rrinker Well actually, it does,
if you want to detect cars with resistor wheelsets as well as the locomotives. With a track-based detection system, for DC there needs to be additional circuitry to keep a trickle of power inthe rails even when there is no moving loco.
Well actually, it does, if you want to detect cars with resistor wheelsets as well as the locomotives. With a track-based detection system, for DC there needs to be additional circuitry to keep a trickle of power inthe rails even when there is no moving loco. With DCC, there's always power. With an optical detection system, either IR beam-breakers or CDS cells, it won;t matter - those types of systems are compeltely independent of the rails. However, they only detect at certain spots - ie, where the sensor is. A track-based system will detect a loco, lighted car, or car equipped with resistor wheelsets ANYWHERE in the block. There are pros and cons to both systems, basically it comes down to what the end result is - CTC and automation pretty much require a track based system, if you just want some basic signal indications to change as trains move about the layout, a beam-type system will work just fine.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
larakmatuszaktcCan anyone advise me as to the proper sensor/signal placement Now I'm confused. What difference does DC or DCC make to sensor placement?
matuszaktcCan anyone advise me as to the proper sensor/signal placement
The next thing that makes a difference is what signaling protocol you intend to follow. For some prototypical protocols it will make a difference if you going to be using two color or three color lights, if you are going to have the signals be turnout route sensitive or not, if you are going to have turnout signals, and finally if you want to sense train direction (block ahead is red if train is same direction as you, red flashing if facing, etc.). You basically need a sensor every place that the system needs to know if there is a train there or not.
Don't forget that you can use CSD cells for optical detection too. With them you just use room lighting and place them between the rails of the track. If you run with the room lights off or dim, they won't work for detection. I am using primarily CSD cells, except in dark areas, with CTI and NCE DCC.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
i used the dallee block detection starter pack # 655. $84.95. comes with 3 detectors and a regulated power supply that requires 12 volts ac. there are cheaper models out there but these have a dpdt relay. there is no electrical connection between the detector and the dcc track power so there is no problem with dcc. the track feeder from the dcc buss to the rail goes through a detector coil on the detector module. they are very sensitive. i haven't found these at any hobby shop or online supplier so i had to order from them directly. it might be easier for you to use the atlas signals with their detection and operation systems
Thanks everyone. I am going to check out CTI's website. Also, Karl the train lenght should never exceed the siding length which allows for 10 cars. Does anyone make the logic boards that would be needed to operate thsi type of signal system? Also, do the Dallee detectors interfere with DCC operation and what Dallee detector is this - do you have a Dallee product number?
Thanks for your response, I am modeling the Monon - early 1950's I know what signals I want to use and the layout is NCE DCC.
For optical or light sensors, it doesn't make a difference between DC or DCC. Check out www.cti-electronics.com They have a system that you can set signals up on and write your own logic. Something that most systems can't do. I am using CTI myself. I just took down a layout that had automated staging using CTI.
i am using dallee track detectors that sense current flow to energize a dpdt relay. i have one working signal now and have three detectors placed around my layout to operate the signal. the signal is an atlas g type double target signal operated by relays with circuits i designed like the prototype signals i worked on. the signal turns red the instant that one wheel crosses the ij and will not turn yellow until the train gets to the next detector and green when it gets to the third. the dallee detectors are so sensitive they will detect the current being drawn by n scale decoders that are not even selected to run. i have several more signals to install and a completely functional ctc system is planned for my bi-level n scale layout as my wallet allows.
Now I'm confused (It happens more every year). What difference does DC or DCC make to sensor placement?
I would put a single IR LED between the two tracks and an IR detector on the far side of each track. You might need to use two sets (or more) in parallel depending on length of train vs length of siding (main). If either beam is broken then that piece of track is occupied. With proper logic you can detect many conditions.
Karl
The mind is like a parachute. It works better when it's open. www.stremy.net
DC or DCC? That's going to make a big difference. If DCC, what brand of control system do you have?
Also, what era do you model, and what part of the country? Some models of signals are better than others, but you wouldn't want to put modern signals on an old-time logging railroad.
It takes an iron man to play with a toy iron horse.
I am planning to install a signal system. My layout is a bi-directional single track mainline with several passing sidings. Can anyone advise me as to the proper sensor/signal placement that would sense a waiting train in the passing siding and give proper signal instructions to the affected blocks. I would like to use optical or ir sensors. Any advice is greatly appreciated. Thank you.