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Programming/CV Read Error


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hi

given prior success and friendliness of people responding to queries, I was hoping someone could help here

when I ask railmaster to read cvs, it is telling me all cvs are 255.  From searching the site, that suggests that there is some sort of connection error.  Given trains are running fine, I'm not sure how that can be.  Equally, I've checked and rechecked the programming wires are in the correct terminals.  Any ideas / other suggestions on how to fix?

thanks

david

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hi

given prior success and friendliness of people responding to queries, I was hoping someone could help here

when I ask railmaster to read cvs, it is telling me all cvs are 255.  From searching the site, that suggests that there is some sort of connection error.  Given trains are running fine, I'm not sure how that can be.  Equally, I've checked and rechecked the programming wires are in the correct terminals.  Any ideas / other suggestions on how to fix?

thanks

david

David,

Are you using a separate programming track connected by wires to the programming output terminals of your controller? What type of controller are you using?

Ray

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Thanks Ray - I'm using elink plus laptop.  I take all locos save for one being programmed off the track as I've not built a separate programming track yet.   i simply switch the wires into the programming terminal of the elink 

david 

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How are the wires connected to the track? Make sure you don't have any non-DCC power connectors attached. Try taking the Pullman coaches off the track when reading cvs. Do you have any accessory decoders connected to the track? I would strongly recommend getting a spare piece of track to use as a programming track, rather than switch the wires from your main layout.

Ray

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You really should set up a separate programming track for the best chance of success.  It doesn't have to be a large complicated setup, just a single short length of track such as a  R600 with a R8242 power clip will do, or a R8241 digital power track is all that's needed.  Alternatively you can solder the programming wires directly to the rails of a plain piece of track instead.  It doesn't need to be a permanent setup either, once you've done the programming it can be disconnected from the elink and put away until you next need it.

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I have seen this problem before, AND unlike you, I use a separate programming track piece.

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My workaround solution is to disconnect my wires on the controller going to main layout track output. Leaving JUST my programming track piece connected to the programming output of the controller.

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It's only a theory, but I believe the programming output is a very low power signal and it does seem to be affected by any noise / interference present on the main track output. Disconnecting the main track from the controller works for me and I can now read CVs correctly that previously returned 255. Maybe it will work for you too. It does mean that you will have to bite the bullet and use a proper programming track piece and not your main track for reading / writing CVs.

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I would really urge you (as others have also recommended) to use a separate programming track piece. It doesn't have to be sophisticated. I use an off-cut length of flexi-track with two short wires (600mm) soldered directly to each rail. The two short wires then connect to the programming output of the controller.

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Thanks Chris / Ray/ RJ

have followed advice and set up an independent programming track.  To be honest, i'd not particularly seen the point before.  have now managed to get non-255 values. 

strikes me as odd though that it works when you do that but not on the main track.  I can't see electrically how it's any different

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Pleased to hear that you've made progress.

 

We could speculate forever as to why it works on a separate track.  Maybe the main track has more capacitance between the rails or induced voltage from nearby electrical equipment, we'll probably never know.

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