I have wired magnetic opening sensors connected and working in the home burglar alarm. Today I tried to add others without being able to detect them.
Up to now one sensor on each zone (gives 1 a 8) 1 contact on GND e 1 with resistance 6,8 K alla zona.
They are 1 zone I put two in parallel each with relative resistance (6,8 K) the control unit not only does not detect the one just added but not even what worked before.
Someone can tell me if it's a resistance problem or something else?
It seems to me that the resistance shouldn't be higher than 6k8. As Amilcare says, the requested value remains and if one of the two opens it signals you, but it is obvious that one cannot determine which of the two.
So you would have an output that connects zone A and then zone B that connects to ground.