Aux power supply use

I use all TIU channels and power both TIUs with wall warts through the AUX port.  If feeding through FIXED & the breaker feeding FIXED 1 opens, your trains on the other channels will run, but not under control.

You have some different issue, adding an AUX power supply to the TIU will not change the current draw of any of the channels.  Many folks, including me, run with an AUX supply to the TIU, I've never seen anything like this.  My first inclination would be to check phasing of all the power supplies.  I use a totally isolated power brick for my AUX power to the TIU, that eliminates any consideration of phasing of that power source.

Sounds like he may have 2 feeds on FIXED 1?????

Mike, it's not a complete disconnect.  One pole stays connected, which is why it's not good to use the same power supply for FIXED 1 and AUX.  GRJ is absolutely correct when he says, "I use a totally isolated power brick for my AUX power to the TIU, that eliminates any consideration of phasing of that power source."

Mike,

You don't have any jumper wires connected from Fixed 1 to any other channels by chance?

Brooksmj posted:

Question:

Is the remote supply input for the tiu electronics supposed to be used when the fixed 1 input is also used?

I am using all 4 channels of my tiu for track power.  Channel 1 fixed is used to run both transformer mode  trains and dcs mode. 

When the fixed channel 1 goes through varying voltage levels without a remote supply i figured the tiu electronics would suffer so i added a remote supply in conjunction with the fixed input 1.

Upon doing this i noticed 4 amps being drawn constantly so i removed the remote supply.

Does anyone have experience or knowledge of how to handle this configuration.

Thanks

Mike

 

 

 

 

 

 

 

 

I'm not sure what you mean by "remote power supply"    Do you mean AUX power supply? 

The tiu need a power supply to operate,  function,  turn on.... Only 2 way to do it... Power to fixed 1 or an  aux supply.

What did you use for an AUX power supply?    Polarity could enter the  picture if not a completely  separate power supply.

Thanks all so much for the replies.  I am totally amazed at the wonderful quick.  I am sort of isolated here in Dundee, NY from other train buffs, particularly O gauge, and I really appreciate having other people who are willing to share and talk trains.

Anyhow,

I was indeed talking about the AUX input in conjunction with the Fixed 1 input.  What I don't understand is the "Catch 22"  ( ****ed if you do and ****ed if you don't) use of the Fixed input as the power for the electronics.  If using the Fixed input supplies the board electronics, then what happens when the voltage goes way down when operating conventional trains. 

I also thought the 4 amp drain might be a ground loop so I tried two different old transfomers I had laying around with AC plug reversals in case the supplies were not isolated.  I do indeed have all of the grounds of the outputs connected so that the Legacy signal can pass to all of the tracks since I operate both DCS and Legacy.  On reflection I did not reverse the AC connection to the AUX input.  I am still confused if it is OK to just use the Fixed 1 input, which seems to work OK without the AUX input.  I just want to understand how it is supposed to work and what is expected.

Mike,

   You should only use one not both, as Guns advises lots of us use the Aux mode to power the TIU, it opens up the Fixed #1 to run trains and also makes the e-stop work fully.  Do not power from both Aux and Fixed#1.  

PCRR/Dave

As a follow up :

 The power supplies I tried on the AUX input were completely different then the supplies to feed INPUTS 1-4.  I am feeding FIXED 1 and 2 with a Lionel ZWL and the VARIABLE 1 and 2 with an MRC pure power dual.  I used the ZWL on the Fixed inputs because I have looked at the waveform of the ZWL on a scope  in the past and I know it is is a weird non-sinusoidal wave that has to be measured with a true RMS meter for an accurate reading.  I was afraid this nonlinearity might affect the Variable channel FETS. response.

I was indeed talking about the AUX input in conjunction with the Fixed 1 input.  What I don't understand is the "Catch 22"  ( ****ed if you do and ****ed if you don't) use of the Fixed input as the power for the electronics.  If using the Fixed input supplies the board electronics, then what happens when the voltage goes way down when operating conventional trains. 

This is why we use an aux power supply. The aux power keeps the tiu turned on even if power is removed (fuse)   or lowered on fixed 1.

