Vaisala viewLinc 4.1 - Manual (Page 28)

Chapter 3: Alarms
24 © 2012 Vaisala Canada Inc
About Alarms
There are several types of alarms in viewLinc: threshold
alarms, communication alarms, event log validation alarms,
and device sampling alarms. If you are using validatable
devices, you may also receive device validation alarms and
calibration alarms.
Users with the appropriate ACL permissions can set
threshold alarm limits and when conditions exceed these
limits, alarms are triggered which notify key staff of the
condition. Staff with Acknowledge Alarms permissions or
higher then acknowledge the alarms in viewLinc.
All transactions are recorded in the Event Log and the
Historical database.
Threshold Alarms
Threshold Alarms notify users when conditions (such as
temperature and relative humidity) are outside acceptable
limits.
Threshold alarms are not enabled by default. To trigger
threshold alarms when certain thresholds are exceeded,
users with assigned permissions must configure them.
Communication Alarms
Communication Alarms notify users when communication
between a host (Device Host or viewLinc Server) and its
devices is down. This may be because viewLinc Server can
not communicate with the device, or the device connection to
a host has been severed. Communication alarms serve as a
system health test, alerting you if there is a problem that
might disrupt viewLinc monitoring and alarming.
Event Log Validation Alarms
An Event Log Validation Alarm indicates when changes have
been made to the event log from outside the viewLinc
system. Each entry in the event log has its own CRC which is
verified - if any changes have been made, an alarm is
automatically created, rendering data non-validatable. It
checks the CRC of event files, checks the CRC of event