My Application is to Design a File Alarm Monitoring System for a Multi-Storied Building, where there are Fire Alarms at various points in the building.
Each Fire Alarm device provides with a Potential Free NO/NC contact, depending on 'alarming'/'not alarming' condition. The distance between the
Monitoring Device & Fire Alarm Devices may go upto 1200 m.
What may be the most suitable 'IC', I can use to sense the 'NO/NC' contact, accuratele from such a long distance ? I have to consider signal level loss & noise interferance.
Use of wireless device like ZigBee/cc1000 in not absolutely posible.
I have decided to use 2-wires(1-input & 1-output) to monitor each Fire Alarm Device.
Through the 'Output-wire' I will send moderate frequency(say 4kHz-10kHz) signal at 0V-12V amplitude, which will
'feedback'/'not feedback'(depending on 'NO/NC' of Fire Alarm Device) to 'Input-wire' of the Monitoring Device. Will it work ? Or suggest better option/s.