Now I am really confused.  How can you not use both if you use the AUX input for the electronics and and are running trains with the FIXED 1 input. 

What you guys are doing is what I tried and got the 4 amp load on the FIXED channel all the time, even with the voltage turned down on the fixed input source

Nothing wrong with hooking up both.    Power to fixed 1 automatically turns the tiu on. The aux  supply  in just in case fixed 1 fails or you 're not going to use it...... Example... I'm only using the var channels. 

 Is your Lionel and MRC transformer phased together? 

Mike B, I suggest this.  As I said above, you do use an INDEPENDENT power supply to the AUX port even when using all 4 channels for trains.

Get a wall wart of 14-18 volts, AC or DC output (at least 500ma capacity if you only have a TIU, up to 2 amp capacity of you have 5 AIUs) and plug it into AUX; do NOT pull power from a layout transformer for this.  Hook up your transformers to the Fixed and Variable inputs, after phasing them.

When you apply power to the AUX port, an LED should come on inside the TIU, near the Variable 1 black input terminal.  The LED will flash to indicate the TIU ID#

Don't forget the U connection on the command base ties both transformers together via the outside rails.... If the transformers  are  out of phase there's a problem.  

Thanks Greg and RJR.  It is really helpful.  I thought the AUX supply had to be AC.  I have tons of DC wart supplies but no AC wall adapters, which is why I used an old train transformer.  The supplies are phased, but I will double check that.  The grounds of both supplies are indeed connected at the outputs of the TIU.  Do you know the polarity requirements of the AUX input for DC.  Is the center positive?  I did not see an indication in the manual.

Thanks,

Mike

RJR,

   You and I set up in the same manner, powering the TIU thru the aux with an independent power supply.   I happen to like the RS 18/24 power supply, but the TIU can be powered with a few different power supplies, and they all work well.  Your advise about Phasing the train running transformers is right on the money also, Phase them before you ever hook them up, mark the plugs for repeat usage if you take your layout up and down, as I do at Christmas time.

PCRR/Dave

Actually, though I use the center pin as ground, I don't think the polarity of the AUX supply matters.  It goes into a full-wave bridge and supplies DC to the electronics, so it will work with either polarity. 

gunrunnerjohn posted:

Actually, though I use the center pin as ground, I don't think the polarity of the AUX supply matters.  It goes into a full-wave bridge and supplies DC to the electronics, so it will work with either polarity. 

Yep! the center    pin on tiu  is common to the black on fixed 1...... If using a separate power supply for aux power it doesn't matter.  However if trying to use the accessory posts on the same transformer supping track power it matters.

Emphasis on "separate" in the AUX power supply.  Obviously, it shouldn't share a common ground with anything on the layout!

Brooksmj posted:

Now I am really confused.  How can you not use both if you use the AUX input for the electronics and and are running trains with the FIXED 1 input. 

What you guys are doing is what I tried and got the 4 amp load on the FIXED channel all the time, even with the voltage turned down on the fixed input source

Remember that the fixed channels have a solid connection between the inputs and the outputs.  I suspect you have something feeding power into the output of the fixed #1 channel.

Mike,

The following, from pages 95-96 of The DCS Companion 3rd Edition, is why you always want to use the Aux. Power port to power the TIU:

Advantages to Powering the TIU Through the Aux. Power Port

Essentially, the TIU is a computer. This means that each time its power is interrupted, it must reboot when power is restored. This reboot process takes a small amount of time, during which commands sent by the DCS Remote cannot be received by the TIU. If the TIU is powered by power present on Fixed Channel #1, turning off this power, even momentarily, will cause the TIU channels to behave in different ways. Although commands from the DCS Remote sent on any channel cannot be received while the TIU is turned off, the various TIU channels will react as follows:

• Trains connected to Fixed Channel #1 will simply stop running
• Variable channels will shut down and not pass power to the tracks. Trains running on tracks controlled by these channels will also simply stop running
• Power will continue to pass through Fixed Channel #2. Trains running on tracks connected to this channel will continue to operate. DCS (or TMCC) engines will continue doing whatever they were last doing when power to the TIU was turned off. However, the operator will have no control of these trains from the DCS Remote.

