diff --git a/dataLogger.py b/dataLogger.py
index 434f0ad..313b27e 100644
--- a/dataLogger.py
+++ b/dataLogger.py
@@ -240,9 +240,10 @@ def evalTapers():
 
 
 def main():
-    global main_plc
+    global main_plc, device_types
 
     readConfig()
+    device_types = getDeviceTypes()
     if setupTags():
         pass
     else: