i try to fix a module to deactivate the hotel's room airconditioner after 30sec of the opening of the door. I got a magnetic contact in the door and i need to give a N/O contact to the air conditioner technician not through a relay but through an optocoupler. Any ideas please??? Thank you

 

this is not simple as you think.
you need to show us your AC connection terminals and a brief description of what you want to do.
Modifying or adding circuits to an already operating equipment are not for beginners.

 

I placed the alarm security system. The A/C technician needs only a N/O contact without wiring connection(but through the optocoupler) from the magnetic contact of the door. Our project is till there, the connection of this is not our business.
I just need to open the contact after a few seconds of opening the door.

 

for that you will need the circuit diagram
But for me the circuit board is all I need to do it.

 

You can use a delay-on-break relay.
You can send a small signal through your door contact. When the signal is broken (if its NC and the door is opened) it will break the connection to rhe delay-on-break relay.

The relay will count the amount of time you set then kill the AC.

http://www.airotronics.com/site/timing_delaybreak.php

the relay can operate an optocoupler, but I am confused why you need the opto. The relay I linked to has 100% load isolation.

 

Personally I think the timing should be implemented by the A/C guy on his side.

You just give him the current opened/closed status of the door and he decides when to turn on/off the A/C.

Come to think of it, problems or fault in the security system or wiring could result in rapid closed/opened status and rely on this signal to turn On/Off the A/C will damage the A/C. The onus is on the A/C circuitry to prevent such condition from damaging his equipment.