Oldham BM25, User Manual

Page: 29 / 80

3
– Operation
29
Alarms
The BM 25/25W features visual and audible indicators:
■
Visual indicators: clear text messages on the display, one 360° red flashlight that is
visible from all directions
■
Audible indicators: two loud speakers (103 dB @ 1m)
Gas alarms
The gas monitor features:
■
Two instantaneous thresholds per channel for combustible, toxic or oxygen gases.
■
One falling and one ascending alarm for Oxygen (two falling alarms in option).
■
One STEL ( Exposure Limit, country dependent) threshold per channel equipped
with a toxic gas sensor. The STEL value corresponds to the average of gas
measurements made over the last 15 minutes.
■
One TWA ( Time Weighted Average, country dependent) threshold per channel
equipped with a toxic gas sensor. The TWA value corresponds to the average of
gas measurements made over the last 8 hours.
When an alarm is triggered, the monitor will fire its audible and visual indicators at
different frequencies depending on the alarm type:
■
Low Gas Alarm (Alarm 1): two-tone, slow (1 Hz).
■
High Gas Alarm (Alarm 2): two-tone, fast (2 Hz).
■
Alarm Transfer (repeated alarm): two-tone, very slow (0.5 Hz).
■
Fault: mono-tone, continuous (0 Hz).
The display will also indicate the alarm message(s) (ALARM 1, ALARM 2,
AL. TRANSFER, STEL, TWA, mini, etc.) as well as the gas measurement. In alarm
mode, the monitor will display the peak values (min or max depending on the gas type)
until acknowledgement button is pressed.
Alarm information has priority over fault information.
Gas Alarms Acknowledgement
Latching Alarms
The audible alarm will be silenced when the button is pressed. The visual alarm will
continue to blink while the gas measurement is outside the set limits. The visual alarm
will turn off automatically when the measurement is within the set limits.
If after two minutes the gas measurement is still outside the set limits, the audible
alarm will be automatically reactivated; this function can be deactivated by factory.