If the TIU is powered through Fixed Channel #1 rather than the Aux. Power port and there's a derailment on the tracks connected to Fixed Channel #1, the following will occur:

• The TIU will immediately stop receiving commands from the DCS Remote
• All trains running on tracks connected to Fixed Channel #1 or to a Variable Channel will come to a halt when the TIU's internal fuse or an external fuse for Fixed Channel #1 blows, or the transformer or other external circuit breaker trips
• All trains running on tracks connected to Fixed Channel #2 will continue to operate, however, they will not respond to commands from the DCS Remote.

The above scenario will continue with some trains stopped and others unable to be controlled until the power to the TIU is restored or all track power is shut down. Further, the E-Stop button on the DCS Remote will not be useable. Not a good situation!

TIU Aux. Power Sources

There are several sources of power that may be used to power the TIU through the Aux. Power port. In general, any AC or DC power supply that provides 1.5 amp of power at a voltage between 12 and 22 volts and has a suitable connector that fits the Aux. Power port will work.

One source of power for the TIU's Aux. Power port is any one of the smaller MTH transformers, such as the Z500, Z750 or Z1000, or the MTH #50-240 Z-DC24 power supply. Their barrel plugs exactly fit the TIU's Aux. Power port. If using one of these power supplies, it is important not to use the Z-Controller that may be included with them.

Another source of power for the TIU's Aux. Power port is the Radio Shack #273-331 Enercell™ Switchable 18/24VAC 1 AMP Power Adapter with #273-344 Enercell™ Adaptaplug™ M. It should be used on the 18 volt setting. However, since this power supply is rated for only 1.0 amp, it should be used only to power a TIU to which AIUs are not connected.

A third source of power for the TIU's Aux. Power port is the 14 volt output of an MTH Z4000 transformer using an appropriate barrel connector. It should be noted that if the Z4000's 14 volt output is used, it should be used solely for this purpose and not used to power any other device.

Although the polarity of the power source for the Aux. Power port is typically not a concern, there are two caveats in that regard that are noteworthy:

• If the Z4000’s 14 volt output is used to power the TIU via the TIU's Aux. Power port, polarity is important and must be correctly observed. If polarity is reversed, and one or both of the Z4000's handles are used to power the TIU's channels, a short circuit through the Z4000 can result
• If a brick-type transformer is used to power the TIU via the TIU's Aux. Power port and the non-accessory output of the brick is being used for other purposes, including powering a TIU channel or powering switch tracks that use non-derailing mechanisms, polarity is important and must be correctly observed. Otherwise, a short circuit through the brick-type transformer can result.

This and a whole lot more is all in “The DCS Companion 3rd Edition", available for purchase  from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book.

Thanks for the picture.  Sorry for the lag in my responses, I have been time division multiplexing this morning.

You made me put my thinking cap on.  I just drug up a full wave bridge circuit from memory and drew it and traced current for each polarity scenario and low and behold it follows the same path through the load on each alternation even though I hypothetically put DC in instead of AC for each cycle, verifying the OK use of a DC supply even though the manual does not

I was reading the 4 amp load on the meter of the Fixed input 1 ZWL source, even with the handle set to 0 output of the ZWL.  I will go back and recheck my phasing and also try a DC supply for the AUX input. 

Off to lunch and cardio rehab for this old 1948 chassis.

Thanks a million for all the time and advice.

I have been powering  the TIU from my MRC  PP Dual Acc posts. Why is this bad? Everyone is saying to use a separate supply. I did pay attention to the polarity of the barrel plug when I wired it.

John,

I have been powering  the TIU from my MRC  PP Dual Acc posts. Why is this bad?

As long as this circuit is only powering the TIU and nothing else, you should be fine.

However, if this circuit also powers anything else and that other item has a short circuit that takes down the circuit, it would also shut down your TIU, as well.

I use the ACC posts only for the TIU. Thanks, Barry, for the reassurance. I had your book on the table the whole time I was building this layout, and it sure has paid off.

All is well that ends well.

I have hooked up an 18V DC Power supply to the AUX input from my large box of power supplies.  No unusual current draws.   Now, time to run some trains. 

Thanks everyone for solving this for me.

Mike