Vaisala DMT340 - Manual (Page 79)

Chapter 4 _________________________________________________________________ Operation
VAISALA ________________________________________________________________________ 77
Display Alarms
The Display Alarm feature provides two independently configurable
alarms for transmitters with the display/keypad option. Each alarm tracks
a selected quantity, with freely configurable limit values. Each alarm also
has a configurable hysteresis value to prevent unnecessary triggering
when the measurement fluctuates around an alarm limit. The alarms can
be configured for any quantity supported by the transmitter. The
configuration of the Display Alarms can only be done using the
display/keypad option.
You can have the alarm activate inside or outside the specified range by
setting the limits correctly:
- To have the alarm activate when the measured quantity is outside the
specified range, set the Act. above limit higher than the Act. below
limit.
- To have the alarm activate when the measured quantity is inside the
range, set the Act. above limit lower than the Act. below limit.
The alarm limits are shown on the graph display as thicker dotted lines.
When a display alarm is activated, the automatic scaling of the graph
display always keeps the limits in view.
1103-062
Figure 52 Alarm Limits Shown on Graph Screen
When an alarm is activated, an alarm note is displayed on the display,
and the lights of the display will blink. If the data logger module is
installed, the alarm note includes the time and date of the alarm.
1103-063
Figure 53 Display Alarm Active
Multiple alarms can be active at the same time; the alarm that was
triggered first will be shown on the display. The next active alarm is