diff --git a/schainpy/model/proc/jroproc_voltage.py b/schainpy/model/proc/jroproc_voltage.py
index 76413af..74427ed 100644
--- a/schainpy/model/proc/jroproc_voltage.py
+++ b/schainpy/model/proc/jroproc_voltage.py
@@ -655,7 +655,7 @@ class Decoder(Operation):
         if not self.isConfig:
             
             if code is None:
-                if not dataOut.code:
+                if dataOut.code is None:
                     print "Code is not defined"
                     raise ValueError, "Code could not be read from %s object. Enter a value in Code parameter" %dataOut.type