Information on the detectors used with environment monitoring solutions.
A relay is an electrically operated switch and in environment detectors, low current switching signal relays are used to indicate a change in operating state from ON to OFF or OFF to ON. A signal relay can be Normally Open (NO) or Normally Closed (NC). When a change in state is monitored, from NC to NO or NO to NC, an action can be taken. An example is a Smoke Alarm sensing smoke and changing the state of a relay as an audible and LED alarm is signalled. The relay can be monitored remotely by an environment monitor.
A current clamp typically consists of two parts which are secured around the cable to be monitored. The clamp uses the ‘Hall effect’ and the magnetic field caused by current flowing through the monitored cable which induces a small voltage across the sensor. The voltage is proportional to the current and is amplified and measured to generate a reading. The use of a clamp meter prevents the need to cut into or damage a cable and allows the clamp to be placed onto ‘live’ in-situ installations without disruption.