R8247 points decoder

[Paul B1707821924]

Hi guys another newby question - I have my track layout and surface point motors (8) wired up - to Select module - track and locos all work fine - I have a R8247 decoder which Ive programmed the first block of 4 as per the select unit operators manual (ie 61-64) and all 4 switch no problem - then disconnected them then connected the next block of 4 and programmed them to 65-68 all work no proiblem - now when I connect all 8 in the 4 separate outputs only the last 4 programmed work - Ive looked in the manual and it says the select is 'capable  of operating up to 39 points  ... when used in conjuction with R8427 decoder module. The point decoder can operate up to 4 points  etc'. So does this mean I can only operate 4 points at a time with the select and R8247 decoder and if so would it be better to get another decoder - or operate all the points via DC and passing contact swith and bin the R8247 - the cost involved is greater (around £90-100 as against 45) for the passing contact switch element bearing in mind I already have on-on switches for R406 signals with a DC supply - or am I doing something wrong phew - thanks in advance

[Chrissaf]

I think you have got a complete misunderstanding of how you use the R8247 accessory decoder and point motors.

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The R8243 surface mounted point motors are not programmable electronic devices, all they contain is a simple magnetic solenoid coil that operates a soft iron slug back and forth inside them to physically operate the point.

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When you attached the first four point motors to your one and only R8247 decoder and programmed the addresses 61 to 64. You are only programming the physical ports on the R8247 itself, not the point motors.

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It sounds like you disconnected those four point motors and connected four fresh ones, then re-programmed the same R8247 to addresses 65 - 68.

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All you have done, is over-written the four original addresses you set (61  - 64) with the new 65 - 68 addresses. Thus it is no wonder that the original 61 - 64 addresses are now non functional.

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Each block of four point motors needs its own dedicated physical R8247 Accessory Decoder.

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Such that:

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The  1st Physical R8247 is configured as 61 - 64

The 2nd Physical R8247 is configured as 65 - 68

The  3rd Physical R8247 is configured as 69 - 72

etc

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Regarding your comment:

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I already have on-on switches for R406 signals with a DC supply

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You cannot use on-on switches to operate points. You have to use a 'passing contact' switch which is something completely different. The Hornby 'passing contact' switches are very expensive for what they are, plus they are not 100% compliant to work efficiently with any CDU that might be installed.

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Regarding your comment:

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Ive looked in the manual and it says the select is 'capable  of operating up to 39 points  ... when used in conjuction with R8427 decoder module.

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This should read:

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".. when used in conjuction with R8427 decoder modules."

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"modules" in plural meaning more than one.

39 point motors needs up to ten R8247 Accessory Decoders to support that number of point motors.

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[Paul B1707821924]

Thanks - yes I priobably do have a misunderstanding -as Im pretty new to this game  but when you read the bumf in the manual it 'mplies' that the decoder can operate 39 solenoid accessories - I assumed, wrongly so - that this meant all at once - QPQ select 61 and switch - select 67 and switch - obviously not so

OK I understand now that I need  another decoder - which is less expensive and more reliable than using my DC supply with contact switches

In the comment that I already have on on switches it was just to indicate that I have a DC power supply to power any contact switches as required i got these after another question previously regarding the use of the Select to change the R406 signal lights - so I obtained a guagemaster dc supply and the yellow on on switches - these too are expensive as you say 

The manual perghaps should read modules but doesnt - says module - hence my assumption

Thanks for your help - Im sure there will be more questions - now off to get a new R8247

[96RAF]

There will definitely be more questions if the R8247 he gets is a Rev 2 version with Special Modes.

[Paul B1707821924]

I already have the Rev 2 version - does this make a difference?

[Chrissaf]

Not really.......The Revison 2 R8247 has more configurable capability for more advanced users. It still does the same basics that the original R8247 does. And you would need a Select with firmware revision 1.6 or above to make use of these advanced features.

[96RAF]

Rev 2 version of R8247 should be set to Standard Mode as default.

As Chris says to get the best out of the thing needs a controller than can write to CVs.

[Chrissaf]

I assumed, wrongly so - that this meant all at once - QPQ select 61 and switch - select 67 and switch - obviously not so.

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Yes.... the Select can choose any point address you like between 61 and 99. Thus the Select can handle the whole range. But as to how many of the addresses actually work is down to how many Accessory Decoders are connected to the Select and are configured with the addresses in that 61 to 99 range.

