Servo motors for points - DCC - RailMaster - eLink

[PJ_model_trains]

 

Has anyone used the ESU Precision Servo's Ref: 51804 with a DCC - ADS-8 decoder in RM with the eLink?

 

I have been looking at Traintronics TT300 system with built in decoders but already have 3x DCC ADS-8 decoders for Hornby solenoid motors under my layout.

 

[Rog RJ]

ADS8 decoders are specifically for solenoid motors (that's what the "S" means) so are not usable with servo's.  Servo's need special drivers which send pulses of accurate duration (normally between 1.0 and 2.0 milliseconds) at specific intervals.   You can't just give them a positive or negative pulse to make them change direction.

[PJ_model_trains]

Cheers Roger

Wasn't thinking at the time of writing !!!

[Fishmanoz]

The AD range should be able too, but then you only have ADSs under your layout.

 

But then an ADS is only an AD with a CDU added to each port.  I wonder if you can simply change it back to be an AD?

[PJ_model_trains]

I am a little frustrated here but in fairness these are down to my capabilities.

 

I need to consider all ideas that could work for me, that is the hard part. As many know I have to rely on my wife and a friend to upend my layout to work under it or move when family comes to stop with us. So, I am seriously considering a completely new layout. The new one will fit on a side bedroom wall (not under the window as previously considered). It will be hinged so that it can fold upwards without lifting.

 

The feasibility has been done and I know I can get 5'x2' board to my left, 4'x4' board to my right and join the two with a 3' x 1'6'' board in front of me. From this I can get 8 sidings to my left and two loops to my right (reverse loops) with 3 rails joining each side. An additiona board can then fit in the middle that will be easily removable, with track coming off the loop to my right and adding another 4 sidings in the middle.

 

Feasibility done, I then look as to what I can reach, with the removeable section in the middle taken out the farthest point away from me would be 2' 6'' probably the most I can reach and maybe still with a struggle. So far so good but...

 

I then have to look at servo's or point motors, I don't want solenoid nless I have to, but with 20 points some may have to be for a time. Then is the next thought, do I go for a servo and wire to change the point or do I go for a servo motor like the TrainTronics TT300? The TT one seems simpler but, I am not sure I can line one up underneath with the degree of accuracy needed when first setting one up. I struggle to get to one side of the board due to my situation I won't be able to get to both to line it up. Asking a woman to help with something like this would be worse than asking them to wire a plug!!!

 

So based on the above and my limitations, what do you think would be easiest for me. 

 

[PJ_model_trains]

Try Hobbyking.com for servos, as cheap as 30 bob each.

 

Have you used any of these?

 

[Chrissaf]

I have.  They are good value for money, but as with anything you get what you pay for. I bought a batch of 20. Out of the 20, two were faulty. Exchanged without quibble. This equates to a 10%  failure rate, but I might just have been unlucky. Of the 18 remaining, a further 6 were very slightly off configuration with regard to their centre position adjustment (not user adjustable as done as part of the manufacturing process). This is not a big issue unless you want to use the full travel of the Servo (point operation is unlikely to need full Servo travel).

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I would just like to re-iterate the comment I made in my very first reply on page 1 of this thread. The significance of which seems to have been overlooked. The way a Servo works requires an Accessory Decoder that is specifically designed for Servos. Please review my 1st reply on page 1 again to appreciate why a specific Servo decoder is required.

[PJ_model_trains]

Thanks Chrisaff

Some good information there, thanks also for feedback on your experience. ;o)

 

[Pete172]

Hi PJ,

As  Chrissaf said, you need to use a DCC decoder for servo motors.

I decided to use the ESU SwitchPilot Servo accessory decoder, to control the servos, via my Elite & Railmaster setup. The servo motors I use are just the standard Tower Pro SG90 (cheap & available on the net).

I posted instructions on this Railmaster Forum a while ago, so if you choose to use this decoder, then just follow the instructions in the link below, and you should be up & running quickly.

 

https://www.hornby.com/uk-en/forum/esu-switchpilot-servo-works-with-railmaster/

 

Hope this helps,

Peter

[Chrissaf]

Just to add to Pete's post. If I recall correctly the Tower Pro SG90 is the 30 shilling Servo you can get via Hobbyking. It is a widely available Servo available from many sources, but at different prices. For example, Rapid online do them for about £2.10 plus VAT.

