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Discussion Starter · #1 ·
Hi I have read the previous threads about the points decoders and I suppose I am looking for some clarificatrion. I have the NCE Power cab and the club layout (Caistor) has just purchased the Pro cab. Now I know that both of these can cope with route setting and multiple point control but which point decoders are the best bet? Not necesarily the cheapest but of course VFM has to be a consideration. I have read the info about the SDM82 by Wiggy and as I deal with Digitrains which I presume he does I have been tempted in that direction but what are the viable alternatives? For instance what about the Hornby accessory decoder which controls 4 ppints at once? I think the club layout has in the region of 35 sets of points so I suppose cost will come into the equation as ever but for instance if the SDM82 does 4 for £56 is there another option that multiplied to cover the 35 sets of points will be better VFM?

Any assistance with this will be as ever much appreciated.
 

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Are you using solenoids (Peco or Seep) or slow-motion motors (Tortoise etc)?

In either case the cheapest decoders are likely to be the MERG kits. VFM may depend on whether you want to join MERG and also whether you want to assemble them yourself. The version for slow motion motors is about £9.50 and the one designed for solenoids, with built-in capacitor discharge, is about £11.50 (each controls 4 sets of points). I've put together about 10 of these for my new layout but it's not advanced enough to test them yet so I can't speak from service experience.

The cheapest commercial ones I've seen are probably Littfinski (www.ldt-infocenter.com) though I have no personal experience at all of these. I've heard that many decoders can't cope with solenoids, as they are designed for the European and US markets where they move points by less drastic means.
 

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Discussion Starter · #3 ·
QUOTE (Edwin @ 17 Apr 2007, 12:44) <{POST_SNAPBACK}>Are you using solenoids (Peco or Seep) or slow-motion motors (Tortoise etc)?

In either case the cheapest decoders are likely to be the MERG kits. VFM may depend on whether you want to join MERG and also whether you want to assemble them yourself. The version for slow motion motors is about £9.50 and the one designed for solenoids, with built-in capacitor discharge, is about £11.50 (each controls 4 sets of points). I've put together about 10 of these for my new layout but it's not advanced enough to test them yet so I can't speak from service experience.

The cheapest commercial ones I've seen are probably Littfinski (www.ldt-infocenter.com) though I have no personal experience at all of these. I've heard that many decoders can't cope with solenoids, as they are designed for the European and US markets where they move points by less drastic means.
Hi Edwin I think they are all Peco but definitely not tortoise. Where can I read about the MERG kits? I have looked at the website before but to be honest a lot of it goes straight over my head I am afraid.

Cheers Chris
 

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QUOTE (chriswright03 @ 17 Apr 2007, 13:29) <{POST_SNAPBACK}>Hi Edwin I think they are all Peco but definitely not tortoise. Where can I read about the MERG kits? I have looked at the website before but to be honest a lot of it goes straight over my head I am afraid.

Cheers Chris

Me too! You have to remember that MERG includes many experts who have developed their own hardware and software for model railway control and choose to make them available to others in the form of kits, documentation and advice. Not surprisingly, different people sometimes have different solutions to the same problem and this can give rise to some interesting debates!

Then there's a larger group of non-experts who hope to make use of that knowlege and hopefully learn something too. I'm definitely in the latter group though I hope I have been able to contribute in a small way by suggesting a new feature for one of the decoders and when the kit designer changed the software I helped with the documentation.

The DCC kits are one of the most useful MERG items IMHO, because although developed to work with an 'encoder' connected to a hardware panel they can also be configured to work with any NMRA command station that supports accessories. In view of other postings here I'm not going to offer an opinion on whether they will work with Hornby!

There's a bit of info on the kits in http://www.merg.info/kits.htm, with more (but rather technical and confusing) on http://www.merg.info/resources/dcc.htm. You need basic soldering skills and tools to put them together and you will need to connect them to the programming track and set up their CVs manually, unlike some decoders which 'auto-learn' their addresses.
 

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That Merg kit sounds very good value for money!

I don't think that from what I've been told the Powercab can actually operate the Hornby decoder.

Yes I do use Digitrains!
Chris has had to take a Hornby decoder back as it wouldn't work with the Powercab, but Doug has managed to get the decoder to work with a different system by using Paged mode?

Dont know how to go about programing in paged mode on the Powercab!

Whatever you go for make sure it has capacitor discharge built in, you really do need it.
Also it means the decoder can be connected to the main track 'bus'

Ian
 

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Discussion Starter · #6 ·
QUOTE (wiggy25 @ 17 Apr 2007, 16:28) <{POST_SNAPBACK}>That Merg kit sounds very good value for money!

I don't think that from what I've been told the Powercab can actually operate the Hornby decoder.

Yes I do use Digitrains!
Chris has had to take a Hornby decoder back as it wouldn't work with the Powercab, but Doug has managed to get the decoder to work with a different system by using Paged mode?

