Senstar Corporation LM100 User Manual

4. Snow removal (as required)

If the weather conditions at your site include snow falls, the fence should be kept clear of 
accumulating snow. If snow accumulates against and around the fence, it will absorb and 
dampen the vibrations caused by an intrusion attempt. In addition, if there is significant snow 
accumulation, the snow can serve as a bridging aid to defeat the system.

If your Senstar LM100 system is having a problem with nuisance alarms during inclement weather, 
connect the UCM to the gateway and review the alarm history to try to determine the source of the 
nuisance alarms. Investigate the areas near the luminaire(s) with the highest alarm count. Inspect 
the fence to ensure it is in good condition and there are no loose fittings that can cause metal on 
metal contact. Check the attachment and test the detection of any luminaire(s) with a higher than 
average nuisance alarm rate.

For network based systems, run a UCM response plot through the Network Manager during 
periods of inclement weather. If the weather causes an unacceptable number of nuisance alarms, 
review the plot and the processor history and adjust the Threshold to mitigate the effects of the 
weather. For standalone systems that encounter an unacceptable number of nuisance alarms 
during inclement weather, connect the UCM to the gateway, review the processor history and 
adjust the Threshold to mitigate the effects of the weather.

To determine if there are any loose fittings or parts of the fence that can cause nuisance alarms in 
windy weather, grip a fence panel in the middle and push and pull on the fence with an increasing 
motion. Run a response plot to record the shake tests, and listen for any metal on metal contact. 
Review the plot, looking for any response spikes that are over the threshold. If the shake test 
causes metal on metal contact, or generates response spikes over the threshold, locate and 
correct the problems on the fence. This will help to prevent weather related nuisance alarms.

The gateway includes both a high pass and a low pass filter which can be used to screen out some 
sources of nuisance alarms. Before adjusting the Target Filters, verify that the fence is not loose 
and that there are no objects or vegetation that may be contacting the fence in strong winds. The 
default value for the high pass filter is 2 Hz, the default value for the low pass filter is 400 Hz.

•

If the site is encountering an unacceptably high NAR during moderate to strong winds, 
increase the high pass filter setting slightly to lessen the effects of wind sway and continue 
monitoring for nuisance alarms.

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If the site is encountering detection problems (low sensitivity) rather than nuisance alarms, the 
most likely source of the problem is loose fence conditions. Repeat the profiling procedure and 
compare it to the original sensitivity profile. Once the location of the low sensitivity has been 
determined, correct the problem by repairing the damaged section of fence. 
If the fence has been restored to the fullest extent possible and the sensitivity problems 
persist, it may be necessary to install additional luminaires in this area. 

After adjusting the Threshold, retest the system to ensure that the 
detection meets the site’s security requirements.

Figure 58: Target Filters

high pass filter

low pass filter