R8247 Points Decoder cofiguration

[Roger-1227646]

Hi there,

We have been building a layout for the first time so are complete novices as far as configuring the points decoder and would be grateful for an advice you could give / help.

We have 5 PAD's with 20 points connected.

We intended to use them in Standard mode with the point address's being from 1 to 20 so nothing complicated there.

The first 3 decoders work fine with access to points 1 - 12

The last two failed to work! We did try to work out if in fact they were trying to access other addresses's but failed there.

I looked at cv33 for both of them and it gave 255. I changed it to 0 and then checked and guess what it showed 255 again.

On decoder 4 I looked at cv513 and that was 255 so tried to change that to 4 (or 5 for decoder 5) but on checking it showed 255. The same applies to CV1.

Out if pure interest I looked at cv9 and yes it showed 255.

Any words of wisdom would be gratefully appreciated.

regards

Roger

[Chrissaf]

What DCC controller are you using?

Note that the R8247 can be factory reset by writing 8 to CV8.

I suggest a factory reset and start again from the beginning.

[Roger-1227646]

Hi Chris,

The DCC controller is an Elite running the latest F/w

I will try the reset later

Many thanks

Roger

[Fishmanoz]

Three things Roger:

• readings of 255 indicate that CV cannot be read, not that it contains a value of 255
• default these decoders come with addresses 1-4. So if you try to program other addresses and fail, they will still be on 1-4. That’s also a good reason to not use 1-4 in your setup. Sometimes decoders lose their programming and revert to 1-4 (without writing 8 to CV8), with this a possibility after a short circuit on the layout. If you then switch one of the real 1-4 points, you may accidentally operate others with unexpected results
• are any of your points operated in pairs as crossovers etc? If so, you can usually operate these on the same address connected to the same decoder port. This will leave you with free ports for future expansion. It is a fact of railway modelling that any and all layouts with 20 points will soon have at least 21, probably more.

[Roger-1227646]

The plot thickens. by trying various combinations of cables to ports on the 2 decoders it appears that each has 1 faulty port.

On trying to use the port you get a cv reading of 255 whereas the others reset and configure ok.

Returning them to Amazon today.

Many thanks to everyone for their help with this problem.

[96RAF]

There was a bug in the Select firmware v1.1 that damaged R8247s by inducing relay flutter. This flutter only happened when port 1 was selected, hence after a reset if ports 2, 3 or 4 were selected all was well, but as soon as port 1 was selected it all went belly up, requiring a further reset. Unfortunately such flutter could cause fatal damage. Often these damaged acc decoders turn up on eBay as new, but in reality scrap.

When programming addresses into an R8247 (any version) if you connect a solenoid to port 4 and set it mid travel, when programming has completed the motor will click over indicating success. The reason for setting mid position is you do not know which direction of throw it is wired to, so mid position uses either way.

[Roger-1227646]

Gentlemen,

My thanks to everyone for all their help with my question.

The 2 new decoders arrived and were programmed OK and all is working.

Again many thanks

Roger

[96RAF]

Good to know Roger - thanks for the feedback.