CDU

[john_goodwin1]

I am currently building a new railway and currently on with the off scene storage yards where I am utilising Hornby point motors and the R8216 Accesory units from a previous layout to reduce cost. Will the power from my Elite controller be sufficient for throwing the points consistently or should I add a CDU which I have seen mentioned in various places. If so what type, where would i get it from and where would this need wiring in?

Sorry but not up on electrics. 

Secon point is I find the wire from the point motors is very fine, is this ok in the scheme of things or is there any way to alter this.

Will be using Elite controller with Railmaster on a laptop     

[Chrissaf]

...and the R8216 Accessory units from a previous layout to reduce cost. Will the power from my Elite controller be sufficient for throwing the points consistently or should I add a CDU which I have seen mentioned in various places.

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You cannot connect a CDU directly to a DCC Accessory Decoder. The only way it can be done, is to use the output of the Accessory Decoder to operate a pair of 12 volt relays, then use the contacts on the relays to operate the points via an external CDU.

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Here is an example using an R8247, the decoder that replaces the R8216

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The R8216 is obsolete for a reason, it has severe functional limitations. Since you have used these before, you must be familiar with them and operate within those functional limits. Personally, I would take the opportunity to upgrade the Accessory Decoders to more modern technology (sadly not made by Hornby) that use far more powerful integrated CDUs, are 'self learning' thus easy to configure and install, and have auxiliary contacts that can be used to operate other things such as interlocked signals for example.

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Second point is I find the wire from the point motors is very fine.....

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Personally, I would take the opportunity to upgrade the Hornby factory fitted point motor wires to a minimum 24/0.2mm wire [24 strands of 0.2mm wires].

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Will the power from my Elite controller be sufficient for throwing the points consistently.

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For you to ask this question you must have had such experience previously with using your R8216 accessory decoders. Some users have no issues, some do. It really seems to be subject to the actual point motors that are used. The relay schematic above is actually a real life physical implementation on my layout. My R8247s just did not have the grunt to operate my Peco PL-10WE point motors. The W versions have different solenoid coils to the normal PL-10E versions. I had to resort to the external CDU overlay to get a working solution. I did not have the luxury of being able to send the kit back for a refund and get something else, as I had everything in storage unused for over a year before I started building my layout, so I had to work with what I had product wise. The relays and external CDUs have worked flawlessly, but added some significant additional cost.

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These are my relay boards that the schematic above represent.

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[Flashbang]

Your R8216, as to does the R8247, Hornby accessory decoder has a single built in CDU.  It only has one CDU which is shared between all four outputs, when used in pulse output mode.  So really no additional items are needed.  However the small down side is the one CDU shared between four outputs. So if you're route setting where more than two motors move at once, the internal CDU may well not be able to operate correctly, as it needs a second or so to reach the fully recharged state again after its initial discharge.  But if you can arrange a one second + delay between each point motor movement when route setting then it will be fine. For single or a pair of points moving together it should be fine, especially if you use the 4.0Amp power supply which your Elite uses.

If possible use a low power solenoid motor such as the PL-10W or PL-10WE ..  W=low power. E=Extended length drive pin.  These are of course not Hornby point motors!  

There are alternative DCC Accessory decoders that do have a CDU for each output. Sold in 2. 4 or 8 outputs per unit.  😀

[Chrissaf]

I have no issue using PL-10E motors, but as I said in my first reply, the reason I used the external CDU with relay solution was because my R8247s just wouldn't operate a PL-10WE under any circumstances. In theory the green coiled PL-10WE motors should have been OK as they have higher resistance / lower current coils. But in reality they wouldn't function at all robustly on my Elite and 4 amp supply, not even enough to overcome the Peco point spring. This was without the Peco point being fitted to the layout and just on the test bench table top with the PL-10WE directly fitted to the point via the mounting lugs. thus poor alignment was not the issue. I can only state what were my personal experiences of the R8247 / PL-10WE combination.

[96RAF]

In answer to your question about the point motor wiring being flimsy.

I agree and have just written up a simple modification that although directed at the surface mount motros could he adapted to the R8014 standard units as well to provide plug in convenience.

 http://www.halton96th.org.uk/r8243pointmotor.html

 

Ref your R8216s. Although the current R8247s can be updated by Hornby to the new V2.0 (cv7 = 135) spec, the older R8216 will not update so you are stuck with the present fixed pulse only limitation.

 

Edit - in defence of the poor old R8216 I have had one operating on various layouts from new in 2006. Never gave me a moments trouble in all those years. Now redundant in favour of the added value R8247 V2.0, which apparently does everything except make tea - and of course it does not have the all important self learn facility.