The recommended wiring for RR-CirKits CT coils (used for block detection) is one wire pair from a Cat5 cable. No further info is given so it appears that it assumes you will solder the Cat5 wire pair to the 2 coil leads. I can do that if it is my only option but I am not sure in advance how much wire to attach to the coil when running my track feeders. I would prefer to add the coil to the feeder wire and come back later to install the Cat5 wire to the coil but I don't want to do a lot of soldering under my layout. This preference is driven by my desire to install coils for all my anticipated blocks (over 125) even if I am not installing the detection boards for all coils at the same time.
Any option such as a tiny slide on connector that would be the right size for the coil connection pins? I have not found such a connector. If that will not work, my next option is to solder short wires with a 2 pin connector then come back later to wire the coils to my detection circuit. Would prefer to avoid soldering that many coils since my old hands are not as steady as they used to be.
Paul D
N scale Washita and Santa Fe RailroadSouthern Oklahoma circa late 70's
While there may be some connector pins out there that fit the coils, they won't be crimp on to the wire, they will have to be soldered. Being that this is small wire, and a small pin you need to solder, it won't be anything like trying to solder heavy feeders.
On the reverse end, but I would test this to be sure, or at least run it past Dick, you could crimp on an RJ45 plug, and at the bench wire some RJ45 sockets to a short harness that connects to the BOD-8 or whichever device you are using. I just don't know if you would get excessive crosstalk leading to false detection because of the plug and socket. This would have to be tested.
To figure wire length, it's not that hard - each run of Cat 5 wire handles 4 coils. So stretch out a length from the device end to the furthest of the group of 4 you are connecting to that run, plus a little extra. You would slit the outer jacket all the way back to where the first coil of the group of 4 is, and then cut each pair to end by the corresponding coil. It's a quick solder to attach the coil to the wire, both are small and don't have a lot of thermal resistance. If you can snake the harness under the layout after the coils are attached, you could solder them at the bench and then install a completed harness.
OR take a tip from more than a few people here and run ALL the wiring right behind the fascia, not under the layout. Feeder wires stretching from the facia back a couple of feet to the track isn't that big a deal, and you can do all wiring standing up (or sitting, depending on your layout height), not upside down underneath in the dark.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Good point on the Cat5 wiring via RJ45. I have used the RJ45 approach extensively on a previous layout and I had planned to use it again on my new layout. I have a bunch of the Leviton Cat5 data modules (6 keystone jacks) that let me use them as a consolidate junction point to my centralized electronics. I can wire the coils in groups of 4 to a keystone jack then run a standard Cat5 cable to one of the keystone jacks on the data modules. I have used this approach with good success in the past and I have all the parts to do it again. However, that was with Tortoise machines and control panels.. Your point about crosstalk at the jack is valid. RR-CirKits points out the need to keep the coil wires away from high power lines like the rail buss to avoid cross talk via induction. I need check and see if there is any issue with cross talk with RJ45 jacks. I don't think so but I will check.
I already run all my wiring near the facia to make it more accessable. All my electronics are mounted on 4 large slide out shelves scattered around the layout so I can slide them out for easy access. My new layout was built with easy access in mind. Crawling around under a layout is too difficult for my old body.
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carl425I've experimented with a wire wrap tool for this application. I don't have any long term results to share, but it seems to work fairly well.
Sounds like a good way to attach the wire in prep for soldering.
PEDSounds like a good way to attach the wire in prep for soldering.
That is my plan, but if you really hate soldering, it may work alone. The wrap holds pretty tightly.
Many things, even industrial electronics subject to high vibration and so forth (think machine tools), used to all be wire wrap contruction. However, for proer wire wrap, you need to have the right typ of wire (Cat 5 network cable isn;t is) and the post on which you wrap the wire really needs to be square so the sharp edges can bite into the wire and form a sealed connection - those current transformers, at least the ones I have around as samples, all have plain round PC mount pins. I don't see that being realiable for just wrapping the wire around the post. Real wire wrapping, once you get the hang of it, is fast and every bit as reliable as a soldered joint - on circuit boards though you do have to plan a little bit when there's more than one connection to a given pin.
The more I think about it, the dumber my response seems - the RJ45 jacks work fine for 1Gb ethernet and even faster now (with higher Cat rated cable) so I seriously doubt there would be any crosstalk or false signals generated by bringing the Cat5 4 pair cable into an RJ45 jack exactly as is done with Ethernet. The key is to maintain the twists right to the end as best as possible. I've seen poor installations where the wire is stripped and untwisted a foot back from either the plug or on the punch block with the jacks, and then peopel wonder why they have network issues with computers plugged in to that port. There's actually a spec for maintaining the twists which results in the whole assembly still meeting Cat5 standards. So it should be fine to use keystone jacks or even an RJ45 patch panel with 110 type punchdowns at the location of the detection circuits and then plug in the coils with RJ45 plugs. Just keep the pairs together, the twisted pairs is what keeps the crosstalk down and avoids other signal propogation issues. It doesn;t matter when using RJ45 jacks for somethign like a Tortoise, as long as you know which wire at the end is which pin in the jack, but for the current transformers you can just follow the standard Ethernet wiring which keeps each pair on a particular color.
When runnign the wire, just avoid runnign the Cat5 parallel to your DCC bus, or any other sort of power bus. If the wires have to cross (and they almost certainly will), just cross as close to 90 degrees as possible. It's unavoidable to be in parallel, just don;t bundle them together. For example, if there are two bays under the layout formed by the supports, put the DCC bus in one and the sensor lines in the other.
You could put the drop from the track in a screw terminal connector, leave enough wire to make the loop for the detector. This allows you to solder the wire to coil at the work bench, loosen the screw for the feeder, then run the track power through the coil and re-attach to terminal strip.
This also allows the flexibility of choosing the length of wire coming from your coil. Note that long distances probably are not going to work very well.
LION knows knot about RR-CirJuts CT coils... But with 125 blocks, you are going to use a LOT of WIRE. And wire is expensive.
LION does NO soldering under the table, all wires are brought to the fascia. LION has installed several 25pair cat3 telephone type cable (50 conductors) between the control panel of him and the layout of him.
LION has a 36 lever GRS Model 5 Interlocking machine, and so all switch points and home sigha.s are controlled by the machine. All ot the contacts from the maching (a single wire from each lever... ether +12v dc normal, or -12 vd reversed is all that is needed)
The output board from the machine is mounted next to the cables from the layout.
Here is a typical junction board (although if you have money, you could use a standard telephone punchdown block) on the layout of the LION.
In this photo it only shows the cables out to the layout, the interlocking machine and other connections have not yet been attached to it.
Here is what the other end of a section of cable looks like.
As you can see, all of the conductors here are white, as this cable was taken from an old 1920s vintage pipe organ. It has six 'ropes' of 11 conductors each. One rope would service one station as there are twho tracks in each station. This wire had no rubber or plastic insulation, but was simply wrapped with string and wax. I had to test out each strand to connect it correctly. This panel will (or now does) connect to switch machines.
So, here is a station panel for train control and the signal system. You may want something more ellegant, but that costs money that LIONs do noth ahve. Nails are cheaper.
And below is relay room of LION...
If you know electronics better than LION, you could do it more efficiently, but lion doubts that you could do it cheaper no matter what you do.
LION uses a magnetic switch between the rails to detect a passing train by a magnet glued under a car. LION would be careful putting strong magnets on the locomotive since that may interfere with the magnetic flux of the motor.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS