common tie in on AIU

Jeff,

 

From page 72 of The DCS O Gauge Companion 2nd Edition:

An easy way to connect Common to all of the IN terminals is to first connect a 

wire to all of the IN terminals of an AIU and then connect one end of the wire to transformer Common. Then, connect the other end of the wire to the first IN terminal of the next AIU.

 

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 Barry. I did see that you mentioned that in your excellent book. I guess my ? Was how do people like to do this? Run little jumpers from input to input on the aiu? Run common inputs of the aiu to a terminal block? I'm trying to do this do it does not look like a rats nest of wires Thanks again. Jeff

I strip a length of wire, make a fold and insert the fold in an AIU terminal. Then, I loop under the other two terminals, make another fold and insert it, and repeat.

Aha, makes sense. Much thanks

Alternate wiring scheme for connecting to the AIU “IN” terminals:

I have used “shorting” bus bars to connect to the “IN” terminals on my AIUs.

 

A photo of a small 9 position bus bar that I have purchased on Ebay is attached.

 

I use 3 of these bus bars for connecting to each of the 20 “IN” terminals on my AIUs.

These bus bars are wired together using jumper wires. (The 3 bars provide 27 available terminals.)

 

I also have built an AIU Patch Board for convenience when connecting to switches and accessories. I use red and green color coded terminal strips which can be labeled to make troubleshooting easier. My terminal strip labels match the names added to the MTH DCS hand held controller.

 

 

Note: The bus bars are hidden in the photo of the patch board.  They are mounted directly below the "green" terminal strips.

 

For my control system I also have added individual relays for controlling turnouts (switches). These relays are operated by 12 VDC and draw a low current to operate. The relays are activated by the AIUs.

 

A photo of my patch board is attached.

 

 

Mmmmm, something to think about.  Very nice, elegant set up.  Looks like it makes it easier than having to mess with the tiny screws on the AIU more than once.

 

Thanks for the ideas.

Another aspect of my control system design is the use of "plug and play" interconnecting cables.  All my control system components are securely mounted on individual boards which are assigned a board number. The cables connecting between all these boards are labelled by board number, signal name and are color coded. This makes troubleshooting a lot easier. I use "Euro style" terminal blocks for all interconnections. They are not expensive and are easy to use. These terminal blocks can be cut to size with a razor saw. The standard blocks have 12 terminals. I cut them down to 10 positions to match the AIU terminals.

 

See attached photo.

 

Here is the "mating" control board. As can be seen the terminal blocks are also color coded and exactly match the terminations on the patch board. I have called this board my Relay Board because it contains the relays that operate the switch solenoids (shown in red) and power the tracks (shown in green). 

 

As shown on the relay board the "green" terminals (on the left) are wired via a cable coming from the 20 ACC terminals on the 2 AIUs.  These relays control track power from the TIU to the individual "blocks".

 

As shown on the relay board the "red" terminals (on the right) are wired via a cable coming from the 20 SW terminals on the 2 AIUs. These relays control the solenoids on my MTH RealTrax turnouts.

 

The white "Euro" terminals also shown on the relay board then wire out to the track and the solenoids.  Another pair of color coded and labelled cables are used to make connections to these terminals.

 

 

That is some of the nicest wiring I have seen.  Amazing organization.

I think I will use your idea for terminal blocks in front of the AIU.  

Thanks-

Jeff

The terminal strips shown on these wiring boards are mounted on shelves. Much of the wiring from the AIUs and going to the relays does not show since it is wired to other terminal strips placed below these shelves. For access to this concealed wiring any one of the shelves can be easily moved out of the way by removing 2 screws.

 

 

Very nice indeed!  Good thing I asked this ? Will make my AIU task both easier, and better organized.

 

Thanks Jeff