Addressable Gas Detection System Manual
Addressable System Manual
62
Issue 2, January 2015
Modification of alarm levels
The values can be modified in steps by touching the
–
on the left or the
+
on the
right side of the horizontal alarm bar or by typing the numbers into the numeric
indication on the right side. Due to the modification of one alarm set point also the
range of the red bars for the alarms will be modified accordingly. If the typed value
for an alarm level is outside of the accepted range the plausibility check will modify it
automatically, e.g. when typing in the LEL profile for alarm 3 the value of “80”
corresponding to 80 % of the LEL this value will be corrected to “60” which is the
maximum value specified in this profile.
When leaving the screen after modification, the old and sets of parameters for the
channel are indicated with the modified values in red. The modification has to be
confirmed with OK or may be cancelled.
“Instantaneous Alarm” and “Time Weighted Average Alarm”
Fig. 4.5.5.e) Alarm settings details in case of Instantaneous and Time Weighted Average
thresholds
In some profiles, e.g.
“toxic STEL”,
additionally to alarm thresholds for
instantaneous alarms time weighted alarms may be specified. A typical application is
the Short Time Exposure Limits (STEL) with an average time of 15 min. Other
profiles may allow modifying the average time between 1 min. and 30 min. for each
alarm individually.
In some profiles (e.g. the LEL-profile) time weighted average alarms are forbidden by
the relevant metrological standards for gas detection devices. In such profiles the
whole part of the menu related to time weighted alarms is not visible.
The setting of alarm levels for time weighted alarms has to be carried out after the
setting of the instantaneous alarms. The possible range for setting the time weighted
alarms is specified by the instantaneous alarm set points.
If only time weighted alarms are required for an application the value for all 3
instantaneous alarm levels may be set to the maximum possible value, in the profile
for toxic gases this will be 100% of the measuring range.
