jamesed

Using Cobalt IP Digitals will simplify things. What Nigel was pointing out is that if you intend to power you motors from an accessory bus then you need to connect your frog dropper to terminal S2C (6th terminal down in the photo) and not to S1-FROG (3rd terminal down) so that your frog isn't powered from the accessory bus. Having connected the frog to S2C you then need to wire S2-L and S-2R to your track bus. The S2 terminals are a completely isolated single pole changeover switch. The down side of this is that you don't then have the S2 switch available to control signals or mimic panel LEDs etc. The changeover on a Cobalt takes place at the mid point of travel of the switch rail so this means that you don't have to make any wiring modifications to the Electrofrog points. Just solder a dropper to the group of wires directly beneath the frog and leave all the link wires in tact. Just make sure you've got the dcc polarity correct on each motor as you go along - if it's wrong you'll get a short but is quickly rectified by swapping over the track bus wires in the DCC IN tetminals. I run my Cobalts from the track bus and don't find that to be a problem. Their current draw is extremely low. This enables me to use the S1-Frog terminal and I then run coloured light signals from the S2 terminals feeding 12v dc into S2-C

A very simple way to switch ABC zones in and out to avoid one train catching another is to use Block Signalling IR sensors which are very simple to fit and don't need any computer control. One of the models they make includes a relay which can be used to switch the abc module in or out of circuit. https://blocksignalling.co.uk/BOD2-RLY So, as the first train passes over the sensor it switches in the abc module which will slow and stop the following train. After a pre-set time delay the module switches the abc out of circuit again and the train starts to move again. An IR module can also be placed in the track towards the end of a station platform and set with a very short delay. When the train has completely moved out of the station it then releases the following train to approach the station and enter the platform. With careful positioning of sensors you can then put a second sensor on the approach to the station so that the abc is activated again to stop the second train. The combination of these IR modules and a very basic abc module (the Lais ones are fine or they are quite simple to build yourself) gives you good automation options without needing computer control.

Try an find a suitable Zimo decoder if you can. An 8 pin wired version will do the job fine. Apart from the fact that most people agree that Zimo make some of the best decoders, if you're intending to buy a Z21 then these are designed to provide additional functionality with Zimo decoders so are a very good match. Zimo ABC is easy to set up (especially on a Z21) and is pretty reliable on distance stopping.

Are the two wires we see in the photo and soldered to the pads the orange and grey pair (moror connections) or the red and black pair (from track pick ups).? Use a meter to check continuity to work out which socket pins they are wired to and that will tell you which way around the socket is.

The Z21 has it's own wifi router with it's own SSID and doesn't connect directly to the internet. Only those users of their system are likely to be connected to it so bandwidth should never be a problem. An iPad, Andtoid tablet or phone connects directly to the Z21 router so no reliance necessary on 4G/5G or a local wifi network. Potentially wifi channel clash could be an issue but it's quite simple to work out what channel(s) the exhibition hall wifi network is on and set up the Z21 router to use a different channel further away in the band. Also, remember that Pete Waterman's layout is designed to be exhibited in Chester Cathedral throughout the summer months rather than big model railway exhibitions.

It seems that we won't have long to wait now for the new Zimo MN180N18 decoder. Their press release dated 20th January states that they should start shipping this month (February). Read about it HERE.

Anyone in the East Devon area we'd love to see you there on Sunday 5th March from 10.00am to 4.30pm. On display: The Group's OO gauge layout Our own N gauge work in progress dcc layout with an opportunity to drive a train using our Z21 control system. The Group's new O gauge layout (also under construction). A number of visiting exhibitors including the highly acclaimed Moors View N gauge layout. Just one trade stand selling second hand items of all guages at affordable prices. Plus tea, coffee and cake. Only £3 entry with accompanied children free.

Hmm I think there is a danger here that we might both be getting a bit pedantic about this! In that vein all I will add is that the "bus" is the bus wires, the "droppers" are the droppers and the "track" is the track. Whilst I agree that they all form part of the same circuit, in this instance I was most clearly referring specifically to the "bus". Don't forget that the track is very different from the bus wire. Usually made of nickel silver these days it has a higher resistance/impedance to copper wire. This adds to the impedance between the loco decoder and the controller. That's why it's recommended that we install a dropper to each section of track directly to the bus rather than looping wires from one bit of track to another. The contact between the wheels of the loco and the track will also increase the load to source impedance. Many of these things we cannot do anything about which is why it's important that where we can make a difference (low impedance bus wiring, droppers to each section of track, minimising bus joins, clean track etc.) it's well worth doing the best we can. I seem to remember recently reading somewhere that on some exhibition layouts they now install two pairs of droppers to each track length as standard. I can see the logic of that for portable layouts.