Dont know how to go about programing in paged mode on the Powercab!

Whatever you go for make sure it has capacitor discharge built in, you really do need it.
Also it means the decoder can be connected to the main track 'bus'

Ian
Well the Hornby decoder includes a CDU but I still don't know if it works with the Powercab. I will ring Chris and ask him for his opinion. So does the SDM82 work OK off the power bus and is it easy enough to get the powercab to talk to it?

Chris Wright
 

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Discussion Starter · #7 ·
QUOTE (Edwin @ 17 Apr 2007, 15:02) <{POST_SNAPBACK}>Me too! You have to remember that MERG includes many experts who have developed their own hardware and software for model railway control and choose to make them available to others in the form of kits, documentation and advice. Not surprisingly, different people sometimes have different solutions to the same problem and this can give rise to some interesting debates!

Then there's a larger group of non-experts who hope to make use of that knowlege and hopefully learn something too. I'm definitely in the latter group though I hope I have been able to contribute in a small way by suggesting a new feature for one of the decoders and when the kit designer changed the software I helped with the documentation.

The DCC kits are one of the most useful MERG items IMHO, because although developed to work with an 'encoder' connected to a hardware panel they can also be configured to work with any NMRA command station that supports accessories. In view of other postings here I'm not going to offer an opinion on whether they will work with Hornby!

There's a bit of info on the kits in http://www.merg.info/kits.htm, with more (but rather technical and confusing) on http://www.merg.info/resources/dcc.htm. You need basic soldering skills and tools to put them together and you will need to connect them to the programming track and set up their CVs manually, unlike some decoders which 'auto-learn' their addresses.
Thanks for that Edwin and I shall have a look at the sites with the links you provided. Stand by for any questions though!?

Chris
 

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Discussion Starter · #8 ·
Hi all just to reopen this thread for a while - we are at the stage now in the club of adding points motors to the boards that do not have them already and still considering which decoders to use. There are advantages with the SDM82 for ease of use and the MERG kits for value and no doubt they both have their downsides as well but I have another question. As it is (or will be) an exhibition layout it is obviously split into a number of boards and needs to be transported. With the last layout 'Westwold' there was sometimes damage incurred when in transit so this time we are taking particular care to try and avoid that especially with the underboard wiring. We have used copper tape (not a big fan one way or the other personally) and we are using jack plugs and sockets to join the power bus at the boards. Sorry the question is here honest - how do we best join the power leads from the various points on one board to an accessory decoder on another? For example one board will have two points on it and another maybe six so there are the eight that the SDM82 will deal with. So is it better to avoid extra wiring crosssing boards and the problems of connections? That I assume would mean using smaller capability decoders ie 2 and 4 as opposed to the 8 of the SDM.

Any advice would be most helpful at this stage before we plough on and find out there is a better way. I appreciate the more seperate accessory decoders we have the more the cost rises so there is as ever a financial trade off with practicality but a few ideas from any of you out there that have come across this before will be appreciated.

Chris
 

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My preference would be to keep the board interconnects to a minimum and if that means having redundant circuits on some boards, so be it. I do have a tendency to over engineer a solution.

The question you need to ask yourself is this:-
"Do I want to save x pounds and endure the high stress / pressure fix up at the exhibition site when I arrive and discover that something has broken?".

The other plus for the redundancy approach is that the accessory decoders will always be reusable in a future project. Solid state electronics has a long life span.

I think your final solution will involve a mix of redundancy and some additional board interconnects - it's economics.

David
 

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Discussion Starter · #10 ·
QUOTE (dwb @ 28 May 2007, 11:46) <{POST_SNAPBACK}>My preference would be to keep the board interconnects to a minimum and if that means having redundant circuits on some boards, so be it. I do have a tendency to over engineer a solution.

The question you need to ask yourself is this:-
"Do I want to save x pounds and endure the high stress / pressure fix up at the exhibition site when I arrive and discover that something has broken?".

The other plus for the redundancy approach is that the accessory decoders will always be reusable in a future project. Solid state electronics has a long life span.

I think your final solution will involve a mix of redundancy and some additional board interconnects - it's economics.

David
Hi David thanks for that. I tend to agree and that is what our aim has been to keep the connections to a minimum. I think in the interests of piece of mind and reliability partial redundancy is the option it is just a matter of then finding the right decoders for the job be they 2 4 or 8 functions. I think we have had quoted prices of around £11 per point not including the point motor as a guide to what is should cost.

