I have a Digitrax BD168 card that I will be using for block detection. I have all of the wiring diagrams planned out no problem, but have a question regarding what gauge wire to solder to the actual card edge connector. Digitrax states that the pins on the connector are designed for 20 gauge wire, which again is not a problem. But this raises a question: if I am using 12 gauge wire for all of my track bus wires, doesn't using smaller 20 gauge wire to connect the larger 12 gauge bus wires to the BDL168 compromise the use of the larger bus wires? In my mind, even a short section of 20 gauge wire between the booster and the rails basically limits that bus wire as if it was run entirely using 20 gauge wire. Isn't this pretty much how a fusable link works in automotive circuits? I know I must be missing something since I see 12 gauge bus wires and 20 gauge wires to the BDL168 used too many times to be incorrect. Thanks for any advice! Jamie
I think the purpose of the 12 ga. wire is to reduce the voltage drop on a long run of wire. A short section of smaller gauge wire would be Ok to hook the board up.
I use crimp terminals with 14 gauge wire I'm using 14 gauge bus wires, and I wired 14 gauge to my PM42 and BDL 168 using Molex .062" crimp terminals formed to fit the 44pin connector's solder points. The Molex terminals gives me much better mechanical contact than simply soldering wires to the solder points. It also allows me to avoid any minute resistance issues from having smaller gauge wire.
HO rail joiners fit the connector's tabs nicely. Solder the whole works after "crimping" the wire into the other end of the joiner.
You should have no problems with 20 AWG wire. Using short sections of 20 gauge wire will not effect the detectors. Using 14 or 12 ga wire for the buss is just because it has a lower resistance per foot than 20 gauge which is rated for around 8 amps itself.
OK, I'm not an electrical engineer but was an electronic Technician until I retired in '95. For signal wire 20 GA. is good wire. For power buss 12 or 14 GA. will do in most applications. 12 GA. is rated at 20 amps, and as stated before the reason for using it is for its low resistive properties. You all a Great day.:tb-biggrin:
That's wrong. The resistance of a wire is proportional to the length of the wire, so if most of the wire in the circuit is 12 gauge and just a little bit is 20 gauge, the total resistance of the circuit will be much less than if all the wire was 20 gauge. Well...yes...but no. 20 gauge wire isn't going to act as a fuse in model railroad wiring. (Well, maybe in G scale. ) The reason we use larger wire for buses is because we are trying to avoid noticeable voltage drop that would affect the speed of our trains or the reliability of DCC messaging. In most model railroad situations, 20 gauge wire is nominally adequate for the amount of current drawn by a train (again, a disclaimer is needed especially for larger scales.)
Thanks for the help gang. Got everything wired up nicely, but I have a problem when powering up. The BDL168 comes up just fine, but when I power up the DCS100 booster, I get 9 beeps and the booster goes offline. According to Digitrax docs, 9 beeps by the DCS100 means that something is mucking up Loconet. I have not started any debugging yet other than a thorough visual inspection of all the connections and wire routings. I wanted to post here before I break out the multimeter to see if anyone has any experience with this or similar issues. BTW, the BDL168 is the only Loconet device I have in the system other than booster/decoders. Jamie
WOO-HOO...EVRYTHING WORKS!!! Sorry for the "all caps" announcement, but this is super cool especially for an uber-nerd such as myself. All I did was disconnect the Loconet cable from the BDL168 to the DCS100, powered up the booster, and everything ran just fine. I then plugged the BDL168-to-DCS100 Loconet cable back in and "voila!" the block detection kicked in perfectly. I even see the block occupancy messages coming in to JMRI via the Loconet Monitor as expected. I also powered everything down then back up, and everything comes up just fine without the 9 beep alert. Not sure what was wrong, but unplugging the cable and plugging it back in did the trick (loose connection???). Jamie
