diff --git a/src/backscattering_experimental_data/factory/measurement.py b/src/backscattering_experimental_data/factory/measurement.py
index 54f853f..9f52853 100644
--- a/src/backscattering_experimental_data/factory/measurement.py
+++ b/src/backscattering_experimental_data/factory/measurement.py
@@ -7,7 +7,7 @@ from astropy.units import (
 )
 from astropy.units.physical import time
 from gwpy.time import Time, from_gps
-from numpy import array, where
+from numpy import array, where, diff
 
 from ..component import Component
 from ..lockingstate import LockingState
@@ -101,9 +101,11 @@ class MeasurementFactory:
             frame="trend",
             force_virgotools=force_virgotools,
         )
-        state_data = data["V1:META_ITF_LOCK_index"].data.astype(int)
-        if sum(state_data.diff().abs()) != 0:
-            indexes = where(array(state_data.diff().data) != 0)[0]
+        state_data = array(data["V1:META_ITF_LOCK_index"].data).astype(
+            int
+        )
+        if sum(abs(diff(state_data))) != 0:
+            indexes = where(diff(state_data) != 0)[0]
             times_change = (
                 data["V1:META_ITF_LOCK_index"].t0
                 + indexes * data["V1:META_ITF_LOCK_index"].dt
@@ -122,7 +124,7 @@ class MeasurementFactory:
                     LockingState(state_data[index + 1]).name,
                 )
             raise Exception(message)
-        state = LockingState(data["V1:META_ITF_LOCK_index"].data[0])
+        state = LockingState(state_data[0])
         injection_power = data["V1:INJ_IMC_TRA_DC_mean"].mean()
         dark_fringe_power = data["V1:DET_B1p_DC_mean"].mean()