XLINK 500/100 Operations & Maintenance Manual page # 98
9.6.2.
Low Alarm
When the Alarm Type is set to Low, if the sensor reading is less than or equal to Alarm Threshold,
the station goes into alarm.
That station will go out of alarm when the sensor reading goes above Alarm Threshold plus Alarm
Deadband.
9.6.3.
ROC Alarm
ROC stands for Rate Of Change. ROC alarms compare the current measurement reading with a
past reading. If
Alarm ROC Interval
is
Since Last Meas
, the past reading is the last scheduled
reading made according to
Measurement Time
and
Measurement Interval.
If
Alarm ROC Interval
is
Since Last Tx
, the past reading is the one that was included in the last
alarm transmission. If there is no past transmission, the first reading made after boot up is used.
If the absolute difference between the two readings (absolute of current reading minus past
reading) is greater or equal to the
Alarm Threshold
, the station goes into alarm.
The same station goes out of alarm if the absolute difference between the two readings
(absolute of current reading minus past reading) is less than the
Alarm Threshold
minus
Alarm
Deadband.
Exception:
ROC alarms setup for
Since Last Tx
do not generate out of alarm events or
transmissions.
9.7.
Logging Settings
9.7.1.
Logging Interval
Logging Interval
dictates how often to log sensor data.
Change the
Logging Interval
to measure sensors more frequently than to log them. This is useful
for alarm setups, in which you want to check the water level once a minute in order to detect
fast-rising water, but one only wants to log the water level data once an hour. For this scenario,
the
Measurement Interval
would be one minute, and the
Logging Interval
would be one hour.
For alarm conditions, it is possible to set
Alarm Logging
to
Every Reading.
That would result in
the water level in the example above being logged once a minute when the system was in alarm,
and logging once only once an hour when not in alarm.
If
Logging Interval
is set to zero, the station will log every measurement. It is the same as having
the
Logging Interval
equal to the
Measurement Interval.
LinkComm provides a
Log All
checkbox: when checked, the station will measure and log at the
Measurement Interval.
Having a
Logging Interval
that is shorter than the
Measurement Interval
is a bad setup.
Only logged readings may be transmitted.