7
SensTool
50
Vanderbilt
Seismic Detectors Application Guide
I-200153-1
08.2016
8.3
Recording ambient noise levels
SensTool via a GM7xx detector has the facility to monitor and record the background noise levels of
parts of an installation. If there are concerns over high noise levels prior to installation or if post instal-
lation problems exist, then it is strongly recommended that the installation is monitored to assist with
the removal of the problem.
The GM7xx via Senstool has the facility to monitor for 18 hours. A monitoring exercise should be es-
tablished during the noisiest part of the day, when most activity/noise is present, this can be mechani-
cal human or electrical.
For monitoring purposes, mount a detector as close to the final location as possible. Ensure that a
suitable ac power source is available for the duration of the test to supply primary power to the laptop
p.c. Select the duration of the monitoring period (up to 18 hours) and run the test. The test will auto-
matically terminate. The results of the test will show the background noise levels in real time as the
test results are linked to the p.c.’s clock. The recording shows the signal strength of any noise de-
tected and also the details of the integration alarm as a %. The recording will also indicate any alarms,
which with some local investigation should determine the activity that caused the alarm. It is preferable
that the noise is reduced or stopped but if this cannot be achieved, then the digital filters and the sen-
sitivity setting can be changed to remove the alarm. If the alarm is process related and the process is
only for a short duration, then the application of the remote input signal will reduce the sensitivity of the
detector to 12.5% of the original setting. Local regulations will determine if this is a permissible option.
Figure 8-2: SensTool detector signal
