So your not setting the variable channels to fixed? You have them set to variable with the start set high?
You lost me here.
Yep that's exactly what I do. Here's my startup procedure:
1) use remote out let control to turn on 120v power for the layout. The TIU, WIU, PH180's, Accessory Transformer all turn on at the same time.
2) if using the WIU, wait 45 seconds for for the unit to boot up, connect to the TIU and transmit WIFI signal.
3) open app or use remote to advanced VAR1 and/or VAR2 from 0 to 21.5 volts and then advance to 22 volts for max power.
4) Have fun running trains.
I like using my variable channels this way because now I can cut power to one or two tracks without shutting anything down. Cut the power to the outside track, switch out an engine and then turn the power back on with my remote or app from right where I was standing, the inside track keeps running, and I don't have to go to a transformer or brick to kill the power or turn it back on.
Derailment situations are a bit interesting with the TIU like this. In the event that a breaker opens with the PH180, I'll command the TIU to set the power to 0 volts before I reset the breaker. That doesn't work, Even the though the remote or app says 0 volts, the TIU applies max power from the PH180 after resetting the breaker and all of my engines will miss the watchdog. At this point I have two options, I can zero the power to the track again, the TIU obeys and the engines go through a shutdown sequence, or I can use DCS to shut each engine down and restart to operate with DCS mode.