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Discussion in 'DCC & Electronics' started by rogerw, Mar 8, 2007.
What does loco net add to a system. what does it do? Thanks Roger
Loconet is to the Digitrax system what the cables are in your office LAN, it lets you plug in controllers anywhere on the layout that you have a LocoNet panel.
It means that you don't have to have your controller in a fixed location, you can move it around (or if you have a hand-held controller, walk around) you just plug it in where ever you have a Loco-net jack.
So why not just use a wireless controller?
Cost. The loconet is cheap, a wireless throttle is about half as much again, plus you need wireless stations, at about $150 a pop - the bigger the room, the more you need.
So does the loconet offer more than just plugging in a tethered controler?
Yes. It's how Digitrax communicates with controllers and other things. Digitrax has a technobabble explanation on their website. Basically, for most users it's how you'll connect extra throttles to the system. It will also connect block-occupancy detectors, to use with signally and track indicators. If you're going to connect your RR to a computer, you'll do it (partly) through LocoNet.
LocoNet is the network architecture for the Digitrax DCC system. While the DCC signals on the rails going between the command station and decoders are standardized by the NMRA, everything else is left up to the manufacturer. Each manufacturer has their own way of implementing a command network so that the throttles can talk to the command station and issues commands to the trains and whatnot.
Now I could get into a more technical explanation about how LocoNet works (and why I think it's superior to other DCC manufacturers networks), but all you really need to understand is that it's the network that Digitrax throttles use to communicate with Digitrax boosters/command stations, as well as any extra components such as the stationary decoders for controlling switch machines or block occupancy detectors. They just call it LocoNet so they don't have to refer to it as the "command bus" or some other generic term.
If you're using your computer to drive your layout like I am, your computer is also connected to LocoNet through an adapter. I'm using the LocoBuffer USB, which connects to your computer using a standard USB plug and takes a LocoNet connection in.
If you're interested in learning more about it, you can read Digitrax's writeup here.
even if you use a wireless throttle like the DT400R you will need to plug it in to change to a different loco address. It makes it handy to have a loconet connection on every side of your table(if you have a walk around layout) so you dont have to go all the way around the table to address another loco. I really dont like having to plug it in but I think digirtax did this to prevent someone from walking into a trainshow with a controller and playing with someone elses trains from across the room so i guess it makes sense. Im going to throw this in too, I have seen on another forum that a guy had three bad radio receiver panels from digitrax, they were losing signal for a few seconds every once in a while while he was running trains. Mine did that and digitrax told me to make sure the zephyr and the remote are not addressed to the same loco. It cured my problem. Sorry for the long response but I guess I felt like typing this morning,,, good luck,,,,,,,,, ,,,,,,,,,, ,,,,,,,, st
That has to do with the way Digitrax handles controlling loco addresses on the throttles on LocoNet. Normally, you can only have a particular loco address assigned to one throttle at a time. This prevents two people from inadvertently operating the same train and wondering what's going on when weird behaviour ensues.
I thought what's supposed to happen is that when you set the address on the throttle, it checks to make sure that address is not in use by another throttle on the network. If it is, you have to override it, or "steal" as Digitrax refers to it, in order to gain control of the loco. I'm guessing that didn't work in this case, as you somehow had the Zephyr throttle and the remote throttle both set to the same address. Now I only have a Zephyr and no extra throttles, but this is my understanding of how it works. More than one throttle trying to issues commands to the same loco = communication breakdown.
dorkmaster, You are right when you say you have to steal it, but you also need to release it from the other controller, they controller you steal it from can be shut to 0 speed and the brake lever on, but every once in a while it will still miss with the signal, not sure how but it sure cured my problem, Once I steal a loco I set the zephyr to a loco address i dont have on the track. By the way, I might add I'm no expert, also Roger, sorry I stole your thread but thought maybe if you went this way it might help down the road ,,,,, ,,,,, ,,,,, st
I have seen a situation at our club (www.hotrak.ca) where two Digitrax throttles were addressing the same locomotive... It was a little weird - most times, the system will throw up the "Steal Loco?" question. Once you have stolenit, the original throttle no longer addresses that loco... or at least, that's what is supposed to happen.
As for wireless, the throttle must interface with the network somewhere. In the case of wireless, it simply does this via a receiver that is wired to the network. So you get to walk around "unencumbered", but the reciever is still tied in.
For a simplistic explanation of what the Digitrax LocoNet does, visit this part of my website.
the first thing you have to do if you want to understand what DCC is all about - that is if you want to know more than simply connecting two wires to your layout, plugging in a throttle and running the trains instead of running the track - is to forget everything you every know about the old DC analog system. Don't even think about it.
Now that you've got your mind cleared of you-know-what, when you think of DCC, think of a networked computer system. If you work in an environment of networked computers, you're away to the races in getting a deeper understanding of DCC.
What looks like a printer, feels like a printer, and acts like a printer, is not a printer. It is a computer with a special function (it prints information out on paper).
What looks like a scanner, feels like a scanner, and acts like a scanner, is not a scanner. It is a computer with a special function (it scans information and digitizes it into your PC).
Similarly with DCC.
What looks like a loco, feels like a loco, and acts like a loco, is not a loco. It is a computer with a special function (it happens to run like a loco, though).
What looks like a throttle, feels like a throttle and acts like a throttle, is not a throttle. It is a computer with a special function (it happens to run the locos, activate the switches).
What looks like track, feels, like track, and acts like track is not track. It is a local area network with a special function (it also happens to keep the trains on the track).
when you look at your layout, you are not looking at your layout. You are looking at a computer network. The throttles, the locos, the trackwork, the switches, the switch motors are all part and parcel of a computer network.
So, this all means that you are going to have to make a paradigm shift in your thinking if you want to learn more about DCC. This may be difficult at first but if you persevere and stick with it, you will come to learn more about this wonderful computer network that we call Digital Command Control.
If you try to learn it all at once, you will get very frustrated. So, take a maximum of 15 minutes a day and try to learn a little bit about DCC. Ask questions, however dumb they may sound to you in this discussion forum and in others. After a few months, you will begin to sound like an expert. That's the way I did it.
Have fun with DCC. (I am!)
Hello RogerW. Now that you've visited my website and have a basic understanding of DCC and their relationship to computers, we can start to answer you question of what does LocoNet add to the system.
There are three parts to a DCC system -
1) trackwork - this is obvioius
2) command station/booster - the special box you bought, and
3) the wiring that your throttle plugs into.
The first part of the DCC system is the trackwork on your layout. This trackwork is part of the Local Area Network, or LAN. It is through this trackwork LAN that messages are sent to and from your loco. The standards for transmitting these messages are subject to NMRA standards. Since the standards have been standardized, this is why you can install a Decoder from Manufacturer A in one of your locos and a decoder from Manufacturer B in another loco and run both locos on the track.
The wiring that your throttle plugs into is also part of the LAN. It is through this wiring that your throttle communicates with your loco. What this wiring looks like will depend upon the manufacturer of your DCC system. Some manufacturers use a telephone-type plug for this wiring. Other manufacturers use 9-pin computer plugs for this wiring. Some manufacturers use 6 wire telephone cable in this wiring. Other manufacturers use 2 or 4 wires in this wiring. this implies that there are NO common standards for this part of the LAN. Each manufacturer has their own standards. Which is one reason why a throttle from Manufacturer A is not likely to work on the DCC system from Manufacturer B. Digitrax calls their wiring system LocoNet. It is simply a 6-wire Local Area Network or LAN.
Now to the command station/booster. The function of the command station/booster is to take signals generated at both ends (the trackwork and the throttle wiring), and translate them into signals that the other part of the network will understand. In addition, the command station/booster takes the voltage signal from the throttle wiring end of the LAN and boosts it from a low voltage/amperage (typically about 12 volts and a few milliamps) to a higher voltage (typically about 12 volts and 5 amps) to put it out onto the tracks. This is so that the locos can run. Again, each manufacturer has their own standards.
Still with us?
station/booster. The command station booster takes the signals received from the two parts of the system
Now that you're still with us, let us answer your question.
What does LocoNet add to the DCC system.
DCC systems usually follow two types of system architecture. this systems architecture is very technical. If you are looking for technical specs, you might want to see what the loconethackers@yahoogroups discussion forum does.
For an non-technical explanation, we'll try to keep things simple.
Like I said, there are two types of systems architecture for a DCC system - polled architecture and LAN architecture.
Polled architecture sort of looks like this. The command station/booster, in turn, goes to each device plugged into the system (throttles, locos, decoder-connected switch machines, etc) and asks each device, in turn, "do you have any commands for me?" If device 1234 has a command, the command station/booster executes the command (stop loco 1234). then it goes on to the next device. If device 5677 has a command, the command station/booster executes the command (decrease speed in loco 5677), then goes on to the next device. If device 890 has a command, the command station/booster executes the command (close turnout 890). And so on. This is how a DCC system using polled architecture works.
The other type of system architecture is a Local Area Network. In this case, the command station/booster acts like a traffic cop at the corner of a busy intersection. The job of the command station/booster is to make sure that the traffic (in this case, the traffic is generated by throttles, by locos, by decoder equipped switch motors, etc) keeps flowing. As you can see, this concept is quite different from a polled architecture.
