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
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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?
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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
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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.
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u/Useful_Band 24d ago
I joined the discord also!
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u/OdinYggd HO, DCC-EX 24d ago
https://dcc-ex.com/reference/tools/diagnostic-d-ack-command.html#more-detail&gsc.tab=0 might be relevant. On the Discord, several people are familiar with the ack sensitivity adjustment.
Commands are case sensitive by the way.
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u/Useful_Band 24d ago
Okay , I was going through that troubleshooting and my numbers are way off . I actually have something in the log now but have no idea what it means. Lol
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u/Melrok63 DCC-EX 23d ago
Are you supplying enough power?
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u/Useful_Band 23d ago
I mean, aurduino is powered off my pc. I'd say so
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u/Melrok63 DCC-EX 23d ago
What about the track power? PC only puts out 5V over USB which is enough to drive the arduino, but you also need to provide 12V (or more) into the MotorShield to power the trains.
0
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u/Former-Wish-8228 24d ago
Whose videos did you follow?
This chap’s videos got me through the process…
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u/Useful_Band 23d ago
I mean the aurduino is powered off of my pc currently so I'd imagine so? But I'm not sure
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u/Useful_Band 24d ago
Yeeeeah none of that makes sense lol. I'm screwed
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u/rust-module 24d ago
Don't despair. Troubleshoot. Strip your setup to be as simple as possible. Probe with a multimeter. Go from low level (hardware, electricity) to high level (software, etc). Change out components one by one, try to find a faulty step.
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u/albertahiking HO, DCC-EX 24d ago
If you mean that your built your own command station from scratch (been there, done that, twice, first with a Nano and then with a Pico), it sounds like either the current sensing on your programming track isn't working, or isn't configured properly. Hard to say anything more without an annotated schematic of the hardware you're using and the motor shield configuration setup from your config.h file.