diff --git a/scripts/live_triggermap.py b/scripts/live_triggermap.py
index 35a7e6318fdeb92d6c864d252767e48611b41712..888b763124169838b36c24c5cfdc8a17fdd16984 100755
--- a/scripts/live_triggermap.py
+++ b/scripts/live_triggermap.py
@@ -74,7 +74,7 @@ class DOMHits(Module):
 
         event_hits = blob['Hits']
         with lock:
-            hits = np.zeros(self.det.n_doms * self.det.n_dus)
+            hits = np.zeros(self.det.n_doms)
             for dom_id in event_hits.dom_id:
                 du, floor, _ = self.det.doms[dom_id]
                 hits[(du - 1) * self.det.n_doms + floor - 1] += 1