test.xml
- <Settings ModelNumber="1" SerialNumber="13">
- <Channels>
  <Channel Name="FSC" Voltage="12" Threshold="15" /> 
  <Channel Name="SSC" Voltage="10" Threshold="20" /> 
  </Channels>
- <Pods>
  </Pods>
  </Settings>
  
use XML::Simple;
$inst_set= XMLin($file); 
foreach my $Channel(@{$inst_set->{Channels}->{Channel}}){
    if($Channel->{Voltage}){$settings_file=$file} #if the Voltage exists, it must be the settings file
    }
}