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• Let's say you want to operate the point connected to DCC Address 67 (Port 3 on Physical R8247 number 2).
• The Select sends out a broadcast Data Packet with the target DCC address 67 in the data packet header.
• Since this is a broadcast, ALL decoders and I mean ALL (locomotive decoders as well as accessory decoders) are listening to the stream of data coming out of the Select controller.
• The Physical R8247 number 1 (configured with addresses 61 - 64) hears the data packet addressed to 67, but ignores it because 67 is not one of its configured port addresses.
• Meanwhile the Physical R8247 number 2 (configured with addresses 65 - 68) also hears the same data packet, but this time recognises the 67 DCC address in the data packet header as being an address it is configured to respond to.
• So Physical R8247 number 2 implements the command that is also included in the main body of the data packet. In this case, the command is to operate the point attached to port 3 (DCC Address 67).
• Also note that ALL the locomotive decoders also hear this DCC Address 67 broadcast data packet, but ignore it because DCC Address 67 is not their configured DCC Address and the data packet format is not constructed as a 'loco' data packet type**.

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Note**: The broadcast data packet also contains data to tell the decoder whether the DCC packet is meant for a locomotive or an accessory decoder. This is why many controllers (but not the Select) can use the same address for both locos AND accessory decoders.

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For example, if using the Elite, you can have DCC Address 03 as being a loco, and the same 03 DCC Address can also be used with an accessory decoder.

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When you are entering the address on an Elite you have additional loco or accessory buttons to press to tell the Elite what kind of DCC address you are entering. So that the Elite can construct the appropriate kind of data packet format. A 'loco' data packet format or an 'accessory' data packet format.

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There is no equivalent buttons on the Select, so the Select uses the assigned addresses themselves to decide what kind of data packet format to construct and send to the track...... 01 to 59 for locos and 61 to 99 for accessories.

[HH]

@chris

You seem like a v knowledgeable guy - would love some help?

I'm trying to help my 80 year old dad with his points decoder.

So he connected 2 decoders 1-4 and 5-8 - all 8 points work. He has then tried to connect 2 more decoders 9-12 and 13-16 and the rail master won't recognize them but you can assign them the numbers but they and they then won't work. I'm not sure how to help him, is it a V1/2 issue? 3 and 4 are def V2.

I'm sure we are doing something wrong. Would love some help, please.

[Chrissaf]

The revision 2 R8247 is yet to be fully integrated into RailMaster. But the outstanding integration only affects the advanced features of the R8247 V2 product. The current RailMaster will still work at the basic level with version 2 R8247s.

For basic Solenoid operation with addresses 9-12 and 13-16 the normal R8247 V1 methodology will still work with V2 R8247s as well.

Here is a full 'step by step' tutorial for setting up R8247's [written for the V1 version and V2 compatible for basic Solenoid point operation].

https://uk.hornby.com/community/forum/programming-accessory-decoders/?p=1/

Note however that this is a historical post from the old forum. We are still waiting for historical images to be transferred across from the previous forum servers [owned by and located in a different hosting company premises]. So the link above leads to a text based tutorial currently devoid of images, but there still should be enough information in the text to assist with the correct configuration methodology.

[Brew Man]

I must say when I was starting up I looked at all this and decided to stick to DC for my points and other accessories while using DCC for loco operation. I found DCC for accessories quite an expensive option, what with the cost of the decoders at around £50 a throw and besides, isn't it nice to pull levers and press switches?

[Fishmanoz]

Chris, given HH seems to have already managed to program a second decoder to 5-8, it would seem he already knows how to program 8247 addresses. He should then be able to use the same procedure to successfully program the 3rd and 4th decoders to group addresses 3 and 4. But I could be wrong.

HH, to check if you have simply failed to program the 3rd and 4th decoders, and given you still have them all wired up to the track, what happens when you throw point 1? Is this point the only one to change, or perchance do points 9 and 13 throw as well? If so, you haven’t actually programmed the addresses you want. They are still on default points 1-4. Then Chris’s instructions will help.

If they fail to throw any point, it would be best to reset them by writing 8 to CV8 on the programming track, assuming your controller can write CVs. Then start again using Chris’s instructions.

[Chrissaf]

Fishy,

He said he is trying to do it for his dad, thus there is no evidence to conclude that he did the 5 to 8 decoder. It may also be that his dad never did the 5 to 8 decoder either. It might have been done by anybody.

PS He is using Railmaster. He says so in his post.

[96RAF]

Two things here HH.

First is programming the physical modules using RM.

Secondly each point on the track-plan needs to be told which port on which module it has to operate.

The first bit you do by connecting each module in turn direct to the RM controller PROG terminals and using the point and signal icon give them their required addresses.

The second bit you do in Design Mode (set-square icon) having called up your track plan. Right click on each point in turn and fill in the details of the port you will use to operate that point.

[Fishmanoz]

Oops, apologies for missing the “rail master” reference.

My suggestion still confirms if any programming of the 3rd and 4th 8247s has taken place or if they are still on default addresses when tried in conjunction with Rob’s RM configuration suggestions above. You can configure 8247s until you are blue in the face but the points will only operate if you configure the point setup to match the 8247 address.

[Chrissaf]

My original first reply. Provides a link to my 'Step by Step' tutorial for setting up R8247s using RM. The tutorial includes both the actual programming process on the 'programming track' as well as the configuration of the points on the RM track plan to operate the points thereafter.