog versus dead frog ...

LIVE FROG
Advantages:

• No dead spots in the track
• When entering a turnout thrown against you from the frog end, the train stops (shorts) preventing a derailment.

Disadvantages:

• Need contacts to route power reliably to the frog, which is more work since using the points alone is not reliable over time.
• A short on a DCC layout during “normal operations” is generally BAD.

DEAD FROG
Advantages:

• Easy to do – no extra wiring
• No short if the turnout is thrown against you – you just go on the ground like the prototype ( which can about 10% of the time cause a short ... so nothing's perfect).

Disadvantages:

• Dead spots in the track can be bad
• May have to cut gaps around the frog – which means more work.

WHAT I PREFER
I prefer dead frog turnouts. Modern all-wheel pickup diesels don't even notice them, although some older steamers without all wheel pickup may have trouble, as well as really short wheelbase locos.

You can get dead frog DCC friendly turnouts from several sources today:

• Atlas code 83 Super -Switch (#4, #6, or #8)
• Peco insulfrogs
• MicroEngineering turnouts
• Walthers/Shinohara DCC Friendly models (although in high demand so are often out of stock)

Older Shinohara/Walthers turnouts need modification to be made DCC friendly.


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Here's a photo of a Shinohara/Walthers old-style turnout that's been modifed to be DCC friendly (this turnout was recycled from an earlier layout, which is why it looks kind of grungy).

Study the photo and you can see what was done to make it DCC friendly.

• Replace the throwbar with a printed-circuit (PC) board throwbar. Remove the foil from the center of the throwbar so you don't short the two points. The foil under the stock rail helps conduct power to the nearby point so you don't rely on point contact alone for them to get power.
• Attach each point to its closure rail with half a rail joiner. This makes the point the same polarity as its closure rail, which minimizes the chance for a short at the point end if there is ever a derailment there.
• Solder a PC tie under the closure rails, to route power from the stock rails to the closure rails. Remove the foil in the middle of this PC tie so you don't short the two closure rails together.
• Cut gaps around the frog, and fill the gaps with black or gray styrene plastic glued in place with superglue. Leave the frog unpowered.

If you modify an older turnout as shown, even if you get a derailment at a turnout, you will only infrequently also get a short.

WHAT IF I NEED TO USE LIVE FROG?
If you do need to use live frog turnouts, then put an 1156 bulb in the feeder wire to the frog. This way, if you do happen to get a short from running the turnout the wrong way, only the one who gets the short will be affected by it – not the whole power district or layout.

TOPIC NEXT POST: Programming loco decoders

[electrolove]

Joe:

Thanks for the great clinic. One question for you. Whalthers/Shinohara DCC friendly turnouts, can they be used right out of the box without problems?

[jfugate]

QUOTE: Originally posted by electrolove

Joe:

Thanks for the great clinic. One question for you. Whalthers/Shinohara DCC friendly turnouts, can they be used right out of the box without problems?

Yes, that's the beauty of all the DCC friendly turnouts listed. You just install them, solder track feeders to the stock rails, and you're done.

[electrolove]

Thanks Joe for your quick answer. [:D]

QUOTE: Originally posted by jfugate

QUOTE: Originally posted by electrolove

Joe:

Thanks for the great clinic. One question for you. Whalthers/Shinohara DCC friendly turnouts, can they be used right out of the box without problems?

Yes, that's the beauty of all the DCC friendly turnouts listed. You just install them, solder track feeders to the stock rails, and you're done.

[n2mopac]

QUOTE: Originally posted by jfugate

Ron:

Yes, that would work, assuming there is only one track feeder to the train block, and it has an 1156 bulb in it.

Great! One more question (I think this was addressed above, but I can't find it). Is there a limit to the number of bulbs you can wire into a layout. I, for example, am presently laying the main that I intend to power with MRC's Prodigy Advance. It comes with a 2.5 amp power supply and I intend to run a 5 amp booster as the main progresses. What would be the maximum number of blocks/bulbs that I could use with such a setup, and how do I figure that number. (I know just enough about electronics to make me REALLY dangerous.)

Thanks again for all your insight. This is all very timely and helpful to me as I am constructing my new layout right now and am venturing into DCC for the first time on it. Thanks again.

