Why use aux power for the TIU?

Marty R,

   It frees the Fixed one up so you can power something else, especially when you have the Z4K and side receiver for conventional running of different trains.

I definitely like the Aux power sourse.   The larger your layout becomes the more

channels you need.

PCRR/Dave

If all you're doing is using a programming track, you don't need to use Aux. Power. However, for normal train operations, using Aux. Power has several advantages. From pages 92-93 of The DCS O Gauge Companion 2nd Edition:

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. PS2 (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!

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!

Thanks

I'm not on pg 92 yet. You make an awesome index

Marty,

   The better question might be is there any good reason not to use Aux power.

In reality there are many reason to actually use Aux power and very few not to.

The E-stop button is my favorite for the use of Aux power.

PCRR/Dave

 Aux power shall be used! now to find the topic with the proper size connector. I have a 16V 4A wallwart, it jus has the weong connector.

Barry,

I tried to explain myself before on this matter and feel I didn't get across my point, so I'll try again.

The writeup (in blue) relates to the reader what happens if power is coming thru Fixed Channel #1.

For example:

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.

So, what happens if the TIU is powered by the AUX port?  You've given the "BAD" results if powered by FIXED #1, but not the "GOOD" results if powered by AUX.

Bob,

So, what happens if the TIU is powered by the AUX port?  You've given the "BAD" results if powered by FIXED #1, but not the "GOOD" results if powered by AUX.

None of the above. Each channel is unaffected by issues with Fixed #1. It's "business as usual".

Just ranting, but it would have been considerate of MTH to make this very clear in the documentation, instead of suggesting an expensive Z brick is ideal and not really saying why. Thanks for making it clear.

Marty,

instead of suggesting an expensive Z brick is ideal and not really saying why

MTH suggests a Z-brick because it's a product that they sell. They would have to be nuts to suggest that someone go find the cheapest power source that they can, since doing so could cause problems for MTH if someone used something inappropriate. Likewise, one never recommends another manufacturer's product if one has a similar product of their own available.

Further, a Z500 is not a whole lot more (maybe $25) than using a $30 Radio Shack power supply (the one I recommend in my book), which works but really doesn't meet the 1.5 amp spec of the Aux. Power port.

I personally use 4 Z500's with my layout's 3 TIUs and the TIU on the test bench, and use a RS power supply with my spare TIU that I keep in my den.

Each channel is unaffected by issues with Fixed #1.

I threw the Z Brick in as a rant. I'm really more concerned that the PS in't mentioned at all on the outer box, or at my LHS when learning about DCS. As I actually blew my 20A fuse last night (the clearance in my shell was such that w wire was pushing on the motor and the truck locked in a turn.Ths was before I understood the importance. I think it should be in the MTH User Guide as an imprtant precaution for setup. Then my by a connector and make a wall eart work , wouldn't be an issue.

I seriously don't want it to seem that I am asking you to defend MTH. I appreciate your taking the time and sharing.

I probably should remember that if I ever add 4-5 total AIUs, to upgrade the AUX power supply past the 1 amp RS supply.  Especially since I use routes and lots of switches can throw in a row.

Mike

mike;

That's a real good reason to use the Z-500 brick, right there. Extra power is not a bad thing. 

I use my Z-500 brick for Aux Power except during Christmas, when it's on the layout in the living room. During that time I have a wall wart that does the job.

As I add TIU's and AIC's the wall wart will certainly overload.

So before next Christmas I'm buying another Z-1000 brick for that layout.

There is no need to spend $60.00 at radio shack. They sell one for around $20.00 that has an 18v - 24v switch on it that works fine. Catolog # 273-1690 1000ma or 1 amp. I have been using one for years.  Have never blown a Tiu or any other equipment with it. It is made so that you can change the low voltage plug for use in multiple applications. They sell a wide selection of plugs that can be used. When you buy it they will match the plug that you need for the TIU. Set it to 18 Volts and you are good to go.

Forest.

Forest,

There was a typo in my previous post. The ‰S power supply is actually about $30, not $60, including the tip that you need (AdaptaPlug "M") to match the TIU's barrel jack.

I've now corrected my post.

Barry - for your 3rd addition - Radio shack renumbered - power supple is now #273-331 and the adapter is 273-344...  I just bought three...  hey - my very first post . the DCS O gauge Companion is a phenomenal tool...  thank you... 

Rick,

I already have that in my notes - thanks!

Is this adaptor ok to use?

John,

Is this adaptor ok to use?

If I'm correct in that 20 volts at 10 VA translates to 0.5 amps, then this transformer cannot be used to power a TIU.

MTH states that 1.0 amp is required, although the Radio Shack #273-331 "Enercell­™ Switchable 18/24VAC 1 AMP Power Adapter with #273-344 Enercell™ Adaptaplug™ M

is 1 amp and works fine. 

10VA at 20VAC is .5amps, which would be way on the small side since MTH recommends 1.5 Amps.  Many of us get away with 1 amp.  I suppose if you do not have any AIUs, it might work.  Be better to spend the $30 and get the one mentioned above.

Mike

does mth sell one. or should u use z 500 and can u use the z 500 when you use zw to power track