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Principles for signal decoders (LocoNet/LCC)

 

Greetings!
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I am still in the design stage for my layout, and am looking into the signaling options.
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As I understand it, the central computer only tells a signal decoder to show an allowing aspect or not, and it its up to the decoder to determine which aspect is applicable, using status messages it has heard over the LocoNet/LCC. A signal decoder also can broadcast its new state whenever it changes aspect.
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I have three questions:
1. Can the central computer instruct the decoder *which* aspect to display or is it only a binary go/stop order? If yes: how many different aspects can be ordered?
2. When a decoder broadcasts its new state, does it specify *which* allowing aspect it is showing, or is it only a binary go/stop? If yes: how many different aspects can be communicated?
3. In many signaling systems, a signal can give a proceed aspect for a train movement or a shunt movement. How does the central tell the decoder which of these to use? (In the signaling system I am modelling, shunting is governed by separate lights, which may be intergated into the main signal or be part of a separate dwarf/shunt signal.)
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Thanks in advance
 

LCC allows you to assign an event to each aspect to be displayed. It will send a discrete event when ¡°x Aspect Is Displayed¡±
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An LCC node also can receive a single ¡°request¡± event and choose the aspect based on other status events received. And you could send a separate ¡°shunt request¡± event.?

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Anders,

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You are talking about two rather different systems, LCC and LocoNet. LocoNet devices do not have significant local processing of signal logic. They typically have all the logic in the central computer. LCC is different that there is the ability to have the bulk of the signal logic local to the node driving the signal. But LCC could also be used just like the LocoNet as a choice. Signaling is not an easy process due to the amount of choice the designer has in how to implement it.

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Most of your questions fall in the category of your choice based on how you design the system and the choices of the hardware you use.

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-Ken Cameron, Member JMRI Dev Team

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I use JMRI for my signals.
JMRI has a lot of signal systems defined.
I use AAR1946 for my prototype.
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JMRI signal mast logic determines which aspect needs to be displayed.
I don't know how some of the other hardware like the Digitrax works.
JMRI sends a signal aspect message over Loconet to the signal hardware.
I use a smart controller (QuadLN_S) that controls servo turnouts, routing, and drives signal LEDs.
That controller translates the JMRI aspect message into LED drives and even can use a servo to drive semaphore position.
I find it useful because I don't have to do any programming to utilize the JMRI signal aspect message.
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--
Ken
NYNH&H, Old Colony Division, Cape Cod Branch (1949-1959)
Loconet * JMRI 5.11.5 * OSX,Win10,Ubuntu
Blog: ?
Youtube:

 

A signal system requires ¡°sensor¡± input to make decisions.
Bare minimum would be block detection, turnout position and desired routing from a dispatcher.
HOW that decision is made is based upon the system selected, they work and all require some effort in setup.
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LCC nodes take the messages sent from the sensors broadcast on the network and based upon the setup logic will display the signal output. Each Node is ¡°programmed¡± to make the decisions or ignore the messages.
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Loconet / CMRI Net or other systems that use JMRI as the main "center" does the same, except the sensor data is collected by the JMRI computer, then the logical decisions are made ( Simple Signal Logic or Logix functions ) and sent out to the various devices to display the signal aspect. The network for these link the JMRI computer and the devices just take the data provided and display the output. More technical terms is ¡°master-slave¡±?
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As for the signal aspects displayed, its all done in setup and most every aspect is possible. Keep in mind, most model railroaders will enjoy signals but may get lost with too many aspects. Keep them simple, we dont have the miles of track to work with, so a few compromises is required.?
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Ive presented signal systems at RPM¡¯s and my advice is do some research and explore the options. Signals are MUCH easier to do today thanks to JMRI and others who produce great products. RR-circuits produces LCC products and more, Loconet has several devices available ( Digitrax ). NCE has some products. CMRI ( Dr Chubb ) has several devices. Also check out what the Arduinos can do, some people are building on those as the node devices. Im sure there are other items out there too.
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JMRI is incredible at the options and support provided, I cant imagine trying to do signals without it. Explore the hardware tab.
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There is pros and cons for any of the systems, it is a large project but doable. The bottom line is normally the cost.?
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