User Manual

Table Of Contents
Optical Master Unit
PRODUCT DESCRIPTION AND USER’S MANUAL
© Axell Wireless Ltd A1829300 rev H 33 (86)
Relay Output for Sum Alarm
The External Alarm and Battery Module contains a relay output. The relay can be used to indicate the summary
status of the OMU. Each alarm source can be configured to affect the relay or not.
3.4.2 Alarms and End of Alarms
When the Control Module detects a failure, an alarm is transmitted to the Axell Element Manager, informing
the operator about the error condition. When the alarm has ceased, an end of alarm is sent to the AEM, stating
that the alarm source is now OK.
Each “alarm” and “end of alarm” updates the AEM database with the latest status of the alarm source, ensuring
that the AEM operator always has the correct repeater status in the system.
To generate an alarm a number of consecutive measurements must first show an error state. This can be
configured for each alarm source separately.
To generate an end of alarm only one OK measurement is needed.
Alarm level
Time
Alarm threshold
Alarm is sent after three
seconds above threshold
End of alarm is sent as
soon as status is OK
If an alarm should constantly toggle between OK and ERROR the communications interface might be blocked.
To prevent this there is a parameter called Minimum Alarm Repetition Cycle. This parameter defines how
many minutes must elapse before a new alarm can be transmitted from the same alarm source.
Alarm Threshold
Initial alarm End of Alarm
Three minutes have elapsed and a
new alarm is transmitted
Minimum alarm
repetition
Alarm level
Time
This illustration shows an alarm source with an upper threshold, and a fluctuating level around the alarm
threshold. The initial alarm will be sent as indicated. The next alarm will be transmitted after three minutes,
when the minimum alarm repetition period has elapsed.