DCC based automation (with Transponding focus)

[The_Ghan]

John,

 

My response was delayed by my wife's timetable ....  .... I should wrap it up and send it to you in the next six hours.

 

Aesthetically, soldering to the bottom of the track is the way to go, but that isn't what I do.  I found it too difficult.  I also failed at soldering to the joiners.  I was using Peco track for my subway at the time and the finish to the bottom of the joiner didn't want to accept solder.  Also, it was hard to fit the joiners once soldered.

 

You're going to have HOURS of soldering ahead of you.  I recommend drilling very small holes in the plastic track ballast and bringing the wires up through on the OUTSIDE of the rails.  Then solder to the outside of each rail.  I use Molex computer wires to do this as discussed in a separate thread.  If your layout is temporary then I recommend this kind of approach because you can unclip things and put them away.  There is nothing worse than spending hours unravelling your wires.

 

Molex link on eBay: http://cgi.ebay.com.au/4Pin-IDE-ATA-Power-Supply-Molex-SATA-adapter-cable-/370392231244?pt=LH_DefaultDomain_0&hash=item563d18ed4c ... cut of the black end and throw it away.  Solder the wires to the track and the other end is pre-wired for you. I make up custom lengths using these plugs - separate items for male and female: http://cgi.ebay.com.au/ATA-ATX-Power-Supply-Molex-Plug-w-Male-pins-mini-ITX-/220628280636?pt=LH_DefaultDomain_0&hash=item335e78653c

 

Mini connectors:  I also use the mini connectors from this guy ... http://stores.ebay.com.au/towzatronics ... they are colour coded and come in 2, 4, 6 and 9 pin set-up.

 

By the way, you only need to strip about 5mm of wire (1/5 inch) and solder immediately above and to one side of the hole so that you can pull the excess cable back down.  I forgot to mention the BIG advantage of soldering on the outside of the rail - you can SEE when a joint fails and EASILY repair it without removing any track. 

 

Finally, don't use the plug in connectors.  The joints aren't good enough for DCC and they become a nightmare with time.

 

Cheers

 

The_Ghan

[Darklighter]

I also failed at soldering to the joiners. 

 

How come? I'm no expert in soldering but I found it quite simple. Here is a good tutorial: http://cargoplus.dynalias.net:82/content/view/18/19/

[Martijn Meerts]

I forgot to mention the BIG advantage of soldering on the outside of the rail - you can SEE when a joint fails and EASILY repair it without removing any track.

 

You can also see where the joint is, which can (if you're no good at soldering/have bad equipment/use heavy wire) stick out like a sore thumb :)

 

I have experience with both soldering to the side (did that with my fathers layout, some joints are fine, some stick out big time. We painted the track rusty brown though, which makes the joints less visible, but at the same time also makes it less visible to see if a joint is bad), soldering to the bottom (with both Tomix and Peco track), and with bottom solder joints being bad (Tomix track, one of my early attempts.)

 

 

As for not being able to solder to joiners, depends on the metal the joiner is made of. Some types of metal are just impossible to solder to with a regular equipment.

[john_ibw]

The soldering talks is starting to worry me. I am going to try a few tonight and tomorrow. I will try the joiners first, then I will attempt the sides of the rails. I would like to avoid further purchases this month if I can so won't really consider the connectors unless absolutely necessary. Circuit breaker has kicked in as regards to my spending on trains. Cool-off period is about 4 to 6 weeks before spending can resume :)

 

BTW, I have received my Digitrax consignment today. Will start with a few drop-in installations and have the programming track setup. Looks like a busy active weekend.

 

The_Ghan: please take your time. It will be a while before the decoders are in and I am on basic DCC up and running.

[john_ibw]

How come? I'm no expert in soldering but I found it quite simple. Here is a good tutorial: http://cargoplus.dynalias.net:82/content/view/18/19/

 

Thanks Darklighter. The pictures and instructions make it look like I may be able to do it. But, I have not soldered in years and will have to try a few practice ones before I am certain I can solder good and lasting joints. Martijn mentioned about the metals playing a part in the ability to solder on them. I hope the ones I have will not throw a surprise at me. If nothing else works, I will attempt the following solder-less option until I find someone who can solder and is willing to bail me out. http://sites.google.com/site/josephbales/unitrackfeedertutorial

[The_Ghan]

I also failed at soldering to the joiners. 

 

How come? I'm no expert in soldering but I found it quite simple. Here is a good tutorial: http://cargoplus.dynalias.net:82/content/view/18/19/

As I mentioned in my post, I was using Peco joiners and Peco track.

[The_Ghan]

John,

 

Here's my first draft.  There is a document and a drawing.  Let me know what you think.  Response welcome from all members.

 

Cheers

 

The_Ghan

JohnsLayout-Doc.pdf

JohnsLayout-Dwg.pdf

[David]

John,

 

Here's my first draft.  There is a document and a drawing.  Let me know what you think.  Response welcome from all members.

 

Cheers

 

The_Ghan

 

Since you seem to have some real world experience with the RX4 I have a question - when joined with a BDL168s do the transponding blocks replace, augment or consume multiple detection blocks? Assuming I have a single BLD168s, and plug in 2 RX4 modules, what is the maximum number of blocks I can now wire up?

 

From reading the documentation I originally got the impression that the RX4 consumed some of the detection blocks - 2 detection blocks consumed to create 1 transponding block - so the assembled package would have 8 blocks (all transponding). However reading elseswhere it seemed like they augmented it - you would have 24 blocks, 8 of which performed transponding.

 

Is there an alternate source of documentation for Digitrax equipment? I find their documentation never actually gets to practical usage - lots of pinout labels, but no mention of what those labels mean or what they should be connected to. The decoder wiring diagram included with every manual is about the only documentation that I haven't needed an external source to clarify.

