Cobalt Digital with Elink and Railmaster

[Fishmanoz]

Wow, he has staff now, things must be going well. 

[RB51]

The correct address for Richard is

 

[removed]

 

He is away until tomorrow - when no dount he will be inundated with e-mails etc. R-

 

Admin edit: Until we have confirmation from Richard that we can use that email address please use the email address Flashbang has quoted below

[Flashbang]

I don't believe that personal address should be displayed on an open public forum!

The correct method of contact is by the email address provided on the DCC Concepts 'Contact Us' page (Sales@DCCConcepts.com) or use their web based contact form!

 

[RB51]

Good point - thanks for that. I did send an e-mail to Sales@ but was asked to send it directly to Richard at the address I gave. I accept that it was wrong to post it w/o his permission - I'll give myself some lines. R-

[merciaman]

Hi everyone my first time using the forum so please bear with me. I am in the process of building an 8ft X 4ft DCC layout using predominantly Hornby products. I have a track bus with dropper wires with everything operated by the E-Link / Railmaster system (4amp supply) At the present time I have 22 surface mounted Hornby points, linked to six R8247 accessory decoders. In essence, everything is working ok, but to tidy up the layout I am considering changing some of the points to DCC Concepts Cobalt IP Digital point motors.

Before doing so I thought I would try out a Cobalt unit to test programming and installation. I did a test bed trial first to de-centralise the unit and then programmed the unit with a point address and everything went to plan. I then installed the unit on one point wired up to the track bus and again the unit worked as it should do. I then did a running trial with a loco combined with using the point in question and again everything worked fine.

So to my problem / query. On one occasion, when testing the system, the loco derailed and short circuited the system but once I cleared the system, the Cobalt motor re-centred itself in a mid-way position. I then needed to operate the point again (using E-Link) to restore the point to its correct position. My concern is that if I install a number of Cobalt motors and have a short circuit, I will have to reposition all of the Cobalt points before I can start running locos again. I am trying to establish therefore whether any other members of the forum have encountered a similar problem and if so how was it overcome.

Sorry for all of the detail but I know that forum members like to have as much information as possible before seeking to respond to questions.

 

 

[Chrissaf]

Merciaman, welcome to the forum. Yes you are quite right, the detailed information you have provided is very beneficial indeed to providing you with a targeted solution reply.

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There are many posts on this forum describing the issues of DCC loss of configuration problems caused by short transient short circuits. I myself had issues of one particular R8247 keep on loosing configuration after being damaged by a short.

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It is impossible to guarantee 100% protection from these things happening on a DCC controlled layout, but it is technically possible to provide a simple technical modification to your DCC distribution BUS that will at least help to reduce and perhaps even eliminate the risk of these problems arising in the future. In my own case, since I implemented this modification I have not lost configuration of a single DCC device.

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So what is this miraculous cure modification I hear you ask.

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Simple.....a 100 ohm 2 or 3** watt resistor in series with 0.1uF 50 volt ceramic capacitor wired across your BUS. Note: that this resistor will get warm to the touch, this is quite normal.

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Note** the page linked below suggests a 0.5 or 1 watt resistor, my preference is for a 2 or 3 watt resistor to give more even heat distribution on the resistor surface (it feels slightly cooler to the touch compared to the suggested resistor wattage).

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The theory behind this solution is fully described in this web resource:

https://sites.google.com/site/markgurries/home/dcc-general-best-practices/wiring-planing/snubbers-rc-filter

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As well as reading the linked document itrself, follow the embeded link at the end of item 3 in the list of the document section 2 titled "Decoders lose programming?".

[Chrissaf]

Post 'edit' window expired. Thus, this supplementary reply.

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Reading your post again. I see that your Cobalts didn't appear to lose programming, just that they changed their position. However, the modification I outlined may still help to fix this issue and would certainly give some 'peace of mind' against more serious 'short circuit' induced issues arising.

[Nick_]

Merciaman, I currently  have 3 cobalt digital IP motors and have never had them re-centre on a short circuit, so hopefully it was an unusual action not the norm. 

[Fishmanoz]

Even if you had a whole lot centre themselves, fixing it is easy if you have configured set points on startup. Then all you will need to do is close RM and re-open and all should be back to where the points should be.

[merciaman]

Thanks for the initial feedback everyone. Noting the detailed response from Chrissaf, I already have a 2.5W resistor and 0.1 uF capacitor in series wired at each open end of my track bus?

With regard to the response from Fishmanoz, I am sure the points are configured at start up as well, but I will cross check this.

From the three initial comments it would appear that no-one has experienced the Cobalt re-centering itself following a short circuit, so even though the point is working correctly when operated via Railmaster, maybe I haven't de-centred it correctly?