diff -r dea107dce0c4 -r 750eeb7230a1 plcopen/structures.py
--- a/plcopen/structures.py	Mon Aug 14 21:31:01 2017 +0300
+++ b/plcopen/structures.py	Mon Aug 14 22:23:17 2017 +0300
@@ -137,7 +137,7 @@
             param_name = param_type
             param_type = variables[param_type]
         elif len_of_not_predifined_variable > 1:
-            param_name = "IN%d"%base
+            param_name = "IN%d" % base
             base += 1
         else:
             param_name = "IN"