diff --git a/script/device/Mythen.py b/script/device/Mythen.py
index fae1dc8..8108178 100644
--- a/script/device/Mythen.py
+++ b/script/device/Mythen.py
@@ -47,11 +47,11 @@ class Mythen(DeviceBase, Readable):
 
     def start(self):
         caput( self.prefix + ":cam1:Acquire",1) 
-        setState(State.Busy)
+        self.setState(State.Busy)
        
     def stop(self):
         caput( self.prefix + ":cam1:Acquire",0) 
-        setState(State.Ready)
+        self.setState(State.Ready)
 
     def get_total_counts(self):
         ret = caget( self.prefix + ":Stats5:Total_RBV", 'i')