Monthly Archives: March 2016

Using the Detector Status Feature

In my last blog, I described Detector Drift Compensation and how addressable detectors compensate for contaminates. In this edition, I would like to continue with this subject and touch upon Detector Status.

Detector Status is a snapshot of the internal values of the addressable detectors on the Silent Knight addressable fire alarm control panels. A popular feature, Detector Status can be uploaded via SKSS software or viewed through the annunciator(s) on the system.


The values shown in Detector Status provide indications of the current state of the detector, detector thresholds, and a history over time of its status. While each value has importance, there are a few specific values that I would like to mention:

  • CAV – Clear Air Value – The current value or state that the detector. This is first value that should be observed and provides the basis in relation to all of the other values
  • MT – Maintenance Threshold – The threshold value that determines when a detector is in a maintenance condition. When the CAV value reaches the MT value, the detector enters a Maintenance Alert condition. When a Maintenance Alert condition occurs on a detector, the panel does not annunciate or report this condition. it is only observed when viewing detector status.
  • TT – Calibration Threshold – The threshold value that determines when a detector is out of calibration. When the CAV value reaches the TT value, the detector enters a Calibration Trouble condition. The panel will annunciate and report this event.
  • ATL – Alarm Threshold – The threshold value that determines when the detector goes into alarm. When the CAV value reaches the ATL value, the detector enters an alarm condition. The panel alarms appropriately.
  • NFPA72 – A Yes or No condition. If No is indicated for a detector, it is out of calibration and not functioning properly. It would need to be cleaned or replaced.

The Detector Status feature is very useful to ensure that the addressable detectors are functioning properly. It can be uploaded and viewed at any time and is U.L. listed for the required Calibrated Smoke Test on systems.

Did you know that SKSS can be downloaded for free from the Silent Knight website? Click here to access the SKSS page and download the latest release.


About the Author
Jack Grones is an Application Engineer with Silent Knight and holds a NICET Level III certification.  Jack joined Silent Knight in 1978 and is responsible for applications and technical support.