Bus Wiring with Digitrax PM42greenspun.com : LUSENET : Wiring for DCC : One Thread
Starting my first layout. Have decided to go DCC and use Digitrax PM42s to provide circuit protection to power districts. Seems this changes the traditional "around the layout" bus configuration to a simplified bus that is direct from the booster to the PM42 board with feeders to respective rails in each district. Correct?
-- Howard Petersen (firstname.lastname@example.org), February 03, 2005
You do connect the booster directly to the PM42. Then you would run four seperate bus buses from the PM42 to different areas of your layout. From these sub buses you run your feeders.
-- Allan Gartner (email@example.com), February 04, 2005.
Using a circuit breaker (PM42) now complicates DCC wiring a little more due the initial DCC wiring method of just providing 2 wires to the layout and connecting all the tracks to the same 2 wires, to a slightly more complicated wiring arrangement but still much easier than DC block control. With this arrangement you have "power zones" or districts depending on how many circuit breakers, and when you have a short circuit the booster does not cut out, just the affected circuit breaker. This makes for happier operation if you have a few operators.
The larger the layout the more circuit breakers. Locate your booster in a central location and run wires to the circuit breakers and the 2 wires from the circuit breaker are now your "track power bus". This arrangement keeps power bus lengths less than 30' which will reduce problems that can arise from noise. See section on DCC waveforms at http://www.wiringfordcc.com/dcc_waveforms.htm
I would fit an ammeter as described at http://www.wiringfordcc.com/track.htm#a4 to monitor how much current the booster is supplying and when this gets near the limit, then you would add a second booster and more circuit breakers of that booster.
-- Marcus Ammann (firstname.lastname@example.org), February 05, 2005.