diff --git a/Laser_utils.py b/Laser_utils.py
index 157f387cf390107d52bf686ff7b5cbb05b0779ec..55e44a39839904268223b15df6cb537af77727e9 100644
--- a/Laser_utils.py
+++ b/Laser_utils.py
@@ -1,8 +1,7 @@
-def positionToDelay(data, key, origin=0, invert = False, reflections=1):
+def positionToDelay(pos, origin=0, invert = False, reflections=1):
     ''' converts a motor position in mm into optical delay in picosecond
         Inputs:
-            data: dataset containing delay stage motor position
-            key: key of the delay stage
+            pos: array-like delay stage motor position
             origin: motor position of time zero in mm
             invert: bool, inverts the sign of delay if True
             reflections: number of bounces in the delay stage
@@ -12,7 +11,7 @@ def positionToDelay(data, key, origin=0, invert = False, reflections=1):
     '''
     c_ = 299792458 *1e-9 # speed of light in mm/ps
     x = -1 if invert else 1
-    return 2*reflections*(data[key]-origin)*x/c_
+    return 2*reflections*(pos-origin)*x/c_
     
 def degToRelPower(x, theta0=0):
     ''' converts a half-wave plate position in degrees into relative power