Errr, sorry I don't understand what you are getting at. By definition the ends of the bus wire must either be the start or the end of the bus. If you've got spurs (and I've already explained why it's better to avoid them if possible from the design stage) then stick another snubber on the end of them too. Adding more snubbers won't do any harm but won't necessarily do any good either and certainly won't make up for poor wiring. I agree with you about bus lengths but the answer to that is in making sure you use an appropriate sized cable. Whilst a 20m long bus might be too long for 1.5mm sq cable it won't be too long for 2.5mm sq. cable. On the other hand 20m long bus wired as a ring circuit would probably be fine with 1.5mm sq. cable. Theoretically you can use 4mm sq. cable for a bus if you are concerned about the length/impedance but very few of us would ever find that to be necessary. ( I wonder what size bus cable they use on Pete Waterman's Making Tracks layout in Chester Cathedral? It's all about the overall impedance and choosing the right cable, minimising joins, soldering droppers all of which contribute to that. It isn't helpful to say that long power bus runs are bad because you have to know and understand the other factors to define what is too long.

That's interesting Iain. I'd like to explore that a bit if you don't mind as I know you're a very knowledgeable chap when it comes to anything dcc. (Sorry to others if this is diversifying away from the original thread topic.) My comments about using snubbers were made based upon my experience with DMX512 which is effectively RS485/RS422 and is used across the entertainment industry to control digital lighting. It has some similarities with DCC in that it's a square wave signal and at 250kHz it works at a higher frequency than dcc but that's still a relatively low frequency compared with, say, standard ethernet at 100MHz. Where it differs mainly is that it isn't carrying power and is just an 8 bit digital signal. Now, with dmx512 the end of a data line (which is usually run along a microphone type cable) always needs to be terminated, although this is achieved simply with a resistor. (I've seen the consequences of forgetting to terminate it!) A DCC snubber also has capacitors in circuit which I'd assumed was to cope with the higher power transient spikes. So, my theory was that the snubber served two purposes, to terminate the dcc signal and minimise reflections but also to absorb (up to a point) any transient voltages. Now, maybe my theory is wrong so this is where I'd find your explanation helpful. I appreciate that as the frequency reduces, wave form reflection becomes less of an issue. Are you saying that at 9kHz the effect is so minimal it can be ignored? Next, in terms of protection to suppress transient voltages, I can see that what you've said about putting the snubber anywhere on the layout makes sense but if we apply that logic then most decent dcc controllers have that circuitry built into the outputs anyway which would imply that deploying a snubber is pointless because the protection is already present. My research on this seemed to imply that ideally you want your snubber to be as close as possible to the source of the transient spikes. Obviously we can't always predict where that will be so putting it at the end of the bus wires seems to make sense as we've then at least halved the distance from the source to the closest suppression snubber for anything more than half way along. Hence, on a bus wired as a ring circuit there's no need for snubbers at all because both ends are protected anyway by the dcc controller. So, my theory is that by fitting a snubber at the end of the bus pair we are achieving two things. We're providing a termination for the data signal to prevent reflections and we're providing transient voltage suppression at the optimum position. If my logic on this is wrong I'm always keen to learn so please do explain where I'm going off piste.

I'm not suggesting that you should never have spurs. What we're all aiming for is to do as much as we can over a wide number of things to minimise the bus impedance and avoid transient voltages (often referred to as spikes). If you add a spur to your bus the chances are that you're not going to be able to make an effective solder join on 2.5mm sq. cable so you are likely to use some sort of connector block. Every time you break the bus and use a connector of some sort you are adding to the overall impedance. If you are using screw connectors (i.e. choc blocks) then as time goes by and the copper oxidises and flattens, which also results in the screw down becoming looser then the impedance in that joint will start to increase significantly. If you have one such spur then it may not cause a problem but if you have a number of them it may have an impact over time. If you can keep your bus as a continuous run without any breaks then that is a bonus which will contribute to keeping the impedance low. If you are building a modular layout then joins in the bus will be inevitable between board sections. In this case if's worth looking at how joins are made. Speakon connectors are a popular choice but there are other options. The reason we terminate the ends of bus cables is because the wave form of the signal can be reflected at the bare end and sometimes this can cause interference or phase cancellation. The purpose of terminating with a 'snubber' is to supress this reflection. It doesn't eliminate it entirely but hopefully reduces it to a level which is less likely to cause a problem. For this reason, the fewer bare ends we have on any dcc system the better but if you have two or three then that's unlikely to cause a problem. It's just better, if you can, at the design stage, to plan your wiring routes to allow for a continuous bus without spurs. All these little things can add up and compensate for where, perhaps, you have to make compromises in other areas.

