Alarm Calculations; Alarm Acknowledgement - Trolex XD One User Manual

XD One_User manual_P5644.1601_Rev B
Advice outlined in EH40/2005 states that where no specific STEL is listed, a figure three times
that of long-term exposure limit should be used. However, always refer to local guidelines
and legislation to ensure that alarm warning thresholds are set at appropriate and permissible
values for the intended operating environment.

13.1 Alarm calculations

The XD One uses the following calculation for the monitoring of STEL threshold breach.
STEL, where STEL TIME is in minutes:
The XD One uses the following calculation for the monitoring of long-term exposure reading/
TWA threshold breach.
TWA, where TWA TIME is in minutes:
Note: The TWA calculation will reset on device power cycle, the sum is calculated on device
start up and initial sampling to the current run time and will accumulate until the device is
switched off.

13.2 Alarm acknowledgement

In the event that a warning alarm is triggered, the XD One will auto-latch to ensure that
a conscious action is made to acknowledge the warning. During alarm state, users can
acknowledge triggered alarms, which will silence the audio alarm; however, the LED warning
indication will remain illuminated (solid) to indicate the alarm conditions are still present.
At the point of particulate levels decreasing below the permissible threshold (95%) of the
alarm set point, the alarm will reset and the illuminated LED will switch off.
35