修复 膜左右空气数据，按【计算】 时， 会变为负数。 正常应该为0

Project.FLY.FilmCasting.AutoDie/FLY.FilmCasting.AutoDie/Server/HeatCell.cs

@@ -369,7 +369,10 @@ namespace FLY.FilmCasting.AutoDie.Server
             int[] offsets = new int[ChannelCnt];
             for (int i = 0; i < ChannelCnt; i++)
             {
-                offsets[i] = (int)Math.Round(thickpercents[i] * Kp);
+                if (double.IsNaN(thickpercents[i]))
+                    offsets[i] = 0;
+                else
+                    offsets[i] = (int)Math.Round(thickpercents[i] * Kp);
             }
             Offsets = offsets;
             UpdatePreHeats();