diff --git a/custom_components/adaptive_cover/coordinator.py b/custom_components/adaptive_cover/coordinator.py
index a430938..6a70d24 100644
--- a/custom_components/adaptive_cover/coordinator.py
+++ b/custom_components/adaptive_cover/coordinator.py
@@ -607,16 +607,18 @@ def state(self) -> int:
     def interpolate_states(self, state):
         """Interpolate states."""
         normal_range = [0, 100]
+        new_range = []
         if self.start_value and self.end_value:
             new_range = [self.start_value, self.end_value]
         if self.normal_list and self.new_list:
             normal_range = list(map(int, self.normal_list))
             new_range = list(map(int, self.new_list))
-        state = np.interp(state, normal_range, new_range)
-        if state == new_range[0]:
-            state = 0
-        if state == new_range[-1]:
-            state = 100
+        if new_range:
+            state = np.interp(state, normal_range, new_range)
+            if state == new_range[0]:
+                state = 0
+            if state == new_range[-1]:
+                state = 100
         return state
 
     @property