The logic for twisting wires is to hold them close together to reduce inductive field interference. Running the wires close parallel and then cable tieing them together achieves the same effect. However, it's much easier to solder on droppers if they're not twisted and initially run parallel so that's a really good option. You can then cable tie them together once you've finished soldering all your droppers if you wish. Ths whole twisted bus wire argument is perpetuated by DCC Concepts who have a vested interest in promoting it because they sell their own twisted wire. Twisted wires can be helpful but it's not essential. In fact, if you run your bus wires up to about 1cm apart it's quite likely that this will be fine as the inductance impact will be low. As you move further apart then it becomes more of an issue. Decent dcc decoders can quite capably handle a low level of transients.

A 4'x7' layout is fairly small so 1.5mm sq cable should be fine. As others have said, any standard copper electrical cable will do the job fine. If necessary strip off the outer insulation so you have two individual cables. Red/black, brown/blue doesn't matter; use whatever colours you wish; there is no "standard". Run the two lengths of cable fairly close to each other and then once you've soldered on all your 'droppers' (for which 16/0.2 is perfect) cable tie the two bus wires together. This will minimise any inductive field interference and is just as good as twisting the wires which is something you'll see often promoted (especially by one particular manufacturer that happens to sell twisted bus wire). Avoid having spurs off your bus if you can, it's far better to keep your bus as a single continuous run. There are good arguments for running it as a ring and bringing both ends back to the controller but despite being good with most controllers there are a couple of dcc controller manufacturers who state this method isn't suitable for their equipment so check first. If you have an open end to your bus wires it may be beneficial to terminate the ends with what is commonly referred to as a dcc 'snubber'. These are readily available to buy cheaply online or you can make your own with just a few components.

There are a few points here. First the simple answer, 7x0.1mm equipment wire will do the job, which is 30AWG but you could go down to 32AWG if you wish. Next, if there is a socket in the loco and the tender has been prepared to accept a speaker then it's designed to take a decoder. If the one you've got doesn't fit then you have the wrong decoder. The solution to this is buy a decoder which fits the space available. In the long run that will be a far better option. Finally, it is concerning that you state you have used 16x0.2mm wire for your dcc bus. That's far too small by any standard and will cause you ongoing problems. With dcc it's not just about the current capacity (although 2A is still likely to be under rated especially if you are operating sound fitted locos). You need headroom to cope with the transient voltage peaks and troughs of the wave form to protect the integrity of the signal. The impedance of your small wire bus will be too high. Most people use 2.5mm sq cable (13awg approx) or on a small layout you may be fine with 1.5mm sq (15awg approx) . That will help ensure the bus impedence is low enough for the integrity of the dcc signal although other factors, like minimising any joins, soldering droppers etc. will also play a part in that. Your 16x0.2mm wire will be ideal for the droppers between the track and the dcc bus.

You shouldn't need to solder directly on to the decoder. Remove the decoder and you should see that you have a row of pins visible down one side of the N18 socket which you can attach wires on. Download a pdf copy of the Zimo MX Small Decoder Manual and in there you'll find a diagram showing what is wired to which pin on the decoder. You need to identify the Positive and Ground pins on the socket to attach your stay alive wires to. Alternatively, trace the wiring for positive and ground to the loco pcb and you might find there are some solder pads on there to wire to. Either way, it avoids waving your soldering iron anywhere near the decoder!

Oops, thanks for correcting that Iain. I did indeed mean cv29. I'll go back and edit the previous post just in case anyone refers to it in the future. You are, of course also right about reading the value of cv29 but in this case I was assuming the decoder would be new with default settings or at least have had a reset routine done on it first in which case just add 1 should be all that may be needed.

