Atlas #6924 non derail circuit board

I've never used the Atlas circuit board, however, I don't see why it would be connected to the AIU at all, since its goal is to act independently of the AIU or any control panel switches when throwing a switch track.

You know Barry, I thought the same thing. I thought that the Atlas circuit is similar to the AIU in terms of both sending signals to the switch so wouldn't they both be fighting to send signals to the turnout? All the diagrams that I have seen from Atlas show the circuit board connected to the AIU. Another question, couldn't I also control the switch with the DCS remote with the AIU alone instead of the circuit board?

quote:

couldn't I also control the switch with the DCS remote with the AIU alone instead of the circuit board?

You could, however, you wouldn't get the electronic auto-nonderailing capability that the Atlas board provides.

So I guess it's better to use the circuit board and it will do the switch and prevent auto nonderailing for me and not need the AIU for that switch and just connect the power source directly to the circuit board and the circuit board to the machine switch. Is this correct?

Thanks

The 6924 Relay board is designed for electric non-derail input and switching from push buttons, AIU, TMCC ASC, SC-2 or any combination of all. Keep in mind that all switching is done with Common input leads either from the AIU or the two outside rails T (Through) or O (Out)
Universal Switch Control Board - Non-Derail Wiring Instructions Click on the underlined phrase to link.

Typical Non-Derail Wiring with MTH AIU

The 6924 relay board.
(1.) Inhibits motor burnout, a problem with Atlas switch motors.
(2.) Adds electric non-derail, Atlas switches are a spring-loaded mechanical non-derail.
(3.) Allows for Power routing, to reduce dead spots common to all switches.
(4.) Allows for Signal control interface, used of lights like the Atlas 6931 dwarf light.

Adding AIU or ASC control allows for all switch control from a handheld remote in addition to, or instead of push buttons.

Hi all,

 

I had a question if the non derail circuit board can be used on a pair of #5 switches that crosses over between loops. How would this be wired and would one circuit board be enough for both? Here is a pic.

 

Thanks

 

Hi Borderman

 

I use the 6924 extensively for control of long switches, such as #5, and the 0-54/0-72 curved switch. I use it mainly to power the closure rails to prevent engine stalling, but it also conveniently provides LED drive for my control panel indicators. My control panel uses SPDT momentary toggles (ON-NONE-ON) to drive the 6924. I also connect the AIU switch control outputs in parallel with the toggle switch.

 

Also in parallel with the toggle and AIU output, I have anti-derail detection wheel presence detectors. I found the hard way that anti derail operation is really necessary when you power the closure rails (as in sparks, blown fuses, and much cussing). I use wheel presence detectors because I did not want to cut the rail - just an engineers quirk. I use the detectors on both outside rails for redundancy (I tie both outside rails to TIU output return on my layout).

 

The 6924 will happily drive both pairs of a crossover, too, no sweat.

 

I've attached a typical wiring diagram and a photo of my wheel presence detectors. Note that I have chosen to provide 18V hot to the switch terminal center point, rather than 18V common as recommended by ATLAS, just personal preference.

 

 

 

NYLBFAN,

 

Please tell us more about the wheel presence detectors. Did you make them? How do they work? Details?

Hmm. Nylbfan I like this idea. I'm just getting ready to wire my Atlas switches with DZ-2500 machines for non derail. I was dreading cutting the rails as I'm not sure how close to the turnout they needed to be. These could be easily set up to test and then added permanently when the right place is established.

Ron

Hi Ron,

No need to cut the rails if you decide to add the 6924. Flip the switch over and clip the wires that are conected to the outer rails closest to the frog. They are on the Atlas wiring diagram marked T & O, you can then connect to the wires for your isolated rail imput or better yet soder directly to the rail with the wire that you are planning to run back to the 6924 board. As far as the rail isolation all you need at that point is two plastic rail joiners. Very cheap, they work great and you will not see them once they are installed. The rail on the switch is plenty of rail distance assuming you are not using a tortice switch in which case I would move the isolated rail joiner one or two track sections out.

 

I am currently running over 40 turnouts wired through 22 6924 boards (18 are paired) and all run through my AIU. Going on 4 years with no problems, Kind of expensive on the front end but they have so many benifits. One of my favortes is having the ability to use power routing. I have used it on every switch and I never have an engine stall whish is amazing given the number of 7.5 turnouts I use. Regardless of how you choose to hook them up, I think you will be glad you did. Good luck with you Railroad!