diff --git a/source/ID.m b/source/ID.m
index 82627073d10d34d3732be224357ed37227b8af15..e62f1abef8348f94ba6358d43e82e9e8bdcceb99 100755
--- a/source/ID.m
+++ b/source/ID.m
@@ -5,8 +5,8 @@ function id = ID(varargin)
 % Setup constants
 toolbox = 'RWTHMindstormsEV3';
 appendix = '';
-if nargin > 0 && ischar(varargin{0})
-    appendix = [':', varargin{0}];
+if nargin > 0 && ischar(varargin{1})
+    appendix = [':', varargin{1}];
 end
 
 % Get stack trace