diff --git a/utils/Quality_Relabel.py b/utils/Quality_Relabel.py
index a4c53ba..62de37d 100644
--- a/utils/Quality_Relabel.py
+++ b/utils/Quality_Relabel.py
@@ -353,6 +353,7 @@ class Quality_Relabel:
         :param title: ΟΤΚΎ±κΜβ
         :return:
         """
+        SP = 0 if SP < 0 else SP
         plt_.plot(np.linspace(SP, EP, (EP - SP) * self.frequency),
                   self.signal_select[channel][SP * self.frequency:EP * self.frequency], label=channel,
                   color=self.color_cycle[0])