Some advice please.
I have a circular track and am going to be using a non loop DCC bus wire. I read somewhere that if I am not using a looping bus wire that I will need to also make a break in the track. Is this correct? If it is could anyone explain why and how?
Thank you
If it is just a circle of track then no all you need is one wire to each track.
It is only if you have any points that it can get more complicated.
Just to add to Brian's answer if I may...
Whilst it should probably work having a simple circular track without a rail break on an analogue system when it comes to DCC one must remember that as well as supplying power the track is also the means by which the base station communicates with the decoder chips. Where these signals are fed into a loop of track they travel in both directions around the loop, and can lead to the decoder in the loco getting the same command twice - once from the signal travelling clockwise then again from the signal travelling anticlockwise - or the 2 signals end up meeting in some way (if my understanding is correct and they are a wave form added to the AC signal then they could cancel each other out by meeting 'out of phase' or double up if they both 'in phase', or anything in between when the 2 wave forms are superimposed) that alters the signal the decoder receives.
This can confuse the chip so it behaves unexpectedly or might even damage it, so in the same what that the DCC bus is not looped (not joined at then ends to form a loop) then ideally the rails should be gapped as well. This should be fairly easy to do by using insulating rail joiners to keep the ends of the rails aligned, or laying the track and cutting gaps in both rails. I'd suggest a razor saw so they are not too wide over something like a slitting disc in a dremel or other powered mini drill as these tend to make quite big gaps.
Hope that helps.
Thank you, really helpful. I am taking the track over a 2 baseboards so will be cutting both rails (twice). If I understand you correctly that should do it?
If you have got 2 base boards then using the board joints as the isolation gaps is the way to go, and then feed the 2 half circles from the bus running the length of the layout, joining the 2 bus wires with plugs (for example) at the board joint.
Essentially the idea is to link the bus from one board to that of the other, just once to avoid producing a loop in the bus, then linking each bit of track to the bus on each board.
That should avoid the situation where DCC signals are in a loop of track, but I think you've worked that out :D
Brilliant. Thank you. :)
I am totally confused the layout I have done this time as DCC and to help and get it correct I contacted Peco as they offer how to wire you layout, the attached is what they came back with, BUT at slow speeds on either of the loops my loco's going slow will randomly stop, is this because of power going in at two many places ?
If it is at totaly random places then it is a fault with the locos.
That could be dirty wheels or faulty power contacts to the wheels.
If it is in the same place every time it is a problem with the track.
That could be a poor electrical conection at rail joints, dirty track or poorly laid track with kinks, dips of steps at rail joints etc.
009 track has to be spot on to get good running.
Quote from: Graham Foster on August 08, 2024, 15:06I am totally confused the layout I have done this time as DCC and to help and get it correct I contacted Peco as they offer how to wire you layout, the attached is what they came back with, BUT at slow speeds on either of the loops my loco's going slow will randomly stop, is this because of power going in at two many places ?
I very much doubt that. There are plenty of people who take the line that in DCC (DC too) every individual piece of track should have its own dropper wires fed from a substantial power bus (i.e. thick copper wires) beneath the baseboard and rail joiners should not be relied upon for carrying the power. I don't think such a thing as too many power connections applies (unless they are crossed/conflict and cause a short).
Do you have a DCC track voltage tester? There are a number of different ones available. However if the locos stop only at slow speeds it suggests an issue with power pickup and the locos are unable to coast over sections where it loses contact briefly (e.g. due to any of the issues mentioned by Brian).
To go back to some basics DCC works by the decoder chip in the loco taking the 15 volts (from memory) AC current from the track, converting this to 12 volt DC and feeding that direct to the motor - much in the same way an analogue controller taking in 16 volts AC (from a transformer plugged into the 240 volts mains supply if you are in the UK) and converting that to 12 volts which is fed to the track (then in turn through the wheels and pick ups to the motor).
The clever bit with DCC is that a signal is superimposed on the AC frequency that the decoder interprets as instructions to slow down, speed up, turn the lights on or off or make certain noises (if it's a sound chip).
The potential issue with an oval loop of track is that the signals fed into the rails travel in both directions around the loop, and unless the loco is directly opposite the feed point the signal going one way will arrive at the loco before that coming the other way. This shouldn't be an issue but the decoder getting multiple instructions in very quick succession can cause it to get a bit confused causing issues with running, especially at slower speeds where any faltering in running will be more noticeable.
Looking at your track plan whilst both circuits are electrically isolated from one another via the double rail breaks in the passing loop at the bottom of the plan) I think you might also need double rail breaks between the feeds on the curves running along the short sides of the layout (essentially dividing the layout electrically in two along a line from left to right across the plan) to stop multiple signals running round the track ovals and arriving at the loco multiple times. The effect is a bit like being nagged by your spouse/child/boss/pet or whatever, and the chip responds by essentially say 'if you just shut up and give me a chance to think I'll do what you ask!'
That being said it's probably also worth giving your loco wheels and track a clean first. The electrical signals are quite small in comparison to the AC in the rails and the decoders sometimes need all the help they can get to 'see' them, so wheels and rails need to be kept as clean, if not cleaner than for an analogue (DC) layout, and with no signal to tell it what to do, or no power from the tack to run the motor from the running will be affected.
Hope that helps...
Something I should have mentioned before when you say a loco stops at random when running at slow speed is that does nudging the loco and perhaps turning the speed up a bit cause it to move again, or is the command station indicating something is wrong by cutting out, beeping or flashing some warning?
If the command station cuts out with a loco on the track then there is an issue, most probably a temporary short, perhaps when the wheels of a loco bridge a gap. If the command station cuts out when there are no locomotives on the track and (say) when you change the points trying different combinations of route then it is likely to be a track wiring problem.