I'm going to assume you are OO so you've got a bit of space to play with. If you are N gauge then fitting in what you need may be an issue. I think your first instinct was correct. It will be a lot simpler to have a decoder in each of the end coaches. Any old 2 function decoder with wired outputs will do the job. It doesn't matter if it's a function only or standard decoder, just buy whatever is the cheapest you can get your hands on that is a suitable physical size. It will be easy to install because you've already got pickups wired to the lighting pcb. Just snip these wires half way along and connect the pair of wires from the pickups to the track wires (red and black) on the decoder. Then you'll need a 3 wire to 2 wire converter. There are plenty of these around (look at DCC Conccepts or Rails of Sheffield who both sell them. There are plenty around because Kato users need them all the time and they are typically about £8 for a pack of three. Simply connect the common positive (blue), function output A and function output B (yellow and white) to the 3npin side of the converter and then connect your pair of wires from the lighting pcb to the other 2 pin side of the converter. Then program the decoder address. The function outputs should by default be mapped to F0f and F0r. Hey presto it should all work fine. If both cars are showing the same colour at the same time just put one back on the track and add 1 to the default value of cv29 which will sort that out.

There is an obvious answer here, especially if you are undecided as yet whether your layout will be dc or dcc. Why not use Cobalt IP Digital motors? Ok, your initial reaction to this suggestion may be to think that at £24 each that's a mad suggestion but let's think it through. They will work just as well on a dc or dcc layout. If you prefer to control them from simple switches or pushbuttons rather than dcc control you can. It's just a case of buying some cheap switches and wire them straight to the relevant terminals (no soldering or even screw terminals to be bothered with). They use hardly any power to run so if you are on dcc they can be powered from your bus or if you are running on dc then any old power supply giving between 7-23 volts will do the job. The ex-laptop psu mentioned earlier will do the job fine. You certainly won't need a cdu which is a cost saving. If you are on dcc then you'll almost certainly want live frog switching which is built in so nothing extra to buy. You can use the S2 relay terminals to drive your mimic panel (which answers your other thread) without buying anything extra. If you decide to go dcc, either now or in the future, you don't need to buy decoders; they'll work straight from your dcc bus. If you are using electrofrog points you don't need to carry out any modifications to how they are wired - they'll work out of the box because the frog polarity switching takes place at the centre of travel. All you have to remember is to remove the spring from the points before you lay them. This is an option which will simplify your wiring and futureproof your layout. If you've currently only got four sets of points then just under a hundred quid to achieve this is a good investment and they come with a lifetime warranty too, so keep your receipt!

Space will be a major factor for you inside the carriage. I have converted a number of my coaches to dcc and, using very small cheap decoders, 13.8x7.3x3.8mm, I've successfully managed to install them beneath the roof and out of view but it was very tight. There is some space in the doorway compartment at the end of the carriage that you might be able to use. Get a small piece of white opaque plastic (something like double sided tape backing) and stick it over the inside of the two windows to conceal it and it won't be noticeable when the carriage is running. I did that on the first carriage I fitted a decoder to before I worked out how to fit it in below the roof. It looks fine and I haven't bothered to go back and change it to the better method. I'll be interested to hear how you get on. I haven't been too bothered by a bit of flickering. In fact it's been quite helpful in seeing where I need to apply a bit of effort in track cleaning! It might be something I decide to play around with one day.

Isn't this all over complicating the issue? Most decent 6 pin decoders have 4 functions anyway. Just because 3 and 4 aren't on the pins doesn't mean you can't use them. Just wire to the solder pads on the decoder. Better still, if you are doing a conversion buy a '6-pin' decoder with wires on like a Zimo MX617R (which if you hunt around you may find available somewhere) which will give you the F3 and blue wire already attached.

You are a star @Shedmaster. That menu icon is black on a dark grey background and I don't think I'd have even seen it if I didn't know what I was looking for. Thank you. All locos now rearranged in the order I want them.

Is there a way to reorder the list of locos as they appear in the main control screen of the app? I can't seem to find a 'sort' option and they simply appear in the order they were created. Ideally I'd like to sort the list either by dcc address or alphabetically. I can't believe it's not possible so I must be missing something!

Is THIS what you are looking for? (2mm dia plugs at 12.7mm centre spacing)

That's an unusual comment. Why not?

I remember taking the overnight Motorail sleeper service from Lonon Euston to Edinburgh back in around 1987. It was quite a leisurely affair. I arrived at the terminal about 10pm and checked my car in. Then I wandered around to join the train and find my sleeper berth. I was tucked up in bed by the time the train pulled out of Euston. We arrived in the early morning at Waverly station but you didn't have to disembark until about 7.30 am or so. By that time all the cars had been unloaded so it was a quick process to walk around and retrieve it before jumping in the car and driving off. A very civilised way to travel. Travelling on Eurotunnel is so efficient nowadays. It would be nice to think lessons could be learnt and this type of service adapted for domestic travel. Sadly I suspect it would't be cost effective.