Wiring layout for DCC occupancy detection

[dakwest]

I am planning an around the room layout that is 6'-6" x 15'. It will be a single power district layout with 22 occupancy detectors. I would like to locate all of the occupancy detector circuits in a central location and run separate feeders to each of the track sections rather that a main bus all around the layout. My main question is this. Should i run a single common bus wire all around the layout and just run single feeders to each occupancy section of track? Or should I run a twisted pair of feeders to each occupancy section of track? 

[rrinker]

 You like wire, to run all that to a central point. Do nt run twisted feeders from the occupancy detectors - they will likely indicate occupied allt he time that way.

Most of the centralized block detectors come in logical groupsing of 8 or 16. FOr each of those 8 or 16 detection sections, they have a signle common rail, but then both rails are gapped before the next detection section coming fromt he seond detector. So if you are using a device with 16 detectors, then you need 2 of them, and there will be 22 wires to each of the detected rails plus 2 more for the two common sides.  If using 8-way devices, then you need 3 of them, and there will be 22 detection feeders plus 3 commons.

 I'm just not a fan of centralizing all that, but neither am I a fan of the typical diode drop detectors that use the centralized wiring method. If you run a bus around the layout, and tap off to feed the detecros, you then only have short feeders from the detectors to the rails, instead of all of those feeders snaking along under the layout. Seems cleaner to me. Plus all the long feeders, if bunched together, can cause false detection because of the wires all being bundled together. 

                             --Randy                                                                                                                                       

[dakwest]

Thanks for the reply. I think I will have to go with your suggestions. I was trying to avoid working under the layout because of my age by placing the detectors in one location, but you are probably correct. I will need to spread out the detectors for best performance. 

[ROBERT PETRICK]

Hey dakwest-

You can still have a centrally located patch panel with the detectors all at one comfortable easy-to-reach working location. You just need to run individual leads (busses) to one rail in each of the 22 detection sections, and one common lead (or maybe two or three, see Randy's post) to power them all.

I have a 12" by 24" plywood panel with two BDL-16s and three SE8Cs (and some other control wires) installed on the benchwork legs just a few inches behind the aisle fascia.

Hope this helps.

Robert 

[gregc]

i recently wired up 5 track staging tracks, each with 4 detection blocks.

i drilled holes thru the to top, dropped and soldered feeders to the rails.   a board with 5  6-channel detectors was mounted to the legs of the layout.    Underneath the layout, i first dragged a bus wire from the detector board under one of the staging tracks and attached it to feeders using suitcase connectors.   

I then ran 4 addition bus wires, as long as necessary, one for each detection block and connected each bus to the feeders for the corresponding block.   each bus was connected to a detector.   This needed to be repeated for 4 additional staging tracks.

i suggest using suitcase connectors to connect wires underneath the layout.

another approach is to make the feeders long enough to reach the fascia and run the bus wires along the fascia to some central point