diff --git a/Script.py b/Script.py
index 4a8d605..c3a8ee6 100644
--- a/Script.py
+++ b/Script.py
@@ -87,7 +87,7 @@ def getValue(self, line, key, default = None):
         if not key in line or (';' in line and line.find(key) > line.find(';')):
             return default
         sub_part = line[line.find(key) + 1:]
-        m = re.search('^[0-9]+\.?[0-9]*', sub_part)
+        m = re.search('^-?[0-9]+\.?[0-9]*', sub_part)
         if m is None:
             return default
         try:
@@ -98,4 +98,4 @@ def getValue(self, line, key, default = None):
     ##  This is called when the script is executed. 
     #   It gets a list of g-code strings and needs to return a (modified) list.
     def execute(self, data):
-        raise NotImplementedError()
\ No newline at end of file
+        raise NotImplementedError()