DCS Operation In Passive Mode

If you have four power districts, why do you need four TIU's?  That gives you sixteen DCS signal outputs.  You can't parallel the outputs to get more signal, so unless you have sixteen separate power districts, I'm not sure what you'd do with the four TIU's.

 

FWIW, we're currently running our modular club layout in passive mode with a Rev. L TIU.  It appears to work as well for us as active mode, but we still have some work to do to get reliable operation.

 

All the channels can output the DCS signal, we're using all four in passive mode.

 

Any power supply that will supply roughly 18 volts at 1.5 amps will work fine.  Barry's book also suggests a 1A Radio Shack supply at 18 volts, so that current capability is somewhat flexible.  A 50 watt MTH brick would be ideal, it comes with the proper barrel connector to connect right up.

Regarding AIU operation, Yes.  The AIU is only a series of relays and it is the communication between the remote and TIU that operates it.  I am supposing you will have a DCS remote.  FWIW.

Gunrunner, Thanks for the info.  I was thinking that if I wired in a star pattern the length of wire from the TIU to the track could not be longer than 30 feet.  (I thought I read that but I've read so much about control systems I may have it mixed up).  I thought that I would need to place the TIU's somewhat evenly around the layout to keep the signal strength high.  

 

The layout is kind of long going around and through some walls.  If I run one TIU and use the four outputs, one to each power district, would the signal be too weak?

 

Angelo

 

 

I think remote / tiu range might be a bigger problem. That's why we have 4 tiu at different locations in a 80 foot long room . You can probably get the dcs signal with 1 tiu and  4 tiu channels however 2 tiu in different locations would be much  better in my opinions.... keep the remote range in the back of your mind when you start to wire.  it can vary whether pointing the remote directly at the tiu, whether the tiu is located above or below the layout. etc.

No switching lead!

Another thing to keep in mind.  The remote communicates directly with the TIU.  So, even if you scatter them around, that won't help the remote to TIU link, if one TIU is too far away from the remote, you'll have trouble talking to it.

 

My personal opinion is that you'll probably be better off keeping the TIU's somewhat centralized as much as possible, and certainly not scattered into other rooms.

 

If you have Barry's DCS O Gauge Companion 2nd Edition book, some good wiring guidelines are on page 55-56.

 

I think trying to "double up" on power is probably a mistake.  I'd create smaller power districts with the plain 180W brick powering each TIU channel.  Given the suggested maximum of track blocks not exceeding 100 feet, I think your layout may exceed that for some of the power districts.  I'm also wondering why you don't dispense with the TPC's and just use the TIU to handle the power.  Are you trying to offer conventional running?  If so, you have two variable channels on each TIU.  360 watts of power on a single track feed is into small welding capability, I like to keep individual track feeds to 10A maximum.

John,

That's more like 33 feet/track block and 350 feet per channel (Rev. L TIU).

Hmm...  I guess I didn't see that the Rev. L had a separate specification.  Where is that mentioned in your 2nd Edition?  I looked all around in that section and didn't see it. 

 

OH, I see it, I did my math wrong!  You're right, I got confused about tracks and blocks.

 

That makes his issue easier to solve.

Thanks for the info Gunrunner John. I've got a lot of planning to do and everyone’s help here on the forum makes understanding and planning these control systems that much easier!

 

Barry, Your book is an excellent source of information!

 

Rich I will make an attempt to incorporate a switching lead.

 

Gregg thanks for the tip, I’m going to plan on mounting the TIUs slightly above the layout.