diff --git a/examples/ESRF_ORM_example/correct_orbit.py b/examples/ESRF_ORM_example/correct_orbit.py
index 4f9ac89..1185317 100644
--- a/examples/ESRF_ORM_example/correct_orbit.py
+++ b/examples/ESRF_ORM_example/correct_orbit.py
@@ -17,7 +17,7 @@
 
 ## get reference
 ref_h, ref_v = ebs.get_bpms("BPM").positions.get().T
-reference = np.concat((ref_h, ref_v))
+reference = np.concatenate((ref_h, ref_v))
 ########################################################