Door Sensor Alarms Explained

The following information explain the types of alarms generated by the Door Sensors connected to your RF500 Monitoring System.

Continuous Door Alarms

A Continuous Door Alarm is defined as an alarm that is triggered whenever a door is left continuously open for a period of more than X minutes.

Please refer to the ‘Door Alarms’ chapter under ‘Transmitter Alarms’ in the RF500-Webview Help Guide for a detailed explanation of Continuous Door Alarms.

Average Door Alarms

An average Door Alarm Door is defined as an alarm that is triggered whenever a door is left open for more than X minutes cumulatively, in a given period of up to 60 minutes. This alarm captures many individual shorter door open times, that may fail to trigger a continuous door alarm, but are nonetheless still important.

Please refer to the ‘Door Alarms’ chapter under ‘Transmitter Alarms’ in the RF500-Webview Help Guide for a detailed explanation of Average Door Alarms.

Reading Door Alarm Data

Both continuous and average door alarms are enabled or disabled together, therefore if the average door alarm is not required, setting the average limit equal to the average period causes the average alarm never to occur because the limit can not be exceeded.

Whenever a continuous door alarm is triggered an Event only is generated, tabular data will not be coloured to indicate the alarm.

A representation of tabular data shown above shows a typical reading. The readings reported for the door channel are given as two values:

• The first number is the cumulative number of minutes that the door has been open throughout the averaging interval, which in this example, is the preceding 60 minutes.
• The value in parentheses is the cumulative number of minutes that the door has been open throughout the averaging interval given as a percentage of the averaging interval.

The percentage gives a measure of how much time a door actually spends opened which could represent a problem in a real world application. Consider the following scenario:

A door to a laboratory is monitored using RF500 and the continuous alarm is set to 20 minutes to capture a “door left open” event. If that door is opened then closed after 19 minutes have elapsed, then immediately opened again for 19 minutes then closed, the continuous alarm event would not have been generated; however that door has effectively been open for 38 minutes during the previous 40 minutes or so. With an averaging interval of 60 minutes the RF500 system would report a door reading of approximately 63% or with an averaging interval of 40 minutes a door reading of close to 100% would be reported. It may be the case that this high level of “door open” condition may cause environmental controls to be overloaded.