TheRailwire

General Discussion => DCC / Electronics => Topic started by: asciibaron on November 20, 2009, 08:37:04 PM

Title: DCC block detection
Post by: asciibaron on November 20, 2009, 08:37:04 PM
what are the current methods for block detection with DCC?  i'm trying to sort out my needs ahead of construction so i don't run into a "why did i put this leg here" moment.

what are you using for signaling?
what are you using for route control?
Title: Re: DCC block detection
Post by: cv_acr on December 08, 2009, 10:28:03 AM
My club is looking into using hardware + software from CTI (http://cti-electronics.com/) for our signals and CTC system. Their panel display isn't that fancy, but their programming software seems pretty slick; you just program "when" conditions, and it detects when variables and conditions change and so will execute your logic as soon as the condition becomes true.
Title: Re: DCC block detection
Post by: Philip H on December 08, 2009, 10:52:58 AM
I'm seriously thinking about cribbing Dave Vollmer's methods (http://www.thevollmerfamily.com/Pennsy/Projects/signals.html (http://www.thevollmerfamily.com/Pennsy/Projects/signals.html)) for my switching layout - it's small enough that signals aren't required, but I think they will be fun.

I'm also thinking about adding some Fusee's as described in MR by Lance Mindheim.
Title: Re: DCC block detection
Post by: Ian MacMillan on December 09, 2009, 09:38:04 AM
Is everyone also using one hardware detector per detection block, or are you using two hardware detectors per block ie one on each end of the block.
Title: Re: DCC block detection
Post by: cv_acr on December 09, 2009, 10:41:30 AM
We're planning to use current detectors on the buses for each track block, plus backing those up with optical detectors at the boundaries of control points so that cars sitting across a short block will be detected even when there's nothing drawing current.
Title: Re: DCC block detection
Post by: John on December 09, 2009, 11:28:57 AM
I only use one detector per block .. my blocks are fairly long .. generally between cross overs or major switches
Title: Re: DCC block detection
Post by: eric220 on December 09, 2009, 02:30:45 PM
I use current sensors on the power busses with one sensor per black.  In theory, that should detect anything in the entire length of the block, and it functions quite well with locomotives.  The major drawback, of course, is that rolling stock must have resistor wheelsets, lighted interiors, or some other method that will draw current in order for the system function properly.  I'm still working on that part...
Title: Re: DCC block detection
Post by: Ian MacMillan on December 09, 2009, 06:19:29 PM
Ok thats where I was thinking most everyone was.

However if I wanna have trains stop automatically for stop signals I'd technically need 3 "blocks" per detection block right? Main detection, and then "braking" blocks before each signal?

I've yet to sit down and really go through the technical stuff for this yet, so I only have a basic concept of how it works off the top of my head.
Title: Re: DCC block detection
Post by: John on December 09, 2009, 06:59:27 PM
Ok thats where I was thinking most everyone was.

However if I wanna have trains stop automatically for stop signals I'd technically need 3 "blocks" per detection block right? Main detection, and then "braking" blocks before each signal?

I've yet to sit down and really go through the technical stuff for this yet, so I only have a basic concept of how it works off the top of my head.

Not sure .. I personally wouldn't automate this stuff ... thats what crews are for .. but .. look in the JMRI website .. Jacobsen had a layout that did exactly that at a Java conference a while back .. he shares the python code etc ..

http://jmri.sourceforge.net/jython/javaone/

Title: Re: DCC block detection
Post by: Ian MacMillan on December 09, 2009, 07:20:15 PM
Everything is going to be manual at operating sessions, but during regional open houses, like Tour de Chooch, you generally get about 200 people over the day coming to view the layout, and I want to have it automated as there is no way to really be able to run the layout and talk to everyone. I'd like it to be somewhat protoypical operations wise on open houses, and not just two roundy round trains.
Title: Re: DCC block detection
Post by: asciibaron on December 10, 2009, 03:13:14 PM
Everything is going to be manual at operating sessions, but during regional open houses, like Tour de Chooch, you generally get about 200 people over the day coming to view the layout, and I want to have it automated as there is no way to really be able to run the layout and talk to everyone. I'd like it to be somewhat protoypical operations wise on open houses, and not just two roundy round trains.

you would need 4 per block.  the end points and the breaking points at each end.
Title: Re: DCC block detection
Post by: Ed Kapuscinski on December 11, 2009, 11:11:32 AM
Why not just give yourself some track that goes "dead" when the signals drop?