Chris
 

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>I think we have had quoted prices of around £11 per point not including the point motor as a guide to what is should cost.
That's probably about right for commercial stuff though I think the Lenz LS150 comes in at less than that /but/ you may need to get a beefy power supply to go with it if you are using Peco solenoids. There have been a few threads on this Forum about getting LS150s to drive more than Peco solenoid at a time - <cue Wiggy....>

Having completed my first control panel, I have finally admitted that I am a Point-aholic. There are 34 of the things which means saving 3 or 4 pounds a point is worth doing, and that's before I get to the other three panels that the layout will need by the time it is completed. I've had a close read of the MERG website and decided that their stuff is worth a try, so I've joined up and will be trying out a couple of their kits over the summer. Accessory decoders are not nearly so complex as loco decoders, so there's no reason why the MERG stuff should be every bit as good, apart from the fact that I will be the one putting them together.

David
 

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I have just been experimenting with the Team Digital SMD8 (forerunner of the SMD82) and using it with both PowerCab and PowerPro systems. It works a treat with both and can control 8 point motors of various origin (the type for each output can be defined in the SMD8 setup). It is possible using the NCE to change each point individually or set up a macro to define routes.

Wiring is a doddle - power comes from the track bus. On our demo layout I have used an Express Models DCC wiring kit, so no soldering of connections into the SMD8, just crimped on to the bus. I have experienced no power problems with switching Peco point motors of the SW type.

At £52.00 for 8 outlets this is considerably less than the £11 per point motor discussed earlier.

Regards

John R
Bromsgrove Models
 

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Discussion Starter · #13 ·
Thanks for that guys. I am going to see what the others at the club make of the MERG kits but I am interested in the SDM's as well. John what is the difference between the SDM82 and the SDM8 apart from price? I think they would be ideal except for the added problem of wires having to be joined at the boards. We really are trying to avoid having to have more wires across board joints than we have to. For example if we had the SDM of either vairety and we had two points on one board and six on the other that would require the wires from two point motors going across to the other board to the SDM which means more connections to go wrong. I appreciate the power bus provides the power but the individual points have to be connected to the decoder don't they?

I have sort of volunteered to sort this out before we jump in and make our choice/purchase so would like to get it right in my head before I go to the club and present my findings.

Chris
 

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I don't have any of the newer SMD82s in stock, so don't have one to compare. However, looking at the manual, one of the main physical differences seems to be the connectors on the board that link to the points - on the newer SMD82 these are screw terminals, on the SMD8 they are 4 x RJ12 connectors. In some ways the RJ12s are better as they are more robust - they use 6 core telephone cable, with 3 wires to each point motor. You could actually use this structure to link boards together using RJ12 connectors and the NCE UTP panels - would make linking boards quite straightforward.

Regards

John R
Bromsgrove Models
 

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QUOTE on the SMD8 they are 4 x RJ12 connectors. In some ways the RJ12s are better as they are more robust - they use 6 core telephone cable, with 3 wires to each point motor. You could actually use this structure to link boards together using RJ12 connectors and the NCE UTP panels - would make linking boards quite straightforward.

They sound like just the thing for Mark's 6+2 scenario. I would put RJ12s at the point motor end as well and then make up individual cables for each point from the SMD8. To move the layout, disconnect the cable from each end, (label it!), stow it a box, and travel to site safe in the knowledge that nothing is going to get broken; just lost
. All you need is some kind of cable trunking / clips to keep it tidy when installed.

David
 

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Discussion Starter · #16 ·
QUOTE (BromsMods @ 28 May 2007, 15:16) <{POST_SNAPBACK}>I don't have any of the newer SMD82s in stock, so don't have one to compare. However, looking at the manual, one of the main physical differences seems to be the connectors on the board that link to the points - on the newer SMD82 these are screw terminals, on the SMD8 they are 4 x RJ12 connectors. In some ways the RJ12s are better as they are more robust - they use 6 core telephone cable, with 3 wires to each point motor. You could actually use this structure to link boards together using RJ12 connectors and the NCE UTP panels - would make linking boards quite straightforward.

Regards

John R
Bromsgrove Models
Now we are talking John! That sounds like just the kiddy for us. We will be using them to connect the NCE daisy chain panels together anyway so a couple more wouldn't hurt and as David says not difficult to keep tidy and up out of harms way. Still need 4 SDM's though!
Chris
 

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QUOTE (dwb @ 28 May 2007, 15:26) <{POST_SNAPBACK}>They sound like just the thing for Mark's 6+2 scenario. I would put RJ12s at the point motor end as well and then make up individual cables for each point from the SMD8. To move the layout, disconnect the cable from each end, (label it!), stow it a box, and travel to site safe in the knowledge that nothing is going to get broken; just lost
. All you need is some kind of cable trunking / clips to keep it tidy when installed.

David

What's the cable thickness on RJ12s? You generally need a thick cable for solenoids, not so much due to current capacity but to minimise the voltage drop when they are at the far end of a cable run. Might be worth trying one from your chosen decoder through a couple of metres of your chosen cable before you spend a lot of money or effort on it!
 
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