DJ's Trains posted:Adrian! posted:Sorry folks, it’s not good yet. The smaller/shorter dcs commands (whistle and stuff go unnoticed) but the moment you ask to “add engine” all the tmcc/legacy trains stop on their tracks.
im going to modify the board so it switches the legacy carrier to a reduced amplitude instead of a hard off....
That's disappointing. I have good and bad days on the SD3R layout. Tried running my MTH PS3 engines there on New Year's Day. Ran fine for a couple of hours and then the simple commands stopped being executed by the engines (setting the speed, direction change, whistle, etc.), I had no problems adding the engines. The only way I could stop the trains was by cutting the track power. In some cases, if there was no response to commands, about 15 seconds later, all the attempted commands would be executed at once, like they were being queued up and then dumped. Weird. I had to pack up my stuff and go home since the system became unusable.
I do have one question for you Adrian. When SD3R switched from four TIUs to one TIU, they connected the single unit up in passive mode (as opposed to running the track power through the TIU). I read that a passive connection has weaker signal than and active one. Would going back to an active connection for the TIU improve the signal or is the difference inconsequential? I know you provided a new TIU and supporting protection electronics for the club, but I don't know how you have it wired.
Thanks again for all your help!
Hi there,
We did look at this for our club (active vs. passive) and the results are in this post from before. As long as you have the power source choked off (like in the panel I gave you) , the signal strength is pretty much the same active or passive. Without the chokes it can be pretty bad (maybe 35% loss of amplitude)... but you definitely have them on that panel. In your SD3R club we measured mostly 10-12V signal excursion on the tracks which is about as good as it gets.
Also the talk of 4 TIUs being better for signal strength I've heard floated is definitely not correct. If you watch the signals on the TIU outputs they take turns 1 at a time. First TIU 1 sends signals, then TIU 2, ... and so on, so the signal strength is identical to a single unit since only 1 is turning on at a time. The only good reason to goto multiple TIUs is if you have too much track (think NJHR scale) building up too much capacitance.
However since it has to do a for loop like:
for(TIU=0;TIU<6;TIU++){
do_command;
}
It means adding engines and reads take a lot longer, especially on the app.
If there's good and bad days then maybe something else is changing? I heard you guys are getting a scope so you can track signal quality day to day. That might expose some time-varying issue. I have plans to modify GRJs booster further with a TTL multi-level output select, but our club has other pressing issues so that will be later in the year.
