diff --git a/Python_script/MeasurementPlot.py b/Python_script/MeasurementPlot.py
index 4a8dd660525c4358d27381dc473cd36dbcbb78a8..4ea0bb5b48c4fb6fa322560186f38300c1766ce0 100644
--- a/Python_script/MeasurementPlot.py
+++ b/Python_script/MeasurementPlot.py
@@ -160,7 +160,7 @@ class MeasurementPlot:
         self.path_collection_fit.set_offsets(np.c_[[], []])
 
         # refresh data for signal1 in subplot for signal0 and signal1
-        signal1s = data_frame[self.reference_signal_names[0]]
+        signal1s = data_frame[self.reference_signal_names[1]]
         minimum, maximum = self.get_extended_min_max(signal1s)
         self.signal1_axis.set_ylim(minimum, maximum)
         self.path_collection_signal1.set_offsets(np.c_[timestamps, signal1s])