Model rail block detector to drive relay

[eTech]

The bridge just provides a two-diode voltage drop regardless of polarity. That sets the voltage fed to the opto.

Ok. So here's how I think the module works.

As long as there is a signal being received at its input, via the track rails (it doesn't matter if the input signal is bi-polar or uni-polar), the output will be ON causing the module output voltage to be low. This would be the normal "Track Unoccupied" condition.

If a train comes along and shunts the track, the input signal is blocked, the module input signal is lost, and the module output then goes high.
This is the "Track Occupied" condition.

An assumption for both of the above conditions is that the module output is pulled up.

 

[rjenkinsgb]

It connects in series with the track power.

 

[Derekm]

I understand the track detector that’s not what I want to know
Back to my original post I want to know how and if I can trigger a timer relay with it

 

[eTech]

I understand the track detector that’s not what I want to know

If you really did, you wouldn't ask the following question.

Back to my original post I want to know how and if I can trigger a timer relay with it

By connecting a pull up resistor as shown in post #9 and as mentioned a few other posts.

 

[Derekm]

Totally confused by comments now thanks anyway

 

[Derekm]

I don’t understand how to connect or what a pull up resister is

 

[augustinetez]

I think the resistor is 330 ohm.

The resistor is 33 ohm, same as the diagram I posted - the last number on standard smd resistors is the 'multipler'.

The hook up diagram (post #9) looks right, but before you do that - power up the timer module without anything else connected and measure across LL Trig and ground to see if there is any voltage there.

If there is, then you won't need the 4.7k resistor.

 

[Derekm]

Thanks for that. When I contacted megapoints controllers and asked whether a timer relay could be attached to the output of the current based block detector I was told.

“It is designed to drive open collector inputs.”

That is what I don’t understand

 

[rjenkinsgb]

“It is designed to drive open collector inputs.”

That means it will work in place of a grounded switch, as I said in post #7.

Your diagram from post #6:

https://www.katranji.com/tocimages/files/438402-214756.pdf

shows a switch connected between GND and "Low level trigger". Just connect the detector output to those two points. Done.

 

[Derekm]

Thankyou very much really appreciate understand now, sorry if I upset anybody it wasn’t my intention