diff --git a/frappy_psi/ccu4.py b/frappy_psi/ccu4.py
index 056f3486..ea79ec2d 100644
--- a/frappy_psi/ccu4.py
+++ b/frappy_psi/ccu4.py
@@ -641,7 +641,7 @@ class NeedleValveFlow(HasStates, Base, Drivable):
     def opening(self, sm):
         if sm.init:
             sm.start_time = sm.now
-        self._speed_sum += sm.dleta()
+        self._speed_sum += sm.delta()
         self.read_motor_state()
         if self.motor_state == M.opening:
             return Retry