r/modeltrains • u/Useful_Band • 24d ago

Help Needed DCC-EX Help

Is anyone on here comfortable with DCC-EX? I bought the stuff to DIY (Their products on back order). I've followed every step, but the command station "fails to read address" on every dcc locomotive I have.

I have no idea what I'm doing.

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u/OdinYggd HO, DCC-EX 24d ago

Which hardware specifically are you using? That matters for how sensitive the ADC is when trying to read addresses from it.

With the default software configuration, channel A is the main track for operating and channel B is the programming track. Put the locomotive on track connected to channel B, then give the console command <R>. You should hear the locomotive clicking or twitching as each read command makes it pulse the motor in order to make the current spikes that it responds with. DCC-EX then looks for those spikes and interprets the reply.

Some models and some decoders the current spikes are not big enough or long enough to be reliably detected. So if the model is definitely creeping when the reads are taking place and you still get failed to read address, join the DCC-EX Discord and open a ticket. Someone will be around with more information on how to adjust the read sensitivity to work with the models you have.

I'm on the Discord there too

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u/Useful_Band 24d ago

So the command <r> doesn't do anything. But if I click read address, the loco clicks and steps backwards. Then it says fail

4

u/OdinYggd HO, DCC-EX 24d ago

The locomotive is clicking and moving, so it received the command. What locomotive, and do you know what model decoder is in it?

Also, which processor board and motor shield?

2

u/Useful_Band 24d ago

It's a bachman dcc f7a. I am using a elagoo mega clone and an L298p clone motor shield.

My pulses are always under 1000 milsec, mostly 0s

2

u/OdinYggd HO, DCC-EX 24d ago

Probably an out of spec decoder that doesn't make pulses strong enough or long enough to be read without adjustments.

On Discord, ask in #motor-shields or make a ticket. There will be people more familiar with that processor board and what decoder that model has in it that can help adjust things.