I have one PM42 wired to my layout with the Digitrax DB150 command station. The PM42 manual does not show how to wire and additional PM42. These manuals are no good! My intuition tells me that I should of course, without anyone telling me, to wire the Loconet cable from my PM42 to the second PM42 being added. However I don’t know what should be done about the rail A and B and ground wires from my first PM42 and weather the wires should or should not be spliced to the second PM42.
Splicing them is exactly how to do it. The track outputs from your DB150 split into as many PM42 sections as you need. It was 4 sections. Now it will be 8 sections. Same goes for the ground connections from each PM42. Connect them all together then run a single wire from the connection to the ground terminal of your DB150 booster.
No this isn’t in the manual because splicing wires shouldn’t be. Case in point, I have 7 PM42’s. How many drawings should be included? That would make a huge manual to illustrate splicing wires together. Think of each PM42 section as a DPDT switch on a DC block system. the wire comes from your power pack to one side of each DPDT switch. How does that single pair of wires connected to the power pack connect to all 8 block switches?
Martin Myers
You would connect them the same way you would wire the track. Rail A goes to the Rail A input on both units, Rail B does the same. Adding a third unit would require jumpers connecting to a Rail A and B source.
Whether you do it from a common point, or from one PM42’s A and B input connections to the next is up to you.
There is no need for separate instructions for installing multiple PM42s. Each one installs the same way. It goes between the track bus and the isolated sections of track. Loconet daisy chains from device to device.
I don’t use the PM42 on my layout, but I don’t know how you can say that the manual is “no good”.
Here is a link to the PM42 manual for those who are interested in this issue. It is 16 pages long, and it is one of the most comprehensive manuals that I have come across for a layout circuit board.
http://www.digitrax.com/static/apps/products/power-management/pm42/documents/PM42.pdf
Rich
Are you sure you REALLY need a 2nd PM42? One PM42 will do up to “4 power sub-districts”.
Since you’re big on diagrams, alloboard, why not post a diagram of your layout with dimensions. That would help give the rest of us some knowledge base to help you more thoroughly.
Tom
Documentation, critical thinking and a good DMM beats intuition any day.[swg]
I agree. It sounds like the OP is trying to do too much too fast without mastering what went before. From his previous posts I appears that he has or is trying to build a rather complex system without fully understanding the required background or the need. He is going to need all the help that the forum members can give.
Joe
I think we all agree with that. Unfortunately, the interaction with the OP is severely limited, since he rarely responds substantively to the questions and comments raised by those of us trying to help him.
Rich
…
I’m not used to DPDT switches. The question is how would I splice them?
I guess it’s true, I condemn myself for tyring to build a complex system too fast.
It may be true, but I’ll improve on that.
Just one example instruction.
You also have to learn to tie your responses to the comment that you are replying to. It took me some time to trace back all four of your most recent replies to the comments that you were responding to.
Regarding Martin’s comment on DPDT switches, he wasn’t suggesting that you use them. He was equating the wiring of multiple PM42s to the wiring of DPDTs in a DC block system.
Rich
I’m done…
Diagrams are overrated…
.
OK so take a deep breath and make a resolution to not add any more complexity until you have mastered what you already have. You may find that you do need to add anything more and can be quite happy with what you have if you concentrate on getting it to perform reliably. You should go over the instructions for the equipment you have and experiment with the equipment until you are sure of what the instructions really mean. Knowing what they say is different than what they mean.
Joe
I need more than four.
Really, it’s just repeating what you’ve done before, but in a different place in the wiring chain. I’m assuming each output of the PM42 that is currently in place goes to more than one feeder - at least, from the track diagrams you posted before. If so, how did you connect the single pair of wires coming out of the PM42 to the multiple feeders? Basically, you do the same thing with the output of the nooster to drop it to each PM42 section.
And then drop in the BDL168’s - the output of a given PM42 section goes to one or more BDL168 input connections. One rail is common between all sections on a given group of BDL168 outputs - that means no insualted joiners, but definitely more than one feeder. The other rail is the one you gap for each BDL168 detection output.
If there are two BDL168 sections in one PM42 zone, you just connect the two BDL168 inputs to the same PM42 output. In some cases it may be 1 for 1, in other palces you may have a higher detection density and all 16 BDL168 sections might be in one PM42 zone. Since you said you have the multipelk input BDL168 breakout boards, it should be fairly easy to run a wire from a PM42 output on that breakout board to one or more of the inputs for the BDL168. When you need multiple wires connect to one, you can splice and solder them, or use terminal strips. If you use terminal strips with the jumpers so that all screws on it are electrically connected, you can then have a wire run from the screw terminal of the PM42 breakout board to a screw terminal on the terminal strip, and then run as many wires as needed, one from each screw, to one of the BDL168 inputs on those breakout boards. This will keep the wiring pretty obvious and uncluttered. I would recommend at least tinning the ends of wires before wrapping them around terminal strip screws, or even better, get some of the crimp on spade or circle lug terminals. They key is to not have a rat’s nest of wires, or you will quickly become lost.
&n