Wiring TIU for both fixed and variable

Tim,

Is there a way to wire the TIU and switch between fixed and variable without always having to move wires on the TIU?

Sure!

 

Just connect your transformer output to both TIU Fixed Channel #1 and either of the Variable channels. Then, connect the Variable channel output to the tracks.

 

Use the following to toggle between Fixed mode and Variable mode on the Variable channel:

• Prees Menu/System/DCS Setup
• Select the Variable channel
• Press the FXD soft key.

The first time you press FXD the channel will be set to Fixed mode. The next time it will be set to Variable mode, etc.

 

This and a whole lot more is all in "The DCS O Gauge Companion 2nd Edition", now available for purchase as an eBook or a printed book from MTH's web store site! Click on the link below to go to MTH's web page for the book!

CNJ Rail,

  No you would need to change the wiring as Barry indicates, or you can use the Z4K with the side receiver to run your conventional trains thru the DCS hand held remote.

As Barry says all this and more is spelled out in his DCS O Gauge Companion book.

Rich also talks about it on the OGR DCS Video Guide. 

PCRR/Dave

Dave,

No you would need to change the wiring

Not exactly.Please se my post above.

Barry,

   I get ya, but he will not be able to run conventional and P2 at the same time, on the same track that way.  Or am I mistaken.

PCRR/Dave

For DCS and TMCC you can use all 4 channels. For conventional you can use all 4 channels with caveats. The variable channels can be controlled via the handheld. The fixed channels can be controlled via the handheld by using a Z-4000 with a side receiver.

 

Too run conventional without a handheld and only using the throttles on any transformers you would need 4 throttles. All 4 TIU channels would be set to fixed.

When doing this the TIU must be powered via the AUX power port instead of fixed 1. This is what I do on one layout even though I have 2 Z-4000s powering the 4 TIU channels. Conventional and throttles go together for me.

 

Running conventional and command on the same track at the same time is difficult because most conventional engines fly at command voltages. Running TMCC and DCS on the same track at the same time can be done easily.

Dave,

I get ya, but he will not be able to run conventional and P2 at the same time, on the same track that way.  Or am I mistaken.

Yes, he will.

 

The only real difference between TIU Tracks and Z4K Tracks is where the voltage is actually modified.

 

With Z4K Tacks, the voltage is adjusted in the Z4000. With TIU Tracks, it's adjusted in the TIU.

Thanks for the fast responses. Barry, if I am understanding you correctly, the pair of wires going to the fixed terminals are powering the TIU and the wires to the variable are controlling the engines. Changing the setting between fixed and variable will change how voltage is applied to the variable channel.

 

With this type of setup, will the amperage being drawn by the engines be going through the variable channel regardless of DCS or conv. being run? The fixed terminal will only have the draw to power the TIU?

Thanks,

Tim

Without use of AUX power the TIU is powered by fixed 1.

Changing the setting between fixed and variable takes the TR button on the handheld out the the equation. In fixed mode the same power that goes into the variable channel comes out. In variable mode the output to the track from a variable channel is controlled via the handheld using the TR button.

 

The variable channel should be set to fixed in 2 situations. When running command engines through a variable channel. When controlling a conventional engine via the throttle of the input transformer. If not set to fixed the TR button needs to be used to put power to the track.

Tim,

With this type of setup, will the amperage being drawn by the engines be going through the variable channel regardless of DCS or conv. being run? The fixed terminal will only have the draw to power the TIU?

Amperage through the Variable channel is a function of what's on the tracks drawing amps.

CNJ, it is not necessary that you use the fixed for DCS and the variable for conventional.  DCS just runs just fine on the variable.  On my layout, which has two TIU's, I use two fixed circuits fed by a Z4000 which has the remote receiver so I can control the Z4000 output voltage from the DCS remote & don't need to use the handles, and four variable circuits.  Any locomotive can run at any location on the layout at any time, be conventional or DCS.

 

if I want to run DCS, I simply set the variable channel for a voltage output adequate to run the trains, or, as Barry noted above, set them to fixed.

 

I can run both DCS and conventional on the same track at the same time, so long as I have the conventional train heavier than the DCS train, but once you get used to DCS, you'll find that's not fun.

Thank you all for the great responses. I am again reminded to how helpful this forum is and how versatile the DCS system can be.

Tim

RJR,

  Roger that.

PCRR/Dave

You can but it's  a bit of a pain... Use the TR button  on   var channel to run conventional. To run ps -2  on the same  var channel  just press ENG.. you can switch back and forth between TR and ENG....  But why???

Greg,

  Because I have an original Conventional 263E Lionel and a P2 MTH 263E that I like to control on the same track at the same time from the DCS hand held remote.

It was my dream as a child to be able to run in this manner, and now it can actually be done.  My Grandfather told me that I would live to see it happen and I like to see them both controlled at the same time, on the same track.  Engineering is a fantastic professional Career, I have incredible memories from a brilliant man that are part of my O gauge train family traditon.

