points /signals and relays

[rogerdee490th]

hi guys hope some one can help me.I have a twin track junction and a colour light signal .I want to make it automatic so it changes when the points are set against it. I need it to change when any one of 3 points are against it. The points are controlled dcc by a pc2 controller and I have some digital relays from guagemaster.

I can connect the relay to the point so the light turns red but if i connect tw0 points they both change . I have tired putting diodes in the wire so one point won't change the other only the light but then the points just click and don't throw!!
Has anyone got any ideas how i can do this simply.
thanks
roger

[Tricky Dicky]

I think you will need to give a little more detail eg what type of motors you are using, type of signal and any other info pertaining to the operation of the motors.

As a simple example using a two aspect signal and say Cobalt motors and assuming you have a separate accessory bus for things like signals and lighting I would do the following;

1. Using one of the independent in built switches on each Cobalt, wire the Common of all three to the +V of your supply.

2. Connect one of the switched terminals of the Cobalt (which one depends which way you want the point set against) then connect all these terminals together on each Cobalt and to one side of the relay coil the other side to 0V. Each switch can now energise the relay coil.

3. The next step depends on the way the signal is wired. If the LEDs are independently wired use the NC terminal to connect to the green LED as the default ON and the red LED to the NO terminal. If the LEDs are commoned then you need a relay with two inbuilt switches so you can wire it as DPDT switch wired to swap polarity.

Richard

[RAF96]

To make the signal change when a point is set contra you can either wire in parallel or series from each point switch towards the relay coil controlling the signal.

If you wire the switches in parallel you will need a diode in each switch circuit to preclude feedback from one circuit into another to avoid false indication. Any point set will allow the signal to change.

If you wire the switches in series then all points need to be set correctly for the signal to change. This way does not require diodes. If any point is not set then the signal stays on hold.

Which method you use depends upon which routes logic path you want. all points set or any point set.

I am sure I have seen a schematic on one of the forums for something similar fairly recently.

[rogerdee490th]

Thanks for your reply's
I am using peco point motors and a train tech pc 2 decoder It is on a separate bus .I tried it with out diodes and as you said got feed back with the other point changing. tried fitting diode's and nothing worked ?
wonder what i am doing wrong pretty sure the diode is the right way around.

[Brian]

Using point motor operated change-over switches - e.g. Peco PL13 or via relay contacts then this should work...

The LED resistor 'R' Ohm rating will depend on the supply volts, but if 12 volt DC is used a 1K0 (1000 Ohm) will be fine. 'R' is not needed if its pre fitted into the signals wiring. Wiring assumes Common Cathode LEDs.

[Tricky Dicky]

OK so Peco motors do not have a built in switch. The best advice when monitoring point position is to monitor the tie bar movement this is the only way to know exactly how a point is set. Any other method such as monitoring a switch on a panel or indicators on a decoder only tells you a signal has been sent but not whether the point has moved or not.

You can still follow my earlier advice by fitting PL-13 switches to your point motors or the PL-32 open microswitch and appropriate mounting plate or simply positioning a micro switch against the tie bar. With the switches wired as described in my previous post 1,2 or all 3 set against will set the red light or if set normally default to green.

I must admit I am not clear on what you are connecting your relay, diode and signal to?

Richard