DCC control of points and signals - guidance for an idiot

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BobDM
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DCC control of points and signals - guidance for an idiot

Postby BobDM » Wed Dec 11, 2019 9:43 am

I am thinking of amending my planned layout from DC to DCC, partly because I'm a complete wally when it comes to wiring :oops: and I want to run several locomotives simultaneously.

I have found out about decoders and the rest from various sources and I gather it is possible to control points and signals using DCC but I don't know how. I could really do with an idiot's guide which starts with "Here is a set of points, here is a DCC controller. What next?" To show you how ignorant I am, I assume all the points have to be individually connected to the main bus cable [if that's the right term] but do you do this via point motors? If all the engines have to have a unique address in the DCC controller how do you do this for points etc which I assume don't have a DCC chip?

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Re: DCC control of points and signals - guidance for an idiot

Postby b308 » Wed Dec 11, 2019 10:15 am

You could do worse than read Flashbang's pages on DCC. Page two cover point control:

https://www.brian-lambert.co.uk/DCC_Page_2.html

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Re: DCC control of points and signals - guidance for an idiot

Postby End2end » Wed Dec 11, 2019 10:28 am

You need ACCESSORY decoders rather than loco decoders to control points and signals.
I'm going to use DCC for train control and simple DC for changing the points, this way I don't have the expense of extra decoders just for the layouts tracks / signals.
Thanks
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RAF96
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Re: DCC control of points and signals - guidance for an idiot

Postby RAF96 » Wed Dec 11, 2019 10:44 am

You can get point motors with built in DCC decoders, but generally you have the controller telling points/accessory decoders what to do and they fire the points motors for you. Self learning decoders can be easier to set up than the more basic type.

It is wise to run a separate points bus wire system apart from your track bus wire system, then if you get a shut down due to a derail because of a badly set point shorting the track, then you can still reset the point to clear the problem, whereas with a combined single points and track everything shuts down.

As stated using DCC for points can be quite fiddly depending upon your controller methodology and many prefer to stick with manually switched methods. It is possible to have both manual and DCC control of points but I won’t clutter your brain with this yet unless you intend to go down that route.

Speaking of routes, you may wish to use a PC to run train operating software and in that case you will need to have your points under DCC control.
Last edited by RAF96 on Thu Dec 12, 2019 9:22 am, edited 1 time in total.
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Mike Parkes
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Re: DCC control of points and signals - guidance for an idiot

Postby Mike Parkes » Wed Dec 11, 2019 6:33 pm

If you use a handset DCC system then if you work the points and signals as DCC there is no need for a control panel.

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Re: DCC control of points and signals - guidance for an idiot

Postby BananaRepublic » Wed Dec 18, 2019 7:54 pm

If you wish to control your points and signals by DCC, you will need accessory decoders on the layout to receive and act on the DCC commands to operate the points and signals. Sometimes these can be built in to point motors, otherwise they are freestanding modules.

Operation of these points and signals by DCC can be carried out by several different methods.

1. Directly from your DCC system handset, or console (for console based systems).
2. From a mimic control panel with physical buttons or switches - via a special DCC module.
3. From a mini point lever frame - via a special DCC module.
4. From an off-the-shelf point switching control panel.
5. Via computer layout control software (computer screen, laptop etc.).
6. From a layout control diagram on the electronic screen of the DCC system - for systems with such facilities (e.g. ECoS, Roco z/Z21)
7. From a dedicated DCC layout control panel - e.g. from Uhlenbrock or Viessmann for use with their respective DCC systems.

1. Is possible with almost all DCC systems apart from a couple of basic entry level systems.
2. to 7. are readily available solutions.
2. 3. & 4. can also be used just to control points (by DCC) on a DC layout.




... ...
Last edited by BananaRepublic on Thu Dec 19, 2019 11:43 pm, edited 1 time in total.

