--- check_sentry3.orig	2014-04-25 14:43:32.870837097 +0200
+++ check_sentry3	2014-04-25 14:44:50.387659839 +0200
@@ -193,7 +193,20 @@
      $count +=1;
 
      # Define the values we are going to test against
-     $nagios_value[$count] = sprintf("%.2f",$poll_results{$key});
+     #$nagios_value[$count] = sprintf("%.2f",$poll_results{$key});
+     # Do this after "$count +=1" so we can correctly index results to exact sensors.
+     # If only humidity sensor "1" and "3" are plugged in don't show result for "2".
+     # e.g "SERVERTECH_HUMIDITY WARNING - Humidity1 @ 39.00%, Humidity3 @ 41.00%
+     # | Humidity1=39.00%;30;85 Humidity3=41.00%;30;85".
+     # This also prevents perf data shifting to a new key if you add a sensor.
+     if ($poll_results{$key} >= 0){
+         $nagios_value[$count] = sprintf("%.2f",$poll_results{$key});
+     } else {
+         # Don't add negative numbers to @nagios_value that cause Nagios::Plugin::Range
+         # (via check_threshold) test to fail.
+         # Also don't add empty sensor data to the perf hashes.
+         next;
+     }
 
      # Process the value
      if ($cmd_flags{do_temp}){
@@ -255,6 +268,8 @@
      }
    }
 
+   # remove undefs now that $message has sensor postions set by $nagios_value[$count]
+   @nagios_value = grep defined, @nagios_value;
    # Remove trailing comma from $message
    $message =~ s/\,+\s+$//g;