diff --git a/solarApp/Service/procArchiveSensorHourly.cs b/solarApp/Service/procArchiveSensorHourly.cs
index fe052f1..70756ae 100644
--- a/solarApp/Service/procArchiveSensorHourly.cs
+++ b/solarApp/Service/procArchiveSensorHourly.cs
@@ -270,6 +270,10 @@ namespace solarApp.Service
                     {
                         IrrDayHour = IrrDay - twoHourAgoIrrDay;// 前一小時的IrrDay - 前兩小時的IrrDay
                     }
+                    if(IrrDayHour < 0)
+                    {
+                        IrrDayHour = 0;
+                    }
                     
                     string ss = $@"UPDATE solar_master.sensor_history_hour
                                    SET IrrDayHour = {IrrDayHour}