OPERATION OF THE AREARAE
2-20
2.6 Alarm Signals
The built-in microprocessor continually updates and monitors
gas concentration levels. It also compares the readings with
programmed TWA, STEL, Low, and High instantaneous gas
concentration alarm limit settings. Whenever the concentration
exceeds any of the preset limits, the buzzer and red LED
immediately warns you of the alarm condition. Additionally, the
AreaRAE alarms if one of the following conditions occurs:
•
Battery voltage falls below a preset voltage level (6.6V)
•
Failure of 10.6 eV or 11.7 eV UV lamp
•
LEL sensor is off
•
Pump
stalls
•
Datalog memory is full
When the low battery alarm occurs, there is approximately 20
to 30 minutes of operating time remaining before the battery
voltage falls below 6.4 V and the monitor automatically turns
off.
Alarm Signal Disabled
It is extremely important to note that the alarm signals are
disabled during the following conditions:
•
PC communication standby mode
•
Calibration
mode
During these modes of operation, real-time monitoring gas
concentration stops. None of the gas concentrations is
calculated, including Peak, STEL and TWA values.
Alarm Signal Latching
It is possible to set up the AreaRAE from a PC or while the unit
is in Program Mode so that when an alarm condition occurs,
the alarm signals remain on even after the alarm condition is
no longer present. This is called the “latching alarm” mode. The
alternative mode is to automatically reset the alarm signal once
the alarm condition is clear. The default alarm mode is
automatically reset. (See Section 4.7.3: Change Alarm Mode.)