Ron

[rrinker]

You can theoretically have as many blocks and light bulbs as you want. Want a block every foot? Go ahead. But the return on investment (not to mention the truckload of light bulbs you would need) isn't going to be very good. Make the blocks too big, and you end up having more trains in the area than the light bulbs support, so they start lighting up and slowign down the trains. That's why the idea of a 'train length' block is as close to ideal as you can get. One train won't trigger the bulbs unless there really is a short.
The output capacity of the DCC system doesn't really have anything to do with how many blocks you can create, only with how many of those blocks can be filled with trains at one time.

--Randy

[Bullitt406]

What about Atlas Custom Line versus Super Switch. Any difference between those other than appearance?

Josh

[selector]

Randy, or Joe ( or an electrical engineer who is reading), I understand Randy's response, and it makes sense. Just for my edification, is there an exponential relationship involved? I ask this because the light bulb will be drawing current all the while if it is ever going to draw current. So, is the draw inversely proportional to ....what, resistance? Help me to appreciate what the bulb is doing when it is not protecting the booster and locos during normal running.

[rrinker]

QUOTE: Originally posted by Bullitt406

What about Atlas Custom Line versus Super Switch. Any difference between those other than appearance?

Josh

As far as i can tell, exactly the same. When the Super Track Code 83 first came out, the Custom Line was the previous revision, not nearly as nice in appearance as the latest versions are. I think Atlas included a bit of what they came up with for the Super Track when they redesigned the Custom Line stuff - at least the Code 83.
Electrically, they are the same.

--Randy

[rrinker]

QUOTE: Originally posted by selector

Randy, or Joe ( or an electrical engineer who is reading), I understand Randy's response, and it makes sense. Just for my edification, is there an exponential relationship involved? I ask this because the light bulb will be drawing current all the while if it is ever going to draw current. So, is the draw inversely proportional to ....what, resistance? Help me to appreciate what the bulb is doing when it is not protecting the booster and locos during normal running.

Acting like a resistor, a low value one. There are devices called Negative Temperature Coefficient Resistors (NTC) that would work the same as the light bulbs, if the proper values can be found. But they cost more than 1156 bulbs.

--Randy

[selector]

Acknowledged, Randy, and thx.

[jfugate]

Great answers, Randy -- thanks!

[n2mopac]

QUOTE: Originally posted by rrinker

QUOTE: Originally posted by selector

Randy, or Joe ( or an electrical engineer who is reading), I understand Randy's response, and it makes sense. Just for my edification, is there an exponential relationship involved? I ask this because the light bulb will be drawing current all the while if it is ever going to draw current. So, is the draw inversely proportional to ....what, resistance? Help me to appreciate what the bulb is doing when it is not protecting the booster and locos during normal running.

Acting like a resistor, a low value one. There are devices called Negative Temperature Coefficient Resistors (NTC) that would work the same as the light bulbs, if the proper values can be found. But they cost more than 1156 bulbs.

--Randy

So, one last clarification, assuming I am not going to put 100 bulbs on my 300 feet of trackwork, is there a point when all of these "resistors" beging to cause a power drain on the system or overload it by their sheer numbers?

Ron

[jfugate]

Ron:

The short answer is: you will not overload your system by adding a dozen or more bulbs in series with your power feeds. It's the locos in the circuit that create the load, not the bulbs.

Now the long answer.

If you design the power feed side of your DCC layout properly, you will typically break things up into two or more power districts, each with their own booster feeding the power. The only exception to this might be the smallest of layouts, like anything under about 50 square feet (the common 4 x 8 is 32 square feet).

By having multiple boosters feeding things, you automatically divide up the bulbs across the layout -- each booster and power district can be thought of as its own isolated system for the most part. The only thing connecting the booster districts together is their common link back to your system's command station. But electrically speaking, each district is its own isolated circuit.

And the bulbs don't do anything until there is current flowing to locos on the track, and while the bulbs are cold, their effect is imperceptible to occupied track. So the real question is how many locos can you load into a single power district? You'll hit the current limit of your booster first from locos on the track -- that's the real concern.

If you wire your layout with train length blocks and one bulb per block, you can have a layout that fills an aircraft hanger and has thousands of train blocks, and you don't need to worry about the bulbs. With a layout that size, you will also have hundreds of power districts -- each with their own booster. And each power district electrically is its own isolated circuit. It's the number of locos typically on the track in a power district that will be your limit, not using 1156 bulbs to do short management.

[Anonymous]

[rrinker]

Exactly. When there is no train in the block, the lights do nothing. The unoccupied track is an open circuit.

[jfugate]

QUOTE: Originally posted by rrinker

Exactly. When there is no train in the block, the lights do nothing. The unoccupied track is an open circuit.

