Network type smoke detectors in NC, NO is what mean?

Networking type smoke alarm and fire alarm host machine supporting the use, is widely used in factories, weak room, supermarket shopping malls and other large-scale places. Contact network type smoke alarm friends may note that the "NC" "NO" two groups of letters, they represent what meaning? Below we introduce.

"NC" is the abbreviation of normally close, it means in contact closed state under normal circumstances, detection has not been detected, the output form of the load current is switched on, also called the normally closed contacts; "NO" is the abbreviation of normally open, it means that under normal circumstances is broken open contact, detection has not been detected, the output current is not turned on, also called the normally open contact. Combined with the network type smoke alarm NC connection, when the detector detect smoke concentrations exceed the standard in the surrounding environment, the normally closed contact is disconnected, sends out the switch quantity signal, start relay output, a fire alarm. NO rule is to the contrary. The general network type smoke detector of normally open and normally closed contact method can free choice, a jumper on the PCB board it, can be set through the jumper normally open or closed.

Just because of the above reasons, the network type smoke alarm is also called switch normally open and normally closed the smoke alarm, smoke alarm.