PCRR/Dave

 

My O Gauge trains are more than just toys to me, they are my most cherished family memories.

I belive Tim stated in his 1st post that he would NOT be running DCS/TMCC and Conventional at the same time. Why add confusion? Toggle between Fixed and Variable with the DCS remote to run 1 mode at a time as you choose.

Laidoffsick,

  Education is often times confusing, but useful.

PCRR/Dave

I don't plan on running DCS and conventional at the same time but it is nice to know I can. I was more concerned with wiring the TIU in a way to be able to run both without moving/switching wires to do so.
Tim C

. Yes you could toggle between  FXD and VAR using Menu/System /dcs set up/ every time you wanted to switch modes  but you could also just leave the var set to var mode, When you want to run command,  scroll up the voltage  to around 20 volts and select engine using the ENG key.  Pretty easy..To go back to conventional press the TR and scroll the voltage back down. Either way works.

Gregg,

but you could also just leave the var set to var mode,

Or you could just leave it set to Fixed and when you want to run conventionally, just press TR, select the track and move the thumbwheel. That will put it back into variable until the DCS is powered off and then back on.

Yes, but wouldn't that  put a high starting voltage on the track, not good for conventional. I think I'd rather scroll up from 0 volts(var mode) rather than down from 20 volts. (fxd)

 

Gregg,

but wouldn't that  put a high starting voltage on the track, not good for conventional.

No, it would not

 

That only occurs when using ALL TIU Tracks. Individual TIU tracks can be set so  that the first thumbwheel click from 0 goes to between 5 and 22 volts, and the default is 5 volts.

If you set the variable channels to fixed, are you saying they come up at 0 volts when you turn on the TIU?  What did I do wrong, mine came up live?

John,

If you set the variable channels to fixed, are you saying they come up at 0 volts when you turn on the TIU?  What did I do wrong, mine came up live?

They'll come up at whatever voltage is going into their inputs.

 

My expectation for someone who is only running conventionaly sometimes and command at others, is that all conventional engines would be either on toggled sidings or off the layout altogether until it's time to operate conventionally.

 

In this case, I'd first press TR, select the track and click voltage to 0. Only then would I place conventional engines in service.

I have my variables set to fixed, & fed from postwar ZW's set at about 18 volts.  When I turn on the power to the layout, the tracks on those circuits immediately (1-2 seconds) come alive at 18 volts, without my doing anything.  If they were being fed from a Z4000, power would of course not come out of the transformer until further action were taken.

That makes it clearer. 

 

I guess you make different assumptions than I do.  I assumed that he wanted to turn on the TIU and have the channels come up with 0 volts.

 

In any case, you clarified the operation, which was the question.

The trouble with assumptions is that two people reach different assumptions.  I learned early in school, "Never assume anything!"

 

[I must admit I sometimes didn't follow school rules.]

Barry,

   Great discription of how to run Conventionally on a DCS layout with a mess up.

PCRR/Dave

Assuming the TIU is on.

Any voltage going into a fixed channel comes directly out. A variable channel set in fixed mode does the same thing.

When a variable channel is set as variable no voltage comes out at power up. Pressing the TR button and then accessing the desired track the screen will show the last voltage from the handheld power down. The first movement of the thumb wheel will put voltage on the track 1 volt higher or lower than said amount. If the track was set at zero the first move of the thumb wheel will bring up minimum voltage setting.

 

The fatal flaw of running command and then switching to conventional is start up voltage. Here is the scenario. You run command with the voltage set at 18v power everything down. Next session you put a K_line conventional engine on the track or a engine locked in forward or reverse. Hit the TR button,go to desired track. The voltage says 18v because that is the setting when you powered down. Still no voltage on the tracks. As soon as you move that thumb wheel big voltage is going to the track. That engine is now flying while you are spinning that thumb wheel down.

 

FYI most K-Line engines start in FWD for a F-N-R-N cycle. Other units cycle N-F-N-R.

 

When running conventional there is no need to turn the DCS signal off unless you desire to run a command engine in conventional mode.

Jim,

Still no voltage on the tracks. As soon as you move that thumb wheel big voltage is going to the track. That engine is now flying while you are spinning that thumb wheel down.

Instead of using the thumbwheel, press the "TVZ" soft key to set the voltage to zero, both on the remote and also on the track.

 

This and a whole lot more is all in "The DCS O Gauge Companion 2nd Edition", now available for purchase as an eBook or a printed book from MTH's web store site! Click on the link below to go to MTH's web page for the book!

Too bad there is not a soft key to change track voltage to Max. The TVM softkey only sets the track max and min voltage. The MIN softkey changes the voltage to MIN.

With a button to change to Max like there is for MIN one could flip from Command to Conventional in 1 keystroke.