[Chrissaf]

Something else to consider when using Servos to drive points. They are a bit on the noisy side, even more so the cheap ones. Remember they are intended to go in a Radio Controlled model that may be either on a race track, on a lake or in the air. There is no incentive to make them quiet. I use my Servos to operate rolling stock decouplers, not points, but when I use them there is a loud but brief motor whine. Well I suppose that does give positive audio feedback that the point has thrown. The thud of a solenoid point is also potentially loud, but only lasts a couple of milliseconds. The Servo whine lasts nearer 250ms and is far more noticable. I am not deriding the use of Servos for points, just bringing to attention additional things to consider.

[PJ_model_trains]

I think some of the comments put me off servos so I am now looking at TrainTronics TT300 and Cobalt iP Digital turn-out/point motors.

 

Part of the decision I admit is that I need something easy and reliable, those sort of things you pay more for!

 

But thank you everyone for your suggestions ;o)

 

[Nick_]

I have found Cobalt iP Digital turn-out/point motors easy to install and program from RailMaster/eLink, just following the instructions supplied by DCC concepts. They are a bit noisy but then so are the solenoids. They make wiring electro frogs up really easy if you're using them. 

[PJ_model_trains]

I have found Cobalt iP Digital turn-out/point motors easy to install and program from RailMaster/eLink, just following the instructions supplied by DCC concepts. They are a bit noisy but then so are the solenoids. They make wiring electro frogs up really easy if you're using them. 

 

Thanks Nick

 

Yes I will be using electrofrog points/turn-outs.

 

I am aware of the IRJ's on both V rails of each electrofrog point but not sure at the present time of what wiring is required to the frog if using Cobalt iP turn-outs. 

 

When you say they are noisy are they as noisy as solenoid motors?

 

[Nick_]

PJ Assuming you make the standard mods to P*co points for DCC (cut the links, wire the switch rails to the outside rails), when using a Cobalt IP digital you connect terminals 1& 2 to your DCC bus (or your track) and terminal 3 to the frog, it's as simple as that.  To my mind they are no more noisy that solenoid motors, probably a bit quieter but the noise goes on for longer that the short sharp 'crack' of a solenoid switching over

[ronp849]

Hi - I have only been interested in model railways for a couple of months now but I already have a layout, a couple of DCC engines and an eLink with Railmaster. (The bug gave me one hell of a bite) 🫨

The layout has in excess of 20 points which I want to electrify with R/C servos. (I also fly model aircraft so I have plenty of spares). I am also thinking of additional animation like signals, level crossing barriers, etc. The problem was finding an interface/driver for that many servos that could connect to the eLink. 

I ended up building my own - capable of driving up the 36 servos and controlled with a laptop via standard ASCII characters. What I need to do now is develop the software to interface with Railmaster either directly via file transfer or indirectly via eLink and DCC.

Does anyone know if the eLink Accessory protocol is generally available or does it follow any published standard?

Can Railmaster be persuaded to send files down a PC com port that I could use in my decoder?

many thanks in advance.

Ron

 

[Chrissaf]

Welcome Ron to the forum.

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Modifying the existing RM application is probably a non starter, it is not open source and the raw code it is built from is not available. There is nothing in it AFAIK that would allow you to use RM to control the sending of files.

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There was a software developer on this forum who builds and runs exhibition model railways (no longer contributes) who built is own DCC Accessory Decoder built around an Arduino to do the very thing your are planning. His home brewed Arduino decoder took standard DCC accessory commands on its input and controlled servos on its outputs (about 20 of them if I recall correctly). At the time when he built his custom interface he was using RM, but has now moved on to a different non Hornby control system, hence why he no longer contributes here.

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The DCC standards are published and can be found here. Good luck.

http://www.nmra.org/index-nmra-standards-and-recommended-practices

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If you later decide to give up on your home brewed approach. I recommend the MegaPoints system for Servo control. It is modular and expandable. The MegaPoints system has an optional DCC decoder interface board (costs £25). This one board can control AFAIK up to 192 servos.

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http://loolee.org/megapoints/index.html

[96RAF]

There was a guy on RMweb forum who sucessfully reverse engineered the eLink,and RM interface, essentially to improve what was there, but the moderators decided that he was breaking forum rules by publishing that data in direct contravention of the RM licence conditions, so all trace of the discussion was removed, thus breaking the trail.