Bingo!

It's the locos that draw the current. The bulbs really are not a consideration until you get a short or put enough locos on the track that you approach 2 amps. THEN, and only then, do the bulbs enter the circuit as a noticeable load -- and they limit the current to just over 2 amps, and *they become* the load.

It's this current limiting feature of the bulbs that makes them do their magic. For $1 each, it's hard to beat their value for adding load controlling short management to a DCC layout.

[jfugate]

TOPIC THIS POST: Programming loco decoders

DCC allows you to independently configure a locomotive decoder with custom settings for that locomotive, so you can literally tune each locomotive to get the best performance out of it..

Loco decoders include the ability to set starting voltage and speed, top speed, configure reverse settings to be different from the forward settings and a whole host of of other options.

This is all done using configuration variables or CVs. While there are some common CVs in the NMRA DCC standard, many CVs are not standard and vary considerably from one decoder manufacturer to another. In order to get the most from a decoder, you can spend hours pouring over complex manuals trying to figure out binary bit settings to get certain features to work as you want.

A free open source decoder programming aid is now available called DecoderPro that alleviates most of the loco decoder programming pain and complexity. You need some sort of PC running either Windows, the Mac OS, or Linux. Using an internet connection, you can download DecoderPro, install it, connect your PC to your command station, and be in point-and-click decoder programming heaven!

The next few series of posts on this forum clinic we'll step through how to download, install, configure, and use DecoderPro to program decoders. Believe me, once you see how easy it is to program even complex decoder settings with DecoderPro, you won't want to go back to doing decoder programming by bit-fiddling with arcane CV's documented somewhere in your decoder manual!


DOWNLOADING DECODER PRO
Navigate your computer browser to this link:

http://jmri.sourceforge.net/

Click on the DecoderPro link on the left, then click on the download link at the top of the page. On this page you will see various versions listed for specific operating systems. In this clinic we focus on Windows, since the lion's share of PC users have that os.


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INSTALLING DECODER PRO
Once you have downloaded DecoderPro, you need to install it. On the DecoderPro main page you will see the install guides listed at the left. Click on the Windows link.


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On this page you can read about what you need to have hardware-wise to install DecoderPro. Your machine must be at least 120MHz Pentium II, have 64MB or more memory, and be able to display 800x600 screen resolution.

You also need to get and install Java. You may already have Java installed on your machine -- you can open a command window on your system and check to see if you already have Java installed. Open a MSDOS command line window and type the command shown here:


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If you have Java installed, you will get a response that lists the Java version, something like what we show here:


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I have Java 1.4.2 installed, which will work just fine – you need to have Java version 1.3.1 or later installed. I'm okay as it is, but for purposes of showing you here how to download and install Java, let's assume I need to download and install it (it's free from Sun Microsystems). Just below the sample “java -version” command you will see the link for downloading Java. Click the link:


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This takes you to a page with a button on it for downloading the latest version of Java. Click the button to download Java:


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Once you have downloaded the Java installer, double click on it, and answer yes to the license agreement. On the next screen, take the typical installation, as shown here:


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Once the install is complete, click the finish button:


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Now if you open the command window and type java -version you should see a version of Java listed. I did have version 1.4.2, but now you can see I have the latest version, which happens to be 1.5.0:


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Go ahead now and double click on the DecoderPro install icon to install DecoderPro itself.


STARTING UP DECODER PRO
With Java installed, you are all set to fire up DecoderPro. Just double click the DecoderPro icon on your desktop. You should see this box come up:


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Notice the programming buttons are grayed out ... that means you need to connect your PC to your command station. We'll cover how to do that in the next installment of this FORUM CLINIC.

TOPIC NEXT POST: Connecting your PC to your command station

[simon1966]

You can also access Decoderpro from the www.decoderpro.com web address. One really important point, to head off any installation problems, is to ensure that the correct version of Java is installed BEFORE you install Decoderpro. If you join the JMRI yahoo group you will quickly notice that 90% of problems with installation are as a result of installing the Decoderpro application before Java is correctly installed.

Decoderpro is an excellent application and is well worth supporting. When one considers that this is a volenteer project, made available for free, it is even more amazing.

There is a new version due out soon that will have support for the latest QSI sound equipped decoders. For now, the support for the sound portion of these decoders is very limited.

[n2mopac]

Thanks, Joe and others, for your very complete and informative answers on my bulb questions. I'm sorry I didn't respond earlier. My 6 year old son has been in the hospital the past four days--just diagnosed with asthma. He is home and doing fine now, but I didn't have opportunity to check back here and respond until today for obvious reasons. Thanks again. I think I have a handle on it now.