If you read the literature, you will see that one of the "benefits" a LAN architecture has over a polled architecture is the "speed" with which the commands are executed. This can be a red-herring because the "speed" difference is in milliseconds and not minutes.
However, the major difference is the way in which new and different devices can be added to the system. In the case of a LAN architecture, as long as the new and different device can produce signals that are compatible with the LAN architecture, it can simply be plugged into the system. For example, it is very easy to plug a personal computer into the LAN system through an interface device and start to control the layout via the computer.
However, in the case of a polled system, it may not be as easily to do so without upgrading some components, such as the command station/booster.
In the case of the Digitrax system, it is a LAN architecture that Digitrax calls LocoNet. LocoNet is a registered trademark of Digitrax. Not only is the name a registered trademark but the actual architecture is copyrighted. This means that, while the wiring and signals from the locos, the tracks, right into the box follow NMRA standards, the wiring and signals in the box and out to the throttles is proprietary to Digitrax. Which is one of the reason why your Lenz or NCE throttle won't work on a Digitrax throttle. It would be like plugging a North Americal radio that operates on 110 volts AC into a European electrical system that operates on 220 volts AC.
Are you still with us? Good. Let's take this a little further with something tangible that you can understand.
The Digitrax system is a Local Area Network architecture that Digitrax calls LocoNet.
There are two parts to the system - the part you can see and the part you can't see.
The part you can't see are the signals that go down the wires. If you read the Big Book of DCC, you will see that the signals go down the wires in the form of "packets". If you are familiar with computer networks, you will recognize what this is right away - it's a LAN. If you don't recognize what this is right away, don't fret. You don't have to know what it's all about -unless you want to get interested in this stuff. In which case, you would join a discussion forum like firstname.lastname@example.org
Let's deal with the part that you can see - the DT100, DT300, DT400 UT1, UT4 throttles, the UP3 or UP5 panels, telephone jacks, 6-wire telephone cable, male telephone plugs, female telephone jacks. For us non-techie types, this is something we can put our hands on.
Not to confuse things to much, but this physical wiring that we can see - from the throttles to the command station, is usually what's referred to as the LocoNet, notwithstanding that LocoNet also refers to the signals and the protocol that is used to generate these signals. But, as I said, we don't have to know what these signals and the protocols are all about - unless you want to get interested in this stuff (if you are a programmer in Java, Visual Basic and other similar languages, then you might be interested in this stuff).
From the physical point of view, all we have to remember is that the physical part of LocoNet - the part you can see - is a 6-wire standard - 6-wire cable, 6-wire telephone jacks, 6-wire male plugs, 6-wire female jacks, etc, etc.
These 6-wires are colour-coded - white, black, red, green, yellow blue. If you strip open a 6-wire telephone cable, you will see these 6 wires in these 6 colours.
When we connect our components together - assuming we want to get into this aspect of DCC, you just have to make sure that we connect white-to-white, black-to-black, red-to-red, green-to-green, yellow-to-yellow, blue-to-blue. If you're interested in this kind of stuff, then visit this page on my website.
So, in conclusion, I hope we've answered your question - albeit in a very round-about way.
Have fun with DCC. (I am!!!)
Thanks bob very informative. I work as a telecom technician and totally understand what your saying and I like the concept. I went with the easy dcc by cvp about a year ago. Still building the layout and have played around with the dcc somewhat. Does the nmra specs for dcc only apply to decoder to command station? Is it easyer to get feed back on train locations/turnout status on the loconet compared to a polled system (which Im guessing the easy dcc is)? Thanks Roger
That's correct. The NMRA standard only defines the communication signals between the command station and the decoders. It is easier to get feedback on turnout status, train locations, etc. on LocoNet because it is a true computer network designed for carrying whatever data you need. If I had my way, they'd standardize the whole thing so you could use Throttles from company A, a command station from company B, block detectors from company C...
Most DCC systems that use a polled bus architecture use one bus line for the throttle commands (the command bus) and another one for controlling turnouts and doing occupancy detection (the feedback bus). With LocoNet, everything is on the one network bus. It's also a freeform design, so you can chain together your LocoNet devices however you want, and it's very easy to add new devices. If you understand how data travels on the Internet and computer LANs with the network stack, LocoNet is actually almost exactly the same architecture, just simplified a bit.
I was just getting started myself recently, and this smarter design, easier expandability and better computer interfacing sold me on Digitrax for my DCC layout. It's only 4' x 8', but I have it fully automated with LocoNet and my laptop computer using a piece of software called TrainController. The best part is that the system expands for larger layouts easily and the software can handle basically any arbitrarily large layout as long as you have enough memory to run it.