Daley Train Log
Page 79
I want to make a few notes to myself about DCC. I have 4 different publications about the topic to help me understand this system.
Larry Strang's publication is only 47 pages and is an excellent place to begin. I used this book when I first began wiring my layout for DCC, but I have forgotten much of the detail and need to refresh my memory.
Chap. 1 The Origin of Command Control
- "It's significant to note that the digital signal travelling through a DCC system, not the individual components, must comply to strict conformance standards in order to meet NMRA approval." [p. 6]
- This is THE key point. The next two points are a straight forward consequence of this.
- "I'd still recommend using a command station, boosters, and throttles from the same manufacturer." [p. 6]
- I am using an MRC system for my command station/booster and throttle.
- "As long as the decoders you use are NMRA-DCC compliant, you'll have no problem." [p. 6]
- I have 2 Digitrax D64 decoders, each of which control 4 of my switches. I also have a reversing loop component which is made by ?
Chap. 2 The Digital Command Control Advantage
- "With Digital Command Control wiring becomes greatly simplified and easier to install." [p. 7]
- This is a huge advantage. The goals is to run trains, not to become an electrician.
- Basically the wiring is a pair of wires (red and black) that parallel the main track line and from which one sends feeder wires to the track. These feeder lines should be about 5 - 10 feet apart, but if there are difficulties, they should be closer together. The idea is simple: keep the current and signal strong at all points on the layout.
- This reminds me - I must go over my wiring and shorten some of the wires so the entire system is in a final state. I am pleased with my approach of using terminal strips to set up the feeder wires to the connector tracks. I have not used solder for any of my connections, making it relatively easy to make changes to the wiring if I need to change something.
- "You can create multiple unit lash-ups or consists (also known as MU) and match the speeds of locomotives from different manufacturers so every locomotive in the consist will run at the same speed." [p. 7]
- I have yet to try this (at the moment I only have one locomotive operational) but it is definitely something I want to try.
- "And you can even program realistic acceleration and deceleration rates ..." [p. 7]
- This is another feature that I have yet to try. It is definitley time to get on top of the features of DCC.
Chap. 3 So How Does It Work?
- Basically the hand-held throttle sends a signal to the command station which then creates a digital signal packet and sends it to a booster which amplifies the signal and sends it down the tracks to the decoders which are either in the locomotive or in a separate stationary decoder (e.g. to control switches). Some decoders can also send a digital signal back to the command station.
- I think my MRC system is capable of handling feedback signals but I need to check on this.
- "The power on the tracks is AC or alternating current, not DC or direct current." [p. 10]
- It is easy to think that the abbreviation DCC somehow means Direct Current. It does not. The abbreviation refers to the method of sending control signals, not the type of power.
- "... with Digital Control there is full power (i.e. voltage) on the track at all times." [p. 10]
- "... the decoder in each locomotive converts AC current to DC and controls the voltage and polarity that travel through the motor." [p. 10]
Chap. 4 DCC System Components
- "Several DCC systems are available, and all are different from each other in price, features offered, and expansion capability." [p.11]
- I selected the MRC Wireless Prodigy system for two reasons: the wireless capability which allows me to walk around the layout while controlling the locomotives and the nature of the hand-held throttle which seemed to be easy to understand. In the background was a third reason - I wanted a company that had a good reputation with model railroad electronics.
- "One of the most critical elements to successfully installing a Digital Command Control system is first rate wiring." [p. 11]
- I followed the guidelines in this book when I set up the wiring for my layout.
- "The two wires are more commonly known as the track bus." [p. 12]
- I used red and black for the two wires in order to keep them separate. The red wire is always for the inner track and the black wire is for the outer wire.
- "The main track bus is 14 gauge wire, which is heavy enough to carry as much power as 5-amp boosters are capable of producing."
- I followed this recommendation.
- "... track feeder wire should be ... 20 to 22 gauge wire. ... track feeders should never be more than 3 feet long." [p. 12]
- I also followed this recommendation.
- "Be sure to solder most of the metal rail joiners connecting sections of track." [p. 13]
- I have not done this (yet). So far it has not been a problem but I must remember to keep this in mind if I start to experience difficulties with the running of the locomotives.
- "The booster's job is to take the packets of data generated by the command station and boost (amplify) them to higher-voltage signals." [p. 14]
- "To figure out how many boosters you will need, add up all the locomotives you will be running at the same time (1 amp per HO locomotive) plus the total amperage of the accessories.
- At least at the moment, I figure that I should be okay with just the one booster as long as I only have 1-4 locomotives running at any one time.
- "For the average N or HO scale model railroad, two boosters is plenty to handle the number of locomotives running at any one time." [p. 15]
- I will only add one more booster when I decide to increase the power.
- "Turning track power on activates every decoder on the layout." [p. 24]
- This makes sense.
- "Two other common reasons for short circuits are: first, driving a train into a block of track where the turnout's points are set against it; and second, a freight car or locomotive whose metal wheels are out of gauge (or derailed) coming into contact with the point rails when they pass through a turnout." [p. 18]
- This is useful information as it helps one determine the reason for a short circuit.
- "My personal belief is that a short circuit involving an insulated frog turnout ... almost always entails some form of derailment." [p. 20]
- Okay, I think I have this idea under control.
- "If you were to combine both boosters and circuit breaker modules to provide short circuit protection, you could easily divide a medium-sized layout into eight power districts by using two boosters and a circuit breaker capable of dividing a panel into four separate districts." [p. 23]
- This sounds like a really good idea. When I decide to add a booster I will set up the wiring as outlined on this page.
- "It's much simpler to connect your accessory decoders directly to the track bus." [p. 24]
- I have done this with the Digitrax D64 decoder for handling turnouts.
- "Radio control DCC is becoming more popular and will most likely become the industry standard." [p. 26]
- It sounds like I have made a good decision.
- "All Digital Command Control layouts should have one section of track where locomotives can have their decoders programmed. ... This is a section of track (generally a siding of some kind) that can be isolated from the rest of the layout. [p. 27]
- Done.
- "Keep in mind that programming will be more reliable when the programming track is near the command module." [p. 28]
- Done.
Chap. 5 Basic Decoder Installations
- "Basic [mobile] decoders usually have eight wires. ... Each wire has a purpose. ... The orange and grey wires are connected to the motor. ... The red wire should be connected to the right-hand rail pickup. ... The black wire goes to the left-hand rail pickup. ... The white wire is connected to the front light, and the yellow wire is connected to the rear light. Both the front light and the rear light are referred to as function zero (F0). ... The green wire is for connecting to function one (F1), which might control ditch lights ... The blue wire is the common wire for all functions - it would be connected to both the front and rear lights and the ditch lights. ... More advanced decoders will have more wires." [p. 31]
- Okay, I think I have that.
- "Decoder installations are getting easier and easier. Many ... now have a standard NMRA plug prewired to accept a ... decoder. These decoders are more commonly known as plug-and-play decoders. ... To install one of these decoders, you simply remove the shell of the locomotive, remove the dummy plug, and plug in the decoder." [p. 32]
- This will be easy in the future, but all of my existing locomotives were bought before this idea became popular.
- If you are installing the decoder by soldering the appropriate wires to the locomotive, "test the installation on the programming track before exposing the decoder to the high voltage put out by the DCC system." [p. 33]
This publication is a superb introduction to DCC! And it was published in 2003.