If you could post a diagram of what you are thinking about it would help.

Can I share the same TIU channel between 2 transformer outputs?

NO!

Electronically controlled transformers take a very dim view of connecting outputs together!

John,

I have two very long loops of track connected by four Ross switches.  The switches allow trains to move from the inner loop to the outer loop.  I have two ZW-L transformers.  One for each very long loop.  You mentioned that electronically controlled transformers take a dim view of connecting outputs together.  The outer ZW-L works fine with the inner ZW-L when a train crosses from the outer block of track to the inner.  I am assuming this is because the break in the track at the switches is really not connecting the transformers, but what about when the train travels across the switch on the outer to inner loop?  At this time the engine and cars make a small connection of outputs.

As long as the volts are the same there will be no spark. If  the volts are different then there is a spark.  

@Gerald Jackson posted:

As long as the volts are the same there will be no spark. If  the volts are different then there is a spark.  

Very well said Gerald, but it could also be much worse than a simple spark.  If the throttle settings are radically different between inner and outer loops you could get a melted wire inside a lighted passenger car, if that car has pickups on both trucks.  One truck's pickup will see a very low voltage and the other's a very high voltage as the car straddles the insulating pin between the loops.

This is effectively a short circuit, and a strong one at that because of the large voltage difference, although it disappears as soon as the car clears the insulating pin.

Remember to keep the throttle settings close so that this temporary short is a tiny one (low difference in voltage) and not a large one (high difference in voltage) to avoid melted wires.

BTW -- Some folks, like @gunrunnerjohn for instance if I recall correctly, go through the extra trouble of adding a fuse, or electronic equivalent, inside the car spliced in the middle of any wire that connects the two pickups together.  In our case here it would blow, if the voltage extremes were high, and save the day.  And, it also protects in the same way during pickup-to-outside rail short-circuits, through one truck and then the other, during derailments.

Mike

@Mellow Hudson Mike posted:

BTW -- Some folks, like @gunrunnerjohn for instance if I recall correctly, go through the extra trouble of adding a fuse, or electronic equivalent, inside the car spliced in the middle of any wire that connects the two pickups together.  In our case here it would blow, if the voltage extremes were high, and save the day.  And, it also protects in the same way during pickup-to-outside rail short-circuits, through one truck and then the other, during derailments.

And take note that I use a PTC, which is a self-resetting fuse, so there's no "blowing" involved, just opening the circuit until the excessive current source is removed.   A true fuse would require cracking the car to replace the fuse.

Get two WIUs and network the TIU's together instead. You don't have to use the "SuperTIU" mode.

Connecting Additional WiFi Interface Units in MTH Network Mode

To connect additional WiFi Interface Units for use with additional TIUs in MTH Network mode, follow
the instructions below:

• Set the second WiFi Interface Unit’s MTH/Home selector switch to Home.

• Connect the second WiFi Interface Unit to the second TIU by connecting the USB Port on a Rev.
L TIU to the USB Port on the WiFi Interface Unit. If the TIU is an older model, use a Serial to USB
cable to connect the two devices. In this case, refer to Part XII - DCS Upgrading and Remote Backup/
Restore, 4. Required Cables and Connectors later in this book for a description of the exact cable
that’s required.

• Attach the included antenna, and plug the second WiFi Interface Unit’s power supply into an AC outlet
and the power supply's cable into PWR port on the WiFi Interface Unit.

• Wait a minute or two for the WiFi Interface Unit's PWR, Wi-Fi and TIU LEDs to light.

• On the first (master) WiFi Interface Unit, press the WPS button. The white WPS LED will begin flashing.

• Immediately press the WPS button on the second WiFi Interface Unit. The WPS button must be
pressed within 1 minute. The white WPS LED will begin flashing.

• Wait for the white WPS LED on the second WiFi Interface Unit to come on steadily, and then turn
off.

• Select and open WiFi settings on the smart device.

• Choose the MTH WiFi network from the smart device's list of wireless networks.

• The smart device should indicate that it is connected to the MTH WiFi network.