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Flashbang
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Re: DCC control of points and signals - guidance for an idiot

Postby Flashbang » Thu Dec 19, 2019 4:07 pm

BananaRepublic wrote:If you wish to control your points and signals by DCC, you can do this by several different methods.

1. Directly from your DCC system handset, or console (for console based systems).
>Snip>
1. Is possible with almost all DCC systems apart from a couple of basic entry level systems.
2. to 7. are readily available solutions.
2. 3. & 4. can also be used just to control points (by DCC) on a DC layout.
... ...


I feel BananaRepublic number 1 item needs further expanding.. You can not directly operate a point or signal motor from the DCC system. There has to be a decoder interfacing between the DCC system and the motor. This decoder, called normally an accessory decoder, can be an external unit or built into the motor itself. But the need to have a decoder is paramount. :D
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Re: DCC control of points and signals - guidance for an idiot

Postby Bufferstop » Thu Dec 19, 2019 4:36 pm

On a small layout with few signals, the built in decoder is preferable to the accessory unit, especially if you want physical switches or levers, otherwise you end up running as much wiring for DCC as you would need for a DC setup. In fact if accessory units and switches are involved there will be the same number of wires, just shorter.
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RAF96
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Re: DCC control of points and signals - guidance for an idiot

Postby RAF96 » Thu Dec 19, 2019 9:34 pm

Confusion seems to be creeping in here with talk of switches and dcc operation.

DCC operation of points from a controller is via an accessory decoder (stand alone or built into the point motor). No switches involved unless we talk about switches attached to the point for the purposes of operating frog switching or operating an associated signal.

Switch operation of points is normally by way of switches on a mimic panel to the motor (via a cdu If solenoid). No DCC involved.

If DCC is required as well as manual switching then an accessory decoder can fire into the coil of a relay which powers the point motor in parallel with any manual switching.
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BananaRepublic
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Re: DCC control of points and signals - guidance for an idiot

Postby BananaRepublic » Thu Dec 19, 2019 11:58 pm

RAF96 wrote:
Switch operation of points is normally by way of switches on a mimic panel to the motor (via a cdu If solenoid). No DCC involved.

If DCC is required as well as manual switching then an accessory decoder can fire into the coil of a relay which powers the point motor in parallel with any manual switching.


In my previous post, I was referring to switching from a mimic panel (physical switches or buttons) to operate points by DCC.
i.e. selecting a route by setting the switches on the mimic panel, causes the appropriate DCC commands to be sent to the accessory decoders controlling the respective point motors.
I wasn’t referring to manual, non-DCC control of the points.

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Re: DCC control of points and signals - guidance for an idiot

Postby Dad-1 » Fri Dec 20, 2019 9:26 am

Hi BobDM & Others.

I operate my first layout's points via DCC using the main control system, built in 2008 and
still working in the loft today without any problems.
To some degree I think the number of points on you layout can influence choice of system.
That first layout of mine has 9 points and a couple of slips all worked via Hornby accessory
decoders. Each decoder has 4 output ports to operate on 4 different addresses, however
many are operating a pair of points as a crossover using just one address. With just 12
addresses I just remember what address number operates which point. Easy enough on
smaller layout that you've built - 'cos you know what you've done.

On a larger layout I found it easier to run two bus systems, one for track power, the other
connected to all the point decoders. Keeping the two separate has several advantages as
already mentioned by one of the posters. What I also have is a plug in arrangement by each
accessory/point decoder where I can if wanted unplug the separate point feed and plug the
decoders into my main track power bus.

I didn't find the wiring difficult at all, but where you have many points in close proximity you
are bound to have many wire runs, 3 wires for each point, but so easy I don't see how that
becomes difficult.

I will add that I like mimic board with stud & probe as I use on others layouts. No need to
remember any addresses, just touch the stud for the route you want. 12V analogue, easy.
As to computerized control, that's beyond me, I hate computers !!

Geoff T
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