DCC is really about getting power and control information to the track. But there’s another side to it: how do the commands from the throttle (the controls) get to the DCC system, and how do different parts of the DCC system communicate with each other? The first part isn’t covered by the NMRA’s DCC standards, so each manufacturer does the throttle-to-command-station link in their own proprietary manner. The second part is partially standardized, as the NMRA has Recommended Practice RP-9.1.2 Power Station Interface to describe how a command station sends commands to booster stations, but they don’t say anything about how devices like stationary decoders or occupancy detectors report their status, although there’s a draft of a standard for an “NMRAnet” control bus being developed which will probably fill this gap, someday.
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Tags: DCC, Digitrax, LocoNet, JMRI, Design

As I’m finishing up the wiring for the two upper-level loops (one of which will be DCC-only, the other will be the switchable DC/DCC line), I’m also getting my DCC electronics set up and ready for use. There are several aspects to this, and I’ll cover others in future musings. But today I’m going to write about track and motor voltage. I could have just used the command station as it came, and it probably would have worked fine. But I like understanding exactly what’s going on under the hood, and so I ran a number of tests and spent some time researching what the track voltage should be, and why, and what that meant for the motor on a train. And if I ever add a booster, it will be important for it and the command station to be set to output the same voltage (this avoids problems when a train bridges between two power districts), so I may as well pick a voltage now.
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Tags: DC, DCC, Design, Unitrack, Digitrax

This weekend went largely to the beginning of the final (I hope) laying of the subway track, which has been in place, in whole or in part, through more than six months of construction. As a result, it has gotten a bit dirty. All track was pulled up, cleaned with isopropyl alcohol on a cotton pad, and relaid. At the same time, insulated unijoiners (black, in the photo above) were inserted to divide the track into electrical blocks (for power feeds and future occupancy detectors) and power feeds were wired up to terminal strips under the table. I didn’t get it all done, perhaps a bit more than half, but I should be able to finish it during the week and run trains by next weekend.
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Tags: Construction, Design, Riverside, Electrical, DC, Foam, Expressway, Scenery, Unitrack

The subway level track is nearly complete, with the underlying foam and cork glued down, and the Unitrack in place. Read More...

Tags: E233, DCC, Design, Electrical, Subway, E231, Lighting, Construction