Ron

[selector]

That must have been a scare, Ron! Good to hear that he is okay and you can relax with us again.

[Anonymous]

Trains are fun, kids are forever. Hope your son is doing much better.

My daughter fought asthma when she was younger (never went into the hospital), but between the hamster dying and her getting older she's doing much better. I hope the same can happen for your son.

Mark in Utah

[Anonymous]

Hi Everyone, just joined a short time ago and am new to just about all of this. I am currently just doing my homework so as not to make too many 'dumb, didn't do your research' kind of mistakes. You know, the ones that cost $$$? Just been cruising the threads trying to get the feel of things and I am truly impressed with everyones' knowledge of everything RR. The layout photos are awesome. I hope to tap into the huge talent base for info and tips.

Joe- thanks for the clinic. It really helps to hear from someone who has your knowledge and experience. All of the reading on DCC has had me in a fog as to the aspect of wiring the layout. So far this has clarified things a great deal.

Thanks to all
Dave

[jfugate]

Dave:

Glad to hear you find this info useful ... that's why I take the time to post it here!

[:D]

[Anonymous]

Joe, thanks for all your tips.

I'll likely print out this thread and throw it into my MRR'ing notebook. I'm sure DCC is in my future.

Good stuff.

The best part is your info is more up to date than any book could be by the time it's printed!

[jfugate]

TOPIC THIS POST: Connecting your PC to your command station

Once you have DecoderPro installed on your PC, you need to connect your PC to your command station so you can program decoders from it.

A note on PCs: Obviously, a laptop will be the most convenient type of PC to use for programming decoders with DecoderPro. If you look on ebay, you can often find used laptops with enough horsepower to easily run DecoderPro for a few hundred dollars. Newer laptops, on the other hand, often don't have a serial port – and a serial port (also known as an RS-232 port) is generally how DecoderPro expects you to connect your PC to DCC your command station. Modern laptops have dropped the older style serial port in favor of newer USB ports.

Fortunately, the loss of the serial port on modern laptops in favor of USB ports has caused USB to Serial Port convertors to become common to address this need. These devices typically cost from $20 - $60. The Keyspan converter, which costs about $50, has been thoroughly tested by the DecoderPro developers and found to work reliably, so they recommend it. Here's a link: http://keyspan.com/products/usb/USA19HS/#otherImages

USB to Serial Port converter

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If you have an NCE system, connecting a PC to your command station couldn't be easier: you just plug in a standard 9-pin serial cable into the command station and off you go.

Connecting a PC to an NCE system is easy (9-pin port in upper middle-right)

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For EasyDCC, which I have, you need to construct your own cable, because the EasyDCC end requires an RJ-11 phone plug. I cover how to build one of these cables in the special features section of my upcoming video on all things DCC.


For Lenz, you need to get the LI computer interface (about $100), and then use a standard 9-pin serial cable to connect your computer to the system.

Connecting a PC to a Lenz system means you need to buy more hardware



For Digitrax, you need an adapter to connect your computer to LocoNet. Your choices are ( in order of preference): LocoBuffer II, LocoBuffer, or an MS-100. Your best bet is to use a LocoBuffer II, which goes for $60 from RR-CirKits.

Connecting a PC to a Digitrax system means you need to buy more hardware


For more details, or to learn about other DCC systems and how to connect to them, go to the DecoderPro hardware connectivity guide at: http://www.decoderpro.com/hardware/

If you want to use DecoderPro to program decoders with an Atlas, Bachman, or MRC DCC system, you are simply out of luck.

Once you have your PC connected to your command station then the fun begins! Inside DecoderPro, go to the preferences panel. This opens automatically the first time the program is run, or you can select it from the "Edit" menu. Select your system from the dropdown box, in my case I select EasyDCC since that's my system. Depending your system, you may have to select a baud rate -- the documentation that comes with your system's computer interface should tell you what to select. You can also go to the DecoderPro hardware link above for more detail.

Click "Save". You'll be asked if it's OK for the program to quit, click "Yes". Restart DecoderPro, and the programming buttons should no longer be grayed out, so you're all set to go!

Let's look at how to program a loco decoder with DecoderPro next.

TOPIC NEXT POST: Super-simple decoder programming with DecoderPro

[jfugate]

Just making sure everyone is aware I've posted another clinic installment today.