diff --git a/AsbCloudApp/Services/Subsystems/ISubsystemOperationTimeService.cs b/AsbCloudApp/Services/Subsystems/ISubsystemOperationTimeService.cs
index 07e41895..605d844c 100644
--- a/AsbCloudApp/Services/Subsystems/ISubsystemOperationTimeService.cs
+++ b/AsbCloudApp/Services/Subsystems/ISubsystemOperationTimeService.cs
@@ -36,7 +36,15 @@ namespace AsbCloudApp.Services.Subsystems
         /// <param name="request"></param>
         /// <param name="token"></param>
         /// <returns></returns>
-        Task<IEnumerable<SubsystemOperationTimeDto>?> GetOperationTimeAsync(SubsystemOperationTimeRequest request, CancellationToken token);        
+        Task<IEnumerable<SubsystemOperationTimeDto>?> GetOperationTimeAsync(SubsystemOperationTimeRequest request, CancellationToken token);
+
+        /// <summary>
+        /// Временной диапазон за который есть статистика работы подсистем
+        /// </summary>
+        /// <param name="idSubsystem"></param>
+        /// <param name="token"></param>
+        /// <returns></returns>
+        Task<IEnumerable<SubsystemOperationTimeDto>?> GetDateRangeOperationTimeAsync(int idSubsystem, CancellationToken token);
     }
 #nullable disable
 }
diff --git a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs
index 1961c74f..5b0fdbb1 100644
--- a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs
+++ b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs
@@ -185,9 +185,9 @@ namespace AsbCloudInfrastructure.Services.Subsystems
 
         }
 
-        private (DateTimeOffset, DateTimeOffset) GetDateRangeOperationTime(int idSubsystem)
+        private async Task<(DateTimeOffset, DateTimeOffset)?> GetDateRangeOperationTime(int idSubsystem, CancellationToken token)
         {
-            var dateRange = db.SubsystemOperationTimes
+            var dateRange = await db.SubsystemOperationTimes
                 .Where(o => o.Id == idSubsystem)
                 .GroupBy(o => o.IdSubsystem)
                 .Select(g => new
@@ -195,7 +195,11 @@ namespace AsbCloudInfrastructure.Services.Subsystems
                     DateFirst = g.Min(o => o.DateStart),
                     DateLast = g.Max(o => o.DateEnd)
                 })
-                .FirstOrDefault();           
+                .FirstOrDefaultAsync(token);
+            if (dateRange == null)
+            {
+                return null;
+            }
             (DateTimeOffset dateFirst, DateTimeOffset dateLast) result = (dateRange.DateFirst, dateRange.DateLast);
             return result;
         }