THAT would be some PTC...
Title: Re: DCC block detection
Post by: John on December 11, 2009, 11:48:34 AM
Everything is going to be manual at operating sessions, but during regional open houses, like Tour de Chooch, you generally get about 200 people over the day coming to view the layout, and I want to have it automated as there is no way to really be able to run the layout and talk to everyone. I'd like it to be somewhat protoypical operations wise on open houses, and not just two roundy round trains.

you would need 4 per block.  the end points and the breaking points at each end.

How so?
Title: Re: DCC block detection
Post by: Hiroe on December 14, 2009, 03:46:40 PM
We're planning to use current detectors on the buses for each track block, plus backing those up with optical detectors at the boundaries of control points so that cars sitting across a short block will be detected even when there's nothing drawing current.

This is what i had originally planned over at CV; but with how huge the layout is, i've not gotten around to installing any of the optical detectors yet. Ultimately they may not be necessary, as i've been working the current detectors to a level of precision that they'll detect a hand placed across the rails in the block. Drop a few resistance wheelsets in every train, and everything should be good to go.
Title: Re: DCC block detection
Post by: Ian MacMillan on December 14, 2009, 06:50:09 PM
Ok another dumb detector question...

In the blocks, can you still have non detecting feeders in a detected block? Some of my blocks are going to be about 12' long and obviously I don't want only on set feeding the rail.
Title: Re: DCC block detection
Post by: John on December 14, 2009, 07:08:43 PM
Ok another dumb detector question...

In the blocks, can you still have non detecting feeders in a detected block? Some of my blocks are going to be about 12' long and obviously I don't want only on set feeding the rail.

No .. all your feeders will need to be on the detected buss .. here is what you do ..

run your red / black buss around the layout .. wire your detector at the block .. however you do that .. then run a 3rd buss line with one side of the detector and drop your feeders from that ..

what detectors are you using?

http://rr-cirkits.com/TowerController/connections-2.gif
Title: Re: DCC block detection
Post by: cv_acr on December 14, 2009, 10:36:52 PM
Ok another dumb detector question...

In the blocks, can you still have non detecting feeders in a detected block? Some of my blocks are going to be about 12' long and obviously I don't want only on set feeding the rail.

No .. all your feeders will need to be on the detected buss .. here is what you do ..

run your red / black buss around the layout .. wire your detector at the block .. however you do that .. then run a 3rd buss line with one side of the detector and drop your feeders from that ..

what detectors are you using?

http://rr-cirkits.com/TowerController/connections-2.gif

Current detectors go on the bus for the block, not an individual feeder. Branch the feeders for the individual pieces of rail _after_ the detector.
You almost need to start thinking like you're wiring an old-school straight-DC layout when it comes to blocking for signal systems.
Title: Re: DCC block detection
Post by: Walkercolt on December 24, 2009, 01:13:08 AM
I'm a bit late entering into this, but Digitrax can make signaling relatively painless, with most other brands of DCC systems too. By far the easiest way they have, is you run another "LocoNet" (telephone cable) with detectors, and on the last car in the consist put a "transponder" that can be battery powered. You can make semiphores signals "tumble-down" in SP-type prototypical fashion, without miles of wires and a million dollars worth of electronics. ATS signaling will cost a bit more, and will work far better with an old second-handed (slow/almost any processor) running things. I know someone who got a $50 garage sale 'puter that runs his entire DCC layout (if he wants it to), and it's fully signaled. Too bad he's in (gasp!) HO! No, he's got a nice medium-large (about 2 car garage-size) layout, and it operates flawlessly.