Repeat the above steps for any additional WiFi Interface Units.
By using this method, these additional WiFi Interface Units will connect to the WiFi Interface Unit that
was set to MTH mode as if it was a router, thus allowing the DCS Application to connect to the additional
WiFi Interface Units though the WiFi Interface Unit that was set up in MTH mode.

As Barry would say, "This and a whole lot more" available in the DCS WiFi Edition

Scott Smith

Thanks for the info, Scott.

I do have 2 Rev L TIU's and 2 WiFi adapters.

I have the 3rd edition of Barry's DCS book.  I will be receiving the WiFi book tomorrow.  I am assuming the info you provided is from that book.

Given that this approach to network the TIU's relies on WiFi, will the traditional DCS remote be able to be used across both TIU's (like in Super TIU mode)?  Or do I have use a phone/tablet?

Another question...I haven't used my WiFi adapters yet...can you connect the TIU's to your home network or do you have to use a MTH network?

I have 2 TIU's and a total of 8 tracks at the club. The remote does not play well in that enviroment. It may or may not find your engines. You will be shocked at how fast the WIFI units find your engines and how easy it is to control all of them. As the directions show above you should have the first WIFI unit set to the MTH network and set the second unit to find the first unit's DCS network.

Scott Smith

@gunrunnerjohn posted:

Can I share the same TIU channel between 2 transformer outputs?

NO!

Electronically controlled transformers take a very dim view of connecting outputs together!

A related question:

On our modular layout we run 10v and 14v accessory wires through each module.  They are supplied by a single Z4000.   As members have added more accessories, we recently had a banana plug heat and fail due to the load.  So now we wish to distribute the load over 2 Z400s.  So the question is, can we connect the two 10v outputs in parallel and the two 14v outputs in parallel?  We plan to feed the layout at 2 points.  

Or should we isolate the 2 halves of the layout and have a Z4000 feed each half?

Bob

@RRDOC posted:

A related question:

On our modular layout we run 10v and 14v accessory wires through each module.  They are supplied by a single Z4000.   As members have added more accessories, we recently had a banana plug heat and fail due to the load.  So now we wish to distribute the load over 2 Z400s.  So the question is, can we connect the two 10v outputs in parallel and the two 14v outputs in parallel?  We plan to feed the layout at 2 points.  

Or should we isolate the 2 halves of the layout and have a Z4000 feed each half?

Bob

Divide the load and feed each half separately.

While the accessory outputs are not electronically controlled- they are literally taps of fixed voltage windings right off the core transformer, the problem with load sharing and paralleling- the weak point is terminals and connections. You might not actually equally share the load and one transformer takes the brunt of this. Even slight variations and resistance change the equation and current sharing.

Seems like knowing the actual current being drawn would be helpful.  Just because a banana plug failed doesn't mean you need to rework things.  I'm not sure what a banana plug is rated at for current, but if only one overheated some good current data could help you figure out what to do.

Cheaply made banana plugs, like I bought from Home Depot, can wear out from plugging and unplugging. The prongs will no longer make full contact with the TIU. This will cause the TIU output to overheat melting the TIU output plugs.

Scott Smith

While a higher quality banana plug may have been the problem, I think we will go with sharing the load over 2 Z4000s.  We are already using both for track power.  We have 2 power feeds with a Y connection between 2 modules, and it will be easy  to isolate the 10v and 14v feeds on one side of the Y.

The meltdown occurred last week while displaying at the York State Fair.   To reproduce the amperage draw, we will have to wait until next year when we will have the full sized layout set up plus a collection of kids hammering on all the accessory pushbuttons at once!

Bob

Two things to do to help prevent melting banana connectors:

First, open the TIU and check the connctions betweenthe PCB and the banana receptical. These use nuts on the banana posts, whch can work loose, causing high resistance and sufficient heat to melt the connector. Tighten all of them, both input and output.

Second, all banana plugs are not alike! Some are very loose in the receptical, which again, leads to high resistance and heat. Take a thin blade screw driver and insert it into a slot in the plug. Give it a slight twist to expand the size of the plug. Repeat in each slot for each plug. They should now fit very snuggly in the receptical.

Chris

LVHR