diff --git a/SolarPower/Controllers/PowerStationController.cs b/SolarPower/Controllers/PowerStationController.cs
index d89c2d2..c857286 100644
--- a/SolarPower/Controllers/PowerStationController.cs
+++ b/SolarPower/Controllers/PowerStationController.cs
@@ -3321,7 +3321,7 @@ namespace SolarPower.Controllers
                     {
                         status.Add($"s{powerStation.Code}01_inv SITEID錯誤");
                     }
-                    if (powerStation.Code + "01" != sitecheck.Inv_inveter.Substring(0,11) && sitecheck.Inv_inveter != null)
+                    if (sitecheck.Inv_inveter != null && powerStation.Code + "01" != sitecheck.Inv_inveter.Substring(0,11))
                     {
                         status.Add($"s{powerStation.Code}01_Inv inveter格式錯誤");
                     }