diff --git a/modules/monitoring/library/Monitoring/Plugin/Perfdata.php b/modules/monitoring/library/Monitoring/Plugin/Perfdata.php
index 146c6a5e0..4d7cb13db 100644
--- a/modules/monitoring/library/Monitoring/Plugin/Perfdata.php
+++ b/modules/monitoring/library/Monitoring/Plugin/Perfdata.php
@@ -100,6 +100,7 @@ class Perfdata
             }
             $step = $key;
         }
+	if ($step <= 0) $step = 1;
         return $prefix
              . number_format($val / $step, 1, ',', '.')
             . ' '