diff --git a/script/PolSwitch.py b/script/PolSwitch.py
index 2c31c9e..6a16ce9 100644
--- a/script/PolSwitch.py
+++ b/script/PolSwitch.py
@@ -80,7 +80,7 @@ for E in setpoints:
 
         if(H>0):
             scan1.append ([E, H], [readback1, readback2], [detector1, detector2, detector4, detector7, tey_norm])
-        if(H<0):
+        elif(H<0):
             scan2.append ([E, H], [readback1, readback2], [detector1, detector2, detector4, detector7, tey_norm])
         else:
             raise Exception('Wrong B field value:' + str(H))