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Help on module busses

Posted: Tue Sep 18, 2018 10:31 pm
by 800627
I am considering a stand-alone layout on four 3ft boards that could alternatively be used as three individual HO modules or as a large single module. In stand-alone mode operation would be by battery on board radio control, one of the advantages of which is no track wiring! However, for use in a larger set-up it would need to be wired for DCC operation and for ease and versatility it would be better if the required busses are through wired on each board.
I have read the specification and Tom Winlow’s additional details, but only having experience of DCC as an operator and not as a builder, I have some queries.

1. The track power bus is straightforward with two red wire module connectors, although they could presumably be any colour(s) on the boards.

2 “Both accessory bus wires should be different colours of the owner’s choosing”. The connectors are different to those on the track bus so there should be no confusion between them. However, should this mean that the two connectors should each be a different colour to the other or that both should be the same colour but not red?
Given that this bus is described as being similar to the track bus and in some situations can be linked to it, and that the end sockets/plugs should be in a similar left/right configuration, I wonder why the connectors need to be described differently. Presumably, provided left went to left, all the connectors could be red, although a second colour is probably more sensible.

3. With BPRC there is no need for a throttle panel, but with a 6ft or 12ft length I wonder if it is necessary to provide one for the use of other operators at meets and, if so, which sort? Whilst the specification gives details of the in- line connectors, there is no mention of the wire colours/pinouts of the plugs and sockets. Are these standard or do people purchase the plugs and sockets ready wired?
Since starting this I have read other threads and am surprised that DCC operation is mandatory but that the various DCC brands are largely incompatible! Is this due to the 6 wires being used differently or merely a connection problem?

4. As an observation, the specification provides for inter module connections to be either 18” jumpers or flying leads extending 18” beyond the end of the baseboard but not the linear position of the on-board sockets. The overlap of the former is less than for the latter and it could be that a jumper falls short on a module where flying leads have been adopted.


Re: Help on module busses

Posted: Sat Oct 06, 2018 5:53 pm
by torikoos
You be best served contacting module owners in your area, as they will be the ones you most likely will be joining your boards up with, follow their wiring colour codes and connector practices etc and you should be in good shape.

Re: Help on module busses

Posted: Thu Oct 11, 2018 2:19 pm
by Mike_R
1. All our track sockets are red, most important is that they are clearly marked as the track bus and wired left socket to left rail etc.

2. We (Western Union) use black for the accessory bus, as with 1. they need to be differently marked to avoid being confused with the track bus. They do both carry DCC, but may be off different command stations. They are normally only connected to the track bus if there is no accessory bus connected to the setup. As decoders are connected to this bus it is plugged into the track bus to DCC in this case.
If your module has no need of the bus you could have a long lead that spans your module, you need some way to pass the bus through your module.

3. Because of the throttle bus differences you do not need to provide one, but it is possible to allow for the three main types, Xpressnet, Loconet and NCE, using universal panels. They can use the same wires, so long as no accessories are permanently connected, but they have different connectors. As Koos said check with the groups you are likely to connect with.
Another option is to install temporary throttle panels fixed to the module with long cables to adjoining modules or panels. It is best to provide panels near to switching areas on both sides.

4. Sockets should be mounted on the centreline of the module ends and close to the end so 18" is normally plenty of length.
Personally I would not have flying leads as they are more likely to get damaged and make for awkward connections when matched with another flying lead module.

Re: Help on module busses

Posted: Thu Oct 11, 2018 7:15 pm
by 800627
Thanks for the replies Koos and Mike; I was beginning to wonder if anyone else was using the Forum!


Re: Help on module busses

Posted: Sat Oct 13, 2018 2:35 pm
by Mike_R
I do try to check every week or so, but yes there is very little traffic. I think most are on facebook etc. I find it hard to keep track of those unless glued to the phone, which I'm not. Any useful information gets lost after a short time.

Re: Help on module busses

Posted: Thu Nov 15, 2018 10:19 pm
by torikoos
Good point Mike,

FB is less 'organised', but there are search functions too, which can help. Forum's do have their place, but rely on active participation. As evident on FB also, being a member of several groups there, there is a core 'group' of people that are probably responsible for 90% of content, and the rest posts only sporadically or not at all, just dishing out 'likes' left right and center.

Perhaps people are intimidated and think their own work is inferior, or think they can't write about it. For that reason there are moderators however that can keep any unjustified or harsh feedback under control.

Cheers, Koos