diff --git a/script/scan_guard.py b/script/scan_guard.py
index eaf57f21..6b1752f2 100644
--- a/script/scan_guard.py
+++ b/script/scan_guard.py
@@ -897,19 +897,19 @@ def main():
     guard.controls_active = True
     # True = simulate beam down after a few seconds, False = normal operation
     guard.test = False
-    
+
+    global beam_ok
     guard.connect()
     try:
-        pass
         guard.mainloop()
+        beam_ok = True
     except KeyboardInterrupt:
         logging.info("scan guard aborted by user")
+        beam_ok = True
     except:
         print sys.exc_info()[1]
 
     print "guard shutting down - measurements enabled"
-
    global beam_ok
-    beam_ok = True
     
 #This is to dispose created channels - otherwise, if channel is off, old channels remain and CPU consumption goes 100%.
 import _ca