Hi, everyone,

I am a new user of the DCS system having started to set up one week ago.  I have three loops of track each utilizing separate DCS outputs. Track 1 and 2 use Fixed outputs, respectively.  Track 3 uses Variable/Fixed output 1 (set as Fixed).  The outside rails are connected together at the feed points.  The trains run as expected … no issues.  All three tracks have two short isolated sections for signal control.  Track 1 and 2 do not change the signal at either isolated section.  The signals remain green.  Track 3, however, properly controls the signals, cycling from green to red as the isolated section is entered and changes to red (through yellow on a timer) back to green when the train clears the section.  The signals are controlled by relay boxes, one relay per signal. 12 volts A/C  powers the relays being converted to DC for the relay coils. This system is several years old and has worked flawlessly for all the signals (conventional mode).  I have bench tested the signals and all work properly. The only change this year is the introduction of DCS for train control.  I have spent several hours this morning researching this forum and also searching the Internet for clues.  I can find many references to isolated rail and signals but none to address this problem.  I apologize for the length of this posting but I believe the more info you have, the greater the chance to help with the issue. Thanks for your help.

Buzz 

Original Post

I'd say there has been an unnoticed  wiring change somewhere. Running the track power wires from a transformer or the TIU should not cause two of your signals to quit functioning while the third still functions correctly. An image with wiring diagram would help troubleshoot the issue.

Hi,

Thanks for the comments, I have retraced all the wiring for the tracks and the signals and all is okay.  I did put an ohmmeter between the output of one of my transformers (z1000 brick) to verify that the ground I was expecting at the outside rails was indeed the same.  It was not.  The Variable/Fixed outputs are, indeed, the same, but there is no physical connection between the negative (it's the one not marked "hot") output of the transformer and the black outputs of Fixed 1 and 2.  That's my problem.  I checked the cantilever signals and they work properly … of course, on the work bench with the ground that the signals are expecting.  I am open to any and all suggestions to fix the signals, short of returning to conventional mode.  Thanks, again.

Buzz

The ground outputs of the TIU are not wired together internally (i.e. Fixed 1's ground terminal is not connected internally to any other outputs ground terminal). The ground outputs are only connected to their respective inputs. You can just connect all the ground inputs of the TIU together and all the ground outputs of the TIU together and you should be fine. I have a common ground for all my track. I use Fixed 1 and Fixed 2 on my TIU. I've connected the Fixed 1 and Fixed 2 inputs ground to each other and the Fixed 1 and Fixed 2 outputs grounds to each other without issue.   

Santa Fe, All the Way

Hi, Lou1985, sorry for the delayed response ... had some home projects to do.  Thanks for telling me that I can connect the fixed input/output grounds together ... may make the difference.  I'll see if that makes a difference.  Happy Holidays!  

 

Buzz

 

Add Reply

Post
The DCS Forum is sponsored by
OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
330-757-3020

www.ogaugerr.com
×
×
×
×
×