Normally Open - Trigger

[Suraj143]

I have a normally close signal from a break glass. I want to make a relay active when it opens (breaks).
Is my diagram ok? I also need a break glass status output from the same relay on its other pole. That is why I used a relay.
Relay load is more than 10A DC.

 

[rjenkinsgb]

There is no point at all using an opto-coupler when the two sides have a common ground.

Just put the NC contact where the opto transistor is in that circuit. Or if the input contact must be connected to positive power, invert the transistor and relay etc. and use a PNP transistor.


Most security circuits work on fail-safe type circuits; in the simplest form of that, you could just use the NC contacts on the relay and have it held energised by the glass break switch.

 

[Tony Stewart]

This will work. Use twisted pair or UTP wire.

 

[Suraj143]

Many thanks. I'll make the changes.

 

[AnalogKid]

You can delete R1 and connect the T1 base directly to the switch/R2.

ak

 

[Tony Stewart]

I agree.