更新20260519

Services/ModbusTcpPlcService.cs

@@ -95,7 +95,7 @@ namespace TabletTester2025.Services
         public async Task<float> ReadFloatAsync(ushort startAddress)
         {
             var registers = await ReadHoldingRegistersAsync(startAddress, 2);
-            return UshortToFloat(registers[1], registers[0]);
+            return RegistersToFloat(registers[0], registers[1]);
         }
 
         public async Task<int> ReadIntAsync(ushort startAddress)
@@ -122,13 +122,10 @@ namespace TabletTester2025.Services
 
         public Task WriteFloatAsync(ushort startAddress, float value)
         {
-            byte[] bytes = BitConverter.GetBytes(value);
-            ushort[] registers =
-            {
-                (ushort)((bytes[2] << 8) | bytes[3]),
-                (ushort)((bytes[0] << 8) | bytes[1])
-            };
+            if (!float.IsFinite(value))
+                throw new ArgumentOutOfRangeException(nameof(value), "PLC浮点写入值不能是NaN或Infinity。");
 
+            ushort[] registers = FloatToRegisters(value);
             return ExecuteAsync(master => master.WriteMultipleRegistersAsync(_config.SlaveId, startAddress, registers));
         }
 
@@ -168,16 +165,28 @@ namespace TabletTester2025.Services
             }
         }
 
-        private static float UshortToFloat(ushort high, ushort low)
+        private static float RegistersToFloat(ushort highWord, ushort lowWord)
         {
-            byte[] bytes = new byte[4];
-            bytes[0] = (byte)(high >> 8);
-            bytes[1] = (byte)(high & 0xFF);
-            bytes[2] = (byte)(low >> 8);
-            bytes[3] = (byte)(low & 0xFF);
+            byte[] bytes =
+            {
+                (byte)(lowWord & 0xFF),
+                (byte)(lowWord >> 8),
+                (byte)(highWord & 0xFF),
+                (byte)(highWord >> 8)
+            };
             return BitConverter.ToSingle(bytes, 0);
         }
 
+        private static ushort[] FloatToRegisters(float value)
+        {
+            byte[] bytes = BitConverter.GetBytes(value);
+            return new[]
+            {
+                (ushort)((bytes[3] << 8) | bytes[2]),
+                (ushort)((bytes[1] << 8) | bytes[0])
+            };
+        }
+
         private void CloseConnection()
         {
             try { _master?.Dispose(); } catch { }