[john_ibw]

Here's my first draft.  There is a document and a drawing.  Let me know what you think.  Response welcome from all members.

 

The_Ghan. Thank you! You have spent considerable time on this obviously. I hope I can do justice to your time and effort.

 

What do I think? The assumptions you made at the start? Spot on! The design and suggestions sound too good to be true for a DCC newbie. I can’t ask for a better start. I would have taken forever to get to this point with some serious damage along the way. To start with, I will convert to DCC with the blocks and have that up and running. Changes to the tracks to make it less parallel as you suggested, I would hold it for a while if you don’t mind. I completely understand and I am with you on making it lesser parallel. It is just that my layout is temporary for now. When I am at a more permanent residence, I will relay the track with better design elements. I will have the must-have programming track incorporated though.

 

My bench? 4 foldable trestle table laid out in the living room. I can walk around the layout. It is temporary and hence stuff like back don’t arise for the moment.

 

BTW...2 drop-in decoder installed, Zephyr is out of the box, connected and all well so far. With factory default settings, I can move, turn on / off lights! So, I am a DCC convert officially tonight. Two trains! All cars are not lighted though. When I say 2 trains, 2 trains that will move after DCC conversion. A few cars have lights. It is 1 AM, my neck hurts but I am pleased with the results. I will get a few more done this weekend.

 

From doing a quick check on the inventory, I am short of one BLD. And I do not have the PM42 either. Of course the power district can wait a little longer.

 

Thanks again!

[john_ibw]

Some pics of the DCC conversions. Image quality is not the best. I have now finished converting 3 trains :)

 

The quality of work on the wired conversion will not match the ones I have seen here, but I am glad I was able to pull it off. The soldered joints seem to stick.

 

With the last one, for a moment I thought I fried a decoder. There was a short and I smelt something burning. To my surprise, the decoder works! Not sure what is the extent of damage. I hope it won't cause me trouble at a later date.

[KenS]

Since you seem to have some real world experience with the RX4 I have a question - when joined with a BDL168s do the transponding blocks replace, augment or consume multiple detection blocks? Assuming I have a single BLD168s, and plug in 2 RX4 modules, what is the maximum number of blocks I can now wire up?

 

From reading the documentation I originally got the impression that the RX4 consumed some of the detection blocks - 2 detection blocks consumed to create 1 transponding block - so the assembled package would have 8 blocks (all transponding). However reading elseswhere it seemed like they augmented it - you would have 24 blocks, 8 of which performed transponding.

 

I'll throw my two cents out, with the caveat that I'm still wiring things up, and haven't seen my system in operation yet.

 

I had the same confusion on first reading Digitrax's manual. And additional info is hard to come by, although Digitrax has a separate Application Note that adds a bit of clarity.

 

As far as I can tell, and it's reading a bit between the lines, the RX1 sensors are a function in addition to the 16 occupancy detectors.  You can wire four of them on the four inputs to the BLD168, and get train identification everywhere, but no ability to refine that within the four sub-blocks of that input.  That could be useful if you have a set of closely-spaced blocks where you need to detect position in fine detail, but would never have more than one train.

 

If you want to use fewer blocks for one train, another technique is to run two (or more? I can't tell from the documentation if that would work) occupancy detector output wires through one RX1 sensor, and have shared indentification in those blocks.  That would be useful, for example, with the decelleration and stop sections The_Ghan suggested, as both could share an RX1.

 

However, one concern I have there is what happens if you have multiple detectors on one train (cab and motor, for example) doing transponding.  I suspect this would work for a moving train, as one detector enters first, and is the one detected.  But for a stationary train, my suspicion is that two would interfere with each other, and neither would be correctly identified.

 

Finally there's the basic approach Digitrax describes in the manual, where you pick 4 or 8 of the 16 outputs and run them each through an RX1.  With that you get all 16 detecting the presence of something, and 4 or 8 doing both that and reporting the identity.  That can be useful if you don't need to locate trains on power-up, just when moving, and you have track you want to divide into detection blocks for signaling purposes (so trains can prototypically follow each other with various speed restrictions based on proximity) with long runs where the train is on one track, so you know from the last identification detctor passed what train is in each subsequent block.

[The_Ghan]

Hi David,

 

Please see my answers below in blue.  Also, read the following digitrax document:

 

http://www.digitrax.com/ftp/bdl16rx4pm42appnote.pdf

 

Cheers

 

The_Ghan

 

 

Since you seem to have some real world experience with the RX4 I have a question - when joined with a BDL168s do the transponding blocks replace, augment or consume multiple detection blocks? They augment detection blocks.  You can wire them up to transpond on sections that are also detected or to transpond on 4 sections that have no detection.  Assuming I have a single BLD168s, and plug in 2 RX4 modules, what is the maximum number of blocks I can now wire up?  24 - 16 detection blocks plus 8 transponding blocks.

 

From reading the documentation I originally got the impression that the RX4 consumed some of the detection blocks - 2 detection blocks consumed to create 1 transponding block - so the assembled package would have 8 blocks (all transponding). However reading elseswhere it seemed like they augmented it - you would have 24 blocks, 8 of which performed transponding.    Your latter assumption is correct.

 

Is there an alternate source of documentation for Digitrax equipment? I find their documentation never actually gets to practical usage - lots of pinout labels, but no mention of what those labels mean or what they should be connected to. The decoder wiring diagram included with every manual is about the only documentation that I haven't needed an external source to clarify.  I've not found any good commentry on the use of Digitrax products.  I rely on the generic Digitrax documentation and lots of patience and testing.