21
3 Operation
Then the device returns to measuring mode. The measured val
-
ues are displayed.
Measurement data
In number format:
e.g. 0.00 % vol.
As a trend bar divided into 10 parts ranging from 0 % LEL to
100 % LEL in increments of 10 %.
For the
Warning %LEL
application, the
EX-TEC PM 4
features
three alarm thresholds.
Alarm thresholds
z
Alarm threshold 1 (AL1 – pre-alarm):
– When this alarm threshold is exceeded, an audible alarm and
a visual alarm are triggered and
AL1
appears on the display.
– The audible alarm (2-Hz intermittent tone) is distinctly differ
-
ent from the operating signal.
– The audible alarm can be acknowledged by pressing the
key. The visual alarm remains active.
– When the level drops below this alarm threshold concentra
-
tion, the alarms switch off.
z
Alarm threshold 2 (AL2 – main alarm):
– When this alarm threshold is exceeded, an audible alarm
and a visual alarm are triggered and
AL2
appears on the
display.
– The audible alarm (5-Hz rapid intermittent tone) is distinctly
different from the operating signal.
– The AL2 alarm cannot be acknowledged.
– When the level drops below this alarm threshold concentra
-
tion, the alarm can be acknowledged.
